draft-ietf-manet-dymo-05.txt   draft-ietf-manet-dymo-06.txt 
Mobile Ad hoc Networks Working I. Chakeres Mobile Ad hoc Networks Working I. Chakeres
Group Boeing Group Boeing
Internet-Draft C. Perkins Internet-Draft C. Perkins
Expires: December 22, 2006 Nokia Expires: April 5, 2007 Nokia
June 20, 2006 October 2, 2006
Dynamic MANET On-demand (DYMO) Routing Dynamic MANET On-demand (DYMO) Routing
draft-ietf-manet-dymo-05 draft-ietf-manet-dymo-06
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 1, line 35 skipping to change at page 1, line 35
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on December 22, 2006. This Internet-Draft will expire on April 5, 2007.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The Internet Society (2006).
Abstract Abstract
The Dynamic MANET On-demand (DYMO) routing protocol is intended for The Dynamic MANET On-demand (DYMO) routing protocol is intended for
use by mobile nodes in wireless multihop networks. It offers use by mobile nodes in wireless, multihop networks. It offers
adaptation to changing network topology and determines unicast routes adaptation to changing network topology and determines unicast routes
between nodes within the network on-demand. between nodes within the network on-demand.
Table of Contents Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 6 4. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Route Table Entry . . . . . . . . . . . . . . . . . . . . 6 4.1. Route Table Entry . . . . . . . . . . . . . . . . . . . . 6
4.2. DYMO Messages . . . . . . . . . . . . . . . . . . . . . . 7 4.2. DYMO Messages . . . . . . . . . . . . . . . . . . . . . . 7
4.2.1. Generalized MANET Packet and Message Structure . . . . 7 4.2.1. Generalized MANET Packet and Message Structure . . . . 7
4.2.2. Routing Message (RM) . . . . . . . . . . . . . . . . . 8 4.2.2. Routing Messages (RM) - RREQ & RREP . . . . . . . . . 8
4.2.3. Route Error (RERR) . . . . . . . . . . . . . . . . . . 10 4.2.3. Route Error (RERR) . . . . . . . . . . . . . . . . . . 10
5. Detailed Operation . . . . . . . . . . . . . . . . . . . . . . 12 5. Detailed Operation . . . . . . . . . . . . . . . . . . . . . . 12
5.1. DYMO Sequence Numbers . . . . . . . . . . . . . . . . . . 12 5.1. DYMO Sequence Numbers . . . . . . . . . . . . . . . . . . 12
5.1.1. Maintaining A Node's Own Sequence Number . . . . . . . 12 5.1.1. Maintaining A Node's Own Sequence Number . . . . . . . 12
5.1.2. Incrementing a Sequence Number . . . . . . . . . . . . 13 5.1.2. Incrementing OwnSeqNum . . . . . . . . . . . . . . . . 13
5.1.3. Sequence Number Rollover . . . . . . . . . . . . . . . 13 5.1.3. OwnSeqNum Rollover . . . . . . . . . . . . . . . . . . 13
5.1.4. Actions After Sequence Number Loss . . . . . . . . . . 13 5.1.4. Actions After OwnSeqNum Loss . . . . . . . . . . . . . 13
5.2. DYMO Routing Table Operations . . . . . . . . . . . . . . 13 5.2. DYMO Routing Table Operations . . . . . . . . . . . . . . 13
5.2.1. Judging New Routing Information's Usefulness . . . . . 13 5.2.1. Judging Routing Information's Usefulness . . . . . . . 13
5.2.2. Updating a Route Table Entry with Fresh Routing 5.2.2. Creating or Updating a Route Table Entry with New
Information . . . . . . . . . . . . . . . . . . . . . 14 Routing Information . . . . . . . . . . . . . . . . . 15
5.2.3. Route Table Entry Timeouts . . . . . . . . . . . . . . 15 5.2.3. Route Table Entry Timeouts . . . . . . . . . . . . . . 15
5.3. Routing Message . . . . . . . . . . . . . . . . . . . . . 15 5.3. Routing Messages . . . . . . . . . . . . . . . . . . . . . 17
5.3.1. RREQ Creation . . . . . . . . . . . . . . . . . . . . 15 5.3.1. RREQ Creation . . . . . . . . . . . . . . . . . . . . 17
5.3.2. RREP Creation . . . . . . . . . . . . . . . . . . . . 16 5.3.2. RREP Creation . . . . . . . . . . . . . . . . . . . . 18
5.3.3. RM Processing . . . . . . . . . . . . . . . . . . . . 16 5.3.3. RM Processing . . . . . . . . . . . . . . . . . . . . 18
5.3.4. Adding Additional Routing Information to a RM . . . . 18 5.3.4. Adding Additional Routing Information to a RM . . . . 20
5.4. Route Discovery . . . . . . . . . . . . . . . . . . . . . 18 5.4. Route Discovery . . . . . . . . . . . . . . . . . . . . . 20
5.5. Route Maintenance . . . . . . . . . . . . . . . . . . . . 19 5.5. Route Maintenance . . . . . . . . . . . . . . . . . . . . 21
5.5.1. Active Link Monitoring . . . . . . . . . . . . . . . . 19 5.5.1. Active Link Monitoring . . . . . . . . . . . . . . . . 21
