Mobile Ad hoc Networks Working Group                          C. Perkins
Internet-Draft                                                 Futurewei
Intended status: Standards Track                             I. Chakeres
Expires: September 13, 2012 April 26, 2013                                           CenGen
                                                          March 12,
                                                        October 23, 2012

                Dynamic MANET On-demand (AODVv2) Routing
                        draft-ietf-manet-dymo-22
                        draft-ietf-manet-dymo-23

Abstract

   The Dynamic MANET On-demand (AODVv2) routing protocol is intended for
   use by mobile routers in wireless, multihop networks.  AODVv2
   determines unicast routes among AODVv2 routers within the network in
   an on-demand fashion, offering on-demand convergence in dynamic
   topologies.

Status of this Memo

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   This Internet-Draft will expire on September 13, 2012. April 26, 2013.

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Table of Contents

   1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Applicability Statement  Terminology  . . . . . . . . . . . . . . . . . . .  4
   3.  Terminology . . . . . .  5
   3.  Applicability Statement  . . . . . . . . . . . . . . . . . . .  5  7
   4.  Data Structures  . . . . . . . . . . . . . . . . . . . . . . .  7  8
     4.1.  Route Table Entry  . . . . . . . . . . . . . . . . . . . .  7  8
     4.2.  AODVv2 Messages  . . . . . . . . . . . . . . . . . . . . .  8
       4.2.1.  Generalized Packet and Message Structure . . . . . . .  9
       4.2.2.  Routing Message (RteMsg) - RREQ and RREP . . . Information Elements  . . . . 10
       4.2.3.  Route Error (RERR)  9
     4.3.  RteMsg-specific Protocol Elements  . . . . . . . . . . . . 11
     4.4.  Route Error (RERR)-specific Protocol Elements  . . . . . . 11 12
   5.  Detailed Operation for the Base Protocol . . . . . . . . . . . . . . . . . . . . . . 12 13
     5.1.  AODVv2 Sequence Numbers  . . . . . . . . . . . . . . . . . 12 13
       5.1.1.  Maintaining A Node's Own Sequence Number . . . . . . . 12
       5.1.2.  Numerical Operations on OwnSeqNum  . . . . . . . . . . 13
       5.1.3.  OwnSeqNum Rollover . . . . . . . . . . . . . . . . . . 13
       5.1.4.
       5.1.2.  Actions After OwnSeqNum Loss . . . . . . . . . . . . . 13
     5.2.  AODVv2 Routing Table Operations  . . . . . . . . . . . . . 13
       5.2.1.  Judging Routing Information's Usefulness . . . . . . . 13
       5.2.2.  Creating or Updating a Route Table Entry with
               Received Preferable Routing Information Entries . . . . . . . 15
       5.2.3.  Route Table Entry Timeouts . . . . . . . . . . . . . . 16 15
     5.3.  Routing Messages . . . . . . . . . . . . . . . . . . . . . 16
       5.3.1.  RREQ Creation  . . . . . . . . . . . . . . . . . . . . 16
       5.3.2.  RREP Creation  . . . . . . . . . . . . . . . . . . . . 17
       5.3.3.  RteMsg Handling  . . . . . . . . . . . . . . . . . . . 18
     5.4.  Route Discovery  . . . . . . . . . . . . . . . . . . . . . 21 20
     5.5.  Route Maintenance  . . . . . . . . . . . . . . . . . . . . 22 21
       5.5.1.  Active Next-hop Router Adjacency Monitoring  . . . . . 22 21
       5.5.2.  Updating Route Lifetimes During Packet Forwarding  . . 23 22
       5.5.3.  RERR Generation  . . . . . . . . . . . . . . . . . . . 23 22
       5.5.4.  RERR Handling  . . . . . . . . . . . . . . . . . . . . 24 23
     5.6.  Unknown Message and TLV Types  . . . . . . . . . . . . . . 25 24
     5.7.  Advertising Network Addresses  . . . . . . . . . . . . . . 25 24
     5.8.  Simple Internet Attachment . . . . . . . . . . . . . . . . 25 24
     5.9.  Multiple Interfaces  . . . . . . . . . . . . . . . . . . . 27 25
     5.10. AODVv2 Control Packet/Message Generation Limits  . . . . . 27
   6.  Administratively Configured Parameters and Timer Values 26
     5.11. Optional Features  . . . 27
   7.  IANA Considerations . . . . . . . . . . . . . . . . . 26
       5.11.1. Expanding Rings Multicast  . . . . 29
     7.1.  AODVv2 Message Types Specification . . . . . . . . . . 26
       5.11.2. Intermediate RREP  . . 30
     7.2.  Message and Address Block TLV Type Specification . . . . . 30
     7.3.  Address Block TLV Specification . . . . . . . . . . . 27
       5.11.3. Precursor Notification . . 31
   8.  Security Considerations . . . . . . . . . . . . . . 27
       5.11.4. Reporting Multiple Unreachable Nodes . . . . . 31
   9.  Acknowledgments . . . . 28
       5.11.5. Message Aggregation  . . . . . . . . . . . . . . . . . 28
       5.11.6. Adding Additional Routing Information to a RteMsg  . . 32
   10. References 29
     5.12. Administratively Configured Parameters and Timer Values  . 30
     5.13. IANA Considerations  . . . . . . . . . . . . . . . . . . . 33
       5.13.1. AODVv2 Message Types Specification . . . . . . 33
     10.1. Normative References . . . . 33
       5.13.2. Message and Address Block TLV Type Specification . . . 33
       5.13.3. Address Block TLV Specification  . . . . . . . . . . . 34

     5.14. Security Considerations  . 33
     10.2. Informative References . . . . . . . . . . . . . . . . 34
     5.15. Acknowledgments  . . 33
   Appendix A.  Changes since the Previous Version . . . . . . . . . 34 . . . . . . . . . . 36
   6.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 36
     6.1.  Normative References . . . . . . . . . . . . . . . . . . . 36
     6.2.  Informative References . . . . . . . . . . . . . . . . . . 37
   Appendix B.  Proposed additional changes for LOADng conformance A.  Changes since the Previous Version  . 34 . . . . . . . . 38
   Appendix C. B.  Shifting Responsibility for an Address Network Prefix Advertisement Between
                AODVv2 Routers  . . . . . . . . . . . . . . . . . . . 35 39
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35 39

1.  Overview

   The Dynamic MANET On-demand (AODVv2) routing protocol [formerly named
   DYMO] enables on-
   demand, on-demand, multihop unicast routing among participating AODVv2 routers.
   routers in mobile ad hod networks [MANETs][RFC2119].  The basic
   operations of the AODVv2 protocol are route discovery and route
   maintenance.  Route discovery is performed when an AODVv2 router receives must
   transmit a packet from a node under its responsibility to towards a destination for which it does not have a
   route.  Route maintenance is performed to help ensure that the avoid dropping packets,
   when a route being used to forward packets from the source to the a
   destination remains operational. breaks, and to avoid prematurely expunging routes from
   the route table.

   During route discovery, the originator's an AODVv2 router initiates
   dissemination flooding of a
   Route Request message (RREQ) throughout the network to find a route
   to a particular destination, via the AODVv2 router responsible for
   this destination.  During this hop-by-hop
   dissemination flooding process, each
   intermediate AODVv2 router receiving the RREQ message records a route
   to the originator.  When the target's AODVv2 router receives the
   RREQ, it records a route to the originator and responds with a Route
   Reply (RREP) sent unicast hop-by-hop toward the originating AODVv2 router.
   Each intermediate AODVv2 router that receives the RREP creates a
   route to the target, and then the RREP is unicast hop-by-hop toward
   the originator.  When the originator's AODVv2 router receives the
   RREP, routes have then been established between the originating
   AODVv2 router and the target AODVv2 router in both directions.

   Route maintenance consists of two operations.  In order to preserve
   routes in use, AODVv2 routers extend route lifetimes upon
   successfully forwarding a packet.  In order to react to changes in
   the network topology, AODVv2 routers monitor traffic being forwarded.
   When a data packet is received for forwarding and a route for the
   destination is not known or the route is broken, then the AODVv2
   router of the source of the packet is notified.  A Route Error (RERR)
   is sent toward the packet source transmitted to indicate the route to particular one or more affected
   destination addresses is invalid Broken or missing.  When the source's AODVv2
   router receives the RERR, it deletes marks the route as broken.  Before the route.  If this
   source's
   AODVv2 router later receives can forward a packet for forwarding to the same destination, it will need has to
   perform route discovery again for that destination.

   Similarly to AODV, AODVv2 uses sequence numbers to ensure loop
   freedom [Perkins99].  Sequence numbers enable AODVv2 routers to
   determine the temporal order of AODVv2 route discovery messages,
   thereby avoiding use of stale routing information.  Also, AODVv2 uses
   RFC 5444 message and TLV formats.

2.  Applicability Statement  Terminology

   The AODVv2 routing protocol is designed key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].

   Additionally, this document uses some terminology from [RFC5444].

   This document defines the following terminology:

   Adjacency
      A relationship between selected bi-directional neighboring routers
      for stub or disconnected
   mobile ad hoc networks (MANETs).  AODVv2 handles a wide variety the purpose of exchanging routing information.  Not every pair
      of neighboring routers will necessarily form an adjacency.
      Neighboring routers may form an adjacency based on various
      information or other protocols; for example, exchange of
   mobility patterns by dynamically determining routes on-demand. AODVv2 also handles a wide variety
      routing messages, other protocols (e.g.  NDP [RFC4861] or NHDP
      [RFC6130]), or manual configuration.  Loss of traffic patterns.  In networks
   with a large number routing adjacency
      may also be based upon similar information; monitoring of routers, AODVv2 is best suited for sparse
   traffic scenarios
      adjacencies where routers forward packets to only are being forwarded is required (see
      Section 5.5.1).

   Distance (Dist)
      An unsigned integer which measures the distance a small
   portion message or
      information element has traversed.  The minimum value of distance
      is the other AODVv2 routers, due to the on-demand nature number of
   route discovery and route maintenance.

   AODVv2 IP hops traversed, 0 for local information.  The
      maximum value is applicable 254.  The value 255 is reserved to memory constrained devices, since little
   routing state indicate that
      the distance is unknown.

   AODVv2 Sequence Number (SeqNum)
      An AODVv2 Sequence Number is an unsigned integer maintained in by
      each AODVv2 router.  Only  This sequence number guarantees the temporal
      order of routing information related to active sources and destinations maintain loop-free routes.  The
      value zero (0) is maintained,
   in contrast reserved to most proactive routing protocols indicate that require routing
   information to all routers within the routing region SeqNum for a
      destination address is unknown.

   reactive
      A protocol operation is said to be maintained.

   AODVv2 supports routers with multiple interfaces participating "reactive" if it is performed
      only in the
   MANET. reaction to specific events.  As used in this document,
      "reactive" is essentially synonymous with "on-demand".

   Router Client
      An AODVv2 routers can also perform routing on behalf of other
   nodes, attached via participating or non-participating interfaces.

   AODVv2 routers perform route discovery to find a route to a
   particular destination.  Therefore, AODVv2 routers MUST router may be configured
   to initiate with a list of other IP
      addresses and respond networks which correspond to other non-router nodes
      which require the services of the AODVv2 router for route
      discovery on behalf of certain
   nodes, identified by address.  When and maintenance.  An AODVv2 is always its own client, so
      that the only protocol
   interacting with list of client IP addresses is never empty. corresponds
      to the forwarding table, AODVv2 MAY be configured router process currently performing a calculation or
      processing a message.

   Flooding
      In this document, flooding a message refers to
   perform route discovery for all unknown unicast destinations.

   At any time within an AODVv2 routing region, only one the process of
      delivering the message to every AODVv2 router
   SHOULD in the network.
      This may be responsible for, i.e. "own", any particular address.
   Coordination among multiple AODVv2 routers done according to distribute routing
   information correctly for a shared methods specified in [RFC5148].

   Routable Unicast IP Address
      A routable unicast IP address (i.e. an is a unicast IP address that when
      put into the IP.SourceAddress or IP.DestinationAddress field is
   advertised and can
      scoped sufficiently to be reached via multiple AODVv2 routers) forwarded by a router.  Globally-scoped
      unicast IP addresses and Unique Local Addresses (ULAs) [RFC6130]
      are examples of routable unicast IP addresses.

   Originating Node (OrigNode)
      The originating node is the data source node; if it is not
   described in this document.  The router behavior for shifting
   responsibility for itself
      an address from one AODVv2 router, its AODVv2 router creates a AODVv2 RREQ message
      on its behalf in an effort to another flood some routing information.  The
      originating node is
   mentioned in Appendix C.

   AODVv2 only utilizes bidirectional links. also referred to as a particular message's
      originator.

   Target Node (TargetNode)
      The TargetNode denotes the ultimate destination of a message.

   This Node (ThisNode)
      ThisNode denotes the AODVv2 router currently processing an AODVv2
      message.

   Route Error (RERR)
      A RERR message is used to indicate that an AODVv2 router no longer
      has a route to one or more particular destinations.

   Route Reply (RREP)
      A RREP message is used to supply routing information about the
      RREQ TargetNode to the RREQ OrigNode and the AODVv2 routers
      between them.

   Route Request (RREQ)
      An AODVv2 router uses a RREQ message to discover a valid route to
      a particular destination address, called the RREQ TargetNode.
      When an AODVv2 router processes a RREQ, it learns routing
      information on how to reach the RREQ OrigNode.

   Type-Length-Value structure (TLV)
      A generic way to represent information as specified in [RFC5444].

   Unreachable Node (UnreachableNode)
      An UnreachableNode is a node for which a forwarding route is
      unknown.

3.  Applicability Statement

   The AODVv2 routing protocol is designed for stub (i.e., non-transit)
   or disconnected (i.e., from the Internet) mobile ad hoc networks
   (MANETs).  AODVv2 handles a wide variety of mobility patterns by
   dynamically determining routes on-demand.  AODVv2 also handles a wide
   variety of traffic patterns.  In networks with a large number of
   routers, AODVv2 is best suited for sparse traffic scenarios where any
   particular router forwards packets to only a small percentage of the
   AODVv2 routers in the network, due to the on-demand nature of route
   discovery and route maintenance.

   AODVv2 is applicable to memory constrained devices, since little
   routing state is maintained in each AODVv2 router.  Only routing
   information related to routes between active sources and destinations
   is maintained, in contrast to proactive routing protocols that
   require routing information to all routers within the routing region
   be maintained.

