draft-ietf-manet-dymo-21.txt   draft-ietf-manet-dymo-22.txt 
Mobile Ad hoc Networks Working I. Chakeres Mobile Ad hoc Networks Working Group C. Perkins
Group CenGen Internet-Draft
Internet-Draft C. Perkins Intended status: Standards Track I. Chakeres
Intended status: Standards Track WiChorus Expires: September 13, 2012 CenGen
Expires: January 27, 2011 July 26, 2010 March 12, 2012
Dynamic MANET On-demand (DYMO) Routing Dynamic MANET On-demand (AODVv2) Routing
draft-ietf-manet-dymo-21 draft-ietf-manet-dymo-22
Abstract Abstract
The Dynamic MANET On-demand (DYMO) routing protocol is intended for The Dynamic MANET On-demand (AODVv2) routing protocol is intended for
use by mobile routers in wireless, multihop networks. DYMO use by mobile routers in wireless, multihop networks. AODVv2
determines unicast routes among DYMO routers within the network in an determines unicast routes among AODVv2 routers within the network in
on-demand fashion, offering improved convergence in dynamic an on-demand fashion, offering on-demand convergence in dynamic
topologies. topologies.
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Applicability Statement . . . . . . . . . . . . . . . . . . . 4 2. Applicability Statement . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 7 4. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Route Table Entry . . . . . . . . . . . . . . . . . . . . 7 4.1. Route Table Entry . . . . . . . . . . . . . . . . . . . . 7
4.2. DYMO Messages . . . . . . . . . . . . . . . . . . . . . . 8 4.2. AODVv2 Messages . . . . . . . . . . . . . . . . . . . . . 8
4.2.1. Generalized Packet and Message Structure . . . . . . . 9 4.2.1. Generalized Packet and Message Structure . . . . . . . 9
4.2.2. Routing Messages (RM) - RREQ & RREP . . . . . . . . . 10 4.2.2. Routing Message (RteMsg) - RREQ and RREP . . . . . . . 10
4.2.3. Route Error (RERR) . . . . . . . . . . . . . . . . . . 13 4.2.3. Route Error (RERR) . . . . . . . . . . . . . . . . . . 11
5. Detailed Operation . . . . . . . . . . . . . . . . . . . . . . 15 5. Detailed Operation . . . . . . . . . . . . . . . . . . . . . . 12
5.1. DYMO Sequence Numbers . . . . . . . . . . . . . . . . . . 15 5.1. AODVv2 Sequence Numbers . . . . . . . . . . . . . . . . . 12
5.1.1. Maintaining A Node's Own Sequence Number . . . . . . . 15 5.1.1. Maintaining A Node's Own Sequence Number . . . . . . . 12
5.1.2. Numerical Operations on OwnSeqNum . . . . . . . . . . 15 5.1.2. Numerical Operations on OwnSeqNum . . . . . . . . . . 13
5.1.3. OwnSeqNum Rollover . . . . . . . . . . . . . . . . . . 15 5.1.3. OwnSeqNum Rollover . . . . . . . . . . . . . . . . . . 13
5.1.4. Actions After OwnSeqNum Loss . . . . . . . . . . . . . 15 5.1.4. Actions After OwnSeqNum Loss . . . . . . . . . . . . . 13
5.2. DYMO Routing Table Operations . . . . . . . . . . . . . . 16 5.2. AODVv2 Routing Table Operations . . . . . . . . . . . . . 13
5.2.1. Judging Routing Information's Usefulness . . . . . . . 16 5.2.1. Judging Routing Information's Usefulness . . . . . . . 13
5.2.2. Creating or Updating a Route Table Entry with 5.2.2. Creating or Updating a Route Table Entry with
Received Superior Routing Information . . . . . . . . 17 Received Preferable Routing Information . . . . . . . 15
5.2.3. Route Table Entry Timeouts . . . . . . . . . . . . . . 18 5.2.3. Route Table Entry Timeouts . . . . . . . . . . . . . . 16
5.3. Routing Messages . . . . . . . . . . . . . . . . . . . . . 19 5.3. Routing Messages . . . . . . . . . . . . . . . . . . . . . 16
5.3.1. RREQ Creation . . . . . . . . . . . . . . . . . . . . 19 5.3.1. RREQ Creation . . . . . . . . . . . . . . . . . . . . 16
5.3.2. RREP Creation . . . . . . . . . . . . . . . . . . . . 20 5.3.2. RREP Creation . . . . . . . . . . . . . . . . . . . . 17
5.3.3. Intermediate DYMO Router RREP Creation . . . . . . . . 21 5.3.3. RteMsg Handling . . . . . . . . . . . . . . . . . . . 18
5.3.4. RM Handling . . . . . . . . . . . . . . . . . . . . . 21 5.4. Route Discovery . . . . . . . . . . . . . . . . . . . . . 21
5.3.5. Adding Additional Routing Information to a RM . . . . 25 5.5. Route Maintenance . . . . . . . . . . . . . . . . . . . . 22
5.4. Route Discovery . . . . . . . . . . . . . . . . . . . . . 25 5.5.1. Active Next-hop Router Adjacency Monitoring . . . . . 22
5.5. Route Maintenance . . . . . . . . . . . . . . . . . . . . 26 5.5.2. Updating Route Lifetimes During Packet Forwarding . . 23
5.5.1. Active Next-hop Router Adjacency Monitoring . . . . . 27 5.5.3. RERR Generation . . . . . . . . . . . . . . . . . . . 23
5.5.2. Updating Route Lifetimes During Packet Forwarding . . 27 5.5.4. RERR Handling . . . . . . . . . . . . . . . . . . . . 24
5.5.3. RERR Generation . . . . . . . . . . . . . . . . . . . 27 5.6. Unknown Message and TLV Types . . . . . . . . . . . . . . 25
5.5.4. RERR Handling . . . . . . . . . . . . . . . . . . . . 28 5.7. Advertising Network Addresses . . . . . . . . . . . . . . 25
5.6. DYMO Identifier (DID) . . . . . . . . . . . . . . . . . . 30 5.8. Simple Internet Attachment . . . . . . . . . . . . . . . . 25
5.7. Unknown Message & TLV Types . . . . . . . . . . . . . . . 30 5.9. Multiple Interfaces . . . . . . . . . . . . . . . . . . . 27
5.8. Advertising Network Addresses . . . . . . . . . . . . . . 31 5.10. AODVv2 Control Packet/Message Generation Limits . . . . . 27
5.9. Simple Internet Attachment . . . . . . . . . . . . . . . . 31 6. Administratively Configured Parameters and Timer Values . . . 27
5.10. Multiple Interfaces . . . . . . . . . . . . . . . . . . . 32 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
5.11. DYMO Control Packet/Message Generation Limits . . . . . . 33 7.1. AODVv2 Message Types Specification . . . . . . . . . . . . 30
6. Administratively Configured Parameters and Timer Values . . . 33 7.2. Message and Address Block TLV Type Specification . . . . . 30
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 7.3. Address Block TLV Specification . . . . . . . . . . . . . 31
7.1. DYMO Message Types Specification . . . . . . . . . . . . . 36 8. Security Considerations . . . . . . . . . . . . . . . . . . . 31
7.2. Message and Address Block TLV Type Specification . . . . . 36 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 32
7.3. Address Block TLV Specification . . . . . . . . . . . . . 37 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8. Security Considerations . . . . . . . . . . . . . . . . . . . 37 10.1. Normative References . . . . . . . . . . . . . . . . . . . 33
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 38 10.2. Informative References . . . . . . . . . . . . . . . . . . 33
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Appendix A. Changes since the Previous Version . . . . . . . . . 34
10.1. Normative References . . . . . . . . . . . . . . . . . . . 38 Appendix B. Proposed additional changes for LOADng conformance . 34
10.2. Informative References . . . . . . . . . . . . . . . . . . 39 Appendix C. Shifting Responsibility for an Address Between
Appendix A. Shifting Responsibility for an Address Between AODVv2 Routers . . . . . . . . . . . . . . . . . . . 35
DYMO Routers . . . . . . . . . . . . . . . . . . . . 40 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 40
1. Overview 1. Overview
The Dynamic MANET On-demand (DYMO) routing protocol enables reactive, The Dynamic MANET On-demand (AODVv2) routing protocol enables on-
multihop unicast routing among participating DYMO routers. The basic demand, multihop unicast routing among participating AODVv2 routers.
operations of the DYMO protocol are route discovery and route The basic operations of the AODVv2 protocol are route discovery and
maintenance. route maintenance. Route discovery is performed when an AODVv2
router receives a packet from a node under its responsibility to a
destination for which it does not have a route. Route maintenance is
performed to help ensure that the route being used to forward packets
from the source to the destination remains operational.
During route discovery, the originator's DYMO router initiates During route discovery, the originator's AODVv2 router initiates
dissemination of a Route Request (RREQ) throughout the network to dissemination of a Route Request (RREQ) throughout the network to
find a route to the target's DYMO router. During this hop-by-hop find a route to a particular destination, via the AODVv2 router
dissemination process, each intermediate DYMO router records a route responsible for this destination. During this hop-by-hop
to the originator. When the target's DYMO router receives the RREQ, dissemination process, each intermediate AODVv2 router records a
it responds with a Route Reply (RREP) sent hop-by-hop toward the route to the originator. When the target's AODVv2 router receives
originator. Each intermediate DYMO router that receives the RREP the RREQ, it responds with a Route Reply (RREP) sent hop-by-hop
creates a route to the target, and then the RREP is unicast hop-by- toward the originating AODVv2 router. Each intermediate AODVv2
hop toward the originator. When the originator's DYMO router router that receives the RREP creates a route to the target, and then
receives the RREP, routes have then been established between the the RREP is unicast hop-by-hop toward the originator. When the
originating DYMO router and the target DYMO router in both originator's AODVv2 router receives the RREP, routes have then been
directions. established between the originating AODVv2 router and the target
AODVv2 router in both directions.
Route maintenance consists of two operations. In order to preserve Route maintenance consists of two operations. In order to preserve
routes in use, DYMO routers extend route lifetimes upon successfully routes in use, AODVv2 routers extend route lifetimes upon
forwarding a packet. In order to react to changes in the network successfully forwarding a packet. In order to react to changes in
topology, DYMO routers monitor routes over which traffic is flowing. the network topology, AODVv2 routers monitor traffic being forwarded.
When a data packet is received for forwarding and a route for the When a data packet is received for forwarding and a route for the
destination is not known or the route is broken, then the DYMO router destination is not known or the route is broken, then the AODVv2
of the source of the packet is notified. A Route Error (RERR) is router of the source of the packet is notified. A Route Error (RERR)
sent toward the packet source to indicate the route to that is sent toward the packet source to indicate the route to particular
particular destination is invalid or missing. When the source's DYMO destination addresses is invalid or missing. When the source's
router receives the RERR, it deletes the route. If this source's AODVv2 router receives the RERR, it deletes the route. If this
DYMO router later receives a packet for forwarding to the same source's AODVv2 router later receives a packet for forwarding to the
destination, it will need to perform route discovery again for that same destination, it will need to perform route discovery again for
destination. that destination.
DYMO uses sequence numbers to ensure loop freedom [Perkins99]. AODVv2 uses sequence numbers to ensure loop freedom [Perkins99].
Sequence numbers enable DYMO routers to determine the temporal order Sequence numbers enable AODVv2 routers to determine the temporal
of DYMO route discovery messages, thereby avoiding use of stale order of AODVv2 route discovery messages, thereby avoiding use of
routing information. stale routing information.
2. Applicability Statement 2. Applicability Statement
The DYMO routing protocol is designed for stub or disconnected mobile The AODVv2 routing protocol is designed for stub or disconnected
ad hoc networks (MANETs). DYMO handles a wide variety of mobility mobile ad hoc networks (MANETs). AODVv2 handles a wide variety of
patterns by dynamically determining routes on-demand. DYMO also mobility patterns by dynamically determining routes on-demand.
handles a wide variety of traffic patterns. In networks with a large AODVv2 also handles a wide variety of traffic patterns. In networks
number of routers, DYMO is best suited for sparse traffic scenarios with a large number of routers, AODVv2 is best suited for sparse
where routers forward packets to only a small portion of the other traffic scenarios where routers forward packets to only a small
DYMO routers, due to the reactive nature of route discovery and route portion of the other AODVv2 routers, due to the on-demand nature of
maintenance. route discovery and route maintenance.
DYMO is applicable to memory constrained devices, since little AODVv2 is applicable to memory constrained devices, since little
routing state is maintained in each DYMO router. Only routing routing state is maintained in each AODVv2 router. Only routing
information related to active sources and destinations is maintained, information related to active sources and destinations is maintained,
in contrast to most proactive routing protocols that require routing in contrast to most proactive routing protocols that require routing
information to all routers within the routing region be maintained. information to all routers within the routing region be maintained.
DYMO supports routers with multiple interfaces participating in the AODVv2 supports routers with multiple interfaces participating in the
MANET. DYMO routers can also perform routing on behalf of other MANET. AODVv2 routers can also perform routing on behalf of other
nodes, attached via participating or non-participating interfaces. nodes, attached via participating or non-participating interfaces.
DYMO routers perform route discovery to find a route to a particular AODVv2 routers perform route discovery to find a route to a
destination. Therefore, DYMO routers MUST be configured to initiate particular destination. Therefore, AODVv2 routers MUST be configured
and respond to route discovery on behalf of certain nodes, identified to initiate and respond to route discovery on behalf of certain
by address. When DYMO is the only protocol interacting with the nodes, identified by address. When AODVv2 is the only protocol
forwarding table, DYMO MAY be configured to perform route discovery interacting with the forwarding table, AODVv2 MAY be configured to
for all unknown unicast destinations. perform route discovery for all unknown unicast destinations.
At any time within a DYMO routing region only one DYMO router SHOULD At any time within an AODVv2 routing region, only one AODVv2 router
be responsible for, i.e. "own", a particular address. Coordination SHOULD be responsible for, i.e. "own", any particular address.
among multiple DYMO routers to distribute routing information Coordination among multiple AODVv2 routers to distribute routing
correctly for a shared address (i.e. an address that is advertised information correctly for a shared address (i.e. an address that is
and can be reached via multiple DYMO routers) is not described in advertised and can be reached via multiple AODVv2 routers) is not
this document. The router behavior for shifting responsibility for described in this document. The router behavior for shifting
an address from one DYMO router to another are described in responsibility for an address from one AODVv2 router to another is
Appendix A. mentioned in Appendix C.