5.5.2. Updating Route Lifetimes during Packet Forwarding . . 20 5.5.2. Updating Route Lifetimes during Packet Forwarding . . 21
5.5.3. Route Error Generation . . . . . . . . . . . . . . . . 20 5.5.3. Route Error Generation . . . . . . . . . . . . . . . . 22
5.5.4. Route Error Processing . . . . . . . . . . . . . . . . 21 5.5.4. Route Error Processing . . . . . . . . . . . . . . . . 22
5.6. General DYMO Packet and Message Processing . . . . . . . . 21 5.6. Unknown Message & TLV Types . . . . . . . . . . . . . . . 23
5.6.1. Receiving Packets . . . . . . . . . . . . . . . . . . 21 5.7. Advertising Network Addresses . . . . . . . . . . . . . . 23
5.6.2. Processing Unknown Message and TLV Types . . . . . . . 21 5.8. Simple Internet Attachment and Gatewaying . . . . . . . . 24
5.7. Network Addresses . . . . . . . . . . . . . . . . . . . . 22 5.9. Multiple Interfaces . . . . . . . . . . . . . . . . . . . 25
5.8. Simple Internet Attachment and Gatewaying . . . . . . . . 22 5.10. Packet/Message Generation Limits . . . . . . . . . . . . . 25
5.9. Multiple Interfaces . . . . . . . . . . . . . . . . . . . 23 6. Configuration Parameters and Other Administrative Options . . 25
5.10. Packet Generation Limits . . . . . . . . . . . . . . . . . 24 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
6. Configuration Parameters . . . . . . . . . . . . . . . . . . . 24 7.1. DYMO Message Type Specification . . . . . . . . . . . . . 27
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 7.2. Packet TLV Type Specification . . . . . . . . . . . . . . 27
7.1. DYMO Message Type Specification . . . . . . . . . . . . . 25 7.3. Address Block TLV Specification . . . . . . . . . . . . . 28
7.2. Packet TLV Type Specification . . . . . . . . . . . . . . 25 8. Security Considerations . . . . . . . . . . . . . . . . . . . 28
7.3. Address Block TLV Specification . . . . . . . . . . . . . 26 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29
8. Security Considerations . . . . . . . . . . . . . . . . . . . 26 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 10.1. Normative References . . . . . . . . . . . . . . . . . . . 29
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 10.2. Informative References . . . . . . . . . . . . . . . . . . 30
10.1. Normative References . . . . . . . . . . . . . . . . . . . 27 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31
10.2. Informative References . . . . . . . . . . . . . . . . . . 28 Intellectual Property and Copyright Statements . . . . . . . . . . 32
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29
Intellectual Property and Copyright Statements . . . . . . . . . . 30
1. Overview 1. Overview
The Dynamic MANET On-demand (DYMO) routing protocol enables reactive, The Dynamic MANET On-demand (DYMO) routing protocol enables reactive,
multihop routing between participating nodes that wish to multihop routing between participating nodes that wish to
communicate. The basic operations of the DYMO protocol are route communicate. The basic operations of the DYMO protocol are route
discovery and route management. During route discovery the discovery and route management. During route discovery the
originating node initiates dissemination of a Route Request (RREQ) originating node initiates dissemination of a Route Request (RREQ)
throughout the network to find the target node. During this throughout the network to find the target node. During this
dissemination process, each intermediate node records a route to the dissemination process, each intermediate node records a route to the
originating node. When the target node receives the RREQ, it originating node. When the target node receives the RREQ, it
responds with a Route Reply (RREP) unicast toward the originating responds with a Route Reply (RREP) sent hop-by-hop toward the
node. Each node that receives the RREP records a route to the target originating node. Each node that receives the RREP records a route
node, and then the RREP is unicast toward the originating node. When to the target node, and then the RREP is unicast toward the
the originating node receives the RREP, routes have then been originating node. When the originating node receives the RREP,
established between the originating node and the target node in both routes have then been established between the originating node and
directions. the target node in both directions.