   AODVv2 supports routers with multiple interfaces.  In addition to
   routing for their local processes, AODVv2 routers can also route on
   behalf of other non-routing nodes (i.e., "hosts"), reachable via
   those interfaces.  Any such node which is not itself an AODVv2 router
   SHOULD NOT be served by more than one AODVv2 router.  Although AODVv2
   is closely related to AODV [RFC3561], and has some of the features of
   DSR [RFC4728], AODVv2 is not interoperable with either of those other
   two protocols.

   AODVv2 routers perform route discovery to find a route to a
   particular destination.  Therefore, AODVv2 routers MUST must be
   configured to respond to RREQs for a certain set of addresses.  When
   AODVv2 is the only protocol interacting with the forwarding table,
   AODVv2 MAY be configured to perform route discovery for all unknown
   unicast destinations.

   At all times within an AODVv2 routing region, only one AODVv2 router
   SHOULD be serve any routing client.  The coordination among multiple
   AODVv2 routers to distribute routing information correctly for a
   shared address (i.e. an address that is advertised and can be reached
   via multiple AODVv2 routers) is not described in this document.  The
   AODVv2 router operation of shifting responsibility for a routing
   client from one AODVv2 router to another is mentioned in Appendix B
   Each AODVv2 router, if serving router clients other than itself, is
   configured with information about the IP addresses of its clients.
   There is no requirement that an AODVv2 router have information about
   the router clients of other AODVv2 routers.  Address assignment
   procedures are entirely out of scope for AODVv2.

   AODVv2 only utilizes bidirectional links.  In the case of possible
   unidirectional links, either blacklists (see Section 5.13.2) or other
   means (e.g. adjacency establishment with only neighboring routers
   that have bidirectional communication as indicated by NHDP [RFC6130])
   of ensuring and monitoring bi-directionality is recommended.
   Otherwise, persistent packet loss could occur.

   The routing algorithm in AODVv2 may be operated at layers other than
   the network layer, using layer-appropriate addresses.  The routing
   algorithm makes of some persistent state; if there is no persistent
   storage available for this state, recovery can exact a performance
   penalty in case of AODVv2 router reboots.

4.  Data Structures

4.1.  Route Table Entry

   The route table entry is a conceptual data structure.
   Implementations may use any internal representation so long as it
   provides access to the same information as specified below.

   Conceptually, a route table entry has the following fields:

   Route.Address
      The (host or network) destination address of the node(s)
      associated with the routing table entry.

   Route.Prefix
      The value is the length of the netmask/prefix.  If the value of
      the Route.Prefix is different than the length of addresses in the
      address family used by the AODVv2 routers, the associated address
      is a routing prefix, rather than a host address.

   Route.SeqNum
      The AODVv2 SeqNum associated with a route table entry.

   Route.NextHopAddress
      An IP address of the adjacent AODVv2 router on the path toward the
      Route.Address.

   Route.NextHopInterface
      The interface used to send packets toward the Route.Address.

   Route.Broken
      A flag indicating whether this Route is broken.  This flag is set
      to true if the next-hop becomes unreachable or in response to
      processing to a RERR (see Section 5.5.4).

   The following field is optional:

   Route.Dist
      A dimensionless metric indicating the distance traversed before
      reaching the Route.Address node.

   Not including optional information may cause performance degradation,
   but it will not prohibit the protocol from discovering valid routes.

   In addition to a route table data structure, each route table entry
   may have several timers associated with the information.  Timers and
   timeouts are discussed in Section 5.2.3.

4.2.  AODVv2 Message Structure and Information Elements

   IP Protocol Number 138 (manet) has been reserved for MANET protocols
   [RFC5498].  In the case of possible
   unidirectional links, either blacklists (see Section 7.2) or other
   means (e.g. adjacency establishment with only neighboring routers addition to using this IP protocol number, AODVv2 may
   use UDP at destination port 269 (manet) [RFC5498].

   AODVv2 messages are transmitted in packets that have bidirectional communication as indicated by NHDP
   [I-D.ietf-manet-nhdp]) of ensuring conform to the
   generalized packet and monitoring bi-directionality message format as described in [RFC5444].
   Here is recommended.  Otherwise, persistent a brief description of the format.

      A packet loss formatted according to RFC5444 contains zero or more
      messages.

      A message contains a message header, message TLV block, and zero
      or more address blocks.

      Each of the address blocks may occur.

   The routing algorithm in also have an associated address TLV
      block.

   All AODVv2 may messages SHOULD be operated at layers other than
   the network layer, sent using layer-appropriate addresses.

3.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", the IP protocol number (138)
   reserved for manet protocols [RFC5498]; or the UDP destination port
   (269) reserved for manet protocols [RFC5498] and "OPTIONAL" in this
   document IP protocol number
   for UDP.

   Most AODVv2 messages are sent with the IP destination address set to
   the link-local multicast address LL-MANET-Routers [RFC5498] unless
   otherwise specified.  Therefore, all AODVv2 routers SHOULD subscribe
   to LL-MANET-Routers [RFC5498] to receiving AODVv2 messages.  Note
   that multicast packets MAY be interpreted as described sent via unicast.  For example, this
   may occur for certain link-types (non broadcast mediums), for
   manually configured router adjacencies, or in order to improve
   robustness.

   When describing AODVv2 protocol messages, it is necessary to refer to
   fields in [RFC2119].

   Additionally, this document uses some terminology several distinct parts of the overall packet.  These
   locations include the IP header, the UDP header, and fields from
   [RFC5444].  This document defines uses the following terminology:

   Adjacency
      A relationship between selected bi-directional neighboring routers notational conventions found in
   table 1.

             +---------------------------+-------------------+
             |    Information Location   | Notational Prefix |
             +---------------------------+-------------------+
             |         IP header         |        IP.        |
             |   RFC5444 message header  |      MsgHdr.      |
             |    RFC5444 message TLV    |      MsgTLV.      |
             |   RFC5444 address blocks  |      AddBlk.      |
             | RFC5444 address block TLV |      AddTLV.      |
             +---------------------------+-------------------+

                                  Table 1

   The IPv4 TTL (IPv6 Hop Limit) field for all packets containing AODVv2
   messages is set to 255.  If a packet is received with a value other
   than 255, any AODVv2 message contained in the purpose of exchanging routing information.  Not every pair packet MUST be ignored
   by AODVv2.  This mechanism, known as "The Generalized TTL Security
   Mechanism" (GTSM) [RFC5082] helps to ensure that packets have not
   traversed any intermediate routers.

   The length of neighboring routers will necessarily form an adjacency.
      Neighboring routers may form an adjacency based several different
      pieces of information or protocols; address (32 bits for example, exchange of IPv4 and 128 bits for IPv6)
   inside an AODVv2 routing messages, other protocols (e.g.  NDP [RFC4861] or
      NHDP [I-D.ietf-manet-nhdp]), or manual configuration.  Similarly,
      loss of a routing adjacency may also message depends on the msg-addr-length (MAL) in the
   msg-header, as specified in [RFC5444].

   IP packets containing AODVv2 protocol messages SHOULD be based upon several pieces
      of information, given
   priority queuing and monitoring of adjacencies where packets are
      being forwarded is required (see Section 5.5.1).

   Distance (Dist)
      A metric of channel access.

   AODVv2 messages require the distance a message or piece of information has
      traversed. following information:

   IP.SourceAddress
      The minimum value IP address of distance is the number of IP hops
      traversed.  The maximum value is 65,535.

   AODVv2 Sequence Number (SeqNum)
      An AODVv2 Sequence Number is maintained by each AODVv2 router
      process. node currently sending this packet.  This sequence number
      field is used generally filled automatically by other AODVv2 routers to
      identify the temporal order of routing information generated operating system
      and
      ensure loop-free routes.

   Multihop-capable Unicast IP Address
      A multihop-capable unicast should not require special handling.

   IP.DestinationAddress
      The IP address of the packet destination.  For multicast messages
      the IP.DestinationAddress is a set to LL-MANET-Routers [RFC5498].
      For unicast IP address that
      when put into messages the IP.SourceAddress or IP.DestinationAddress field is scoped sufficiently set to be forwarded by a router.  Globally-
      scoped unicast IP addresses and Unique Local Addresses (ULAs) are
      examples of multihop-capable unicast IP addresses.

   Originating Node (OrigNode) the
      NextHopAddress toward the TargetNode.

   MsgHdr.HopLimit
      The originating node remaining number of hops this message is the source, its allowed to traverse.
      If an AODVv2 router creates message within a RFC 5444 packet has exhausted its
      hop limit, then it should be removed from the packet.

4.3.  RteMsg-specific Protocol Elements

   AODVv2 control message on its behalf in an effort types RREQ and RREP are denoted as Routing Messages
   (RteMsgs) and used to disseminate
      some flood routing information.  RREQ and RREP have
   similar information and function, but have slightly different
   handling rules.  The originating node is also referred
      to as a particular message's originator.

   Route Error (RERR)
      A RERR message main difference between the two messages is used to indicate that an AODVv2 router does not
      have a forwarding route
   RREQ messages are generally broadcast to one or more particular addresses.

   Route Reply (RREP)
      A solicit a RREP, and
   conversely a RREP message is used the unicast response to disseminate routing information about RREQ.  RteMsg creation
   and handling are described in Section 5.3.

   Unicast AODVv2 RteMsgs (e.g.  RREP) unless otherwise specified are
   sent with the RREP TargetNode IP destination set to the RREP OrigNode and Route.NextHopAddress of the AODVv2 routers
      between them.

   Route Request (RREQ)
   route to the TargetNode.

   A RteMsg REQUIRES the following information in addition to the fields
   indicated in Section 4.2:

   AddBlk.TargetNode.Address
      The IP address of the message TargetNode.  In a RREQ the IP
      address of the message TargetNode is used to discover a valid the destination address for
      which route to discovery is being performed.  In a particular
      destination address, called RREP the RREQ TargetNode.  When an AODVv2
      router processes a RREQ, it learns routing information on how to
      reach
      TargetNode is the RREQ OrigNode.

   Target Node (TargetNode) OrigNode address.  The TargetNode address
      is the ultimate destination of first address in a routing message.

   This Node (ThisNode)
      ThisNode corresponds to

   AddBlk.OrigNode.Address
      The IP address of the AODVv2 router process currently
      performing a calculation or attending to originator and its associated prefix length.
      In a message.

   Type-Length-Value structure (TLV)
      A generic way to represent information, please see [RFC5444] for
      additional information.

   Unreachable Node (UnreachableNode)
      An UnreachableNode RREQ the OrigNode is the source's address and prefix.  In a node
      RREP the OrigNode is the RREQ TargetNode's address and prefix for
      which a forwarding route RREP is
      unknown.

4.  Data Structures

4.1.  Route Table Entry

   The route table entry being generated.  This address is a conceptual data structure.
   Implementations may use any internal representation that conforms to the semantics of a route as specified second
      address in this document.

   Conceptually, a route table entry has the following fields:

   Route.Address message for RREQ.

   OrigNode.AddTLV.SeqNum
      The (host or network) destination address AODVv2 sequence number of the node(s)
      associated with the routing table entry.

   Route.Prefix
      Indicates that originator's AODVv2 router.

   A RteMsg may optionally include the associated address is a network address, rather
      than a host address. following information:

   TargetNode.AddTLV.SeqNum
      The value is last known AODVv2 sequence number of the length TargetNode.

   AddBlk.AdditionalNode.Address
      The IP address of an additional node that can be reached via the netmask/
      AODVv2 router adding this information.  Each
      AdditionalNode.Address MUST include its prefix.

   Route.SeqNum  Each
      AdditionalNode.Address MUST also have an associated Node.SeqNum in
      the address TLV block.

   AdditionalNode.AddTLV.SeqNum
      The AODVv2 SeqNum sequence number associated with this routing
      information.

   Route.NextHopAddress
      The IP address

   OrigNode.AddTLV.Dist
      A metric of the adjacent AODVv2 router on the path toward
      the Route.Address.

   Route.NextHopInterface
      The interface used distance to send packets toward reach the Route.Address.

   Route.Forwarding
      A flag indicating whether this Route can be used for forwarding
      data packets.  This flag MAY be provided for management and
      monitoring.

   Route.Broken
      A flag indicating whether this Route is broken. associated OrigNode.Address.
      This flag is set
      to true if the next-hop becomes unreachable or in response to
      attending to a RERR (see Section 5.5.4).

   The following field is optional:

   Route.Dist incremented by at least one at each intermediate
      AODVv2 router.

   AdditionalNode.AddTLV.Dist
      A dimensionless metric indicating of the distance traversed before
      reaching the Route.Address node.

   Not including optional information may cause performance degradation,
   but it will not cause the protocol to operate incorrectly.

   In addition to a route table data structure, each route table entry
   may have several timers associated with reach the information.  These
   timers/timeouts are discussed in Section 5.2.3.

4.2.  AODVv2 Messages

   When describing associated
      AdditionalNode.Address.  This field is incremented by at least one
      at each intermediate AODVv2 protocol messages, it router.

4.4.  Route Error (RERR)-specific Protocol Elements

   A RERR message is necessary to refer used to
   fields in several distinct parts of flood the overall packet.  These
   locations include the IP header, the UDP header, information that a route is not
   available for one or more particular addresses.

   RERR creation and fields from
   [RFC5444].  This document uses handling are described in Section 5.5.

   A RERR requires the following notation conventions.
   Information found information in the table.

             +---------------------------+-------------------+
             |    Information Location   | Notational Prefix |
             +---------------------------+-------------------+
             |         IP header         |        IP.        |
             |         UDP header        |        UDP.       |
             |   RFC5444 message header  |      MsgHdr.      |
             |    RFC5444 message TLV    |      MsgTLV.      |
             |   RFC5444 address blocks  |      AddBlk.      |
             | RFC5444 address block TLV |      AddTLV.      |
             +---------------------------+-------------------+

                                  Table 1

4.2.1.  Generalized Packet and Message Structure

   AODVv2 messages conform addition to the generalized packet field
   indicated in Section 4.2:

   AddBlk.UnreachableNode.Address
      The address of an UnreachableNode and message format
   as described its associated prefix
      length.  Multiple unreachable addresses may be included in [RFC5444].  Here is a brief description RERR.

   A Route Error may optionally include the following information:

   UnreachableNode.AddTLV.SeqNum
      The last known AODVv2 sequence number of the
   format.  A packet unreachable node.  If
      a SeqNum for an address is made up of messages.  A message zero (0) or not included, it is made up of assumed
      to be unknown.  This case occurs when a node receives a message header, message TLV block, and zero or more address blocks.
   Each of to
      forward to a destination for which it does not have any
      information in its routing table.

5.  Detailed Operation for the Base Protocol

5.1.  AODVv2 Sequence Numbers

   AODVv2 sequence numbers allow AODVv2 routers to judge the address blocks may also have an associated address TLV
   block.