DYMO MUST only utilizes bidirectional links. In the case of possible AODVv2 only utilizes bidirectional links. In the case of possible
unidirectional links, either blacklists ( see Section 7.2) or other unidirectional links, either blacklists (see Section 7.2) or other
means (e.g. adjacency establishment with only neighboring routers means (e.g. adjacency establishment with only neighboring routers
that have bidirectional communication as indicated by NHDP that have bidirectional communication as indicated by NHDP
[I-D.ietf-manet-nhdp]) of ensuring and monitoring bi-directionality [I-D.ietf-manet-nhdp]) of ensuring and monitoring bi-directionality
SHOULD be used. Otherwise, persistent packet loss may occur. is recommended. Otherwise, persistent packet loss may occur.
The routing algorithm in DYMO may be operated at layers other than The routing algorithm in AODVv2 may be operated at layers other than
the network layer, using layer-appropriate addresses. For operation the network layer, using layer-appropriate addresses.
at other layers DYMO's routing algorithm likely will not need to
change. Although, modification of the packet/message format may be
required.
3. Terminology 3. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
Additionally, this document uses some terminology from [RFC5444]. Additionally, this document uses some terminology from [RFC5444].
This document defines the following terminology: This document defines the following terminology:
Adjacency Adjacency
A relationship between selected bi-directional neighboring routers A relationship between selected bi-directional neighboring routers
for the purpose of exchanging routing information. Not every pair for the purpose of exchanging routing information. Not every pair
of neighboring routers become adjacent. Neighboring routers may of neighboring routers will necessarily form an adjacency.
form an adjacency based several different pieces of information or Neighboring routers may form an adjacency based several different
protocols; for example, exchange of DYMO routing messages, other pieces of information or protocols; for example, exchange of
protocols (e.g. NDP [RFC4861] or NHDP [I-D.ietf-manet-nhdp]), or AODVv2 routing messages, other protocols (e.g. NDP [RFC4861] or
manual configuration. Similarly, loss of a routing adjacency may NHDP [I-D.ietf-manet-nhdp]), or manual configuration. Similarly,
also be based upon several pieces of information, and monitoring loss of a routing adjacency may also be based upon several pieces
of adjacencies where packets are being forwarded is required (see of information, and monitoring of adjacencies where packets are
Section 5.5.1). being forwarded is required (see Section 5.5.1).
Distance (Dist) Distance (Dist)
A metric of the distance a message or piece of information has A metric of the distance a message or piece of information has
traversed. The minimum value of distance is the number of IP hops traversed. The minimum value of distance is the number of IP hops
traversed. The maximum value is 65,535. traversed. The maximum value is 65,535.
DYMO Identifier (DID) AODVv2 Sequence Number (SeqNum)
A DID is maintained for each DYMO routing process (ThisNode.DID), An AODVv2 Sequence Number is maintained by each AODVv2 router
and the default value is zero (0). Each routing message is tagged process. This sequence number is used by other AODVv2 routers to
with its associated DID (MsgTLV.DID), unless zero (0). Upon identify the temporal order of routing information generated and
receipt of DYMO protocol message a DYMO routing protocol process ensure loop-free routes.
SHOULD only attend to messages with a matching DID value.
DYMO Sequence Number (SeqNum)
A DYMO Sequence Number is maintained by each DYMO router process.
This sequence number is used by other DYMO routers to identify the
temporal order of routing information generated and ensure loop-
free routes.
Forwarding Route
A route that is used to forward data packets. Forwarding routes
are generally maintained in a forwarding information base (FIB) or
the kernel forwarding/routing table.
Multihop-capable Unicast IP Address Multihop-capable Unicast IP Address
A multihop-capable unicast IP address is a unicast IP address that A multihop-capable unicast IP address is a unicast IP address that
when put into the IP.SourceAddress or IP.DestinationAddress field when put into the IP.SourceAddress or IP.DestinationAddress field
is scoped sufficiently to be forwarded by a router. For example, is scoped sufficiently to be forwarded by a router. Globally-
site-scoped or globally-scoped unicast IP addresses. scoped unicast IP addresses and Unique Local Addresses (ULAs) are
examples of multihop-capable unicast IP addresses.
Originating Node (OrigNode) Originating Node (OrigNode)
The originating node is the source, its DYMO router creates a DYMO The originating node is the source, its AODVv2 router creates a
control message on its behalf in an effort to disseminate some AODVv2 control message on its behalf in an effort to disseminate
routing information. The originating node is also referred to as some routing information. The originating node is also referred
a particular message's originator. to as a particular message's originator.
Route Error (RERR) Route Error (RERR)
A RERR message is used to indicate that a DYMO router does not A RERR message is used to indicate that an AODVv2 router does not
have a forwarding route to one or more particular addresses. have a forwarding route to one or more particular addresses.
Route Reply (RREP) Route Reply (RREP)
A RREP message is used to disseminate routing information about A RREP message is used to disseminate routing information about
the RREP OrigNode to the RREP TargetNode and the DYMO routers the RREP TargetNode to the RREP OrigNode and the AODVv2 routers
between them. between them.
Route Request (RREQ) Route Request (RREQ)
A RREQ message is issued to discover a valid route to a particular A RREQ message is used to discover a valid route to a particular
destination address, called the RREQ TargetNode. When a DYMO destination address, called the RREQ TargetNode. When an AODVv2
router processes a RREQ, it learns routing information on how to router processes a RREQ, it learns routing information on how to
reach the RREQ OrigNode. reach the RREQ OrigNode.
Target Node (TargetNode) Target Node (TargetNode)
The TargetNode is the ultimate destination of a message. The TargetNode is the ultimate destination of a message.
This Node (ThisNode) This Node (ThisNode)
ThisNode corresponds to the DYMO router process currently ThisNode corresponds to the AODVv2 router process currently
performing a calculation or attending to a message. performing a calculation or attending to a message.
Type-Length-Value structure (TLV) Type-Length-Value structure (TLV)
A generic way to represent information, please see [RFC5444] for A generic way to represent information, please see [RFC5444] for
additional information. additional information.
Unreachable Node (UnreachableNode) Unreachable Node (UnreachableNode)
An UnreachableNode is a node for which a forwarding route does not An UnreachableNode is a node for which a forwarding route is
exist. unknown.
4. Data Structures 4. Data Structures
4.1. Route Table Entry 4.1. Route Table Entry
The route table entry is a conceptual data structure. The route table entry is a conceptual data structure.
Implementations may use any internal representation that conforms to Implementations may use any internal representation that conforms to
the semantics of a route as specified in this document. the semantics of a route as specified in this document.
Conceptually, a route table entry has the following fields: Conceptually, a route table entry has the following fields:
skipping to change at page 8, line 15 skipping to change at page 8, line 6
Route.Address Route.Address
The (host or network) destination address of the node(s) The (host or network) destination address of the node(s)
associated with the routing table entry. associated with the routing table entry.
Route.Prefix Route.Prefix
Indicates that the associated address is a network address, rather Indicates that the associated address is a network address, rather
than a host address. The value is the length of the netmask/ than a host address. The value is the length of the netmask/
prefix. prefix.
Route.SeqNum Route.SeqNum
The DYMO SeqNum associated with this routing information. The AODVv2 SeqNum associated with this routing information.
Route.NextHopAddress Route.NextHopAddress
The IP address of the adjacent DYMO router on the path toward the The IP address of the adjacent AODVv2 router on the path toward
Route.Address. the Route.Address.
Route.NextHopInterface Route.NextHopInterface
The interface used to send packets toward the Route.Address. The interface used to send packets toward the Route.Address.
Route.Forwarding Route.Forwarding
A flag indicating whether this Route can be used for forwarding A flag indicating whether this Route can be used for forwarding
data packets. This flag MAY be provided for management and data packets. This flag MAY be provided for management and
monitoring. monitoring.
Route.Broken Route.Broken
skipping to change at page 8, line 47 skipping to change at page 8, line 38
A dimensionless metric indicating the distance traversed before A dimensionless metric indicating the distance traversed before
reaching the Route.Address node. reaching the Route.Address node.
Not including optional information may cause performance degradation, Not including optional information may cause performance degradation,
but it will not cause the protocol to operate incorrectly. but it will not cause the protocol to operate incorrectly.
In addition to a route table data structure, each route table entry In addition to a route table data structure, each route table entry
may have several timers associated with the information. These may have several timers associated with the information. These
timers/timeouts are discussed in Section 5.2.3. timers/timeouts are discussed in Section 5.2.3.
4.2. DYMO Messages 4.2. AODVv2 Messages
When describing DYMO protocol messages, it is necessary to refer to When describing AODVv2 protocol messages, it is necessary to refer to
fields in several distinct parts of the overall packet. These fields in several distinct parts of the overall packet. These
locations include the IP header, the UDP header, and fields from locations include the IP header, the UDP header, and fields from
[RFC5444]. This document uses the following notation conventions. [RFC5444]. This document uses the following notation conventions.
Information found in the table. Information found in the table.
+---------------------------+-------------------+ +---------------------------+-------------------+
| Information Location | Notational Prefix | | Information Location | Notational Prefix |
+---------------------------+-------------------+ +---------------------------+-------------------+
| IP header | IP. | | IP header | IP. |
| UDP header | UDP. | | UDP header | UDP. |
| RFC5444 message header | MsgHdr. | | RFC5444 message header | MsgHdr. |
| RFC5444 message TLV | MsgTLV. | | RFC5444 message TLV | MsgTLV. |
| RFC5444 address blocks | AddBlk. | | RFC5444 address blocks | AddBlk. |
skipping to change at page 9, line 22 skipping to change at page 9, line 20
| RFC5444 message header | MsgHdr. | | RFC5444 message header | MsgHdr. |
| RFC5444 message TLV | MsgTLV. | | RFC5444 message TLV | MsgTLV. |
| RFC5444 address blocks | AddBlk. | | RFC5444 address blocks | AddBlk. |
| RFC5444 address block TLV | AddTLV. | | RFC5444 address block TLV | AddTLV. |
+---------------------------+-------------------+ +---------------------------+-------------------+
Table 1 Table 1
4.2.1. Generalized Packet and Message Structure 4.2.1. Generalized Packet and Message Structure
DYMO messages conform to the generalized packet and message format as AODVv2 messages conform to the generalized packet and message format
described in [RFC5444]. Here is a brief description of the format. as described in [RFC5444]. Here is a brief description of the
A packet is made up of messages. A message is made up of a message format. A packet is made up of messages. A message is made up of a
header, message TLV block, and zero or more address blocks. Each of message header, message TLV block, and zero or more address blocks.
the address blocks may also have an associated address TLV block. Each of the address blocks may also have an associated address TLV
block.
For interoperability with other DYMO routers, all DYMO messages For interoperability with other AODVv2 routers, all AODVv2 messages
specified in this document SHOULD sent using the IP protocol number specified in this document SHOULD sent using the IP protocol number
(138) reserved for manet protocols [RFC5498]; or the UDP destination (138) reserved for manet protocols [RFC5498]; or the UDP destination
port (269) reserved for manet protocols [RFC5498] and IP protocol port (269) reserved for manet protocols [RFC5498] and IP protocol
number for UDP. number for UDP.
Most DYMO messages are sent with the IP destination address set to Most AODVv2 messages are sent with the IP destination address set to
the link-local multicast address LL-MANET-Routers [RFC5498] unless the link-local multicast address LL-MANET-Routers [RFC5498] unless
otherwise stated. Therefore, all DYMO routers SHOULD subscribe to otherwise stated. Therefore, all AODVv2 routers SHOULD subscribe to
LL-MANET-Routers [RFC5498] for receiving control packets. Note that LL-MANET-Routers [RFC5498] for receiving control packets. Note that
multicast packets MAY be sent via unicast. For example, this may multicast packets MAY be sent via unicast. For example, this may
occur for certain link-types (non broadcast mediums), improved occur for certain link-types (non broadcast mediums), improved
robustness, or manually configured router adjacencies. robustness, or manually configured router adjacencies.
Unicast DYMO messages (e.g. RREP) unless otherwise specified in this Unicast AODVv2 messages (e.g. RREP) unless otherwise specified in
document are sent with the IP destination set to the this document are sent with the IP destination set to the
Route.NextHopAddress of the route to the TargetNode. Route.NextHopAddress of the route to the TargetNode.
The IPv4 TTL (IPv6 Hop Limit) field for all packets containing DYMO 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 messages is set to 255. If a packet is received with a value other
than 255, it is discarded. This mechanism helps to ensures that than 255, it is discarded. This mechanism helps to ensures that
packets have not passed through any intermediate routers, and it is packets have not passed through any intermediate routers, and it is
known as GTSM [RFC5082]. known as GTSM [RFC5082].
The length of an address (32 bits for IPv4 and 128 bits for IPv6) The length of an address (32 bits for IPv4 and 128 bits for IPv6)
inside a DYMO message depends on the msg-addr-length (MAL) in the inside an AODVv2 message depends on the msg-addr-length (MAL) in the
msg-header, as specified in [RFC5444]. msg-header, as specified in [RFC5444].
The aggregation of multiple messages into a packet is not specified AODVv2 control packets SHOULD be given priority queuing and channel
in this document, but if aggregation does occur the IP.SourceAddress
and IP.DestinationAddress of all contained messages MUST be the same.
Implementations MAY choose to temporarily delay transmission of
messages for the purpose of aggregation (into a single packet) or to
improve performance by using jitter [RFC5148].
DYMO control packets SHOULD be given priority queuing and channel
access. access.
4.2.2. Routing Messages (RM) - RREQ & RREP 4.2.2. Routing Message (RteMsg) - RREQ and RREP
Routing Messages (RMs) are used to disseminate routing information. Routing Messages (RteMsgs) are used to disseminate routing
There are two DYMO message types that are considered to be routing information. There are two AODVv2 message types that are considered
messages (RMs): RREQ and RREP. They contain very similar information to be routing messages (RteMsgs): RREQ and RREP. They contain very
and function, but have slightly different handling rules. The main similar information and function, but have slightly different
difference between the two messages is that RREQ messages generally handling rules. The main difference between the two messages is that
solicit a RREP, whereas a RREP is the response to RREQ. RREQ messages generally solicit a RREP, whereas a RREP is the
response to RREQ.
RM creation and handling are described in Section 5.3. RteMsg creation and handling are described in Section 5.3.
A RM requires the following information: A RteMsg requires the following information:
IP.SourceAddress IP.SourceAddress
The IP address of the node currently sending this packet. This The IP address of the node currently sending this packet. This
field is generally filled automatically by the operating system field is generally filled automatically by the operating system
and should not require special handling. and should not require special handling.