In order to react to changes in the network topology nodes maintain In order to react to changes in the network topology nodes maintain
their routes and monitor their links. When a data packet is received their routes and monitor links over which traffic is moving. When a
for a route or link that is no longer available the source of the data packet is received for forwarding if a route is not known or the
packet is notified. A Route Error (RERR) is sent to the packet route is broken, then the source of the packet is notified. A Route
source to indicate the current route is broken. Once the source Error (RERR) is sent to the packet source to indicate the current
receives the RERR, it can perform route discovery if it still has route is broken. When the source receives the RERR, it knows that it
packets to deliver. must perform route discovery if it still has packets to deliver.
DYMO uses sequence numbers as they have been proven to ensure loop DYMO uses sequence numbers to ensure loop freedom [Perkins99].
freedom [Perkins99]. Sequence numbers enable nodes to determine the Sequence numbers enable nodes to determine the order of DYMO route
order of DYMO route discovery messages, thereby avoiding use of stale discovery messages, thereby avoiding use of stale routing
routing information. information.
2. Applicability 2. Applicability
The DYMO routing protocol is designed for mobile ad hoc networks in The DYMO routing protocol is designed for mobile ad hoc networks.
small, medium, and large node populations. DYMO handles all mobility DYMO handles a wide variety of mobility patterns by dynamically
ranges. DYMO can handle various traffic patterns, but is most suited determining routes on-demand. DYMO also handles a wide variety of
for sparse traffic sources and destinations. DYMO is designed for traffic patterns. In large networks DYMO is best suited for traffic
network where trust is assumed, since it depends on nodes properly scenarios where nodes communicate with only a portion of other the
forwarding traffic to the next hop toward the destination on behalf nodes.
of the source.
DYMO is applicable to memory constrained devices, since little DYMO is applicable to memory constrained devices, since little
routing state needs to be maintained. Only routing information routing state needs to be maintained. Only routing information
related to active destinations must be maintained, as opposed to related to active sources and destinations must be maintained, in
other routing protocols where routing information to all destinations contrast to other routing protocols that require routing information
or a large population destinations must be maintained. to all nodes within the autonomous system be maintained.
The routing algorithm in DYMO may be operated at layers other than The routing algorithm in DYMO may be operated at layers other than
the network layer, using layer-appropriate addresses. Only the network layer, using layer-appropriate addresses. Only
modification of the packet format is required. The routing algorithm modification of the packet format is required. The routing algorithm
need not change. need not change. Note that, using the DYMO algorithm with message
formats (other than those specified in this document) will not be
interoperable.
3. Terminology 3. Terminology
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC2119 this document are to be interpreted as described in RFC2119
[RFC2119]. [RFC2119].
This document uses some terminology from packetbb[I-D.ietf-manet-
packetbb].
This document defines the following terminology: This document defines the following terminology:
DYMO Sequence Number (SeqNum) DYMO Sequence Number (SeqNum)
A DYMO Sequence Number is maintained by each node. This sequence A DYMO Sequence Number is maintained by each node. This sequence
number is used to identify the freshness of related routing number is used by other nodes to identify the order of routing
information and to ensure loop-free routes. information generated by a node and to ensure loop-free routes.
Hop Count (HopCnt) Hop Count (HopCnt)
The number of IP hops a message or piece of information must The number of IP hops a message or piece of information has
traverse to reach the node holding this information. traversed.