   For interoperability with other freshness
   of routing information and consequently ensure loop freedom.

5.1.1.  Maintaining A Node's Own Sequence Number

   AODVv2 routers, all requires that each AODVv2 messages
   specified router in this document SHOULD sent using the IP protocol number
   (138) reserved for manet protocols [RFC5498]; or the UDP destination
   port (269) reserved for manet protocols [RFC5498] and IP protocol network maintain its
   own AODVv2 sequence number for UDP.

   Most (OwnSeqNum).  OwnSeqNum a 16-bit unsigned
   integer.  An AODVv2 messages are sent with router increments its OwnSeqNum under the IP destination address
   circumstances described in Section 5.3.

   Incrementing an OwnSeqNum whose value is the largest largest possible
   number representable as a 16-bit unsigned integer (i.e., 65,535),
   MUST be set to one (1).  In other words, the link-local multicast address LL-MANET-Routers [RFC5498] unless
   otherwise stated.  Therefore, all sequence number after
   65,535 is 1.

5.1.2.  Actions After OwnSeqNum Loss

   An AODVv2 routers router SHOULD subscribe maintain its own sequence number in
   persistent storage.

   If an AODVv2 router's OwnSeqNum is lost, it MUST take certain actions
   to
   LL-MANET-Routers [RFC5498] for receiving control packets.  Note that
   multicast packets MAY be sent via unicast.  For example, avoid creating routing loops.  To prevent this may
   occur for certain link-types (non broadcast mediums), improved
   robustness, or manually configured router adjacencies.

   Unicast possibility after
   OwnSeqNum loss an AODVv2 messages (e.g.  RREP) unless otherwise specified router MUST wait for at least
   ROUTE_DELETE_TIMEOUT before fully participating in
   this document are sent with the IP destination set to the
   Route.NextHopAddress of the route to the TargetNode.

   The IPv4 TTL (IPv6 Hop Limit) field for all packets containing AODVv2
   messages routing
   protocol.  If an AODVv2 protocol message is set to 255. received during this
   waiting period, the AODVv2 router SHOULD perform normal route table
   entry updates but MUST NOT transmit or retransmit any AODVv2 RREQ or
   RREP messages.  If a data packet is received with a value other
   than 255, it is discarded.  This mechanism helps for forwarding to ensures
   another destination during this waiting period, the AODVv2 router
   MUST transmit a RERR message indicating that
   packets have this route is not passed through any intermediate routers,
   available and it is
   known as GTSM [RFC5082].

   The length reset its waiting timeout.  At the end of an address (32 bits for IPv4 and 128 bits for IPv6)
   inside an AODVv2 message depends on the msg-addr-length (MAL) in waiting
   period the
   msg-header, as specified in [RFC5444]. AODVv2 control packets router sets its OwnSeqNum to one (1) and begin
   participating.

   The longest a node need wait is ROUTE_SEQNUM_AGE_MAX_TIMEOUT.  At the
   end of the maximum waiting period a node SHOULD be given priority queuing set its OwnSeqNum to
   one (1) and channel
   access.

4.2.2. begins participating.

5.2.  AODVv2 Routing Message (RteMsg) - RREQ and RREP Table Operations

5.2.1.  Judging Routing Messages (RteMsgs) are used to disseminate routing
   information.  There are two AODVv2 message types that are considered
   to be routing messages (RteMsgs): RREQ Information's Usefulness

   Given a route table entry (Route.SeqNum, Route.Dist, and RREP.  They contain very
   similar information
   Route.Broken) and function, but have slightly different
   handling rules.  The main difference between the two messages is that
   RREQ messages generally solicit incoming routing information for a RREP, whereas particular
   destination in a RREP is the
   response to RREQ. RteMsg creation (Node.SeqNum, Node.Dist, and handling are described in Section 5.3.

   A RteMsg requires the following information:

   IP.SourceAddress
      The IP address of message
   type - RREQ/RREP), the node currently sending this packet.  This
      field incoming routing information is generally filled automatically by classified as
   follows:

   1. Stale (Node.SeqNum < Route.SeqNum)
      If Node.SeqNum < Route.SeqNum (using signed 16-bit arithmetic) the operating system
      and should
      incoming information is stale.  Using stale routing information is
      not require special handling.

   IP.DestinationAddress
      The IP address of the packet destination.  For multicast RREQ the
      IP.DestinationAddress allowed, since that might result in routing loops.

   2. Not safe against loops
      If Node.SeqNum == Route.SeqNum, additional information MUST be
      examined.  If Route.Dist or Node.Dist is set to LL-MANET-Routers [RFC5498].  For
      unicast RREP unknown or zero (0), or
      if Node.Dist > Route.Dist + 1, then the IP.DestinationAddress incoming information is set
      not guaranteed to the
      NextHopAddress toward the RREP TargetNode.

   IP.ProtocolNumber and UDP.DestinationPort prevent routing loops.  Using such incoming
      routing information is not allowed.  The IP Protocol Number 138 (manet) has been reserved for MANET
      protocols [RFC5498].  In addition following pseudocode is
      offered to using this IP protocol
      number, AODVv2 may use indicate the UDP port 269 (manet) [RFC5498] in
      conjunction with logical condition under which the IP Protocol Number 17 (UDP).

   MsgHdr.HopLimit
      The remaining number of hops this message incoming
      information is allowed not guaranteed to traverse.

   AddBlk.TargetNode.Address
      The IP address of the message TargetNode. protect against loops.

      (Node.SeqNum == Route.SeqNum) AND
      ((Node.Dist > Route.Dist + 1) OR
       (Route.Dist is unknown) OR (Node.Dist is unknown))

   3. Offers no improvement
      In a RREQ case of known equal SeqNum, the
      TargetNode information is considered worse
      than the destination address for which existing route discovery table information in multiple cases: (case
      i) if Node.Dist > Route.Dist (it is a more expensive route) AND
      Route.Broken == false; (case ii) if Node.Dist == Route.Dist (equal
      distance route) AND Route.Broken == false AND this RteMsg is
      being performed.  In a RREP the TargetNode
      RREQ.  Such RREQs offer no improvement and SHOULD NOT be
      retransmitted.  Updating route table entries using such incoming
      routing information is the RREQ OrigNode
      address.  The TargetNode address not allowed.

      ((Node.SeqNum == Route.SeqNum) AND
          (((Node.Dist > Route.Dist) AND (Route.Broken == false)) OR
            ((Node.Dist == Route.Dist) AND
             (RteMsg is the first address in a RREQ) AND (Route.Broken == false))))

   4. Offers improvement
      Incoming routing
      message.

   AddBlk.OrigNode.Address
      The IP address information that does not match any of the originator and its associated prefix length.
      In a RREQ the OrigNode above
      criteria is the source's address loop-free and prefix.  In a
      RREP better than the OrigNode is existing routing table
      information.  We provide the RREQ TargetNode's address and prefix for
      which a RREP following pseudo-code to determine
      whether incoming routing information should be used to update an
      existing route table entry.

      (/* signed 16-bit arithmetic */ Node.SeqNum - Route.SeqNum > 0) OR
      ((Node.SeqNum == Route.SeqNum) AND
          [(Node.Dist < Route.Dist) OR
          ((Route.Broken == true) AND (Node.Dist <= Route.Dist + 1)) OR
          ((RteMsg is being generated.  This address RREP) AND (Node.Dist == Route.Dist)]

5.2.2.  Creating or Updating Route Table Entries

   Each route table entry is the second
      address in the message for RREQ.

   OrigNode.AddTLV.SeqNum
      The AODVv2 sequence number of the originator's AODVv2 router.

   A RteMsg may optionally include populated with the following information:

   TargetNode.AddTLV.SeqNum
      The last known AODVv2 sequence number of

   1.  the TargetNode.

   TargetNode.AddTLV.Dist
      The last known Distance Route.Address is set to Node.Address,

   2.  the TargetNode.

   AddBlk.AdditionalNode.Address
      The IP address of an additional node that can be reached via the
      AODVv2 router adding this information.  Each
      AdditionalNode.Address MUST include its prefix.  Each
      AdditionalNode.Address MUST also have an associated Node.SeqNum in Route.Prefix is set to the address TLV block.

   AdditionalNode.AddTLV.SeqNum
      The AODVv2 sequence number associated with this routing
      information.

   OrigNode.AddTLV.Dist
      A metric of Node.Prefix.

   3.  the distance Route.SeqNum is set to reach the associated OrigNode.Address.
      This field Node.SeqNum,

   4.  the Route.NextHopAddress is incremented by at least one at each intermediate
      AODVv2 router.

   AdditionalNode.AddTLV.Dist
      A metric set to the IP.SourceAddress (i.e., an
       address of the distance to reach node that last transmitted the associated
      AdditionalNode.Address.  This field RteMsg packet)

   5.  the Route.NextHopInterface is incremented by at least one
      at each intermediate set to the interface on which the
       incoming AODVv2 router.

4.2.3.  Route Error (RERR)

   A RERR message packet was received,

   6.  the Route.Broken flag is used set to disseminate false,

   7.  if known, the information that a route Route.Dist is
   not available set to the Node.Dist,

   The timer for one or more particular addresses.

   RERR creation the minimum delete timeout (ROUTE_AGE_MIN) is set to
   ROUTE_AGE_MIN_TIMEOUT.  The timer for the maximum delete timeout
   (ROUTE_SEQNUM_AGE_MAX) is set to Node.AddTLV.VALIDITY_TIME [RFC5497]
   if included; otherwise, ROUTE_SEQNUM_AGE_MAX is set to
   ROUTE_SEQNUM_AGE_MAX_TIMEOUT.  The usage of these timers and handling others
   are described in Section 5.5.

   A RERR requires 5.2.3.

   With these assignments to the following information:

   IP.SourceAddress
      The IP address of route table entry, a route has been
   created and the AODVv2 router that sent this packet.  This
      field is generally filled automatically by Route.Forwarding flag set.  Afterward, the operating system route can
   be used to send any buffered data packets and should not require special handling.

   IP.DestinationAddress
      For multicast RERR messages, The IP address is set to LL-MANET-
      Routers [RFC5498].  For unicast RERR messages, forward any incoming
   data packets for Route.Address.  This route also fulfills any
   outstanding route discovery (RREQ) attempts for Node.Address.

5.2.3.  Route Table Entry Timeouts

5.2.3.1.  Minimum Delete Timeout (ROUTE_AGE_MIN)

   When an AODVv2 router transmits a RteMsg, other AODVv2 routers expect
   the IP address is
      set transmitting AODVv2 router to have a forwarding route to the NextHopAddress.

   IP.ProtocolNumber and UDP.DestinationPort
      The IP Protocol Number 138 (manet)
   RteMsg originator.  A route table entry SHOULD be kept in the route
   table for at least ROUTE_AGE_MIN after it has been reserved for MANET
      protocols [RFC5498].  In addition updated.  Failure
   to using this IP protocol
      number, AODVv2 may use maintain the UDP port 269 (manet) [RFC5498] route table entry might result in
      conjunction with lost messages/
   packets, or several duplicate messages.

   After the IP Protocol ROUTE_AGE_MIN timeout a route can safely be deleted.

5.2.3.2.  Maximum Sequence Number 17 (UDP).

   MsgHdr.HopLimit
      The remaining Delete Timeout (ROUTE_SEQNUM_AGE_MAX)

   Sequence number of hops this message information for route table entries is allowed to traverse.

   AddBlk.UnreachableNode.Address
      The address of an UnreachableNode time
   sensitive, and its associated prefix
      length.  Multiple unreachable addresses may MUST be included in deleted after a RERR.

   A Route Error may optionally include time in order to ensure loop-
   free routing.

   After the following information:

   UnreachableNode.AddTLV.SeqNum
      The last known AODVv2 ROUTE_SEQNUM_AGE_MAX timeout a route's sequence number of the unreachable node.  If
      a SeqNum for an address is zero (0) or not included, it is assumed
      to
   information MUST be unknown.  This case occurs when a node receives discarded.

5.2.3.3.  Recently Used Timeout (ROUTE_USED)

   When a message route is used to forward data packets, this timer is set to
   expire after ROUTE_USED_TIMEOUT, as discussed in Section 5.5.2.

   If a destination for which it does route has not have any
      information in its routing table.

5.  Detailed Operation

5.1.  AODVv2 Sequence Numbers

   AODVv2 sequence numbers allow AODVv2 routers been used recently, then a timer for ROUTE_DELETE
   is set to judge ROUTE_DELETE_TIMEOUT.

5.2.3.4.  Delete Information Timeout (ROUTE_DELETE)

   As time progresses the freshness
   of likelihood that old routing information and ensure loop freedom.

5.1.1.  Maintaining A Node's Own Sequence Number

   AODVv2 requires that each AODVv2 router in is
   useful decreases, especially if the network maintain its
   own AODVv2 sequence number (OwnSeqNum) on behalf of nodes are mobile.
   Therefore, old information SHOULD be deleted.

   After the addresses for
   which ROUTE_DELETE timeout if a forwarding route exists it is responsible.  OwnSeqNum SHOULD
   be removed, and the routing table entry SHOULD also be deleted.

5.3.  Routing Messages

5.3.1.  RREQ Creation

   Before an AODVv2 router creates a 16-bit unsigned integer.  The
   circumstances for ThisNode to RREQ it SHOULD increment its
   OwnSeqNum are described by one (1) according to the rules specified in Section 5.3.

5.1.2.  Numerical Operations on OwnSeqNum

   When ThisNode increments its 5.1.
   Incrementing OwnSeqNum it MUST do so by treating will ensure that all nodes with existing
   routing information will consider this new information preferable to
   existing routing table information.  If the sequence number value as an unsigned number.

5.1.3.  OwnSeqNum Rollover

   Incrementing an OwnSeqNum whose value is not
   incremented, certain AODVv2 routers might not consider this
   information preferable, if they have existing better routing
   information.

   First, ThisNode adds the largest largest possible
   number representable as a 16-bit unsigned integer (i.e., 65,535),
   SHOULD be set AddBlk.TargetNode.Address to one (1).  In other words, the sequence number after
   65,535 RREQ; the
   unicast IP Destination Address for which a forwarding route does not
   exist.

   If a previous value of the TargetNode.SeqNum is 1.