IP.DestinationAddress IP.DestinationAddress
The IP address of the packet destination. For multicast RREQ the The IP address of the packet destination. For multicast RREQ the
IP.DestinationAddress is set to LL-MANET-Routers [RFC5498]. For IP.DestinationAddress is set to LL-MANET-Routers [RFC5498]. For
unicast RREP the IP.DestinationAddress is set to the unicast RREP the IP.DestinationAddress is set to the
NextHopAddress toward the RREP TargetNode. NextHopAddress toward the RREP TargetNode.
IP.ProtocolNumber and UDP.DestinationPort IP.ProtocolNumber and UDP.DestinationPort
The IP Protocol Number 138 (manet) has been reserved for MANET The IP Protocol Number 138 (manet) has been reserved for MANET
protocols [RFC5498]. In addition to using this IP protocol protocols [RFC5498]. In addition to using this IP protocol
number, DYMO may use the UDP port 269 (manet) [RFC5498] in number, AODVv2 may use the UDP port 269 (manet) [RFC5498] in
conjunction with the IP Protocol Number 17 (UDP). conjunction with the IP Protocol Number 17 (UDP).
MsgHdr.HopLimit MsgHdr.HopLimit
The remaining number of hops this message is allowed to traverse. The remaining number of hops this message is allowed to traverse.
AddBlk.TargetNode.Address AddBlk.TargetNode.Address
The IP address of the message TargetNode. In a RREQ the The IP address of the message TargetNode. In a RREQ the
TargetNode is the destination address for which route discovery is TargetNode is the destination address for which route discovery is
being performed. In a RREP the TargetNode is the RREQ OrigNode being performed. In a RREP the TargetNode is the RREQ OrigNode
address. The TargetNode address is the first address in a routing address. The TargetNode address is the first address in a routing
message. message.
AddBlk.OrigNode.Address AddBlk.OrigNode.Address
The IP address of the originator and its associated prefix length. The IP address of the originator and its associated prefix length.
In a RREQ the OrigNode is the source's address and prefix. In a In a RREQ the OrigNode is the source's address and prefix. In a
RREP the OrigNode is the RREQ TargetNode's address and prefix for RREP the OrigNode is the RREQ TargetNode's address and prefix for
which a RREP is being generated. This address is the second which a RREP is being generated. This address is the second
address in the message for RREQ. address in the message for RREQ.
OrigNode.AddTLV.SeqNum OrigNode.AddTLV.SeqNum
The DYMO sequence number of the originator's DYMO router. The AODVv2 sequence number of the originator's AODVv2 router.
A RM may optionally include the following information: A RteMsg may optionally include the following information:
TargetNode.AddTLV.SeqNum TargetNode.AddTLV.SeqNum
The last known DYMO sequence number of the TargetNode. The last known AODVv2 sequence number of the TargetNode.
TargetNode.AddTLV.Dist TargetNode.AddTLV.Dist
The last known Distance to the TargetNode. The last known Distance to the TargetNode.
AddBlk.AdditionalNode.Address AddBlk.AdditionalNode.Address
The IP address of an additional node that can be reached via the The IP address of an additional node that can be reached via the
DYMO router adding this information. Each AdditionalNode.Address AODVv2 router adding this information. Each
MUST include its prefix. Each AdditionalNode.Address MUST also AdditionalNode.Address MUST include its prefix. Each
have an associated Node.SeqNum in the address TLV block. AdditionalNode.Address MUST also have an associated Node.SeqNum in
the address TLV block.
AdditionalNode.AddTLV.SeqNum AdditionalNode.AddTLV.SeqNum
The DYMO sequence number associated with this routing information. The AODVv2 sequence number associated with this routing
information.
OrigNode.AddTLV.Dist OrigNode.AddTLV.Dist
A metric of the distance to reach the associated OrigNode.Address. A metric of the distance to reach the associated OrigNode.Address.
This field is incremented by at least one at each intermediate This field is incremented by at least one at each intermediate
DYMO router. AODVv2 router.
AdditionalNode.AddTLV.Dist AdditionalNode.AddTLV.Dist
A metric of the distance to reach the associated A metric of the distance to reach the associated
AdditionalNode.Address. This field is incremented by at least one AdditionalNode.Address. This field is incremented by at least one
at each intermediate DYMO router. at each intermediate AODVv2 router.
Example IPv4 RREQ
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
IP Header
+-+-+-+-+-+-+-+-+
| IP.Proto = UDP|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP.SourceAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP.DestinationAddress = LL-MANET-Routers |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP TTL/HopLimit = 255 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
UDP Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Port = manet |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Packet Header
+-+-+-+-+-+-+-+-+
| ver= 0|0|0|0|0|
+-+-+-+-+-+-+-+-+
Message Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RREQ-type |0|1|0|0| MAL=3 | msg-size=23 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-hoplimit |
+-+-+-+-+-+-+-+-+
Message TLV Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-tlv-block-size=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Body - Address Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Number Addrs=2 |1|0|0|0|0| Rsv | HeadLength=3 | Head :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Head (cont) | Target.Tail | Orig.Tail |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Body - Address Block TLV Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tlv-block-size=6 |DYMOSeqNum-type|0|1|0|1|0|0|Rsv|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Index-start=1 | tlv-length=2 | Orig.SeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
4.2.3. Route Error (RERR) 4.2.3. Route Error (RERR)
A RERR message is used to disseminate the information that a route is A RERR message is used to disseminate the information that a route is
not available for one or more particular addresses. not available for one or more particular addresses.
RERR creation and handling are described in Section 5.5. RERR creation and handling are described in Section 5.5.
A RERR requires the following information: A RERR requires the following information:
IP.SourceAddress IP.SourceAddress
The IP address of the DYMO router that sent this packet. This The IP address of the AODVv2 router that sent this packet. This
field is generally filled automatically by the operating system field is generally filled automatically by the operating system
and should not require special handling. and should not require special handling.
IP.DestinationAddress IP.DestinationAddress
For multicast RERR messages, The IP address is set to LL-MANET- For multicast RERR messages, The IP address is set to LL-MANET-
Routers [RFC5498]. For unicast RERR messages, the IP address is Routers [RFC5498]. For unicast RERR messages, the IP address is
set to the NextHopAddress. set to the NextHopAddress.
IP.ProtocolNumber and UDP.DestinationPort IP.ProtocolNumber and UDP.DestinationPort
The IP Protocol Number 138 (manet) has been reserved for MANET The IP Protocol Number 138 (manet) has been reserved for MANET
protocols [RFC5498]. In addition to using this IP protocol protocols [RFC5498]. In addition to using this IP protocol
number, DYMO may use the UDP port 269 (manet) [RFC5498] in number, AODVv2 may use the UDP port 269 (manet) [RFC5498] in
conjunction with the IP Protocol Number 17 (UDP). conjunction with the IP Protocol Number 17 (UDP).
MsgHdr.HopLimit MsgHdr.HopLimit
The remaining number of hops this message is allowed to traverse. The remaining number of hops this message is allowed to traverse.
AddBlk.UnreachableNode.Address AddBlk.UnreachableNode.Address
The address of an UnreachableNode and its associated prefix The address of an UnreachableNode and its associated prefix
length. Multiple unreachable addresses may be included in a RERR. length. Multiple unreachable addresses may be included in a RERR.
A Route Error may optionally include the following information: A Route Error may optionally include the following information:
UnreachableNode.AddTLV.SeqNum UnreachableNode.AddTLV.SeqNum
The last known DYMO sequence number of the unreachable node. If a The last known AODVv2 sequence number of the unreachable node. If
SeqNum for an address is zero (0) or not included, it is assumed a SeqNum for an address is zero (0) or not included, it is assumed
to be unknown. This case occurs when a node receives a message to to be unknown. This case occurs when a node receives a message to
forward to a destination for which it does not have any forward to a destination for which it does not have any
information in its routing table. information in its routing table.
Example IPv4 RERR
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
IP Header
+-+-+-+-+-+-+-+-+
| IP.Proto = UDP|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP.SourceAddress |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP.DestinationAddress = LL-MANET-Routers |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP.TTL/HopLimit = 255 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
UDP Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Port = manet |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Packet Header
+-+-+-+-+-+-+-+-+
| ver= 0|0|0|0|0|
+-+-+-+-+-+-+-+-+
Message Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RERR-type |0|1|0|0| MAL=3 | msg-size=15 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-hoplimit |
+-+-+-+-+-+-+-+-+
Message TLV Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-tlv-block-size=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Body - Address Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Number Addrs=1 |0|0|0|0|0| Rsv |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UnreachableNode.Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Body - Address Block TLV Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV-blk-size=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
5. Detailed Operation 5. Detailed Operation
5.1. DYMO Sequence Numbers 5.1. AODVv2 Sequence Numbers
DYMO sequence numbers allow DYMO routers to judge the freshness of AODVv2 sequence numbers allow AODVv2 routers to judge the freshness
routing information and ensure loop freedom. of routing information and ensure loop freedom.
5.1.1. Maintaining A Node's Own Sequence Number 5.1.1. Maintaining A Node's Own Sequence Number
DYMO requires that each DYMO router in the network maintain its own AODVv2 requires that each AODVv2 router in the network maintain its
DYMO sequence number (OwnSeqNum) on behalf of the addresses for which own AODVv2 sequence number (OwnSeqNum) on behalf of the addresses for
it is responsible. OwnSeqNum a 16-bit unsigned integer. The which it is responsible. OwnSeqNum a 16-bit unsigned integer. The
circumstances for ThisNode to increment its OwnSeqNum are described circumstances for ThisNode to increment its OwnSeqNum are described
in Section 5.3. in Section 5.3.
5.1.2. Numerical Operations on OwnSeqNum 5.1.2. Numerical Operations on OwnSeqNum
When ThisNode increments its OwnSeqNum it MUST do so by treating the When ThisNode increments its OwnSeqNum it MUST do so by treating the
sequence number value as an unsigned number. sequence number value as an unsigned number.
5.1.3. OwnSeqNum Rollover 5.1.3. OwnSeqNum Rollover
Incrementing an OwnSeqNum whose value is the largest largest possible Incrementing an OwnSeqNum whose value is the largest largest possible
number representable as a 16-bit unsigned integer (i.e., 65,535), number representable as a 16-bit unsigned integer (i.e., 65,535),
SHOULD be set to one (1). In other words, the sequence number after SHOULD be set to one (1). In other words, the sequence number after
65,535 is 1. 65,535 is 1.
5.1.4. Actions After OwnSeqNum Loss 5.1.4. Actions After OwnSeqNum Loss
A DYMO router SHOULD maintain its sequence number in persistent An AODVv2 router SHOULD maintain its sequence number in persistent
storage. storage.
If a DYMO router's OwnSeqNum is lost, it MUST take certain actions to If an AODVv2 router's OwnSeqNum is lost, it MUST take certain actions
avoid creating routing loops. To prevent this possibility after to avoid creating routing loops. To prevent this possibility after
OwnSeqNum loss a DYMO router MUST wait for at least OwnSeqNum loss an AODVv2 router MUST wait for at least
ROUTE_DELETE_TIMEOUT before fully participating in the DYMO routing ROUTE_DELETE_TIMEOUT before fully participating in the AODVv2 routing
protocol. If a DYMO control message is received during this waiting protocol. If an AODVv2 control message is received during this
period, the DYMO router SHOULD handle it normally but MUST NOT waiting period, the AODVv2 router SHOULD handle it normally but MUST
transmit or retransmit any DYMO messages. If a data packet is NOT transmit or retransmit any AODVv2 messages. If a data packet is
received for forwarding to another destination during this waiting received for forwarding to another destination during this waiting
period, the DYMO router MUST generate a RERR message indicating that period, the AODVv2 router MUST generate a RERR message indicating
this route is not available and reset its waiting timeout. At the that this route is not available and reset its waiting timeout. At
end of the waiting period the DYMO router sets its OwnSeqNum to one the end of the waiting period the AODVv2 router sets its OwnSeqNum to
(1) and begins participating. one (1) and begins participating.
The longest a node need wait is ROUTE_SEQNUM_AGE_MAX_TIMEOUT. At the The longest a node need wait is ROUTE_SEQNUM_AGE_MAX_TIMEOUT. At the
end of the maximum waiting period a node SHOULD set its OwnSeqNum to end of the maximum waiting period a node SHOULD set its OwnSeqNum to
one (1) and begins participating. one (1) and begins participating.
5.2. DYMO Routing Table Operations 5.2. AODVv2 Routing Table Operations
5.2.1. Judging Routing Information's Usefulness 5.2.1. Judging Routing Information's Usefulness
Given a route table entry (Route.SeqNum, Route.Dist, and Given a route table entry (Route.SeqNum, Route.Dist, and
Route.Broken) and new incoming routing information for a particular Route.Broken) and new incoming routing information for a particular
node in a RM (Node.SeqNum, Node.Dist, and RM message type - RREQ/ node in a RteMsg (Node.SeqNum, Node.Dist, and RteMsg message type -
RREP), the quality of the new routing information is evaluated to RREQ/RREP), the quality of the new routing information is evaluated
determine its usefulness. Incoming routing information is classified to determine its usefulness. Incoming routing information is
as follows: classified as follows:
1. Stale 1. Stale
If Node.SeqNum - Route.SeqNum < 0 (using signed 16-bit arithmetic) If Node.SeqNum - Route.SeqNum < 0 (using signed 16-bit arithmetic)
the incoming information is stale. Using stale routing the incoming information is stale. Using stale routing
information is not allowed, since doing so might result in routing information is not allowed, since doing so might result in routing
loops. loops.
(Node.SeqNum - Route.SeqNum < 0) (Node.SeqNum - Route.SeqNum < 0)
using signed 16-bit arithmetic using signed 16-bit arithmetic
skipping to change at page 16, line 39 skipping to change at page 14, line 28
the routing information is loop-possible. If Node.Dist > the routing information is loop-possible. If Node.Dist >
Route.Dist + 1, then the routing information is loop-possible. Route.Dist + 1, then the routing information is loop-possible.
Using loop-possible routing information is not allowed, otherwise Using loop-possible routing information is not allowed, otherwise
routing loops may be formed. routing loops may be formed.