Originator (Orig) Originating Node (OrigNode)
The originator is the node that created a DYMO Message in an The originating node is the node that created a DYMO Message in an
effort to disseminate information. effort to disseminate some information. The originating node is
also referred to as a particular message's originator.
Route Error (RERR) Route Error (RERR)
A node generates a RERR to disseminate that it does not have valid A node generates and disseminates a RERR to indicate that it does
route to a particular destination, or set of destinations. not have valid route to a one or more particular destinations.
Route Reply (RREP) Route Reply (RREP)
Upon receiving a RREQ during route discovery, the target node A RREP is used to disseminate routing information about how to
generates a Route Reply (RREP). A RREP is used to disseminate reach the RREQ target node, to nodes between the RREQ target node
routing information, on how to reach the target, to nodes between and the RREQ originator.
the target and the RREQ originator.
Route Request (RREQ) Route Request (RREQ)
A node generates a RREQ to discover a valid route to a particular A node (the RREQ originator) generates a RREQ to discover a valid
destination, called the target. A RREQ also disseminates routing route to a particular destination, called the RREQ target node. A
information on how to reach the originator of the RREQ. RREQ also provides routing information on how to reach the
originator of the RREQ.
Target Target Node (TargetNode)
The target node is the ultimate destination of a message. For The target node is the ultimate destination of a message. For
RREQ the target is the desired destination. For RREP the target RREQ the target node is the desired destination, the destination
is the originator of the RREQ. for which a valid route does not exist. For RREP the target node
is the RREQ originator.
Valid Route
A valid route is a known route where the Route.ValidTimeout is
greater than the current time. Valid routes may be used to
forward data.
When describing DYMO messages, information found in the:
IP header is proceeded with 'IP.'
UDP header is proceeded with 'UDP.'
packetbb message header is proceeded with 'MsgHdr.'
packetbb message TLVs is proceeded with 'MsgTLV.'
packetbb address blocks is proceeded with 'AddBlk.' Type-Length-Value structure (TLV)
A generic way to represent information, see packetbb [I-D.ietf-
manet-packetbb].
packetbb address block TLVs is proceeded with 'AddTLV.' 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.
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 number the semantics of a route as specified in this document.
zero (0) is reserved and can be used to indicate that the field value
for this routing entry is unknown or invalid.
A routing table entry has the following fields: Conceptually, a route table entry has the following fields:
Route.Address Route.Address
The IP destination address of the node associated with the routing The IP destination address of the node associated with the routing
table entry. table entry.
Route.SeqNum Route.SeqNum
The DYMO SeqNum associated with this routing information. The DYMO SeqNum associated with this routing information.
Route.NextHopAddress Route.NextHopAddress
The IP address of the next node on the path toward the The IP address of the next node on the path toward the
Route.Address. 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.ValidTimeout Route.Broken
The time at which a route table entry is no longer valid. A flag indicating whether this Route is broken. This flag is set
if the next hop becomes unreachable or in response to processing a
Route.DeleteTimeout RERR (see Section 5.5.4).
If the current time is after Route.DeleteTimeout the corresponding
routing table entry MUST be deleted.
The following fields are optional: The following fields are optional:
Route.HopCnt Route.HopCnt
The number of intermediate node hops traversed before reaching the The number of intermediate node hops traversed before reaching the
Route.Address node. Route.Address node. Route.HopCnt assists in determining whether
received routing information is superior to existing known
Route.IsInternetGateway information.
1-bit selector indicating whether the Route.Address is a an
Internet gateway, see Section 5.8.
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. If prefix is set to zero (0), unknown, or equal to the prefix. If an address block does not have an associated
address length in bits, this address is a host address. The PREFIX_LENGTH TLV [I-D.ietf-manet-packetbb] , the prefix may be
definition of Route.Prefix is different for gateways; entries with considered to have a prefix length equal to the address length (in
Route.IsInternetGateway set to one (1), seeSection 5.8. bits).
Route.Used Not including optional information may cause performance degradation,
1-bit selector indicating whether this Route has been used to but it will not cause the protocol to operate incorrectly otherwise.
forward data toward the destination.
Not including this optional information may result in sub-optimal In addition to a route table data structure, each route table entry
performance, but it is not required for correct protocol operation. may have several timers associated with the information. These
timers/timeouts are discussed in Section 5.2.3.