5.1.4.  Actions After OwnSeqNum Loss

   An AODVv2 router SHOULD maintain its sequence number known (from a routing
   table entry using longest-prefix matching), it SHOULD be placed in persistent
   storage.
   TargetNode.AddTLV.SeqNum in all but the last RREQ attempt.  If an AODVv2 router's OwnSeqNum a
   TargetNode.SeqNum is lost, not included, it MUST take certain actions is assumed to avoid creating routing loops.  To prevent this possibility after
   OwnSeqNum loss an be unknown by
   handling nodes.  This operation ensures that no intermediate AODVv2 router MUST wait for at least
   ROUTE_DELETE_TIMEOUT before fully participating in
   routers reply, and ensures that the TargetNode's AODVv2 routing
   protocol.  If an AODVv2 control message router
   increments its sequence number.

   Next, ThisNode adds AddBlk.OrigNode.Address, its prefix, and the
   OrigNode.AddTLV.SeqNum (OwnSeqNum) to the RteMsg.

   The OrigNode.Address is received during this
   waiting period, the address of the source for which this
   AODVv2 router SHOULD handle it normally but is initiating this route discovery.  The
   OrigNode.Address MUST
   NOT transmit or retransmit any AODVv2 messages.  If be a data packet is
   received unicast address.  This information will be
   used by nodes to create a route toward the OrigNode, enabling
   delivery of a RREP, and eventually used for proper forwarding of data
   packets.

   If OrigNode.Dist is included it is set to another a number, greater than zero
   (0), representing the distance between OrigNode and ThisNode.

   The MsgHdr.HopLimit SHOULD be set to MSG_HOPLIMIT.

5.3.2.  RREP Creation

   First, the AddBlk.TargetNode.Address is added to the RREP.  The
   TargetNode is the ultimate destination during of this waiting
   period, RREP; the AODVv2 router MUST generate a RERR message indicating
   that this route is not available RREQ
   OrigNode.Address.

   Next, AddBlk.OrigNode.Address and reset its waiting timeout.  At prefix are added to the end of RREP.  The
   AddBlk.OrigNode.Address is the waiting period RREQ TargetNode.Address.  The
   AddBlk.OrigNode.Address MUST be a unicast IP address.  ThisNode
   SHOULD advertise the largest known prefix containing
   AddBlk.OrigNode.Address.

   When the RteMsg TargetNode's AODVv2 router sets its OwnSeqNum to
   one (1) and begins participating.

   The longest creates a node need wait is ROUTE_SEQNUM_AGE_MAX_TIMEOUT.  At RREP, if the
   end of
   TargetNode.SeqNum was not included in the maximum waiting period a node SHOULD set RREQ, ThisNode MUST
   increment its OwnSeqNum to by one (1) and begins participating.

5.2.  AODVv2 Routing Table Operations

5.2.1.  Judging Routing Information's Usefulness

   Given a route table entry (Route.SeqNum, Route.Dist, and
   Route.Broken) and new incoming routing information for a particular
   node according to the rules specified
   in a Section 5.1.

   If TargetNode.SeqNum was included in the RteMsg (Node.SeqNum, Node.Dist, and RteMsg message type -
   RREQ/RREP), the quality of the new routing information is evaluated
   to determine its usefulness.  Incoming routing information is
   classified as follows:

   1. Stale
      If Node.SeqNum TargetNode.SeqNum
   - Route.SeqNum OwnSeqNum < 0 (using signed 16-bit arithmetic) arithmetic), OwnSeqNum SHOULD be
   incremented by one (1) according to the incoming information is stale.  Using stale routing
      information rules specified in
   Section 5.1.

   If TargetNode.SeqNum is not allowed, since doing so might result included in routing
      loops.

      (Node.SeqNum - Route.SeqNum < 0)
          using the RteMsg and TargetNode.SeqNum
   == OwnSeqNum (using signed 16-bit arithmetic

   2. Loop-possible arithmetic) and OrigNode.Dist will
   not be included in the RREP being generated, OwnSeqNum SHOULD be
   incremented by one (1) according to the rules specified in
   Section 5.1.

   If Node.SeqNum == Route.SeqNum OwnSeqNum is not incremented the incoming routing information may cause
      loops if used; in might be
   considered stale.  In this case additional information case, the RREP might not reach the RREP
   Target.

   After any of the sequence number operations above, the RREP
   OrigNode.AddTLV.SeqNum (OwnSeqNum) MUST also be added to the RREP.

   Other AddTLVs in the RREP for the OrigNode and TargetNode SHOULD be
      examined.
   included and set accordingly.  If Route.Dist or Node.Dist OrigNode.Dist is unknown or zero (0), then
      the routing information included it is loop-possible.  If Node.Dist >
      Route.Dist + 1, then set
   to a number greater than zero (0) and less than or equal to 254.  The
   Distance value will influence judgment of the routing information is loop-possible.
      Using loop-possible routing
   (Section 5.2.1) against known information at other AODVv2 routers
   that handle this RteMsg.

   The MsgHdr.HopLimit is not allowed, otherwise
      routing loops may be formed.

      (Node.SeqNum == Route.SeqNum) AND
      ((Node.Dist is unknown) OR
       (Route.Dist set to MSG_HOPLIMIT.

   The IP.DestinationAddress for RREP is unknown) OR
       (Node.Dist > Route.Dist + 1))

   3. Disfavored or equivalent
      In case set to the IP address of known equal SeqNum, the information is disfavored in
      multiple cases: (case i) if Node.Dist == Route.Dist + 1 (it is a
      greater distance route) AND Route.Broken == false; (case ii) if
      Node.Dist == Route.Dist (equal distance route) AND Route.Broken ==
      false AND this
   Route.NextHopAddress for the route to the RREP TargetNode.

5.3.3.  RteMsg is a RREQ.  This condition reduces Handling

   First, ThisNode examines the
      number of RREQ flooded by stopping forwarding of RREQ with
      equivalent distance.

      ((Node.SeqNum == Route.SeqNum) AND
       (((Node.Dist == Route.Dist + 1) AND (Route.Broken == false)) OR
        ((Node.Dist == Route.Dist) AND
         (RteMsg is RREQ) AND (Route.Broken == false))))

   4. Preferable
      Incoming routing information RteMsg to ensure that it contains the
   required information: MsgHdr.HopLimit, AddBlk.TargetNode.Address,
   AddBlk.OrigNode.Address, and OrigNode.AddTLV.SeqNum.  If the required
   information does not match any of exist, the above
      criteria message is loop-free discarded and better than further
   processing stopped.

   ThisNode MUST only handle AODVv2 messages from adjacent routers.

   ThisNode checks if the information existing in AddBlk.OrigNode.Address is a valid routable
   unicast address.  If not, the routing table.  Information message is ignored and further
   processing stopped.

   ThisNode also checks whether AddBlk.OrigNode.Address is an address
   handled by this AODVv2 router.  If this node is always preferable if
      Node.SeqNum - Route.SeqNum > 0 (using signed 16-bit arithmetic).
      In the case of equal sequence numbers, originating
   AODVv2 router, the information RteMsg is
      preferable in multiple cases: (case i) if Node.Dist < Route.Dist;
      (case ii) dropped.

   ThisNode checks if Node.Dist == Route.Dist + 1 AND Route.Broken == true
      (a broken route the AddBlk.TargetNode.Address is being repaired); (case iii) if Node.Dist ==
      Route.Dist AND it a valid routable
   unicast address.  If the address is not a RREP (RREP with equal distance are
      forwarded) OR Route.Broken == true (a broken route valid unicast address, the
   message is being
      repaired).  For completeness, we provide discarded and further processing stopped.

   Next, ThisNode checks whether its routing table has an entry to the following (optimized)
      pseudo-code.

      (Node.SeqNum - Route.SeqNum > 0) OR
   AddBlk.OrigNode.Address using signed 16-bit arithmetic
      ((Node.SeqNum == Route.SeqNum) AND
       ((Node.Dist < Route.Dist) OR
        ((Node.Dist == Route.Dist + 1) AND (Route.Broken == true)) OR
        ((Node.Dist == Route.Dist) AND
         ((RteMsg longest-prefix matching [RFC1812].  If
   a route with a valid Route.SeqNum does not exist, then the new
   routing information is RREP) OR (Route.Broken == true))))) used to create a new route table entry is
   created and updated as described in Section 5.2.2.  Creating or Updating  If a Route Table Entry with Received
        Preferable Routing Information

   The route table
   entry does exists and it has a known Route.SeqNum, the incoming
   routing information is populated compared with the route table entry following information:

   1.  the Route.Address is set to Node.Address,

   2.  the Route.Prefix is set to the Node.Prefix.

   3.  the Route.SeqNum is set to
   the Node.SeqNum,

   4. procedure described in Section 5.2.1.  If the Route.NextHopAddress incoming routing
   information is set to considered preferable, the node that transmitted route table entry is
   updated as described in Section 5.2.2.

   At this
       AODVv2 RteMsg packet (i.e., the IP.SourceAddress),

   5. point, if the Route.NextHopInterface is set to routing information for the interface that this
       AODVv2 packet OrigNode was received on,

   6. not
   preferable then this RteMsg SHOULD be discarded and no further
   processing of this message SHOULD be performed.

   If the Route.Broken flag TargetNode is set to false,

   7.  if known, the Route.Dist a router client of ThisNode this RteMsg is set a
   RREQ, then ThisNode responds with a RREP to the Node.Dist,

   Fields without known values are not populated with any value. RREQ OrigNode (the
   new RREP's TargetNode).  The timer procedure for the minimum delete timeout (ROUTE_AGE_MIN) issuing a new RREP is set to
   ROUTE_AGE_MIN_TIMEOUT.  The timer
   described in Section 5.3.2.  Afterwards, ThisNode need not perform
   any more operations for the maximum delete timeout
   (ROUTE_SEQNUM_AGE_MAX) is set RteMsg being processed.

   As an alternative to Node.AddTLV.VALIDITY_TIME [RFC5497]
   if included; otherwise, ROUTE_SEQNUM_AGE_MAX is set issuing a RREP, ThisNode MAY choose to
   ROUTE_SEQNUM_AGE_MAX_TIMEOUT.  The usage of these timers and others
   are described
   distribute routing information about ThisNode (the RREQ TargetNode)
   more widely.  That is, ThisNode MAY optionally perform a route
   discovery by issuing a RREQ with ThisNode listed as the TargetNode,
   using the procedure in Section 5.2.3. 5.3.1.  At this point, a forwarding route has been created and ThisNode need
   not perform any more operations for the
   Route.Forwarding flag set.  Afterward, RteMsg being processed.

   For each address (except the TargetNode) in the RteMsg that includes
   AddTLV.Dist information, the AddTLV.Dist information is incremented
   by at least one (1).  The updated Distance value will influence
   judgment of the route can be used to send
   any queued data packets and forward any incoming data packets for
   Route.Address.  This route also fulfills any outstanding route
   discovery attempts for Node.Address.

5.2.3.  Route Table Entry Timeouts

5.2.3.1.  Minimum Delete Timeout (ROUTE_AGE_MIN)

   When an AODVv2 router transmits a RteMsg, routing information (Section 5.2.1) against known
   information at other AODVv2 routers expect that handle this RteMsg.

   If the transmitting AODVv2 router to have a forwarding route to resulting Distance value for the
   RteMsg originator.  After updating a route table entry, it SHOULD be
   maintained OrigNode is greater than 254,
   the message is discarded.  If the resulting Distance value for at least ROUTE_AGE_MIN.  Failure to maintain
   another node is greater than 254, the associated address and its
   information might result in lost messages/packets, or in are removed from the worst
   case scenario several duplicate messages.

   After RteMsg.  If the ROUTE_AGE_MIN timeout a route can safely be deleted.

5.2.3.2.  Maximum Sequence Number Delete Timeout (ROUTE_SEQNUM_AGE_MAX)

   Sequence number information MsgHdr.HopLimit is time sensitive, and MUST be deleted
   after a time in order
   equal to ensure loop-free routing.

   After one (1), then the ROUTE_SEQNUM_AGE_MAX timeout a route's sequence number
   information MUST be message is discarded.

5.2.3.3.  Recently Used Timeout (ROUTE_USED)

   When a route  Otherwise, the
   MsgHdr.HopLimit is used to forward data packets, this timer decremented by one (1).

   If ThisNode is set to
   expire after ROUTE_USED_TIMEOUT.  This operation not the TargetNode, AND this RteMsg is also discussed in
   Section 5.5.2.

   If a route has not been used recently, RREQ, then a timer for ROUTE_DELETE
   the current RteMsg (as altered by the procedure defined above) SHOULD
   be sent to the IP multicast address LL-MANET-Routers [RFC5498].  If
   the RREQ is unicast, the IP.DestinationAddress is set to ROUTE_DELETE_TIMEOUT.

5.2.3.4.  Delete Information Timeout (ROUTE_DELETE)

   As time progresses the likelihood that old routing information
   NextHopAddress.

   If ThisNode is
   useful decreases, especially if the network nodes are mobile.
   Therefore, old information SHOULD be deleted.

   After not the ROUTE_DELETE timeout if TargetNode, AND this RteMsg is a RREP, then
   the current RteMsg is sent to the Route.NextHopAddress for the RREP's
   TargetNode.Address.  If no forwarding route exists it to
   TargetNode.Address, then a RERR SHOULD be removed, and issued to the routing table entry SHOULD also be deleted.

5.3.  Routing Messages

5.3.1.  RREQ Creation

   Before an AODVv2 router creates a RREQ OrigNode of
   the RREP.

   By sending the updated RteMsg, ThisNode advertises that it SHOULD increment its
   OwnSeqNum by one (1) according will route
   for addresses contained in the outgoing RteMsg based on the
   information enclosed.  ThisNode MAY choose not to send the rules RteMsg,
   though not resending this RteMsg could decrease connectivity in the
   network or result in a non-shortest distance path.

   The circumstances under which ThisNode might choose to not re-issue a
   RteMsg are not specified in Section 5.1.
   Incrementing OwnSeqNum will ensure that all nodes with existing
   routing information will consider this new information preferable document.  Some examples might
   include the following:

   o  if ThisNode does not want to
   existing advertise routing table information.  If for the sequence number contained
      addresses because it is already heavily loaded

   o  if ThisNode has already issued identical routing information (e.g.
      ThisNode had recently issued a RteMsg with the same distance)

   o  if ThisNode is low on energy and does not
   incremented, certain want to expend energy
      for protocol message sending or packet forwarding

5.4.  Route Discovery

   When an AODVv2 routers might router needs to forward a data packet and it does not consider this
   information preferable, if they
   have existing better routing
   information.

   First, ThisNode adds a forwarding route to the AddBlk.TargetNode.Address destination address, it sends a RREQ
   (described in Section 5.3.1) to discover a route to the RREQ; particular
   destination (TargetNode).

   After issuing a RREQ, the
   unicast IP Destination Address AODVv2 router (OrigNode) waits for which a forwarding route does not
   exist.