(Node.SeqNum == Route.SeqNum) AND (Node.SeqNum == Route.SeqNum) AND
((Node.Dist is unknown) OR ((Node.Dist is unknown) OR
(Route.Dist is unknown) OR (Route.Dist is unknown) OR
(Node.Dist > Route.Dist + 1)) (Node.Dist > Route.Dist + 1))
3. Inferior or equivalent 3. Disfavored or equivalent
In case of known equal SeqNum, the information is inferior in In case of known equal SeqNum, the information is disfavored in
multiple cases: (case i) if Node.Dist == Route.Dist + 1 (it is a multiple cases: (case i) if Node.Dist == Route.Dist + 1 (it is a
greater distance route) AND Route.Broken == false; (case ii) if greater distance route) AND Route.Broken == false; (case ii) if
Node.Dist == Route.Dist (equal distance route) AND Route.Broken == Node.Dist == Route.Dist (equal distance route) AND Route.Broken ==
false AND this RM is a RREQ. This condition reduces the number of false AND this RteMsg is a RREQ. This condition reduces the
RREQ flooded by stopping forwarding of RREQ with equivalent number of RREQ flooded by stopping forwarding of RREQ with
distance. equivalent distance.
((Node.SeqNum == Route.SeqNum) AND ((Node.SeqNum == Route.SeqNum) AND
(((Node.Dist == Route.Dist + 1) AND (Route.Broken == false)) OR (((Node.Dist == Route.Dist + 1) AND (Route.Broken == false)) OR
((Node.Dist == Route.Dist) AND ((Node.Dist == Route.Dist) AND
(RM is RREQ) AND (Route.Broken == false)))) (RteMsg is RREQ) AND (Route.Broken == false))))
4. Superior 4. Preferable
Incoming routing information that does not match any of the above Incoming routing information that does not match any of the above
criteria is loop-free and better than the information existing in criteria is loop-free and better than the information existing in
the routing table. Information is always superior if Node.SeqNum the routing table. Information is always preferable if
- Route.SeqNum > 0 (using signed 16-bit arithmetic). In the case Node.SeqNum - Route.SeqNum > 0 (using signed 16-bit arithmetic).
of equal sequence numbers, the information is superior in multiple In the case of equal sequence numbers, the information is
cases: (case i) if Node.Dist < Route.Dist; (case ii) if Node.Dist preferable in multiple cases: (case i) if Node.Dist < Route.Dist;
== Route.Dist + 1 AND Route.Broken == true (a broken route is (case ii) if Node.Dist == Route.Dist + 1 AND Route.Broken == true
being repaired); (case iii) if Node.Dist == Route.Dist AND it is a (a broken route is being repaired); (case iii) if Node.Dist ==
RREP (RREP with equal distance are forwarded) OR Route.Broken == Route.Dist AND it is a RREP (RREP with equal distance are
true (a broken route is being repaired). For completeness, we forwarded) OR Route.Broken == true (a broken route is being
provide the following (optimized) pseudo-code. repaired). For completeness, we provide the following (optimized)
pseudo-code.
(Node.SeqNum - Route.SeqNum > 0) OR (Node.SeqNum - Route.SeqNum > 0) OR
using signed 16-bit arithmetic using signed 16-bit arithmetic
((Node.SeqNum == Route.SeqNum) AND ((Node.SeqNum == Route.SeqNum) AND
((Node.Dist < Route.Dist) OR ((Node.Dist < Route.Dist) OR
((Node.Dist == Route.Dist + 1) AND (Route.Broken == true)) OR ((Node.Dist == Route.Dist + 1) AND (Route.Broken == true)) OR
((Node.Dist == Route.Dist) AND ((Node.Dist == Route.Dist) AND
((RM is RREP) OR (Route.Broken == true))))) ((RteMsg is RREP) OR (Route.Broken == true)))))
5.2.2. Creating or Updating a Route Table Entry with Received Superior 5.2.2. Creating or Updating a Route Table Entry with Received
Routing Information Preferable Routing Information
The route table entry is populated with the following information: The route table entry is populated with the following information:
1. the Route.Address is set to Node.Address, 1. the Route.Address is set to Node.Address,
2. the Route.Prefix is set to the Node.Prefix. 2. the Route.Prefix is set to the Node.Prefix.
3. the Route.SeqNum is set to the Node.SeqNum, 3. the Route.SeqNum is set to the Node.SeqNum,
4. the Route.NextHopAddress is set to the node that transmitted this 4. the Route.NextHopAddress is set to the node that transmitted this
DYMO RM packet (i.e., the IP.SourceAddress), AODVv2 RteMsg packet (i.e., the IP.SourceAddress),
5. the Route.NextHopInterface is set to the interface that this DYMO 5. the Route.NextHopInterface is set to the interface that this
packet was received on, AODVv2 packet was received on,
6. the Route.Broken flag is set to false, 6. the Route.Broken flag is set to false,
7. if known, the Route.Dist is set to the Node.Dist, 7. if known, the Route.Dist is set to the Node.Dist,
Fields without known values are not populated with any value. Fields without known values are not populated with any value.
The timer for the minimum delete timeout (ROUTE_AGE_MIN) is set to The timer for the minimum delete timeout (ROUTE_AGE_MIN) is set to
ROUTE_AGE_MIN_TIMEOUT. The timer for the maximum delete timeout ROUTE_AGE_MIN_TIMEOUT. The timer for the maximum delete timeout
(ROUTE_SEQNUM_AGE_MAX) is set to Node.AddTLV.VALIDITY_TIME [RFC5497] (ROUTE_SEQNUM_AGE_MAX) is set to Node.AddTLV.VALIDITY_TIME [RFC5497]
skipping to change at page 18, line 17 skipping to change at page 16, line 9
At this point, a forwarding route has been created and the At this point, a forwarding route has been created and the
Route.Forwarding flag set. Afterward, the route can be used to send Route.Forwarding flag set. Afterward, the route can be used to send
any queued data packets and forward any incoming data packets for any queued data packets and forward any incoming data packets for
Route.Address. This route also fulfills any outstanding route Route.Address. This route also fulfills any outstanding route
discovery attempts for Node.Address. discovery attempts for Node.Address.
5.2.3. Route Table Entry Timeouts 5.2.3. Route Table Entry Timeouts
5.2.3.1. Minimum Delete Timeout (ROUTE_AGE_MIN) 5.2.3.1. Minimum Delete Timeout (ROUTE_AGE_MIN)
When a DYMO router transmits a RM, other DYMO routers expect the When an AODVv2 router transmits a RteMsg, other AODVv2 routers expect
transmitting DYMO router to have a forwarding route to the RM the transmitting AODVv2 router to have a forwarding route to the
originator. After updating a route table entry, it SHOULD be RteMsg originator. After updating a route table entry, it SHOULD be
maintained for at least ROUTE_AGE_MIN. Failure to maintain the maintained for at least ROUTE_AGE_MIN. Failure to maintain the
information might result in lost messages/packets, or in the worst information might result in lost messages/packets, or in the worst
case scenario several duplicate messages. case scenario several duplicate messages.
After the ROUTE_AGE_MIN timeout a route can safely be deleted. After the ROUTE_AGE_MIN timeout a route can safely be deleted.
5.2.3.2. Maximum Sequence Number Delete Timeout (ROUTE_SEQNUM_AGE_MAX) 5.2.3.2. Maximum Sequence Number Delete Timeout (ROUTE_SEQNUM_AGE_MAX)
Sequence number information is time sensitive, and MUST be deleted Sequence number information is time sensitive, and MUST be deleted
after a time in order to ensure loop-free routing. after a time in order to ensure loop-free routing.
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useful decreases, especially if the network nodes are mobile. useful decreases, especially if the network nodes are mobile.
Therefore, old information SHOULD be deleted. Therefore, old information SHOULD be deleted.
After the ROUTE_DELETE timeout if a forwarding route exists it SHOULD After the ROUTE_DELETE timeout if a forwarding route exists it SHOULD
be removed, and the routing table entry SHOULD also be deleted. be removed, and the routing table entry SHOULD also be deleted.
5.3. Routing Messages 5.3. Routing Messages
5.3.1. RREQ Creation 5.3.1. RREQ Creation
Before a DYMO router creates a RREQ it SHOULD increment its OwnSeqNum Before an AODVv2 router creates a RREQ it SHOULD increment its
by one (1) according to the rules specified in Section 5.1. OwnSeqNum by one (1) according to the rules specified in Section 5.1.
Incrementing OwnSeqNum will ensure that all nodes with existing Incrementing OwnSeqNum will ensure that all nodes with existing
routing information will consider this new information superior to routing information will consider this new information preferable to
existing routing table information. If the sequence number is not existing routing table information. If the sequence number is not
incremented, certain DYMO routers might not consider this information incremented, certain AODVv2 routers might not consider this
superior, if they have existing better routing information. information preferable, if they have existing better routing
information.
First, ThisNode adds the AddBlk.TargetNode.Address to the RREQ; the First, ThisNode adds the AddBlk.TargetNode.Address to the RREQ; the
unicast IP Destination Address for which a forwarding route does not unicast IP Destination Address for which a forwarding route does not
exist. exist.
If a previous value of the TargetNode.SeqNum is known (from a routing If a previous value of the TargetNode.SeqNum is known (from a routing
table entry using longest-prefix matching), it SHOULD be placed in table entry using longest-prefix matching), it SHOULD be placed in
TargetNode.AddTLV.SeqNum in all but the last RREQ attempt. If a TargetNode.AddTLV.SeqNum in all but the last RREQ attempt. If a
TargetNode.SeqNum is not included, it is assumed to be unknown by TargetNode.SeqNum is not included, it is assumed to be unknown by
handling nodes. This operation ensures that no intermediate DYMO handling nodes. This operation ensures that no intermediate AODVv2
routers reply, and ensures that the TargetNode's DYMO router routers reply, and ensures that the TargetNode's AODVv2 router
increments its sequence number. increments its sequence number.
Next, the node adds AddBlk.OrigNode.Address, its prefix, and the Next, the node adds AddBlk.OrigNode.Address, its prefix, and the
OrigNode.AddTLV.SeqNum (OwnSeqNum) to the RM. OrigNode.AddTLV.SeqNum (OwnSeqNum) to the RteMsg.
The OrigNode.Address is the address of the source for which this DYMO The OrigNode.Address is the address of the source for which this
router is initiating this route discovery. The OrigNode.Address MUST AODVv2 router is initiating this route discovery. The
be a unicast address. This information will be used by nodes to OrigNode.Address MUST be a unicast address. This information will be
create a route toward the OrigNode, enabling delivery of a RREP, and used by nodes to create a route toward the OrigNode, enabling
eventually used for proper forwarding of data packets. delivery of a RREP, and eventually used for proper forwarding of data
packets.
If OrigNode.Dist is included it is set to a number greater than zero If OrigNode.Dist is included it is set to a number greater than zero
(0). (0).
Additional routing information can be added to this RM using the
procedure described in Section 5.3.5.
The MsgHdr.HopLimit SHOULD be set to MSG_HOPLIMIT. The MsgHdr.HopLimit SHOULD be set to MSG_HOPLIMIT.
For RREQ, the MsgHdr.HopLimit MAY be set in accordance with an For RREQ, the MsgHdr.HopLimit MAY be set in accordance with an
expanding ring search as described in [RFC3561] to limit the RREQ expanding ring search as described in [RFC3561] to limit the RREQ
propagation to a subset of the local network and possibly reduce propagation to a subset of the local network and possibly reduce
route discovery overhead. route discovery overhead.
The IP.DestinationAddress for multicast RREQ is set to LL-MANET- The IP.DestinationAddress for multicast RREQ is set to LL-MANET-
Routers. For links that do not support multicast or situations in Routers. For links that do not support multicast or situations in
which unicast messaging is preferred, the IP.DestinationAddress for which unicast messaging is preferred, the IP.DestinationAddress for
unicast RREQ is set to the NextHopAddress. unicast RREQ is set to the NextHopAddress.
Each DYMO routing protocol message SHOULD contain ThisNode.DID's
value in a message TLV (MsgTLV.DID). If ThisNode.DID value is zero
(0) it MAY be omitted.
5.3.2. RREP Creation 5.3.2. RREP Creation
First, the AddBlk.TargetNode.Address is added to the RREP. The First, the AddBlk.TargetNode.Address is added to the RREP. The
TargetNode is the ultimate destination of this RREP; the RREQ TargetNode is the ultimate destination of this RREP; the RREQ
OrigNode.Address. OrigNode.Address.
Next, AddBlk.OrigNode.Address and prefix are added to the RREP. The Next, AddBlk.OrigNode.Address and prefix are added to the RREP. The
AddBlk.OrigNode.Address is the RREQ TargetNode.Address. The AddBlk.OrigNode.Address is the RREQ TargetNode.Address. The
AddBlk.OrigNode.Address MUST be a unicast IP address. ThisNode AddBlk.OrigNode.Address MUST be a unicast IP address. ThisNode
SHOULD advertise the largest known prefix containing SHOULD advertise the largest known prefix containing
AddBlk.OrigNode.Address. AddBlk.OrigNode.Address.
When the RM TargetNode's DYMO router creates a RREP, if the When the RteMsg TargetNode's AODVv2 router creates a RREP, if the
TargetNode.SeqNum was not included in the RREQ, ThisNode MUST TargetNode.SeqNum was not included in the RREQ, ThisNode MUST
increment its OwnSeqNum by one (1) according to the rules specified increment its OwnSeqNum by one (1) according to the rules specified
in Section 5.1. in Section 5.1.
If TargetNode.SeqNum was included in the RM and TargetNode.SeqNum - If TargetNode.SeqNum was included in the RteMsg and TargetNode.SeqNum
OwnSeqNum < 0 (using signed 16-bit arithmetic), OwnSeqNum SHOULD be - OwnSeqNum < 0 (using signed 16-bit arithmetic), OwnSeqNum SHOULD be
incremented by one (1) according to the rules specified in incremented by one (1) according to the rules specified in
Section 5.1. Section 5.1.
If TargetNode.SeqNum is included in the RM and TargetNode.SeqNum == If TargetNode.SeqNum is included in the RteMsg and TargetNode.SeqNum
OwnSeqNum (using signed 16-bit arithmetic) and OrigNode.Dist will not == OwnSeqNum (using signed 16-bit arithmetic) and OrigNode.Dist will
be included in the RREP being generated, OwnSeqNum SHOULD be not be included in the RREP being generated, OwnSeqNum SHOULD be
incremented by one (1) according to the rules specified in incremented by one (1) according to the rules specified in
Section 5.1. Section 5.1.
If OwnSeqNum is not incremented the routing information might be If OwnSeqNum is not incremented the routing information might be
considered stale. In this case, the RREP might not reach the RREP considered stale. In this case, the RREP might not reach the RREP
Target. Target.