4.2. DYMO Messages 4.2. DYMO Messages
When describing DYMO protocol messages, it is necessary to refer to
fields in several distinct parts of the overall packet. These
locations include the IP or IPv6 header, the UDP header, and fields
from packetbb [I-D.ietf-manet-packetbb]. This document uses the
following notation conventions. Information found in the table.
+----------------------------+-------------------+
| Information Location | Notational Prefix |
+----------------------------+-------------------+
| IP header | IP. |
| UDP header | UDP. |
| packetbb message header | MsgHdr. |
| packetbb message TLV | MsgTLV. |
| packetbb address blocks | AddBlk. |
| packetbb address block TLV | AddTLV. |
+----------------------------+-------------------+
Table 1
4.2.1. Generalized MANET Packet and Message Structure 4.2.1. Generalized MANET Packet and Message Structure
All DYMO messages conform to the generalized packet and message DYMO messages conform to the generalized packet and message format as
format as described in[I-D.ietf-manet-packetbb]. described in [I-D.ietf-manet-packetbb]. Here is a brief description
of the format. A packet is made up of messages. A message is made
up of a message header, message TLV block, and zero or more address
blocks. Each of the address blocks may also have an associated
address TLV block.
All DYMO messages are sent using UDP to the destination port TBD. All DYMO messages specified in this document are sent using UDP to
the destination port TBD.
All DYMO messages are sent with the IP destination address set to the Most DYMO messages are sent with the IP destination address set to
link local multicast address LL_ALL_MANET_ROUTER unless otherwise the link local multicast address LL_ALL_MANET_ROUTER unless otherwise
stated. stated. Unicast DYMO messages specified in this document are sent
with the IP destination set to the Route.NextHopAddress of the route
to the target node.
The IP TTL (IP Hop Limit) field for all DYMO messages is set to one The IP TTL (IP Hop Limit) field for DYMO messages is set to one (1)
(1). for all messages specified in this document.
The length of IP addresses (32-bits for IPv4 and 128-bits for IPv6) The length of an IP address (32 bits for IPv4 and 128 bits for IPv6)
inside DYMO messages are dependent on the IP packet header. For inside a DYMO message depends on the IP packet header containing the
example, if the IP header uses IPv6 addresses then all messages and DYMO message/packet. For example, if the IP header uses IPv6
addresses contained in the payload use IPv6 addresses. In the case addresses then all messages and addresses contained in the payload
of mixed IPv6 and IPv4 addresses, IPv4 addresses are carried in IPv6 use IPv6 addresses. In the case of mixed IPv6 and IPv4 addresses,
as specified in [RFC3513]. IPv4 addresses are carried in IPv6 as specified in [RFC3513].
4.2.2. Routing Message (RM) 4.2.2. Routing Messages (RM) - RREQ & RREP
Routing Messages (RM) are used to disseminate routing information. Routing Messages (RMs) are used to disseminate routing information.
There are two DYMO message types that are RM, RREQ and RREP. They There are two DYMO message types that are considered to be routing
contain the same information, but have slightly different processing messages (RMs): RREQ and RREP. They contain very similar information
rules. The fundamental difference between the two messages are that and function, but have slightly different processing rules. The main
RREQ messages require a response; while a RREP is the response to difference between the two messages is that RREQ messages solicit a
RREQ. RREP, whereas a RREP is the response to RREQ.
RM creation and processing are described in Section 5.3. RM creation and processing are described in Section 5.3.
A RM requires the following information: A RM requires the following information:
IP.DestinationAddress IP.DestinationAddress
The IP address of the packet destination. The IP address of the packet destination. For RREQ the
IP.DestinationAddress is set to LL_ALL_MANET_ROUTERS. For RREP
the IP.DestinationAddress is set to the NextHopAddress toward the
TargetNode.
UDP.DestinationPort
The UDP destination port is set to TBD.
MsgHdr.HopLimit MsgHdr.HopLimit
The remaining number of hops this message may traverse. The remaining number of hops this message is allowed to traverse.