   If a previous value of RREP
   indicating the TargetNode.SeqNum is known (from next hop for a routing
   table entry using longest-prefix matching), it SHOULD be placed in
   TargetNode.AddTLV.SeqNum in all but route to the last RREQ attempt. TargetNode.  If a
   TargetNode.SeqNum route is
   not included, it is assumed created within RREQ_WAIT_TIME, OrigNode may again try to be unknown discover
   a route by
   handling nodes.  This operation ensures that no intermediate AODVv2
   routers reply, and ensures that the TargetNode's AODVv2 router
   increments its sequence number.

   Next, issuing another RREQ using the node adds AddBlk.OrigNode.Address, its prefix, procedure defined in
   Section 5.3.1 again.  Route discovery SHOULD be considered to have
   failed after DISCOVERY_ATTEMPTS_MAX and the
   OrigNode.AddTLV.SeqNum (OwnSeqNum) corresponding wait time
   for a response to the RteMsg.

   The OrigNode.Address is the address of the source for which this
   AODVv2 router is initiating this final RREQ.

   To reduce congestion in a network, repeated attempts at route discovery.  The
   OrigNode.Address MUST be
   discovery for a unicast address.  This information will particular TargetNode SHOULD utilize an binary
   exponential backoff.

   Data packets awaiting a route SHOULD be
   used buffered by nodes the source's
   AODVv2 router.  This buffer SHOULD have a fixed limited size
   (BUFFER_SIZE_PACKETS or BUFFER_SIZE_BYTES).  Determining which
   packets to create discard first is a route toward the OrigNode, enabling
   delivery matter of policy at each AODVv2 router;
   in the absence of a RREP, and eventually used for proper forwarding policy constraints, by default older data packets
   SHOULD be discarded first.  Buffering of data
   packets.

   If OrigNode.Dist is included it is set to a number greater than zero
   (0).

   The MsgHdr.HopLimit packets can have both
   positive and negative effects, and therefore settings for buffering
   (BUFFER_DURING_DISCOVERY) SHOULD be set to MSG_HOPLIMIT.

   For RREQ, the MsgHdr.HopLimit MAY administratively configurable.
   Nodes without sufficient memory available for buffering may be set in accordance
   configured with an
   expanding ring search as described in [RFC3561] to limit BUFFER_DURING_DISCOVERY = FALSE; this will affect the RREQ
   propagation
   latency required for launching TCP applications to new destinations.

   If a subset of the local network and possibly reduce route discovery overhead.

   The IP.DestinationAddress for multicast RREQ is set to LL-MANET-
   Routers.  For links that do not support multicast attempt has failed (i.e. an attempt or situations in
   which unicast messaging is preferred, the IP.DestinationAddress for
   unicast RREQ is set multiple
   attempts have been made without receiving a RREP) to the NextHopAddress.

5.3.2.  RREP Creation

   First, the AddBlk.TargetNode.Address is added find a route to
   the RREP.  The
   TargetNode is the ultimate destination of this RREP; TargetNode, any data packets buffered for the RREQ
   OrigNode.Address.

   Next, AddBlk.OrigNode.Address corresponding
   TargetNode MUST BE dropped and prefix are added a Destination Unreachable ICMP message
   (Type 3) SHOULD be delivered to the RREP.  The
   AddBlk.OrigNode.Address is source of the RREQ TargetNode.Address. data packet.  The
   AddBlk.OrigNode.Address MUST be a unicast IP address.  ThisNode
   SHOULD advertise
   code for the largest known prefix containing
   AddBlk.OrigNode.Address.

   When ICMP message is 1 (Host unreachable error).  If the RteMsg TargetNode's
   AODVv2 router creates a RREP, if the
   TargetNode.SeqNum was is not included in the RREQ, ThisNode MUST
   increment its OwnSeqNum by one (1) according to source (OrigNode), then the ICMP is sent
   over the interface from which the source sent the rules specified
   in Section 5.1.

   If TargetNode.SeqNum was included in packet to the RteMsg and TargetNode.SeqNum
   - OwnSeqNum < 0 (using signed 16-bit arithmetic), OwnSeqNum
   AODVv2 router.

5.5.  Route Maintenance

   A RERR SHOULD be
   incremented by one (1) according issued if a data packet is to be forwarded and it
   cannot be delivered to the rules specified next-hop because no forwarding route for
   the IP.DestinationAddress exists; RERR generation is described in
   Section 5.1.

   If TargetNode.SeqNum 5.5.3.

   Upon this condition, an ICMP Destination Unreachable message SHOULD
   NOT be generated unless this router is included in responsible for the RteMsg and TargetNode.SeqNum
   == OwnSeqNum (using signed 16-bit arithmetic)
   IP.DestinationAddress and OrigNode.Dist will
   not that IP.DestinationAddress is known to be included in the RREP being generated, OwnSeqNum
   unreachable.

   In addition to inability to forward a data packet, a RERR SHOULD be
   incremented by one (1) according to the rules specified in
   issued immediately after detecting a broken link (see Section 5.1. 5.5.1)
   of a forwarding route to quickly notify AODVv2 routers that certain
   routes are no longer available.  If OwnSeqNum is a newly unavailable route has not incremented
   been used recently (indicated by ROUTE_USED), the routing information might RERR SHOULD NOT be
   considered stale.  In this case, the RREP might not reach
   generated.

5.5.1.  Active Next-hop Router Adjacency Monitoring

   Nodes SHOULD monitor connectivity to adjacent next-hop AODVv2 routers
   on forwarding routes.  This monitoring can be accomplished by one or
   several mechanisms, including:

   o  Neighborhood discovery [RFC6130]

   o  Route timeout

   o  Lower layer trigger that a neighboring router is no longer
      reachable

   o  Other monitoring mechanisms or heuristics

   Upon determining that a next-hop AODVv2 router has become
   unreachable, ThisNode MUST remove the RREP
   Target.

   After any of affected forwarding routes
   (those using the sequence number operations above, unreachable next-hop) and unset the RREP
   OrigNode.AddTLV.SeqNum (OwnSeqNum) MUST Route.Forwarding
   flag.  ThisNode also be added to flags the RREP.

   Other AddTLVs associated routes in AODVv2's routing
   table as Broken.  For each broken route the RREP timer for the OrigNode and TargetNode SHOULD be
   included and set accordingly.  If OrigNode.Dist is included it ROUTE_DELETE is
   set to a number greater than zero (0) and less than or equal ROUTE_DELETE_TIMEOUT.

5.5.2.  Updating Route Lifetimes During Packet Forwarding

   To avoid removing the forwarding route to 65,535.
   The Distance reach an IP.SourceAddress,
   ThisNode SHOULD set the "ROUTE_USED" timeout to the value will influence judgment of
   ROUTE_USED_TIMEOUT for the routing information
   (Section 5.2.1) against known information at other route to that IP.SourceAddress upon
   receiving a data packet or an AODVv2 routers message.  If the timer for
   ROUTE_DELETE is set, that handle this RteMsg.

   The MsgHdr.HopLimit timer is set to MSG_HOPLIMIT. removed.  The IP.DestinationAddress for RREP Route.Broken flag is set to the IP address of the
   Route.NextHopAddress for
   unset.

   To avoid removing the forwarding route to the RREP TargetNode.

5.3.3.  RteMsg Handling

   First, IP.DestinationAddress
   that is being used, ThisNode examines SHOULD set the RteMsg "ROUTE_USED" timeout to ensure that it contains the
   required information: MsgHdr.HopLimit, AddBlk.TargetNode.Address,
   AddBlk.OrigNode.Address, and OrigNode.AddTLV.SeqNum.  If
   the required
   information do not exist, value ROUTE_USED_TIMEOUT for the message is discarded and further
   processing stopped.

   Next, ThisNode MAY selectively attend route to messages based upon
   information in the message.  ThisNode SHOULD only handle messages
   from adjacent
   IP.DestinationAddress upon sending a data packet or an AODVv2 routers.
   message.  If ThisNode chooses not to handle this
   message, the message timer for ROUTE_DELETE is discarded and further processing stopped.

   ThisNode checks if the AddBlk.OrigNode.Address set, it is removed.  The
   Route.Broken flag is unset.

5.5.3.  RERR Generation

   When an AODVv2 router receives a valid multihop-
   capable (e.g. site or global scope) unicast address.  If packet (from PrevHopAddress), and
   the address
   is router (ThisNode) does not have a valid unicast address, route available for the message is discarded and further
   processing stopped.
   destination of the packet, ThisNode also checks whether AddBlk.OrigNode.Address is uses an address
   handled by this AODVv2 router.  If this node RERR message is the originating used to
   inform one or more neighboring AODVv2 router, routers that its route to the RteMsg
   packet destination is dropped. no longer available.

   When ThisNode checks if the AddBlk.TargetNode.Address is creates a valid multihop-
   capable unicast address.  If new RERR, the address of the first
   UnreachableNode (IP.DestinationAddress from a data packet or
   RREP.TargetNode.Address) is not inserted into an Address Block
   AddBlk.UnreachableNode.Address.  If a valid unicast
   address, prefix is known for the message
   UnreachableNode.Address, it SHOULD be included.  Otherwise, the
   UnreachableNode.Address is discarded and further processing stopped.

   Next, ThisNode checks whether its routing table has an entry assumed to the
   AddBlk.OrigNode.Address using longest-prefix matching [RFC1812].  If be a route host address with a valid Route.SeqNum does not exist, then the new
   routing information is considered preferable and full
   length prefix.  If a new route table
   entry value for the UnreachableNode's SeqNum
   (UnreachableNode.AddTLV.SeqNum) is created and updated as described known, it SHOULD be placed in Section 5.2.2. the
   RERR.  The MsgHdr.HopLimit SHOULD be set to MSG_HOPLIMIT.

   If a
   route table entry does exists and it has a SeqNum information is not known Route.SeqNum, or not included in the
   incoming RERR, all
   nodes handling the RERR will assume their routing information is compared
   associated with the route table entry
   following UnreachableNode is no longer valid and flag those
   routes as broken.

   A RERR MAY be sent to the multicast address LL-MANET-Routers
   [RFC5498], thus notifying all nearby AODVv2 routers that might depend
   on the procedure described in Section 5.2.1. now broken link.  If the incoming
   routing information RERR is considered preferable, unicast, the route table entry
   IP.DestinationAddress is updated as described in Section 5.2.2.

   For each address (except set to the TargetNode) in PrevHopAddress.

   After sending the RteMsg RERR, ThisNode SHOULD discard the packet or message
   that includes
   AddTLV.Dist information, triggered generation of the AddTLV.Dist information MAY be
   incremented.  If RERR.

5.5.4.  RERR Handling

   First, ThisNode examines the resulting Distance value for incoming RERR to ensure that it contains
   MsgHdr.HopLimit and AddBlk.UnreachableNode.Address.  If the OrigNode is
   greater than 65,535, required
   information does not exist, the incoming RERR message is discarded.  If the resulting
   Distance value for another node is greater than 65,535, the
   associated address discarded
   and its information are removed from further processing stopped.

   When an AODVv2 router handles a RERR, it examines the RteMsg. information for
   each UnreachableNode.  The updated Distance value will influence judgment of AODVv2 router removes the routing
   information (Section 5.2.1).

   After handling forwarding
   route, unsets the OrigNode's routing information, then each address
   that is not Route.Forwarding flag, sets the TargetNode MAY be considered for creating and
   updating routes.  Creating Route.Broken flag,
   and updating routes the timer for ROUTE_DELETE is set to other nodes can
   eliminate RREQ ROUTE_DELETE_TIMEOUT for those IP destinations, in the event
   each UnreachableNode.Address found using longest prefix matching that data
   needs to be forwarded to
   meets all of the IP destination(s) now or in following conditions:

   1.  The UnreachableNode.Address is a routable unicast address.

   2.  The Route.NextHopAddress is the near
   future.

   For each of same as the additional addresses considered, ThisNode first
   checks RERR
       IP.SourceAddress.

   3.  The Route.NextHopInterface is the that same as the address is a multihop-capable unicast address.
   If interface on which
       the address RERR was received.

   4.  The Route.SeqNum is not a unicast address, zero (0), unknown, OR the address and all related
   information MUST be removed.
       UnreachableNode.SeqNum is zero (0), unknown, OR Route.SeqNum -
       UnreachableNode.SeqNum <= 0 (using signed 16-bit arithmetic).

   If Route.SeqNum is zero (0) or unknown and UnreachableNode.SeqNum
   exists in the routing table does RERR and is not have a matching route with a known
   Route.SeqNum for this additional address using longest-prefix
   matching, zero (0), then a route is created Route.SeqNum SHOULD be
   set to UnreachableNode.SeqNum.  Setting Route.SeqNum can reduce
   future RERR handling and updated as described forwarding.

   Each UnreachableNode that did not result in
   Section 5.2.2.  If marking a route table
   entry exists with a known
   Route.SeqNum, the incoming routing information as broken route is compared with removed from the RERR, since propagation of
   such information will not result in any benefit.

   Each UnreachableNode that did indicate a broken route table entry following the procedure described SHOULD remain
   in Section 5.2.1.
   If the incoming routing RERR.

   If any UnreachableNode was removed, all other information is considered preferable, (AddTLVs)
   associated with the
   route table entry is updated as described in Section 5.2.2. UnreachableNode address(es) MUST also be removed.

   If the routing information for Route.SeqNum is known and an AdditionalNode.Address UnreachableNode.SeqNum is not
   considered preferable,
   included in the RERR, then it is removed from Route.SeqNum (i.e.
   UnreachableNode.SeqNum) MAY be included with the RteMsg.  Removing
   this information ensures that RERR.  Including
   UnreachableNode.SeqNum can reduce future RERR handling and
   forwarding.

   If no UnreachableNode addresses remain in the information is not propagated.

   At this point, RERR, or if the routing information for the OrigNode was not
   preferable
   MsgHdr.HopLimit is equal to one (1), then this RteMsg SHOULD the RERR MUST be discarded and no further
   processing of this message discarded.

   Otherwise, the MsgHdr.HopLimit is decremented by one (1).  The RERR
   SHOULD be performed.

   If sent to the ThisNode multicast address LL-MANET-Routers [RFC5498].
   Alternatively, if the RERR is unicast, the AODVv2 router responsible for IP.DestinationAddress is
   set to the TargetNode PrevHopAddress.

5.6.  Unknown Message and this RteMsg is TLV Types

   If a RREQ, then ThisNode responds message with a RREP to an unknown type is received, the
   RREQ OrigNode (the new RREP's TargetNode).  The procedure for issuing
   a new RREP message is described in Section 5.3.2.  At this point, ThisNode
   need not perform any more operations for
   ignored.

   For handling of messages that contain unknown TLV types, ignore the RteMsg being processed.