After any of the sequence number operations above, the RREP After any of the sequence number operations above, the RREP
OrigNode.AddTLV.SeqNum (OwnSeqNum) MUST also be added to 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 Other AddTLVs in the RREP for the OrigNode and TargetNode SHOULD be
included and set accordingly. If OrigNode.Dist is included it is set included and set accordingly. If OrigNode.Dist is included it is set
to a number greater than zero (0) and less than or equal to 65,535. to a number greater than zero (0) and less than or equal to 65,535.
The Distance value will influence judgment of the routing information The Distance value will influence judgment of the routing information
(Section 5.2.1) against known information at other DYMO routers that (Section 5.2.1) against known information at other AODVv2 routers
handle this RM. that handle this RteMsg.
Additional routing information can be added to this RM using the
procedure described in Section 5.3.5.
The MsgHdr.HopLimit is set to MSG_HOPLIMIT. The MsgHdr.HopLimit is set to MSG_HOPLIMIT.
The IP.DestinationAddress for RREP is set to the IP address of the The IP.DestinationAddress for RREP is set to the IP address of the
Route.NextHopAddress for the route to the RREP TargetNode. Route.NextHopAddress for the route to the RREP TargetNode.
Each DYMO routing protocol message SHOULD contain ThisNode.DID's 5.3.3. RteMsg Handling
value in a message TLV (MsgTLV.DID). If ThisNode.DID value is zero
(0) it MAY be omitted.
5.3.3. Intermediate DYMO Router RREP Creation
Sometimes a DYMO router other than the TargetNode's DYMO router (call
it an "intermediate DYMO router") has routing information that can
satisfy an incoming RREQ. An intermediate DYMO router can issue a
intermediate DYMO router RREP on behalf of the TargetNode's DYMO
router.
Before creating a intermediate DYMO router RREP, OwnSeqNum SHOULD be
incremented by one (1) according to the rules specified in
Section 5.1.
If OwnSeqNum is not incremented the routing information about
ThisNode might be considered stale by a handling DYMO router. In
this case, the RREP would not reach the RREP TargetNode.
When an intermediate DYMO router originates a RREP in response to a
RREQ on behalf of the TargetNode's DYMO router, it sends the RREP to
the RREQ OrigNode with additional routing information (Address,
Prefix, SeqNum, Dist, etc.) about the RREQ TargetNode. Appending
additional routing information is described in Section 5.3.5.
The Intermediate DYMO router SHOULD also issue a RREP to the RREQ
TargetNode, so that the RREQ TargetNode receives routing information
on how to reach the RREQ OrigNode.
When an intermediate DYMO router creates this RREP, it sends a RREP
to the RREQ TargetNode with additional routing information (Address,
Prefix, SeqNum, Dist, etc.) about the RREQ OrigNode.
5.3.4. RM Handling
First, ThisNode examines the RM to ensure that it contains the First, ThisNode examines the RteMsg to ensure that it contains the
required information: MsgHdr.HopLimit, AddBlk.TargetNode.Address, required information: MsgHdr.HopLimit, AddBlk.TargetNode.Address,
AddBlk.OrigNode.Address, and OrigNode.AddTLV.SeqNum. If the required AddBlk.OrigNode.Address, and OrigNode.AddTLV.SeqNum. If the required
information do not exist, the message is discarded and further information do not exist, the message is discarded and further
processing stopped. processing stopped.
Next, ThisNode decides whether to attend to this message. If the
message contains a MsgTLV.DID it SHOULD match ThisNode.DID's value.
If the message does not contain a MsgTLV.DID it is assumed to be zero
(0) and SHOULD be discarded if ThisNode.DID's value is not zero (0).
Next, ThisNode MAY selectively attend to messages based upon Next, ThisNode MAY selectively attend to messages based upon
information in the message. ThisNode SHOULD only handle messages information in the message. ThisNode SHOULD only handle messages
from adjacent DYMO routers. If ThisNode chooses not to handle this from adjacent AODVv2 routers. If ThisNode chooses not to handle this
message, the message is discarded and further processing stopped. message, the message is discarded and further processing stopped.
ThisNode checks if the AddBlk.OrigNode.Address is a valid multihop- ThisNode checks if the AddBlk.OrigNode.Address is a valid multihop-
capable (e.g. site or global scope) unicast address. If the address capable (e.g. site or global scope) unicast address. If the address
is not a valid unicast address, the message is discarded and further is not a valid unicast address, the message is discarded and further
processing stopped. processing stopped.
ThisNode also checks whether AddBlk.OrigNode.Address is an address ThisNode also checks whether AddBlk.OrigNode.Address is an address
handled by this DYMO router. If this node is the originating DYMO handled by this AODVv2 router. If this node is the originating
router, the RM is dropped. AODVv2 router, the RteMsg is dropped.
ThisNode checks if the AddBlk.TargetNode.Address is a valid multihop- ThisNode checks if the AddBlk.TargetNode.Address is a valid multihop-
capable unicast address. If the address is not a valid unicast capable unicast address. If the address is not a valid unicast
address, the message is discarded and further processing stopped. address, the message is discarded and further processing stopped.
Next, ThisNode checks whether its routing table has an entry to the Next, ThisNode checks whether its routing table has an entry to the
AddBlk.OrigNode.Address using longest-prefix matching [RFC1812]. If AddBlk.OrigNode.Address using longest-prefix matching [RFC1812]. If
a route with a valid Route.SeqNum does not exist, then the new a route with a valid Route.SeqNum does not exist, then the new
routing information is considered superior and a new route table routing information is considered preferable and a new route table
entry is created and updated as described in Section 5.2.2. If a entry is created and updated as described in Section 5.2.2. If a
route table entry does exists and it has a known Route.SeqNum, the route table entry does exists and it has a known Route.SeqNum, the
incoming routing information is compared with the route table entry incoming routing information is compared with the route table entry
following the procedure described in Section 5.2.1. If the incoming following the procedure described in Section 5.2.1. If the incoming
routing information is considered superior, the route table entry is routing information is considered preferable, the route table entry
updated as described in Section 5.2.2. is updated as described in Section 5.2.2.
For each address (except the TargetNode) in the RM that includes For each address (except the TargetNode) in the RteMsg that includes
AddTLV.Dist information, the AddTLV.Dist information MAY be AddTLV.Dist information, the AddTLV.Dist information MAY be
incremented. If the resulting Distance value for the OrigNode is incremented. If the resulting Distance value for the OrigNode is
greater than 65,535, the message is discarded. If the resulting greater than 65,535, the message is discarded. If the resulting
Distance value for another node is greater than 65,535, the Distance value for another node is greater than 65,535, the
associated address and its information are removed from the RM. The associated address and its information are removed from the RteMsg.
updated Distance value will influence judgment of the routing The updated Distance value will influence judgment of the routing
information (Section 5.2.1). information (Section 5.2.1).
After handling the OrigNode's routing information, then each address After handling the OrigNode's routing information, then each address
that is not the TargetNode MAY be considered for creating and that is not the TargetNode MAY be considered for creating and
updating routes. Creating and updating routes to other nodes can updating routes. Creating and updating routes to other nodes can
eliminate RREQ for those IP destinations, in the event that data eliminate RREQ for those IP destinations, in the event that data
needs to be forwarded to the IP destination(s) now or in the near needs to be forwarded to the IP destination(s) now or in the near
future. future.
For each of the additional addresses considered, ThisNode first For each of the additional addresses considered, ThisNode first
checks the that the address is a multihop-capable unicast address. checks the that the address is a multihop-capable unicast address.
If the address is not a unicast address, the address and all related If the address is not a unicast address, the address and all related
information MUST be removed. information MUST be removed.
If the routing table does not have a matching route with a known If the routing table does not have a matching route with a known
Route.SeqNum for this additional address using longest-prefix Route.SeqNum for this additional address using longest-prefix
matching, then a route is created and updated as described in matching, then a route is created and updated as described in
Section 5.2.2. If a route table entry exists with a known Section 5.2.2. If a route table entry exists with a known
Route.SeqNum, the incoming routing information is compared with the Route.SeqNum, the incoming routing information is compared with the
route table entry following the procedure described in Section 5.2.1. route table entry following the procedure described in Section 5.2.1.
If the incoming routing information is considered superior, the route If the incoming routing information is considered preferable, the
table entry is updated as described in Section 5.2.2. route table entry is updated as described in Section 5.2.2.
If the routing information for an AdditionalNode.Address is not If the routing information for an AdditionalNode.Address is not
considered superior, then it is removed from the RM. Removing this considered preferable, then it is removed from the RteMsg. Removing
information ensures that the information is not propagated. this information ensures that the information is not propagated.
At this point, if the routing information for the OrigNode was not At this point, if the routing information for the OrigNode was not
superior then this RM SHOULD be discarded and no further processing preferable then this RteMsg SHOULD be discarded and no further
of this message SHOULD be performed. processing of this message SHOULD be performed.
If the ThisNode is the DYMO router responsible for the TargetNode and If the ThisNode is the AODVv2 router responsible for the TargetNode
this RM is a RREQ, then ThisNode responds with a RREP to the RREQ and this RteMsg is a RREQ, then ThisNode responds with a RREP to the
OrigNode (the new RREP's TargetNode). The procedure for issuing a RREQ OrigNode (the new RREP's TargetNode). The procedure for issuing
new RREP is described in Section 5.3.2. At this point, ThisNode need a new RREP is described in Section 5.3.2. At this point, ThisNode
not perform any more operations for the RM being processed. need not perform any more operations for the RteMsg being processed.
As an alternative to issuing a RREP, ThisNode MAY choose to As an alternative to issuing a RREP, ThisNode MAY choose to
distribute routing information about ThisNode (the RREQ TargetNode) distribute routing information about ThisNode (the RREQ TargetNode)
more widely. That is, ThisNode MAY optionally perform a route more widely. That is, ThisNode MAY optionally perform a route
discovery; by issuing a RREQ with ThisNode listed as the TargetNode, discovery; by issuing a RREQ with ThisNode listed as the TargetNode,
using the procedure in Section 5.3.1. At this point, ThisNode need using the procedure in Section 5.3.1. At this point, ThisNode need
not perform any more operations for the RM being processed. not perform any more operations for the RteMsg being processed.
If ThisNode is not the TargetNode, this RM is a RREQ, the RREQ
contains the TargetNode.AddTLV.SeqNum, and ThisNode has a forwarding
route to the TargetNode with a SeqNum where Route.TargetNode.SeqNum -
RREQ.TargetNode.AddTLV.SeqNum > 0 (using signed 16-bit arithmetic);
then ThisNode MAY respond with an intermediate DYMO router RREP. The
procedure for performing intermediate DYMO router RREP is described
in Section 5.3.3. If an intermediate DYMO router RREP is sent,
ThisNode need not perform any more operations for the RM being
processed.
After handling a RM or creating a new RM, ThisNode MAY append
additional routing information to the RM prior to redistributing this
information, according to the procedure described in Section 5.3.5.
The additional routing information can help reduce route discoveries
at the expense of increased message size.
For each address (except the TargetNode) in the RM 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 routing information (Section 5.2.1) against known
information at other DYMO routers that handle this RM.
If the resulting Distance value for the OrigNode is greater than If the resulting Distance value for the OrigNode is greater than
65,535, the message is discarded. If the resulting Distance value 65,535, the message is discarded. If the resulting Distance value
for another node is greater than 65,535, the associated address and for another node is greater than 65,535, the associated address and
its information are removed from the RM. its information are removed from the RteMsg.
Next, the MsgHdr.HopLimit is decremented by one (1). If this RM's Next, the MsgHdr.HopLimit is decremented by one (1). If this
MsgHdr.HopLimit is greater than or equal to one (1), ThisNode is not RteMsg's MsgHdr.HopLimit is greater than or equal to one (1),
the TargetNode, AND this RM is a RREQ, then the current RM (altered ThisNode is not the TargetNode, AND this RteMsg is a RREQ, then the
by the procedure defined above) SHOULD be sent to the current RteMsg (altered by the procedure defined above) SHOULD be
IP.DestinationAddress LL-MANET-Routers [RFC5498]. If the RREQ is sent to the IP.DestinationAddress LL-MANET-Routers [RFC5498]. If the
unicast, the IP.DestinationAddress is set to the NextHopAddress. RREQ is unicast, the IP.DestinationAddress is set to the
NextHopAddress.
If this RM's MsgHdr.HopLimit is greater than or equal to one (1), If this RteMsg's MsgHdr.HopLimit is greater than or equal to one (1),
ThisNode is not the TargetNode, AND this RM is a RREP, then the ThisNode is not the TargetNode, AND this RteMsg is a RREP, then the
current RM is sent to the Route.NextHopAddress for the RREP's current RteMsg is sent to the Route.NextHopAddress for the RREP's
TargetNode.Address. If no forwarding route exists to TargetNode.Address. If no forwarding route exists to
TargetNode.Address, then a RERR SHOULD be issued to the OrigNode of TargetNode.Address, then a RERR SHOULD be issued to the OrigNode of
the RREP. the RREP.
By sending the updated RM ThisNode is advertising that it will By sending the updated RteMsg, ThisNode advertises that it will route
provide routing for addresses contained in the outgoing RM based on for addresses contained in the outgoing RteMsg based on the
the information enclosed. ThisNode MAY choose not to send the RM, information enclosed. ThisNode MAY choose not to send the RteMsg,
though not resending this RM could decrease connectivity in the though not resending this RteMsg could decrease connectivity in the
network or result in a non-shortest distance path. network or result in a non-shortest distance path.
Some examples of why ThisNode might choose to not re-issue a RM are: Some examples of why ThisNode might choose to not re-issue a RteMsg
if ThisNode does not want to advertise routing for the contained are: if ThisNode does not want to advertise routing for the contained
addresses because it is already heavily loaded; if ThisNode has addresses because it is already heavily loaded; if ThisNode has
already issued nearly identical routing information (e.g. ThisNode already issued nearly identical routing information (e.g. ThisNode
had recently issued a RM with nearly the same distance); or if 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 ThisNode is low on energy and does not want to expend energy for
control message sending or packet forwarding. These types of control message sending or packet forwarding. The exact
advanced behavior are not defined in this specification. circumstances producing such behavior are not specified in this
document.
5.3.5. Adding Additional Routing Information to a RM
Appending routing information can alleviate route discovery attempts
to the nodes whose information is included, if other DYMO routers use
this information to update their routing tables.
DYMO routers can append routing information to a RM. This option
(APPEND_INFORMATION) SHOULD be administratively configurable or
intelligently controlled.
Prior to appending an address controlled by this DYMO router to a RM,
ThisNode MAY increment its OwnSeqNum as defined in Section 5.1. If
OwnSeqNum is not incremented the appended routing information might
not be considered superior, when received by nodes with existing
routing information. Incrementation of the sequence number when
appending information to a RM in transit (APPEND_INFORMATION_SEQNUM)
SHOULD be administratively configurable or intelligently controlled.
Note that, during handling of this RM OwnSeqNum may have already been
incremented; and in this case OwnSeqNum need not be incremented
again.
If an address controlled by this DYMO router includes ThisNode.Dist,
it is set to a number greater than zero (0).
For added addresses (and their prefixes) not controlled by this DYMO
router, Route.Dist can be included if known. If Route.Dist is not
known, it MUST NOT be included.
The VALIDITY_TIME of routing information for appended address(es)
MUST be included, to inform routers about when to delete this
information. The VALIDITY_TIME TLV is defined in Section 7.3.
Additional information (e.g. SeqNum and Dist) about any appended
address(es) SHOULD be included.
Note that the routing information about the TargetNode MUST NOT be
added. Also, duplicate address entries SHOULD NOT be added.
Instead, only the best routing information (Section 5.2.1) for a
particular address SHOULD be included.
5.4. Route Discovery 5.4. Route Discovery
When a source's DYMO router needs to forward a data packet on behalf When a source's AODVv2 router needs to forward a data packet on
of an attached node and it does not have a forwarding route to the behalf of an attached node and it does not have a forwarding route to
data packet's unicast IP destination address, ThisNode sends a RREQ the data packet's unicast IP destination address, ThisNode sends a
(described in Section 5.3.1) to discover a route to the particular RREQ (described in Section 5.3.1) to discover a route to the
destination (TargetNode). particular destination (TargetNode).
After issuing a RREQ, the OrigNode DYMO router waits for a route to After issuing a RREQ, the OrigNode AODVv2 router waits for a route to
be created to the TargetNode. If a route is not created within be created to the TargetNode. If a route is not created within
RREQ_WAIT_TIME, ThisNode may again try to discover a route by issuing RREQ_WAIT_TIME, ThisNode may again try to discover a route by issuing
another RREQ using the procedure defined in Section 5.3.1 again. another RREQ using the procedure defined in Section 5.3.1 again.
Route discovery SHOULD be considered failed after Route discovery SHOULD be considered failed after
DISCOVERY_ATTEMPTS_MAX and the final RREQ's corresponding DISCOVERY_ATTEMPTS_MAX and the final RREQ's corresponding
RREQ_WAIT_TIME. RREQ_WAIT_TIME.
To reduce congestion in a network, repeated attempts at route To reduce congestion in a network, repeated attempts at route
discovery for a particular TargetNode SHOULD utilize an exponential discovery for a particular TargetNode SHOULD utilize an exponential
backoff. backoff.
For example, the first time a DYMO router issues a RREQ, it waits For example, the first time an AODVv2 router issues a RREQ, it waits
RREQ_WAIT_TIME for a route to the TargetNode. If a route is not RREQ_WAIT_TIME for a route to the TargetNode. If a route is not
found within that time, the DYMO router MAY send another RREQ. If a found within that time, the AODVv2 router MAY send another RREQ. If
route is not found within two (2) times the current waiting time, a route is not found within two (2) times the current waiting time,
another RREQ MAY be sent. No more than DISCOVERY_ATTEMPTS_MAX route another RREQ MAY be sent. No more than DISCOVERY_ATTEMPTS_MAX route
discovery attempts SHOULD be made before considering route discovery discovery attempts SHOULD be made before considering route discovery
for this destination to have failed. For each additional attempt, for this destination to have failed. For each additional attempt,
the waiting time for the previous RREQ is multiplied by two (2) so the waiting time for the previous RREQ is multiplied by two (2) so
that the waiting time conforms to a binary exponential backoff. that the waiting time conforms to a binary exponential backoff.
Data packets awaiting a route SHOULD be buffered by the source's DYMO Data packets awaiting a route SHOULD be buffered by the source's
router. This buffer SHOULD have a fixed limited size AODVv2 router. This buffer SHOULD have a fixed limited size
(BUFFER_SIZE_PACKETS or BUFFER_SIZE_BYTES) and older data packets (BUFFER_SIZE_PACKETS or BUFFER_SIZE_BYTES) and older data packets
SHOULD be discarded first. SHOULD be discarded first.
Buffering of data packets can have both positive and negative Buffering of data packets can have both positive and negative
effects, and therefore buffer settings (BUFFER_DURING_DISCOVERY) effects, and therefore buffer settings (BUFFER_DURING_DISCOVERY)
SHOULD be administratively configurable or intelligently controlled. SHOULD be administratively configurable or intelligently controlled.
If a route discovery attempt has failed (i.e. an attempt or multiple If a route discovery attempt has failed (i.e. an attempt or multiple
attempts have been made without receiving a RREP) to find a route to attempts have been made without receiving a RREP) to find a route to
the TargetNode, any data packets buffered for the corresponding the TargetNode, any data packets buffered for the corresponding
skipping to change at page 27, line 7 skipping to change at page 22, line 35
the IP.DestinationAddress exists; RERR generation is described in the IP.DestinationAddress exists; RERR generation is described in
Section 5.5.3. Section 5.5.3.
Upon this condition, an ICMP Destination Unreachable message SHOULD Upon this condition, an ICMP Destination Unreachable message SHOULD
NOT be generated unless this router is responsible for the NOT be generated unless this router is responsible for the
IP.DestinationAddress and that IP.DestinationAddress is known to be IP.DestinationAddress and that IP.DestinationAddress is known to be
unreachable. unreachable.
In addition to inability to forward a data packet, a RERR SHOULD be In addition to inability to forward a data packet, a RERR SHOULD be
issued immediately after detecting a broken link (see Section 5.5.1) issued immediately after detecting a broken link (see Section 5.5.1)
of a forwarding route to quickly notify DYMO routers that certain of a forwarding route to quickly notify AODVv2 routers that certain
routes are no longer available. If a newly unavailable route has not routes are no longer available. If a newly unavailable route has not
been used recently (indicated by ROUTE_USED), the RERR SHOULD NOT be been used recently (indicated by ROUTE_USED), the RERR SHOULD NOT be
generated. generated.
5.5.1. Active Next-hop Router Adjacency Monitoring 5.5.1. Active Next-hop Router Adjacency Monitoring
Nodes MUST monitor connectivity to adjacent next-hop DYMO routers on Nodes MUST monitor connectivity to adjacent next-hop AODVv2 routers
forwarding routes. This monitoring can be accomplished by one or on forwarding routes. This monitoring can be accomplished by one or
several mechanisms, including: several mechanisms, including:
o Neighborhood discovery [I-D.ietf-manet-nhdp] o Neighborhood discovery [I-D.ietf-manet-nhdp]
o Route timeout o Route timeout
o Lower layer feedback that a particular adjacent router is no o Lower layer feedback that a particular adjacent router is no
longer reachable longer reachable
o Other monitoring mechanisms or heuristics o Other monitoring mechanisms or heuristics
Upon determining that a next-hop DYMO router is unreachable, ThisNode Upon determining that a next-hop AODVv2 router is unreachable,
MUST remove the affected forwarding routes (those with an unreachable ThisNode MUST remove the affected forwarding routes (those with an
next-hop) and unset the Route.Forwarding flag. ThisNode also flags unreachable next-hop) and unset the Route.Forwarding flag. ThisNode
the associated routes in DYMO's routing table as Broken. For each also flags the associated routes in AODVv2's routing table as Broken.
broken route the timer for ROUTE_DELETE is set to For each broken route the timer for ROUTE_DELETE is set to
ROUTE_DELETE_TIMEOUT. ROUTE_DELETE_TIMEOUT.
5.5.2. Updating Route Lifetimes During Packet Forwarding 5.5.2. Updating Route Lifetimes During Packet Forwarding
To avoid removing the forwarding route to reach the IP.SourceAddress, To avoid removing the forwarding route to reach the IP.SourceAddress,
ThisNode SHOULD set a timeout (ROUTE_USED) to ROUTE_USED_TIMEOUT for ThisNode SHOULD set the "ROUTE_USED" timeout to the value
the route to the IP.SourceAddress upon receiving a data packet. If ROUTE_USED_TIMEOUT for the route to the IP.SourceAddress upon
the timer for ROUTE_DELETE is set, it is removed. receiving a data packet. If the timer for ROUTE_DELETE is set, it is
removed.
To avoid removing the forwarding route to the IP.DestinationAddress To avoid removing the forwarding route to the IP.DestinationAddress
that is being used, ThisNode SHOULD set a timeout (ROUTE_USED) to that is being used, ThisNode SHOULD set the "ROUTE_USED" timeout to
ROUTE_USED_TIMEOUT for the route to the IP.DestinationAddress upon the value ROUTE_USED_TIMEOUT for the route to the
sending a data packet. If the timer for ROUTE_DELETE is set, it is IP.DestinationAddress upon sending a data packet. If the timer for
removed. ROUTE_DELETE is set, it is removed.
5.5.3. RERR Generation 5.5.3. RERR Generation
A RERR informs DYMO routers that a route to certain destinations is A RERR informs AODVv2 routers that a route to certain destinations is
not available through ThisNode. not available through ThisNode.
When creating a new RERR, the address of the first UnreachableNode When creating a new RERR, the address of the first UnreachableNode
(IP.DestinationAddress from a data packet or RREP.TargetNode.Address) (IP.DestinationAddress from a data packet or RREP.TargetNode.Address)
is inserted into an Address Block AddBlk.UnreachableNode.Address. If is inserted into an Address Block AddBlk.UnreachableNode.Address. If
a prefix is known for the UnreachableNode.Address, it SHOULD be a prefix is known for the UnreachableNode.Address, it SHOULD be
included. Otherwise, the UnreachableNode.Address is assumed to be a included. Otherwise, the UnreachableNode.Address is assumed to be a
host address with a full length prefix. If a value for the host address with a full length prefix. If a value for the
UnreachableNode's SeqNum (UnreachableNode.AddTLV.SeqNum) is known, it UnreachableNode's SeqNum (UnreachableNode.AddTLV.SeqNum) is known, it
SHOULD be placed in the RERR. The MsgHdr.HopLimit is set to SHOULD be placed in the RERR. The MsgHdr.HopLimit is set to
MSG_HOPLIMIT. MSG_HOPLIMIT.
Additional UnreachableNodes that require the same unavailable link
(routes with the same Route.NextHopAddress and
Route.NextHopInterface) SHOULD be added to the RERR, as additional
AddBlk.UnreachableNode.Address entries with their associated prefix.
The SeqNum if known SHOULD also be included. Appending
UnreachableNode information notifies each node that handles this
message of additional routes that are no longer available. This
option (APPEND_EXTRA_UNREACHABLE) SHOULD be administratively
configurable or intelligently controlled.
If SeqNum information is not known or not included in the RERR, all If SeqNum information is not known or not included in the RERR, all
nodes handling the RERR will assume their routing information nodes handling the RERR will assume their routing information
associated with the UnreachableNode is no longer valid and flag those associated with the UnreachableNode is no longer valid and flag those
routes as broken. routes as broken.
Each DYMO routing protocol message SHOULD contain ThisNode.DID's
value in a message TLV (MsgTLV.DID). If ThisNode.DID value is zero
(0) it MAY be omitted.
A multicast RERR is sent to the IP.DestinationAddress LL-MANET- A multicast RERR is sent to the IP.DestinationAddress LL-MANET-
Routers [RFC5498]. Sending the RERR to the LL-MANET-Routers address Routers [RFC5498]. Sending the RERR to the LL-MANET-Routers address
notifies all nearby DYMO routers that might depend on the now broken notifies all nearby AODVv2 routers that might depend on the now
link. If the RERR is unicast, the IP.DestinationAddress is set to broken link. If the RERR is unicast, the IP.DestinationAddress is
the NextHopAddress. set to the NextHopAddress.
At this point, the packet or message that forced generation of this At this point, the packet or message that forced generation of this
RERR SHOULD be discarded. RERR SHOULD be discarded.
5.5.4. RERR Handling 5.5.4. RERR Handling
First, ThisNode examines the RM to ensure that it contains the First, ThisNode examines the RteMsg to ensure that it contains the
required information: MsgHdr.HopLimit and required information: MsgHdr.HopLimit and
AddBlk.UnreachableNode.Address. If the required information do not AddBlk.UnreachableNode.Address. If the required information do not
exist, the message is discarded and further processing stopped. exist, the message is discarded and further processing stopped.
Next, ThisNode decides whether to handle this message. If the
message contains a MsgTLV.DID it SHOULD match ThisNode.DID's value.
If the message does not contain a MsgTLV.DID it is assumed to be zero
(0) and SHOULD be discarded if ThisNode.DID's value is not zero (0).
Next, ThisNode MAY selectively handle messages based upon information Next, ThisNode MAY selectively handle messages based upon information
in the message. ThisNode MAY choose to only handle messages from in the message. ThisNode MAY choose to only handle messages from
adjacent DYMO routers. If ThisNode chooses not to handle this adjacent AODVv2 routers. If ThisNode chooses not to handle this
message, the message is discarded and further processing stopped. message, the message is discarded and further processing stopped.
When a DYMO router handles a RERR, it examines each UnreachableNode's When an AODVv2 router handles a RERR, it examines each
information. The attending DYMO router removes the forwarding route, UnreachableNode's information. The attending AODVv2 router removes
unsets the Route.Forwarding flag, sets the Route.Broken flag, and the the forwarding route, unsets the Route.Forwarding flag, sets the
timer for ROUTE_DELETE is set to ROUTE_DELETE_TIMEOUT for each Route.Broken flag, and the timer for ROUTE_DELETE is set to
UnreachableNode.Address found using longest prefix matching that meet ROUTE_DELETE_TIMEOUT for each UnreachableNode.Address found using
all of the following conditions: longest prefix matching that meets all of the following conditions:
1. The UnreachableNode.Address is a multihop-capable unicast 1. The UnreachableNode.Address is a multihop-capable unicast
address. address.
2. The Route.NextHopAddress is the same as the RERR 2. The Route.NextHopAddress is the same as the RERR
IP.SourceAddress. IP.SourceAddress.