   As an alternative to issuing a RREP, ThisNode MAY choose to
   distribute routing
   information about ThisNode (the RREQ TargetNode)
   more widely.  That is, ThisNode for processing, preserve it unmodified for forwarding.

5.7.  Advertising Network Addresses

   AODVv2 routers MAY optionally perform a route
   discovery; by issuing specify a RREQ with ThisNode listed as the TargetNode,
   using the procedure in Section 5.3.1.  At this point, ThisNode need
   not perform any more operations prefix length for each advertised
   address.  Any nodes (other than the RteMsg being processed.

   If the resulting Distance value for advertising AODVv2 router) within
   the OrigNode is greater than
   65,535, advertised prefix MUST NOT participate in the message is discarded.  If AODVv2 protocol
   directly.  For example, advertising 192.0.2.1 with a prefix length of
   24 indicates that all nodes with the resulting Distance value matching 192.0.2.X are reachable
   through this AODVv2 router.  An AODVv2 router MUST NOT advertise
   network addresses unless it can guarantee its ability for another node is greater than 65,535, the associated forwarding
   packets to any host address and
   its information are removed from within the RteMsg.

   Next, address range of the MsgHdr.HopLimit is decremented by one (1).  If this
   RteMsg's MsgHdr.HopLimit is greater than or equal
   corresponding network.

5.8.  Simple Internet Attachment

   Simple Internet attachment consists of a stub (i.e., non-transit)
   network of AODVv2 routers connected to one (1),
   ThisNode is not the TargetNode, AND this RteMsg is Internet via a RREQ, then the
   current RteMsg (altered by the procedure defined above) SHOULD be
   sent single
   Internet AODVv2 router (IAR).

   As in any Internet-attached network, AODVv2 routers, and hosts behind
   these routers, wishing to be reachable from hosts on the IP.DestinationAddress LL-MANET-Routers [RFC5498].  If the
   RREQ is unicast, Internet
   MUST have IP addresses within the IP.DestinationAddress IAR's routable and topologically
   correct prefix (e.g. 192.0.2.0/24).

   The IAR is set responsible for generating RREQ to find nodes within the
   NextHopAddress.

   If this RteMsg's MsgHdr.HopLimit is greater than or equal
   AODVv2 Region on behalf of nodes on the Internet, as well as
   responding to one (1),
   ThisNode is not route requests from the TargetNode, AND this RteMsg is a RREP, then AODVv2 region on behalf of the
   nodes on the Internet.

         /--------------------------\
        /          Internet          \
        \                            /
         \------------+-------------/
                      |
       Routable &     |
       Topologically  |
       Correct        |
       Prefix         |
                +-----+--------+
                |  Internet    |
         /------|  AODVv2      |-------\
        /       |  Router      |        \
       /        |192.0.2.1/32  |         \
       |        |Responsible   |         |
       |        |  for         |         |
       |        |AODVv2 Region |         |
       |        |192.0.2.0/24  |         |
       |        +--------------+         |
       | +----------------+              |
       | | AODVv2 Router  |              |
       | | 192.0.2.2/32   |              |
       | +----------------+              |
       |              +----------------+ |
       |              | AODVv2 Router  | |
       |              | 192.0.2.3/32   | |
       \              +----------------+ /
        \                               /
         \-----------------------------/

               Figure 1: Simple Internet Attachment Example

   When an AODVv2 router within the
   current RteMsg is sent AODVv2 Region wants to the Route.NextHopAddress for the RREP's
   TargetNode.Address.  If no forwarding discover a
   route exists to
   TargetNode.Address, then a RERR SHOULD be issued to the OrigNode of
   the RREP.

   By sending node on the updated RteMsg, ThisNode advertises that Internet, it will uses the normal AODVv2 route
   discovery for addresses contained in the outgoing RteMsg based on the
   information enclosed.  ThisNode MAY choose not that IP Destination Address.  The IAR MUST respond to send the RteMsg,
   though not resending this RteMsg could decrease connectivity in the
   network or result in a non-shortest distance path.

   Some examples
   RREQ on behalf of why ThisNode might choose to not re-issue a RteMsg
   are: if ThisNode does not want to advertise routing for the contained
   addresses because it is already heavily loaded; if ThisNode has
   already issued nearly identical routing information (e.g.  ThisNode
   had recently issued a RteMsg with nearly the same distance); or if
   ThisNode is low on energy and does not want to expend energy for
   control message sending or packet forwarding.  The exact
   circumstances producing such behavior are not specified in this
   document.

5.4.  Route Discovery Internet destination.

   When a source's AODVv2 router needs to forward a data packet from a node on
   behalf of an attached the Internet destined for a node and it in the
   AODVv2 region reaches the IAR, if the IAR does not have a forwarding route to
   the data packet's unicast IP destination address, ThisNode sends a
   RREQ (described in Section 5.3.1) to discover a route to the
   particular
   that destination (TargetNode).

   After issuing a RREQ, the OrigNode it will perform normal AODVv2 router waits for a route to discovery for
   that destination.

5.9.  Multiple Interfaces

   AODVv2 may be created to used with multiple interfaces; therefore, the TargetNode.  If
   particular interface over which packets arrive MUST be known whenever
   a route packet is not created within
   RREQ_WAIT_TIME, ThisNode may again try to discover received.  Whenever a new route by issuing
   another RREQ using is created, the procedure defined in Section 5.3.1 again.
   Route discovery SHOULD be considered failed after
   DISCOVERY_ATTEMPTS_MAX and interface
   through which the final RREQ's corresponding
   RREQ_WAIT_TIME.

   To reduce congestion Route.Address can be reached is also recorded in a network, repeated attempts at
   the route
   discovery for table entry.

   When multiple interfaces are available, a particular TargetNode node transmitting a
   multicast packet with IP.DestinationAddress set to LL-MANET-Routers
   SHOULD utilize an exponential
   backoff.

   For example, send the first time an AODVv2 router issues a RREQ, it waits
   RREQ_WAIT_TIME packet on all interfaces that have been configured
   for a route AODVv2 operation.

   Similarly, AODVv2 routers SHOULD subscribe to the TargetNode.  If a route LL-MANET-Routers on all
   their AODVv2 interfaces.

5.10.  AODVv2 Control Packet/Message Generation Limits

   To ensure predictable messaging overhead, AODVv2 router's rate of
   packet/message generation SHOULD be limited.  The rate and algorithm
   for limiting messages (CONTROL_TRAFFIC_LIMITS) is not
   found within that time, left to the
   implementor and should be administratively configurable.  AODVv2 router MAY send another RREQ.  If
   a route is
   messages SHOULD be discarded in the following order of preference:
   RREQ, RREP, and finally RERR.

5.11.  Optional Features

   Several optional features of AODVv2, and associated with AODV, are
   not found within two (2) times required by minimal implementations.  These features are expected
   to be useful in networks with greater mobility, or larger node
   populations, or requiring shorter latency for application launches.
   The optional features are as follows:

   o  Expanding Rings Multicast

   o  Intermediate RREPs (iRREPs): Without iRREP, only the current waiting time,
   another RREQ MAY be sent.  No destination
      can respond to a RREQ.

   o  Precursor lists.

   o  Reporting Multiple Unreachable Nodes.  An RERR message can carry
      more than DISCOVERY_ATTEMPTS_MAX route
   discovery attempts SHOULD be made before considering route discovery one Unreachable Destination node for this destination cases when a single
      link breakage causes multiple destinations to have failed. become unreachable
      from an intermediate router.

5.11.1.  Expanding Rings Multicast

   For each additional attempt, multicast RREQ, the waiting time for MsgHdr.HopLimit MAY be set in accordance with
   an expanding ring search as described in [RFC3561] to limit the previous RREQ is multiplied by two (2) so
   that the waiting time conforms
   propagation to a binary exponential backoff.

   Data packets awaiting a route SHOULD be buffered by the source's
   AODVv2 router.  This buffer SHOULD have a fixed limited size
   (BUFFER_SIZE_PACKETS or BUFFER_SIZE_BYTES) and older data packets
   SHOULD be discarded first.

   Buffering subset of data packets can have both positive and negative
   effects, the local network and therefore buffer settings (BUFFER_DURING_DISCOVERY)
   SHOULD be administratively configurable or intelligently controlled.

   If a possibly reduce
   route discovery attempt overhead.

5.11.2.  Intermediate RREP

   This specification has failed (i.e. an attempt or multiple
   attempts have been made without receiving published as a RREP) separate Internet Draft .

5.11.3.  Precursor Notification

   The Dynamic MANET On-demand (AODVv2) routing protocol is intended for
   use by mobile routers in wireless, multihop networks.  AODVv2
   determines unicast routes among AODVv2 routers within the network in
   an on-demand fashion, offering on-demand convergence in dynamic
   topologies.  This document specifies a simple modification to find AODVv2
   (and possibly other reactive routing protocols) enabling faster
   notifications to known sources of traffic upon determination that a
   route to
   the TargetNode, any data packets buffered for the corresponding
   TargetNode are dropped and a Destination Unreachable ICMP message
   SHOULD be delivered such traffic's destination has become Broken.

5.11.3.1.  Overview

   If an AODVv2 router, while attempting to the source.

5.5.  Route Maintenance

   A RERR SHOULD be issued if forward a data packet is to be forwarded and it
   cannot be delivered to a
   particular destination, determines that the next-hop because next hop (one of its
   neighbors) is no forwarding route for longer reachable, AODVv2 specifies that the IP.DestinationAddress exists; RERR generation is described in
   Section 5.5.3.

   Upon this condition, an ICMP Destination Unreachable message SHOULD
   NOT be generated unless this router is responsible for
   notify the
   IP.DestinationAddress and source of that IP.DestinationAddress is known packet that the route to be
   unreachable. the destination
   has become Broken.  In addition to inability the existing specification, the notification
   to forward a data packet, the source is a unicast RERR SHOULD message.

   However, in many cases there will be
   issued immediately after detecting a broken link (see Section 5.5.1) several sources of a forwarding route to quickly notify AODVv2 routers of traffic
   for that certain
   routes are no longer available.  If a newly unavailable route has not
   been used recently (indicated by ROUTE_USED), particular destination.  In fact, the RERR SHOULD NOT be
   generated.

5.5.1.  Active Next-hop Router Adjacency Monitoring

   Nodes MUST monitor connectivity to adjacent next-hop AODVv2 routers
   on forwarding routes.  This monitoring can broken link for the
   next hop in question may be accomplished by one or
   several mechanisms, including:

   o  Neighborhood discovery [I-D.ietf-manet-nhdp]

   o  Route timeout

   o  Lower layer feedback that a particular adjacent router is no
      longer reachable

   o  Other monitoring mechanisms or heuristics

   Upon determining that a next-hop AODVv2 router is unreachable,
   ThisNode MUST remove the affected forwarding path component of numerous other routes (those with an
   unreachable next-hop)
   for other destinations, and unset in that case the Route.Forwarding flag.  ThisNode
   also flags node detecting the associated routes in AODVv2's routing table
   broken link must mark as Broken.
   For Broken multiple routes, one for each broken of the
   newly unreachable destinations.  Each route that uses the timer for ROUTE_DELETE newly
   broken link is set to
   ROUTE_DELETE_TIMEOUT.

5.5.2.  Updating Route Lifetimes During Packet Forwarding

   To avoid removing no longer valid.  For each such route, every node
   along the forwarding route way from the source using that route, to reach the IP.SourceAddress,
   ThisNode SHOULD set node detecting
   the "ROUTE_USED" timeout to broken link, is known as a "precursor" for the value
   ROUTE_USED_TIMEOUT broken next hop.
   All the precursors for a particular next hop should be notified about
   the change in status of their route to the IP.SourceAddress upon
   receiving a data packet.  If destination downstream from
   the timer for ROUTE_DELETE is set, it is
   removed.

   To avoid removing broken next hop.

5.11.3.2.  Precursor Notification

   During normal operation, each node wishing to enable the forwarding route improved
   notification for precursors of any links to its next hop neighbors
   has to keep track of the IP.DestinationAddress
   that precursors.  This is being used, ThisNode SHOULD set the "ROUTE_USED" timeout to done by maintaining a
   precursor table and updating the value ROUTE_USED_TIMEOUT for table whenever the route node initiates or
   relays a RREP message back to the
   IP.DestinationAddress upon sending a data packet.  If node originating a RREQ message.
   When the timer for
   ROUTE_DELETE is set, node transmits the RREP message, it is removed.

5.5.3.  RERR Generation

   A RERR informs AODVv2 routers that a route implicitly agreeing
   to certain destinations is
   not available through ThisNode.

   When creating a new RERR, forward traffic from the address of RREQ originator towards the first UnreachableNode
   (IP.DestinationAddress RREP
   originator (i.e., along the next hop link to the neighbor from a data packet or RREP.TargetNode.Address)
   is inserted into an Address Block AddBlk.UnreachableNode.Address.  If
   a prefix which
   the RREP was received).  The "other" next hop, which is known for the UnreachableNode.Address, it SHOULD be
   included.  Otherwise, neighbor
   along the UnreachableNode.Address way towards the originator of the RREQ message, is assumed to then the
   next precursor for the route towards the destination requested by the
   RREQ.

   Each such precursor should then be recorded as a
   host address with a full length prefix.  If a value precursor for a
   route along the
   UnreachableNode's SeqNum (UnreachableNode.AddTLV.SeqNum) is known, it
   SHOULD next hop.  The same next hop may be placed in the RERR.  The MsgHdr.HopLimit is set service for
   routes to
   MSG_HOPLIMIT.

   If SeqNum information multiple destinations, but for precursor list management it
   is not known or not included in only important to keep track of precursors for a particular next
   hop; the RERR, all
   nodes handling exact destination does not matter, only the RERR will assume their routing information
   associated with particular next
   hop towards the UnreachableNode destination(s).

   When a node observes that one of its neighbors is no longer valid and flag those
   routes as broken.

   A multicast RERR is sent to the IP.DestinationAddress LL-MANET-
   Routers [RFC5498].  Sending
   reachable, the RERR node first checks to see whether the LL-MANET-Routers address
   notifies all nearby AODVv2 routers link to that might depend on the now
   broken link.
   neighbor is a next hop for any more distant destination in its route
   table.  If not, then the RERR is unicast, node simply updates any relevant neighorhood
   information and takes no further action.

   Otherwise, for all destinations no longer reachable because of the IP.DestinationAddress is
   set to
   changed status of the NextHopAddress.

   At this point, next hop, the packet or message that forced generation of this
   RERR SHOULD be discarded.