3. The Route.NextHopInterface is the same as the interface on which 3. The Route.NextHopInterface is the same as the interface on which
the RERR was received. the RERR was received.
skipping to change at page 30, line 14 skipping to change at page 25, line 24
If handling continues, the MsgHdr.HopLimit is decremented by one (1). If handling continues, the MsgHdr.HopLimit is decremented by one (1).
Further, if this RERR's new MsgHdr.HopLimit is greater than 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 and at least one unreachable node address remains in the RERR, then
the updated RERR SHOULD be sent. the updated RERR SHOULD be sent.
A multicast RERR is sent to the IP.DestinationAddress LL-MANET- A multicast RERR is sent to the IP.DestinationAddress LL-MANET-
Routers [RFC5498]. If the RERR is unicast, the IP.DestinationAddress Routers [RFC5498]. If the RERR is unicast, the IP.DestinationAddress
is set to the NextHopAddress. is set to the NextHopAddress.
5.6. DYMO Identifier (DID) 5.6. Unknown Message and TLV Types
Each DYMO routing protocol process MUST have an associated DYMO
Identifier (DID). The DID allows multiple DYMO routing protocol
processes to operate over the same links and on the same device
independently. This function may also be used to administratively
separate DYMO processes with incompatible options, timers, or
extensions.
The DID is similar in function to OSPF Instance ID [RFC5340]
[I-D.ietf-ospf-multi-instance], OSPF Area ID [RFC2328] [RFC5340],
and/or the MANET_ID TLV [I-D.chakeres-manet-manetid].
All DYMO routers with the same DID that come in contact with each
other MUST operate with a compatible set of configuration options,
timing parameters (see Section 6), and protocol extensions. In cases
with non-default options, the DID value SHOULD be administratively
chosen.
The default DID value is zero (0), and using this value requires that
the implementation utilize options and timing parameters compatible
with those defined in Section 6.
Each DYMO routing protocol message sent MUST contain its associated
DID in a message TLV; unless the DID value is zero (0), in which case
it MAY be omitted.
Upon receipt of DYMO protocol message a DYMO routing protocol process
SHOULD only process messages with a DID (MsgTLV.DID) value matching
its own DID (ThisNode.DID).
5.7. Unknown Message & TLV Types
If a message with an unknown type is received, the message is If a message with an unknown type is received, the message is
discarded. discarded.
For handling of messages that contain unknown TLV types, the default For handling of messages that contain unknown TLV types, the default
behavior is to leave the information in control messages unmodified. behavior is to leave the information in control messages unmodified.
Although, this behavior (UNKNOWN_TYPES) MAY be administratively Although, this behavior (UNKNOWN_TYPES) MAY be administratively
controlled. controlled.
5.8. Advertising Network Addresses 5.7. Advertising Network Addresses
DYMO routers specify the prefix length for each advertised address. AODVv2 routers specify the prefix length for each advertised address.
Any nodes (other than the advertising DYMO router) within the Any nodes (other than the advertising AODVv2 router) within the
advertised prefix MUST NOT participate in the DYMO protocol directly. advertised prefix MUST NOT participate in the AODVv2 protocol
For example, advertising 192.0.2.1 with a prefix length of 24 directly. For example, advertising 192.0.2.1 with a prefix length of
indicates that all nodes with the matching 192.0.2.X are reachable 24 indicates that all nodes with the matching 192.0.2.X are reachable
through this DYMO router. through this AODVv2 router.
5.9. Simple Internet Attachment 5.8. Simple Internet Attachment
Simple Internet attachment consists of a stub network of DYMO routers Simple Internet attachment consists of a stub network of AODVv2
connected to the Internet via a single Internet DYMO router (IDR). routers connected to the Internet via a single Internet AODVv2 router
(IDR).
DYMO routers, and hosts behind these routers, wishing to be reachable AODVv2 routers, and hosts behind these routers, wishing to be
from hosts on the Internet MUST have IP addresses within the IDR's reachable from hosts on the Internet MUST have IP addresses within
routable and topologically correct prefix (e.g. 192.0.2.0/24). the IDR's routable and topologically correct prefix (e.g.
192.0.2.0/24).
The IDR is responsible for generating RREQ to find nodes within the The IDR is responsible for generating RREQ to find nodes within the
DYMO Region on behalf of nodes on the Internet, as well as responding AODVv2 Region on behalf of nodes on the Internet, as well as
to route requests from the DYMO region on behalf of the nodes on the responding to route requests from the AODVv2 region on behalf of the
Internet. nodes on the Internet.
/--------------------------\ /--------------------------\
/ Internet \ / Internet \
\ / \ /
\------------+-------------/ \------------+-------------/
| |
Routable & | Routable & |
Topologically | Topologically |
Correct | Correct |
Prefix | Prefix |
+-----+------+ +-----+------+
| Internet | | Internet |
/------| DYMO |-------\ /------| AODVv2 |-------\
/ | Router | \ / | Router | \
/ |192.0.2.1/32| \ / |192.0.2.1/32| \
| |Responsible | | | |Responsible | |
| | for | | | | for | |
| |DYMO Region | | | |AODVv2 Region | |
| |192.0.2.0/24| | | |192.0.2.0/24| |
| +------------+ | | +------------+ |
| +--------------+ | | +--------------+ |
| | DYMO Router | | | | AODVv2 Router | |
| | 192.0.2.2/32 | | | | 192.0.2.2/32 | |
| +--------------+ | | +--------------+ |
| +--------------+ | | +--------------+ |
| | DYMO Router | | | | AODVv2 Router | |
| | 192.0.2.3/32 | | | | 192.0.2.3/32 | |
\ +--------------+ / \ +--------------+ /
\ / \ /
\---------------------------/ \---------------------------/
Figure 3: Simple Internet Attachment Example Figure 1: Simple Internet Attachment Example
When a DYMO router within the DYMO Region wants to discover a route
to a node on the Internet, it uses the normal DYMO route discovery
for that IP Destination Address. The IDR is responsible for properly
responding to RREQ on behalf of the Internet destination.
When a packet from a node on the Internet destine for a node in the When an AODVv2 router within the AODVv2 Region wants to discover a
DYMO region reaches the IDR, if the IDR does not have a route to that route to a node on the Internet, it uses the normal AODVv2 route
destination it will perform normal DYMO route discovery for that discovery for that IP Destination Address. The IDR is responsible
for properly responding to RREQ on behalf of the Internet
destination. destination.
5.10. Multiple Interfaces When a packet from a node on the Internet destined for a node in the
AODVv2 region reaches the IDR, if the IDR does not have a route to
that destination it will perform normal AODVv2 route discovery for
that destination.
DYMO may be used with multiple interfaces; therefore, the particular 5.9. Multiple Interfaces
interface over which packets arrive MUST be known whenever a packet
is received. Whenever a new route is created, the interface through AODVv2 may be used with multiple interfaces; therefore, the
which the Route.Address can be reached is also recorded in the route particular interface over which packets arrive MUST be known whenever
table entry. a packet is received. Whenever a new route is created, the interface
through which the Route.Address can be reached is also recorded in
the route table entry.
When multiple interfaces are available, a node transmitting a When multiple interfaces are available, a node transmitting a
multicast packet with IP.DestinationAddress set to LL-MANET-Routers multicast packet with IP.DestinationAddress set to LL-MANET-Routers
SHOULD send the packet on all interfaces that have been configured SHOULD send the packet on all interfaces that have been configured
for DYMO operation. for AODVv2 operation.
Similarly, DYMO routers should subscribe to LL-MANET-Routers on all Similarly, AODVv2 routers should subscribe to LL-MANET-Routers on all
their DYMO interfaces. their AODVv2 interfaces.
5.11. DYMO Control Packet/Message Generation Limits 5.10. AODVv2 Control Packet/Message Generation Limits
To ensure predictable control overhead, DYMO router's rate of packet/ To ensure predictable control overhead, AODVv2 router's rate of
message generation SHOULD be limited. The rate and algorithm for packet/message generation SHOULD be limited. The rate and algorithm
limiting messages (CONTROL_TRAFFIC_LIMITS) is left to the implementor for limiting messages (CONTROL_TRAFFIC_LIMITS) is left to the
and should be administratively configurable or intelligently implementor and should be administratively configurable or
controlled. DYMO control messages SHOULD be discarded in the intelligently controlled. AODVv2 control messages SHOULD be
following order of preferences RREQ, RREP, and finally RERR. discarded in the following order of preference: RREQ, RREP, and
finally RERR.
6. Administratively Configured Parameters and Timer Values 6. Administratively Configured Parameters and Timer Values
DYMO contains several parameters which MUST be administratively AODVv2 contains several parameters which MUST be administratively
configured. The list of these follows: configured. The list of these follows:
Required Administratively Configured Parameters Required Administratively Configured Parameters
+------------------------+------------------------------------------+ +------------------------+------------------------------------------+
| Name | Description | | Name | Description |
+------------------------+------------------------------------------+ +------------------------+------------------------------------------+
| DID | All DYMO routers with the same DID that | | RESPONSIBLE_ADDRESSES | List of addresses or routing prefixes, |
| | come in contact with each other MUST | | | for which this AODVv2 router is |
| | operate with a compatible set of | | | responsible. If, RESPONSIBLE_ADDRESSES |
| | configuration options, timing | | | is zero, this AODVv2 router is only |
| | parameters, and protocol extensions. If | | | responsible for its own addresses. |
| | non-default potentially incompatible | | AODVv2_INTERFACES | List of the interfaces participating in |
| | options, timing parameters or protocol | | | AODVv2 routing protocol. |
| | extensions are utilized the DID MUST be |
| | set to a non-zero value. |
| RESPONSIBLE_ADDRESSES | List of addresses, and their associated |
| | prefix, for which this DYMO router is |
| | responsible. |
| DYMO_INTERFACES | List of the interfaces participating in |
| | DYMO routing protocol. |
+------------------------+------------------------------------------+ +------------------------+------------------------------------------+
Table 2 Table 2
DYMO contains a number of timers. The default timing parameter AODVv2 contains a number of timers. The default timing parameter
values follow: values follow:
Default Timing Parameter Values Default Timing Parameter Values
+------------------------------+-------------------+ +------------------------------+-------------------+
| Name | Value | | Name | Value |
+------------------------------+-------------------+ +------------------------------+-------------------+
| ROUTE_TIMEOUT | 5 seconds | | ROUTE_TIMEOUT | 5 seconds |
| ROUTE_AGE_MIN_TIMEOUT | 1 second | | ROUTE_AGE_MIN_TIMEOUT | 1 second |
| ROUTE_SEQNUM_AGE_MAX_TIMEOUT | 60 seconds | | ROUTE_SEQNUM_AGE_MAX_TIMEOUT | 60 seconds |
skipping to change at page 34, line 28 skipping to change at page 28, line 29
| ROUTE_RREQ_WAIT_TIME | 2 seconds | | ROUTE_RREQ_WAIT_TIME | 2 seconds |
| UNICAST_MESSAGE_SENT_TIMEOUT | 1 second | | UNICAST_MESSAGE_SENT_TIMEOUT | 1 second |
+------------------------------+-------------------+ +------------------------------+-------------------+
Table 3 Table 3
The above timing parameter values work well for small and medium The above timing parameter values work well for small and medium
well-connected networks with moderate topology changes. well-connected networks with moderate topology changes.
The timing parameters SHOULD be administratively configurable for the The timing parameters SHOULD be administratively configurable for the
network where DYMO is used. Ideally, for networks with frequent network where AODVv2 is used. Ideally, for networks with frequent
topology changes the DYMO parameters should be adjusted using either topology changes the AODVv2 parameters should be adjusted using
experimentally determined values or dynamic adaptation. For example, either experimentally determined values or dynamic adaptation. For
in networks with infrequent topology changes ROUTE_USED_TIMEOUT may example, in networks with infrequent topology changes
be set to a much larger value. ROUTE_USED_TIMEOUT may be set to a much larger value.
Default Parameter Values Default Parameter Values
+------------------------+-------+----------------------------------+ +------------------------+-------+----------------------------------+
| Name | Value | Description | | Name | Value | Description |
+------------------------+-------+----------------------------------+ +------------------------+-------+----------------------------------+
| MSG_HOPLIMIT | 10 | This value MUST be larger than | | MSG_HOPLIMIT | 10 | This value MUST be larger than |
| | hops | the DYMO network diameter. | | | hops | the AODVv2 network diameter. |
| | | Otherwise, routing messages may | | | | Otherwise, routing messages may |
| | | not reach their intended | | | | not reach their intended |
| | | destinations. | | | | destinations. |
| DISCOVERY_ATTEMPTS_MAX | 3 | The number of route discovery | | DISCOVERY_ATTEMPTS_MAX | 3 | The number of route discovery |
| | | attempts to make before | | | | attempts to make before |
| | | indicating that a particular | | | | indicating that a particular |
| | | address is not reachable. | | | | address is not reachable. |
+------------------------+-------+----------------------------------+ +------------------------+-------+----------------------------------+
Table 4 Table 4
In addition to the above parameters and timing values, several In addition to the above parameters and timing values, several
administrative options exist. These options have no influence on administrative options exist. These options have no influence on
correct routing behavior, although they may potentially reduce DYMO correct routing behavior, although they may potentially reduce AODVv2
routing control messaging in certain situations. The default routing control messaging in certain situations. The default
behavior is to NOT enable any of these options; and although many of behavior is to NOT enable any of these options; and although many of
these options can be administratively controlled, they may be better these options can be administratively controlled, they may be better
served by intelligent control. The following table enumerates served by intelligent control. The following table enumerates
several of the options. several of the options.