5.5.4.  RERR Handling

   First, ThisNode examines node first checks to see whether
   the RteMsg link to ensure that it contains the
   required information: MsgHdr.HopLimit and
   AddBlk.UnreachableNode.Address.  If the required information do not
   exist, the message neighbor is discarded and further processing stopped.

   Next, ThisNode MAY selectively handle messages based upon information a next hop for any more distant
   destination in the message.  ThisNode MAY choose to only handle messages from
   adjacent AODVv2 routers. its route table.  If ThisNode chooses not to handle this
   message, not, then the message is discarded node simply updates
   any relevant neighorhood information and takes no further processing stopped.

   When an AODVv2 router handles a RERR, it examines action.

   For each
   UnreachableNode's information.  The attending AODVv2 router removes
   the forwarding route, unsets precursor of the Route.Forwarding flag, sets next hop, the
   Route.Broken flag, and node MAY notify the timer for ROUTE_DELETE is set precursor
   in one of three ways:

   o  unicast RERR

   o  broadcast RERR

   o  multicast RERR to
   ROUTE_DELETE_TIMEOUT for each UnreachableNode.Address found using
   longest prefix matching that meets multicast group PRECURSOR_RERR_RECEIVERS

   Each precursor then MAY execute the same procedure until all of affected
   traffic sources have received the following conditions:

   1.  The UnreachableNode.Address is RERR route maintenance information.

   When a precursor receives a multihop-capable unicast
       address.

   2.  The Route.NextHopAddress is RERR, the same as precursor MUST further
   unicast the RERR
       IP.SourceAddress.

   3.  The Route.NextHopInterface is message towards the same as affected traffic source.  If a
   precursor receives a broadcast or multicast RERR, the interface on which precursor MAY
   further retransmit the RERR was received.

   4.  The Route.SeqNum is zero (0), unknown, OR towards the
       UnreachableNode.SeqNum is zero (0), unknown, OR Route.SeqNum -
       UnreachableNode.SeqNum <= 0 (using signed 16-bit arithmetic).

   During handling if Route.SeqNum traffic source.

5.11.4.  Reporting Multiple Unreachable Nodes

5.11.5.  Message Aggregation

   The aggregation of multiple messages into a packet is zero (0) or unknown and
   UnreachableNode.SeqNum exists not specified
   in this document, but if aggregation does occur the RERR IP.SourceAddress
   and is not zero (0), then
   Route.SeqNum MAY IP.DestinationAddress of all contained messages MUST be set the same.

   Implementations MAY choose to UnreachableNode.SeqNum.  Setting
   Route.SeqNum can reduce future RERR handling and forwarding.

   Each UnreachableNode that did not result in temporarily delay transmission of
   messages for the purpose of aggregation (into a broken route is removed
   from single packet) or to
   improve performance by using jitter [RFC5148].

5.11.6.  Adding Additional Routing Information to a RteMsg

   DSR [RFC4728] includes source routes as part of the RERR, since propagation data of this its RREPs
   and RREQs.  Doign so allows additional topology information will not result
   in any benefit.

   Each UnreachableNode to be
   flooded along with the RteMsg, and potentially allows updating for
   stale routing information at MANET routers along new paths between
   source and destination.  To maintain this functionality, AODVv2 has
   defined a somewhat more general method that did result enables inclusion of
   source routes in a broken RteMsgs.

   Appending routing information can alleviate route SHOULD remain
   in discovery attempts
   to the RERR.

   If any UnreachableNode was removed, all nodes whose information is included, if other AODVv2 routers
   use this information (AddTLVs)
   associated to update their routing tables.

   Note that, since the initial merger of DSR with AODV to create this
   protocol, further experimentation has shown that including the removed address(es) MUST also be removed.

   After handling if Route.SeqNum is known and an UnreachableNode.SeqNum
   additional routing information is not included in the RERR, then Route.SeqNum (i.e.
   UnreachableNode.SeqNum) MAY be added always helpful.  Sometimes it
   seems to the RERR.  Including
   UnreachableNode.SeqNum can reduce future RERR handling help, and
   forwarding.

   If no UnreachableNode addresses remain in the RERR, no other handling
   is required and the RERR is discarded.

   If handling continues, the MsgHdr.HopLimit times it seems to reduct overall
   performance.

   AODVv2 routers can append routing information to a RteMsg.  This is decremented
   controllable by one (1).
   Further, if this RERR's new MsgHdr.HopLimit is greater than one (1)
   and at least one unreachable node address remains in the RERR, then
   the updated RERR an option (APPEND_INFORMATION) which SHOULD be sent.

   A multicast RERR is sent
   administratively configurable or controlled according to the IP.DestinationAddress LL-MANET-
   Routers [RFC5498].  If the RERR is unicast, traffic
   characteristics of the IP.DestinationAddress
   is set network.

   Prior to the NextHopAddress.

5.6.  Unknown Message and TLV Types appending an address controlled by this AODVv2 router to a
   RteMsg, ThisNode MAY increment its OwnSeqNum as defined in
   Section 5.1.  If a message with an unknown type OwnSeqNum is received, not incremented the message is
   discarded.

   For handling appended routing
   information might not be considered preferable, when received by
   nodes with existing routing information.  Incrementation of messages that contain unknown TLV types, the default
   behavior is to leave the
   sequence number when appending information to a RteMsg in control messages unmodified.
   Although, this behavior (UNKNOWN_TYPES) MAY transit
   (APPEND_INFORMATION_SEQNUM) SHOULD be administratively
   controlled.

5.7.  Advertising Network Addresses

   AODVv2 routers specify the prefix length for each advertised address.
   Any nodes (other than the advertising AODVv2 router) within the
   advertised prefix MUST NOT participate configurable.
   Note that, during handling of this RteMsg OwnSeqNum may have already
   been incremented; and in the this case OwnSeqNum need not be incremented
   again.

   If an address controlled by this AODVv2 protocol
   directly.  For example, advertising 192.0.2.1 with router includes
   ThisNode.Dist, it is set to a prefix length of
   24 indicates that all nodes with the matching 192.0.2.X are reachable
   through number greater than zero (0).

   For added addresses (and their prefixes) not controlled by this
   AODVv2 router.

5.8.  Simple Internet Attachment

   Simple Internet attachment consists of a stub network router, Route.Dist can be included if known.

   The VALIDITY_TIME of AODVv2 routing information for appended address(es)
   MUST be included, to inform routers connected about when to the Internet via a single Internet AODVv2 router
   (IDR).

   AODVv2 routers, delete this
   information.  The VALIDITY_TIME TLV is defined in Section 5.13.3.

   Additional information (e.g.  SeqNum and hosts behind these routers, wishing to Dist) about any appended
   address(es) SHOULD be
   reachable from hosts on included.

   Note that the Internet routing information about the TargetNode MUST have IP addresses within NOT be
   added.  Also, duplicate address entries SHOULD NOT be added.
   Instead, only the IDR's routable and topologically correct prefix (e.g.

   192.0.2.0/24).

   The IDR is responsible best routing information (Section 5.2.1) for generating RREQ to find a
   particular address SHOULD be included.

   Intermediate nodes within obey the
   AODVv2 Region on behalf of nodes on following procedures when processing
   AddBlk.AdditionalNode.Address information and other associated TLVs
   that are included with a RteMsg.  For each address (except the Internet, as well as
   responding to route requests from
   TargetNode) in the AODVv2 region on behalf of RteMsg that includes AddTLV.Dist information, the
   nodes on
   AddTLV.Dist information MUST be incremented.  If the Internet.

         /--------------------------\
        /          Internet          \
        \                            /
         \------------+-------------/
                      |
       Routable &     |
       Topologically  |
       Correct        |
       Prefix         |
                +-----+------+
                |  Internet  |
         /------|  AODVv2      |-------\
        /       |  Router    |        \
       /        |192.0.2.1/32|         \
       |        |Responsible |         |
       |        | resulting
   Distance value for       |         |
       |        |AODVv2 Region |         |
       |        |192.0.2.0/24|         |
       |        +------------+         |
       | +--------------+              |
       | | AODVv2 Router  |              |
       | | 192.0.2.2/32 |              |
       | +--------------+              |
       |              +--------------+ |
       |              | AODVv2 Router  | |
       |              | 192.0.2.3/32 | |
       \              +--------------+ /
        \                             /
         \---------------------------/

               Figure 1: Simple Internet Attachment Example

   When an AODVv2 router within the AODVv2 Region wants to discover a
   route to a node on OrigNode is greater than 254, the Internet, it uses message is
   discarded.  If the normal AODVv2 route
   discovery resulting Distance value for another node is
   greater than 254, the associated address and its information are
   removed from the RteMsg.

   After handling the OrigNode's routing information, then each address
   that IP Destination Address.  The IDR is responsible not the TargetNode MAY be considered for properly responding creating and
   updating routes.  Creating and updating routes to other nodes can
   eliminate RREQ for those IP destinations, in the event that data
   needs to RREQ on behalf be forwarded to the IP destination(s) now or in the near
   future.

   For each of the Internet
   destination.

   When a packet from a node on additional addresses considered, ThisNode first
   checks that the Internet destined for address is a node in routable unicast address.  If the
   AODVv2 region reaches
   address is not a unicast address, then the IDR, if address and all related
   information MUST be removed.

   If the IDR routing table does not have a matching route to
   that destination it will perform normal AODVv2 route discovery for
   that destination.

5.9.  Multiple Interfaces

   AODVv2 may be used with multiple interfaces; therefore, the
   particular interface over which packets arrive MUST be known whenever a packet is received.  Whenever known
   Route.SeqNum for this additional address using longest-prefix
   matching, then a new route is created, the interface
   through which the Route.Address can MAY be reached is also recorded created and updated as described in
   the
   Section 5.2.2.  If a route table entry.

   When multiple interfaces are available, a node transmitting entry exists with a
   multicast packet known
   Route.SeqNum, the incoming routing information is compared with IP.DestinationAddress set to LL-MANET-Routers
   SHOULD send the packet on all interfaces that have been configured
   for AODVv2 operation.

   Similarly, AODVv2 routers should subscribe to LL-MANET-Routers on all
   their AODVv2 interfaces.

5.10.  AODVv2 Control Packet/Message Generation Limits

   To ensure predictable control overhead, AODVv2 router's rate of
   packet/message generation SHOULD be limited.  The rate and algorithm
   for limiting messages (CONTROL_TRAFFIC_LIMITS)
   route table entry following the procedure described in Section 5.2.1.
   If the incoming routing information is left to used, the
   implementor and should be administratively configurable or
   intelligently controlled.  AODVv2 control messages route table entry
   SHOULD be
   discarded updated as described in Section 5.2.2.

   If the following order of preference: RREQ, RREP, and
   finally RERR.

6. routing information for an AdditionalNode.Address is not used,
   then it is removed from the RteMsg.

5.12.  Administratively Configured Parameters and Timer Values

   AODVv2 contains several parameters which MUST be administratively
   configured.  The list of these follows:

              Required Administratively Configured Parameters

   +------------------------+------------------------------------------+
   |          Name          |                Description               |
   +------------------------+------------------------------------------+
   |  RESPONSIBLE_ADDRESSES |  List of addresses or routing prefixes,  |
   |                        |      for which this AODVv2 router is     |
   |                        |  responsible.  If, RESPONSIBLE_ADDRESSES |
   |                        |    is zero, this AODVv2 router is only   |
   |                        |    responsible for its own addresses.    |
   |    AODVv2_INTERFACES   |  List of the interfaces participating in |
   |                        |         AODVv2 routing protocol.         |
   +------------------------+------------------------------------------+

                                  Table 2

   AODVv2 contains a number of timers.  The default timing parameter
   values follow:

                      Default Timing Parameter Values

           +------------------------------+-------------------+
           |             Name             |       Value       |
           +------------------------------+-------------------+
           |         ROUTE_TIMEOUT        |     5 seconds     |
           |     ROUTE_AGE_MIN_TIMEOUT    |      1 second     |
           | ROUTE_SEQNUM_AGE_MAX_TIMEOUT |     60    600 seconds    |
           |      ROUTE_USED_TIMEOUT      |   ROUTE_TIMEOUT   |
           |     ROUTE_DELETE_TIMEOUT     | 2 * ROUTE_TIMEOUT |
           |     ROUTE_RREQ_WAIT_TIME     |     2 seconds     |
           | UNICAST_MESSAGE_SENT_TIMEOUT |      1 second     |
           +------------------------------+-------------------+

                                  Table 3

   The above timing parameter values work well for small and medium
   well-connected networks with moderate topology changes.

   The timing parameters SHOULD be administratively configurable for the
   network where AODVv2 is used.  Ideally, for networks with frequent
   topology changes the AODVv2 parameters should be adjusted using
   either experimentally determined values or dynamic adaptation.  For
   example, in networks with infrequent topology changes
   ROUTE_USED_TIMEOUT may be set to a much larger value.

                         Default Parameter Values

   +------------------------+-------+----------------------------------+
   |          Name          | Value |            Description           |
   +------------------------+-------+----------------------------------+
   |      MSG_HOPLIMIT      |   10   20  |  This value MUST be larger than  |
   |                        |  hops |   the AODVv2 network diameter.   |
   |                        |       |  Otherwise, routing messages may |
   |                        |       |     not reach their intended     |
   |                        |       |           destinations.          |
   | DISCOVERY_ATTEMPTS_MAX |   3   |   The number of route discovery  |
   |                        |       |      attempts to make before     |
   |                        |       |   indicating that a particular   |
   |                        |       |     address is not reachable.    |
   +------------------------+-------+----------------------------------+

                                  Table 4

   In addition to the above parameters and timing values, several
   administrative options exist.  These options have no influence on
   correct routing behavior, although they may potentially reduce AODVv2
   routing control
   protocol messaging in certain situations.  The default behavior is to
   NOT enable any of these options; and although many of these options
   can be administratively controlled, they may be better served by
   intelligent control.  The following table enumerates several of the
   options.

                    Administratively Controlled Options

   +-------------------------+-----------------------------------------+

   +--------------------------+----------------------------------------+
   |           Name           |               Description              |
   +-------------------------+-----------------------------------------+
   +--------------------------+----------------------------------------+
   |  BUFFER_DURING_DISCOVERY |   Whether and how much data to buffer  |
   |                          |         during route discovery.        |
   |      UNKNOWN_TYPES APPEND_EXTRA_UNREACHABLE | What action      Whether to take when an unknown TLV |
   |                         |  type is received.  The default action append additional      |
   |                          |      is to forward this    Unreachable information     |
   |                         | unmodified.  Another action would be to |
   |                         |         remove this information. RERR.    |
   |  CONTROL_TRAFFIC_LIMITS  |  AODVv2 control messaging SHOULD be limited to |
   |                          |    limited to     avoid consuming all the network    |
   |                          |            network               bandwidth.               |
   +-------------------------+-----------------------------------------+
   +--------------------------+----------------------------------------+

                                  Table 5

   Note: several fields have limited size (bits or bytes) these sizes
   and their encoding may place specific limitations on the values that
   can be set.  For example, MsgHdr.HopLimit is a 8-bit field and
   therefore MSG_HOPLIMIT cannot be larger than 255.

7.

5.13.  IANA Considerations

   In its default mode of operation, AODVv2 uses the UDP port MANET 269
   [RFC5498] to carry protocol packets.  AODVv2 also uses the link-local
   multicast address LL-MANET-Routers [RFC5498].

   This section specifies several message types, message tlv-types, and
   address tlv-types.

7.1.

5.13.1.  AODVv2 Message Types Specification

                           AODVv2 Message Types

                   +------------------------+----------+
                   |          Name          |   Type   |
                   +------------------------+----------+
                   |  Route Request (RREQ)  | 10 - TBD |
                   |   Route Reply (RREP)   | 11 - TBD |
                   |   Route Error (RERR)   | 12 - TBD |
                   +------------------------+----------+

                                  Table 6

7.2.

5.13.2.  Message and Address Block TLV Type Specification

                             Message TLV Types

   +-------------------+------+--------+-------------------------------+
   |        Name       | Type | Length | Value                         |
   +-------------------+------+--------+-------------------------------+
   |  Unicast Response | 10 - |    0   | Indicates to the processing   |
   |      Request      |  TBD | octets | node that the previous hop    |
   |                   |      |        | (IP.SourceAddress) expects a  |
   |                   |      |        | unicast reply message within  |
   |                   |      |        | UNICAST_MESSAGE_SENT_TIMEOUT. |
   |                   |      |        | Any unicast packet will serve |
   |                   |      |        | this purpose, and it MAY be   |
   |                   |      |        | an ICMP REPLY message.  If a    |
   |                   |      |        | message the reply is not sent, then the received,    |
   |                   |      |        | then the previous hop can assume that     |
   |                   |      |        | assume that the link is unidirectional       |
   |                   |      |        | unidirectional and MAY        |
   |                   |      |        | blacklist the link to this    |
   |                   |      |        | this node.                         |
   +-------------------+------+--------+-------------------------------+

                                  Table 7

7.3.

5.13.3.  Address Block TLV Specification

                          Address Block TLV Types

   +----------------+------------+----------+--------------------------+
   |      Name      |    Type    |  Length  | Value                    |
   +----------------+------------+----------+--------------------------+
   |     AODVv2     |  10 - TBD  |  up to 2 | The AODVv2 sequence num  |
   |    Sequence    |            |  octets  | associated with this     |
   |     Number     |            |          | address.  The sequence   |
   | (AODVv2SeqNum) |            |          | number may be the last   |
   |                |            |          | known sequence number.   |
   |    Distance    |  11 - TBD  |  up to 2 | A metric of the distance |
   |                |            |  octets  | traversed by the         |
   |                |            |          | information associated   |
   |                |            |          | with this address.       |
   |  VALIDITY_TIME | 1[RFC5497] |          | The maximum amount of    |
   |                |            |          | time that information    |
   |                |            |          | can be maintained before |
   |                |            |          | being deleted.  The      |
   |                |            |          | VALIDITY_TIME TLV is     |
   |                |            |          | defined in [RFC5497].    |
   +----------------+------------+----------+--------------------------+

                                  Table 8

8.

5.14.  Security Considerations

   The objective of the AODVv2 protocol is for each router to
   communicate reachability information to addresses for which it is
   responsible.  Positive routing information (i.e. a route exists) is
   distributed via RteMsgs and negative routing information (i.e. a
   route does not exist) via RERRs.  AODVv2 routers that handle these
   messages store the contained information to properly forward data
   packets, and they generally provide this information to other AODVv2
   routers.

   This section does not mandate any specific security measures.
   Instead, this section describes various security considerations and
   potential avenues to secure AODVv2 routing.

   The most important security mechanisms for AODVv2 routing are
   integrity/authentication and confidentiality.

   In situations where routing information or router identity are
   suspect, integrity and authentication techniques SHOULD be applied to
   AODVv2 messages.  In these situations, routing information that is
   distributed over multiple hops SHOULD also verify the integrity and
   identity of information based on originator of the routing
   information.

   A digital signature could be used to identify the source of AODVv2
   messages and information, along with its authenticity.  A nonce or
   timestamp SHOULD also be used to protect against replay attacks.
   S/MIME and OpenPGP are two authentication/integrity protocols that
   could be adapted for this purpose.

   In situations where confidentiality of AODVv2 messages is important,
   cryptographic techniques can be applied.

   In certain situations, like for example sending a RREP or RERR, an AODVv2
   router could include proof include proof that it has previously received valid
   routing information to reach the destination, at one point of time in
   the past.  In situations where routers are suspected of transmitting
   maliciously erroneous information, the original routing information
   along with its security credentials SHOULD be included.

   Note that if multicast is used, any confidentiality and integrity
   algorithms used MUST permit multiple receivers to handle the message.

   Routing protocols, however, are prime targets for impersonation
   attacks.  In networks where the node membership is not known, it is
   difficult to determine the occurrence of impersonation attacks, and
   security prevention techniques are difficult at best.  However, when
   the network membership is known and there is a danger of such
   attacks, AODVv2 messages must be protected by the use of
   authentication techniques, such as those involving generation of
   unforgeable and cryptographically strong message digests or digital
   signatures.  While AODVv2 does not place restrictions on the
   authentication mechanism used for this purpose, IPsec Authentication
   Message (AH) is an appropriate choice for cases where the nodes share
   an appropriate security association that enables the use of AH.

   In particular, routing messages SHOULD be authenticated to avoid
   creation of spurious routes to a destination.  Otherwise, an attacker
   could masquerade as that it has previously received valid routing
   information destination and maliciously deny service to reach
   the destination, at one point of time destination and/or maliciously inspect and consume traffic
   intended for delivery to the destination.  RERR messages SHOULD be
   authenticated in order to prevent malicious nodes from disrupting
   active routes between communicating nodes.

   If the
   past.  In situations where routers mobile nodes in the ad hoc network have pre-established
   security associations, the purposes for which the security
   associations are suspected created should include that of transmitting
   maliciously erroneous information, authorizing the original routing information
   along with its security credentials SHOULD
   processing of AODVv2 control packets.  Given this understanding, the
   mobile nodes should be included.

   Note that if multicast is used, any confidentiality and integrity
   algorithms used must permit multiple receivers able to handle use the message.

9. same authentication mechanisms
   based on their IP addresses as they would have used otherwise.

5.15.  Acknowledgments

   AODVv2 is a descendant of the design of previous MANET on-demand
   protocols, especially AODV [RFC3561] and DSR [RFC4728].  Changes to
   previous MANET on-demand protocols stem from research and
   implementation experiences.  Thanks to Elizabeth Belding-Royer for
   her long time authorship of AODVv2. AODV.  Additional thanks to Luke Klein-
   Berndt, Pedro Ruiz, Fransisco Ros, Koojana Kuladinithi, Ramon
   Caceres, Thomas Clausen, Christopher Dearlove, Seung Yi, Romain
   Thouvenin, Tronje Krop, Henner Jakob, Alexandru Petrescu, Christoph
   Sommer, Cong Yuan, Lars Kristensen, and Derek Atkins for reviewing of
   AODVv2, as well as several specification suggestions.

   Many good ideas from LOADng [I-D.clausen-lln-loadng] are shaping this
   evolution

   This revision of AODVv2 isolates the minimal base specification and
   other optional features to simplify the process of ensuring
   compatibility with the [manet] existing LOADng specification
   [I-D.clausen-lln-loadng] (minimal reactive routing protocol specification.
   specification).  Thanks are due to T. Clausen, A. Colin de Verdiere,
   J. Yi, A. Niktash, Y. Igarashi, SATOH. Satoh.  H., and U. Herberg for their
   development of LOADng and sharing details for ensuring
   appropriateness of AODVv2 for LLNs.

10.

6.  References
10.1.

6.1.  Normative References

   [RFC1812]  Baker, F., "Requirements for IP Version 4 Routers",
              RFC 1812, June 1995.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5082]  Gill, V., Heasley, J., Meyer, D., Savola, P., and C.
              Pignataro, "The Generalized TTL Security Mechanism
              (GTSM)", RFC 5082, October 2007.

   [RFC5444]  Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
              "Generalized Mobile Ad Hoc Network (MANET) Packet/Message
              Format", RFC 5444, February 2009.

   [RFC5497]  Clausen, T. and C. Dearlove, "Representing Multi-Value
              Time in Mobile Ad Hoc Networks (MANETs)", RFC 5497,
              March 2009.

   [RFC5498]  Chakeres, I., "IANA Allocations for Mobile Ad Hoc Network
              (MANET) Protocols", RFC 5498, March 2009.

10.2.

6.2.  Informative References

   [I-D.chakeres-manet-manetid]
              Chakeres, I., "MANET_ID TLV",
              draft-chakeres-manet-manetid-03 (work in progress),
              February 2008.

   [I-D.clausen-lln-loadng]
              Clausen, T., Verdiere, A., Yi, J., Niktash, A., Igarashi,
              Y., and U. Satoh, H., Herberg, U., Lavenu, C., Lys, T., and C.
              Perkins, "The LLN On-demand Ad hoc Distance-
              vector Distance-vector Routing
              Protocol - Next Generation (LOADng)",
              draft-clausen-lln-loadng-01 (work in progress),
              October 2011.

   [I-D.ietf-manet-nhdp]
              Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
              Network (MANET) Neighborhood Discovery Protocol (NHDP)",
              draft-ietf-manet-nhdp-15 (work in progress),
              December 2010.

   [I-D.ietf-ospf-multi-instance]
              Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
              Instance Extensions", draft-ietf-ospf-multi-instance-09
              draft-clausen-lln-loadng-05 (work in progress), January July 2012.

   [Perkins99]
              Perkins, C. and E. Belding-Royer, "Ad hoc On-Demand
              Distance Vector (AODV) Routing", Proceedings of the 2nd
              IEEE Workshop on Mobile Computing Systems and
              Applications, New Orleans, LA, pp. 90-100, February 1999.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

   [RFC2501]  Corson, M. and J. Macker, "Mobile Ad hoc Networking
              (MANET): Routing Protocol Performance Issues and
              Evaluation Considerations", RFC 2501, January 1999.

   [RFC3561]  Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On-
              Demand Distance Vector (AODV) Routing", RFC 3561,
              July 2003.

   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, October 2005.

   [RFC4728]  Johnson, D., Hu, Y., and D. Maltz, "The Dynamic Source
              Routing Protocol (DSR) for Mobile Ad Hoc Networks for
              IPv4", RFC 4728, February 2007.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              September 2007.

   [RFC5148]  Clausen, T., Dearlove, C., and B. Adamson, "Jitter
              Considerations in Mobile Ad Hoc Networks (MANETs)",
              RFC 5148, February 2008.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. 5148, February 2008.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, July 2008.

   [RFC6130]  Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
              Network (MANET) Neighborhood Discovery Protocol (NHDP)",
              RFC 6130, April 2011.

   [RFC6549]  Lindem, "OSPF
              for IPv6", A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
              Instance Extensions", RFC 5340, July 2008. 6549, March 2012.

   [RFC6621]  Macker, J., "Simplified Multicast Forwarding", RFC 6621,
              May 2012.

Appendix A.  Changes since the Previous Version

   o  Protocol  Internet-Facing AODVv2 router renamed to be AODVv2 IAR

   o  "Optional Features" section created to contain features not
      required within base specification, including:

   o

      *  Intermediate RREPs (iRREPs) are to be put into new document. (iRREPs): Without iRREP, only the
         destination can respond to a RREQ.

   o

      *  Precursor lists not supported, based on reported performance loss. lists.

      *  An RERR may reporting multiple unreachable nodes.

      *  Message Aggregation.

   o  Sequence number MUST (instead of SHOULD) be set to 1 after
      rollover.

   o  ThisNode MUST (instead of SHOULD) only handle AODVv2 messages from
      adjacent routers.

   o  Clarification that Additional Routing information in RteMsgs is
      optional (MAY) to use.

   o  Clarification that if Additional Routing information in RteMsgs is
      used, then the Route Table Entry SHOULD be updated using normal
      procedures as described in Section 5.2.2.

   o  Clarification in Section 5.4 that nodes may be configured to
      buffer zero packets.

   o  Clarification in Section 5.4 that buffered packets MUST be dropped
      if route discovery fails.

   o  In Section 5.5.1, relax mandate for monitoring connectivity to
      next-hop AODVv2 neighbors (from MUST to SHOULD), in order to allow
      for minimal implementations

   o  Remove Route.Forwarding flag; identical to "NOT" Route.Broken.

   o  Routing Messages MUST be originated with the MsgHdr.HopLimit set
      to MSG_HOPLIMIT.  Previously, this was not mandated.

   o  Adding additional unreachable destinations to RERR is not
      specified in this document, to match LOADng behavior.

Appendix B.  Proposed additional changes for LOADng conformance
   o  Revise message formats  Maximum hop count set to be compatible 254, with LOADng requirements,
      removing RFC 5444 headers 255 reserved for minimal packet size

   o  Adding RREP-ACK message type instead of relying on reception of
      arbitrary packets "unknown".
      Since the current draft only uses hop-count as sufficient response to establish
      bidirectionality. distance, this is
      also the current maximum distance.

Appendix C. B.  Shifting Responsibility for an Address Network Prefix Advertisement Between AODVv2
             Routers

   Only one AODVv2 router within a routing region SHOULD be responsible
   for a particular address at any time.  If two AODVv2 routers
   dynamically pass responsibility shift the advertisement of an address a network prefix, correct
   AODVv2 routing behavior must be observed.  The AODVv2 router adding
   the new address network prefix must wait for any exiting existing routing information
   about this address network prefix to be purged from the network.  Therefore,
   it must wait at least ROUTER_SEQNUM_AGE_MAX_TIMEOUT after the
   previous AODVv2 router for this address stopped participating and advertising routing
   information on its behalf.

Authors' Addresses

   Charles E. Perkins
   Futurewei Inc.
   2330 Central Expressway
   San Jose,
   Santa Clara, CA  95050
   USA

   Phone: +1-408-421-1172 +1-408-330-5305
   Email: charliep@computer.org

   Ian D Chakeres
   CenGen
   9250 Bendix Road North
   Columbia, Maryland  21045
   USA

   Email: ian.chakeres@gmail.com
   URI:   http://www.ianchak.com/