Administratively Controlled Options Administratively Controlled Options
+---------------------------+---------------------------------------+ +-------------------------+-----------------------------------------+
| Name | Description | | Name | Description |
+---------------------------+---------------------------------------+ +-------------------------+-----------------------------------------+
| APPEND_INFORMATION | Whether to append ThisNode's routing | | BUFFER_DURING_DISCOVERY | Whether and how much data to buffer |
| | information to a RM. | | | during route discovery. |
| APPEND_INFORMATION_SEQNUM | Whether to increment ThisNode's | | UNKNOWN_TYPES | What action to take when an unknown TLV |
| | OwnSeqNum when append ThisNode's | | | type is received. The default action |
| | routing information to a RM. | | | is to forward this information |
| BUFFER_DURING_DISCOVERY | Whether and how much data to buffer | | | unmodified. Another action would be to |
| | during route discovery. | | | remove this information. |
| APPEND_EXTRA_UNREACHABLE | Whether to append additional | | CONTROL_TRAFFIC_LIMITS | AODVv2 control messaging SHOULD be |
| | Unreachable information to RERR. | | | limited to avoid consuming all the |
| UNKNOWN_TYPES | What action to take when an unknown | | | network bandwidth. |
| | TLV type is received. The default | +-------------------------+-----------------------------------------+
| | action is to forward this information |
| | unmodified. Another action would be |
| | to remove this information. |
| CONTROL_TRAFFIC_LIMITS | DYMO control messaging SHOULD be |
| | limited to avoid consuming all the |
| | network bandwidth. |
+---------------------------+---------------------------------------+
Table 5 Table 5
Note: several fields have limited size (bits or bytes) these sizes Note: several fields have limited size (bits or bytes) these sizes
and their encoding may place specific limitations on the values that and their encoding may place specific limitations on the values that
can be set. For example, MsgHdr.HopLimit is a 8-bit field and can be set. For example, MsgHdr.HopLimit is a 8-bit field and
therefore MSG_HOPLIMIT cannot be larger than 255. therefore MSG_HOPLIMIT cannot be larger than 255.
7. IANA Considerations 7. IANA Considerations
In its default mode of operation, DYMO uses the UDP port MANET In its default mode of operation, AODVv2 uses the UDP port MANET
[RFC5498] to carry protocol packets. DYMO also uses the link-local [RFC5498] to carry protocol packets. AODVv2 also uses the link-local
multicast address LL-MANET-Routers [RFC5498]. multicast address LL-MANET-Routers [RFC5498].
This section specifies several message types, message tlv-types, and This section specifies several message types, message tlv-types, and
address tlv-types. address tlv-types.
7.1. DYMO Message Types Specification 7.1. AODVv2 Message Types Specification
DYMO Message Types AODVv2 Message Types
+------------------------+----------+ +------------------------+----------+
| Name | Type | | Name | Type |
+------------------------+----------+ +------------------------+----------+
| Route Request (RREQ) | 10 - TBD | | Route Request (RREQ) | 10 - TBD |
| Route Reply (RREP) | 11 - TBD | | Route Reply (RREP) | 11 - TBD |
| Route Error (RERR) | 12 - TBD | | Route Error (RERR) | 12 - TBD |
+------------------------+----------+ +------------------------+----------+
Table 6 Table 6
skipping to change at page 37, line 9 skipping to change at page 31, line 9
| | | | and MAY blacklist the link to | | | | | and MAY blacklist the link to |
| | | | this node. | | | | | this node. |
+-------------------+------+--------+-------------------------------+ +-------------------+------+--------+-------------------------------+
Table 7 Table 7
7.3. Address Block TLV Specification 7.3. Address Block TLV Specification
Address Block TLV Types Address Block TLV Types
+---------------+------------+----------+---------------------------+ +----------------+------------+----------+--------------------------+
| Name | Type | Length | Value | | Name | Type | Length | Value |
+---------------+------------+----------+---------------------------+ +----------------+------------+----------+--------------------------+
| DYMO | 9 - TBD | DID | ThisNode.DID's value. | | AODVv2 | 10 - TBD | up to 2 | The AODVv2 sequence num |
| Identifier | | length | More information can be | | Sequence | | octets | associated with this |
| (DID) | | | found in Section 5.6 | | Number | | | address. The sequence |
| DYMO Sequence | 10 - TBD | up to 2 | The DYMO sequence num | | (AODVv2SeqNum) | | | number may be the last |
| Number | | octets | associated with this | | | | | known sequence number. |
| (DYMOSeqNum) | | | address. The sequence | | Distance | 11 - TBD | up to 2 | A metric of the distance |
| | | | number may be the last | | | | octets | traversed by the |
| | | | known sequence number. | | | | | information associated |
| Distance | 11 - TBD | up to 2 | A metric of the distance | | | | | with this address. |
| | | octets | traversed by the | | VALIDITY_TIME | 1[RFC5497] | | The maximum amount of |
| | | | information associated | | | | | time that information |
| | | | with this address. | | | | | can be maintained before |
| VALIDITY_TIME | 1[RFC5497] | | The maximum amount of | | | | | being deleted. The |
| | | | time that information can | | | | | VALIDITY_TIME TLV is |
| | | | be maintained before | | | | | defined in [RFC5497]. |
| | | | being deleted. The | +----------------+------------+----------+--------------------------+
| | | | VALIDITY_TIME TLV is |
| | | | defined in [RFC5497]. |
+---------------+------------+----------+---------------------------+
Table 8 Table 8
8. Security Considerations 8. Security Considerations
The objective of the DYMO protocol is for each router to communicate The objective of the AODVv2 protocol is for each router to
reachability information to addresses for which it is responsible. communicate reachability information to addresses for which it is
Positive routing information (i.e. a route exists) is distributed via responsible. Positive routing information (i.e. a route exists) is
RMs and negative routing information (i.e. a route does not exist) distributed via RteMsgs and negative routing information (i.e. a
via RERRs. DYMO routers that handle these messages store the route does not exist) via RERRs. AODVv2 routers that handle these
contained information to properly forward data packets, and they messages store the contained information to properly forward data
generally provide this information to other DYMO routers. packets, and they generally provide this information to other AODVv2
routers.
This section does not mandate any specific security measures. This section does not mandate any specific security measures.
Instead, this section describes various security considerations and Instead, this section describes various security considerations and
potential avenues to secure DYMO routing. potential avenues to secure AODVv2 routing.
The most important security mechanisms for DYMO routing are The most important security mechanisms for AODVv2 routing are
integrity/authentication and confidentiality. integrity/authentication and confidentiality.
In situations where routing information or router identity are In situations where routing information or router identity are
suspect, integrity and authentication techniques SHOULD be applied to suspect, integrity and authentication techniques SHOULD be applied to
DYMO messages. In these situations, routing information that is AODVv2 messages. In these situations, routing information that is
distributed over multiple hops SHOULD also verify the integrity and distributed over multiple hops SHOULD also verify the integrity and
identity of information based on originator of the routing identity of information based on originator of the routing
information. information.
A digital signature could be used to identify the source of DYMO A digital signature could be used to identify the source of AODVv2
messages and information, along with its authenticity. A nonce or messages and information, along with its authenticity. A nonce or
timestamp SHOULD also be used to protect against replay attacks. timestamp SHOULD also be used to protect against replay attacks.
S/MIME and OpenPGP are two authentication/integrity protocols that S/MIME and OpenPGP are two authentication/integrity protocols that
could be adapted for this purpose. could be adapted for this purpose.
In situations where confidentiality of DYMO messages is important, In situations where confidentiality of AODVv2 messages is important,
cryptographic techniques can be applied. cryptographic techniques can be applied.
In certain situations, like sending a RREP or RERR, a DYMO router In certain situations, like sending a RREP or RERR, an AODVv2 router
could include proof that it has previously received valid routing could include proof that it has previously received valid routing
information to reach the destination, at one point of time in the information to reach the destination, at one point of time in the
past. In situations where routers are suspected of transmitting past. In situations where routers are suspected of transmitting
maliciously erroneous information, the original routing information maliciously erroneous information, the original routing information
along with its security credentials SHOULD be included. along with its security credentials SHOULD be included.
Note that if multicast is used, any confidentiality and integrity Note that if multicast is used, any confidentiality and integrity
algorithms used must permit multiple receivers to handle the message. algorithms used must permit multiple receivers to handle the message.
9. Acknowledgments 9. Acknowledgments
DYMO is a descendant of the design of previous MANET reactive AODVv2 is a descendant of the design of previous MANET on-demand
protocols, especially AODV [RFC3561] and DSR [RFC4728]. Changes to protocols, especially AODV [RFC3561] and DSR [RFC4728]. Changes to
previous MANET reactive protocols stem from research and previous MANET on-demand protocols stem from research and
implementation experiences. Thanks to Elizabeth Belding-Royer for implementation experiences. Thanks to Elizabeth Belding-Royer for
her long time authorship of DYMO. Additional thanks to Luke Klein- her long time authorship of AODVv2. Additional thanks to Luke Klein-
Berndt, Pedro Ruiz, Fransisco Ros, Koojana Kuladinithi, Ramon Berndt, Pedro Ruiz, Fransisco Ros, Koojana Kuladinithi, Ramon
Caceres, Thomas Clausen, Christopher Dearlove, Seung Yi, Romain Caceres, Thomas Clausen, Christopher Dearlove, Seung Yi, Romain
Thouvenin, Tronje Krop, Henner Jakob, Alexandru Petrescu, Christoph Thouvenin, Tronje Krop, Henner Jakob, Alexandru Petrescu, Christoph
Sommer, Cong Yuan, Lars Kristensen, and Derek Atkins for reviewing of Sommer, Cong Yuan, Lars Kristensen, and Derek Atkins for reviewing of
DYMO, as well as several specification suggestions. AODVv2, as well as several specification suggestions.
10. References Many good ideas from LOADng [I-D.clausen-lln-loadng] are shaping this
evolution of the [manet] reactive routing protocol specification.
Thanks are due to T. Clausen, A. Colin de Verdiere, J. Yi, A.
Niktash, Y. Igarashi, SATOH. H., and U. Herberg for their
development of LOADng and sharing details for ensuring
appropriateness of AODVv2 for LLNs.
10. References
10.1. Normative References 10.1. Normative References
[RFC1812] Baker, F., "Requirements for IP Version 4 Routers", [RFC1812] Baker, F., "Requirements for IP Version 4 Routers",
RFC 1812, June 1995. RFC 1812, June 1995.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., and C. [RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., and C.
Pignataro, "The Generalized TTL Security Mechanism Pignataro, "The Generalized TTL Security Mechanism
skipping to change at page 39, line 28 skipping to change at page 33, line 34
[RFC5498] Chakeres, I., "IANA Allocations for Mobile Ad Hoc Network [RFC5498] Chakeres, I., "IANA Allocations for Mobile Ad Hoc Network
(MANET) Protocols", RFC 5498, March 2009. (MANET) Protocols", RFC 5498, March 2009.
10.2. Informative References 10.2. Informative References
[I-D.chakeres-manet-manetid] [I-D.chakeres-manet-manetid]
Chakeres, I., "MANET_ID TLV", Chakeres, I., "MANET_ID TLV",
draft-chakeres-manet-manetid-03 (work in progress), draft-chakeres-manet-manetid-03 (work in progress),
February 2008. February 2008.
[I-D.clausen-lln-loadng]
Clausen, T., Verdiere, A., Yi, J., Niktash, A., Igarashi,
Y., and U. Herberg, "The LLN On-demand Ad hoc Distance-
vector Routing Protocol - Next Generation (LOADng)",
draft-clausen-lln-loadng-01 (work in progress),
October 2011.
[I-D.ietf-manet-nhdp] [I-D.ietf-manet-nhdp]
Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
Network (MANET) Neighborhood Discovery Protocol (NHDP)", Network (MANET) Neighborhood Discovery Protocol (NHDP)",
draft-ietf-manet-nhdp-14 (work in progress), July 2010. draft-ietf-manet-nhdp-15 (work in progress),
December 2010.
[I-D.ietf-ospf-multi-instance] [I-D.ietf-ospf-multi-instance]
Lindem, A., Roy, A., and S. Mirtorabi, "OSPF Multi- Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
Instance Extensions", draft-ietf-ospf-multi-instance-02 Instance Extensions", draft-ietf-ospf-multi-instance-09
(work in progress), April 2010. (work in progress), January 2012.
[Perkins99] [Perkins99]
Perkins, C. and E. Belding-Royer, "Ad hoc On-Demand Perkins, C. and E. Belding-Royer, "Ad hoc On-Demand
Distance Vector (AODV) Routing", Proceedings of the 2nd Distance Vector (AODV) Routing", Proceedings of the 2nd
IEEE Workshop on Mobile Computing Systems and IEEE Workshop on Mobile Computing Systems and
Applications, New Orleans, LA, pp. 90-100, February 1999. Applications, New Orleans, LA, pp. 90-100, February 1999.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On-
skipping to change at page 40, line 17 skipping to change at page 34, line 32
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007. September 2007.
[RFC5148] Clausen, T., Dearlove, C., and B. Adamson, "Jitter [RFC5148] Clausen, T., Dearlove, C., and B. Adamson, "Jitter
Considerations in Mobile Ad Hoc Networks (MANETs)", Considerations in Mobile Ad Hoc Networks (MANETs)",
RFC 5148, February 2008. RFC 5148, February 2008.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, July 2008. for IPv6", RFC 5340, July 2008.
Appendix A. Shifting Responsibility for an Address Between DYMO Routers Appendix A. Changes since the Previous Version
Only one DYMO router within a routing region SHOULD be responsible o Protocol renamed to be AODVv2
for a particular address at any time. If two DYMO routers
dynamically pass responsibility of an address correct DYMO routing o Intermediate RREPs (iRREPs) are to be put into new document.
behavior must be observed. The DYMO router adding the new address Without iRREP, only the destination can respond to a RREQ.
o Precursor lists not supported, based on reported performance loss.
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 to be compatible with LOADng requirements,
removing RFC 5444 headers for minimal packet size
o Adding RREP-ACK message type instead of relying on reception of
arbitrary packets as sufficient response to establish
bidirectionality.
Appendix C. Shifting Responsibility for an Address 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 of an address correct AODVv2 routing
behavior must be observed. The AODVv2 router adding the new address
must wait for any exiting routing information about this address to must wait for any exiting routing information about this address to
be purged from the network. Therefore, it must wait at least be purged from the network. Therefore, it must wait at least
ROUTER_SEQNUM_AGE_MAX_TIMEOUT after the previous DYMO router for this ROUTER_SEQNUM_AGE_MAX_TIMEOUT after the previous AODVv2 router for
address stopped participating and advertising routing information on this address stopped participating and advertising routing
its behalf. information on its behalf.
Authors' Addresses Authors' Addresses
Charles E. Perkins
Central Expressway
San Jose, CA 95050
USA
Phone: +1-408-421-1172
Email: charliep@computer.org
Ian D Chakeres Ian D Chakeres
CenGen CenGen
9250 Bendix Road North 9250 Bendix Road North
Columbia, Maryland 21045 Columbia, Maryland 21045
USA USA
Email: ian.chakeres@gmail.com Email: ian.chakeres@gmail.com
URI: http://www.ianchak.com/ URI: http://www.ianchak.com/
Charles E. Perkins
WiChorus Inc.
3590 North First Street, Suite 300
San Jose, CA 95134
USA
Phone: +1-408-421-1172
Email: charliep@computer.org
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