AddBlk.Target.Address AddBlk.TargetNode.Address
The IP address of the message target. In RREQ the target is the The IP address of the message target node. In a RREQ the target
unknown destination. In RREP the target is the RREQ originator. node is the destination for which a forwarding route does not
Only one address can be marked as the target. exist and route discovery is being performed. In a RREP the
target node is the RREQ originator. The target node address is
the first address in the routing message.
AddBlk.Orig.Address AddBlk.OrigNode.Address
The IP address of the message originator. This address is in an The IP address of the node originating this message. This address
address block and not in the message header to allow for address is in an address block and not in the message header to allow for
compression and additional AddTLVs. address compression and additional AddTLVs. This address is the
second address in the message for RREQ.
AddTLV.Orig.SeqNum AddTLV.OrigNode.SeqNum
The DYMO sequence number of the message originator. The DYMO sequence number of the originating node.
A RM may optionally include the following information: A RM may optionally include the following information:
AddTLV.Target.SeqNum AddTLV.TargetNode.SeqNum
The last known DYMO sequence number of the target. If the The last known DYMO sequence number of the target node.
AddTLV.Target.SeqNum is set to zero (0), then only the destination
may respond to this RREQ. AddTLV.TargetNode.HopCnt
The last known HopCnt to the target node.
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
node adding this information. Each AdditionalNode.Address must node adding this information. Each AdditionalNode.Address must
have an associated SeqNum in the message. have an associated SeqNum in the address TLV block.
AddTLV.AdditionalNode.SeqNum AddTLV.AdditionalNode.SeqNum
The DYMO sequence number of the additional node's routing The DYMO sequence number of an additional intermediate node's
information. routing information.
AddTLV.Node.HopCnt AddTLV.Node.HopCnt
The number of IP hops to reach the associated Node.Address. The number of IP hops to reach the associated Node.Address. This
field is incremented at each intermediate hop, for each node
except the target node's HopCnt information.
AddTLV.Node.Prefix AddTLV.Node.Prefix
The Node.Address is a network address ([I-D.ietf-manet-packetbb]). The Node.Address is a network address with a particular prefix
length.
AddTLV.Node.IsGateway
This AddTLV indicates that the Internet is reachable via this
node. That is, all nodes outside this Node's prefix are reachable
via the advertising Node.
AddTLV.Node.IsTarget
If the target is not the first address in the address blocks, this
AddTLV is used to indicate the target.
AddTLV.Node.IsOriginator
In the event that the originator is not the second address in the
address blocks, this AddTLV is used to indicate the originator.
AddTLV.AdditionalNode.IsOffPath
This AddTLV is used to indicate that a node is not on the path
between the originator and the target.
AddTLV.Node.Ignore
If the information associated with this Node.Address should not be
used create or update a route, this flag is set.
Not including this optional information may result in sub-optimal
performance, but it is not required for correct protocol operation.
Example IPv4 RREQ Example IPv4 RREQ
0 1 2 3 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 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 Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP.DestinationAddress=LL_ALL_MANET_ROUTERS | | IP.DestinationAddress=LL_ALL_MANET_ROUTERS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ...
UDP Header UDP Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Port=TBD | | Destination Port=TBD |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ...
Message Header Message Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RREQ-type | Resv |0|0|1| msg-size=24 | | RREQ-type | Resv |0|0|1| msg-size=23 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-hoplimit | msg-hopcnt | msg-tlv-block-size=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-hoplimit | msg-hopcnt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ...
Address Block Message Body - Message TLV Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-tlv-block-size=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Body - Address Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Number Addrs=2 |0|HeadLength=24| Head : |Number Addrs=2 |0|HeadLength=3 | Head :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Head (cont) | Target.Tail | Orig.Tail | TLV-blk-size : : (cont) | Target.Tail | Orig.Tail |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Body - Address Block TLV Block
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: size=7 (cont) | | tlv-block-size=6 |DYMOSeqNum-type|Resv |0|1|0|0|0|
+-+-+-+-+-+-+-+-+
...
Address TLVs
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|DYMOSeqNum-type| Resv |1|0|0|0| Index Start=1 | Index Stop=1 | | Index-start=1 | tlv-length=2 | Orig.SeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| tlv-length=16 | Orig.SeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 Figure 1
4.2.3. Route Error (RERR) 4.2.3. Route Error (RERR)
RERR are used to disseminate that a valid route is not available for A RERR message is used to disseminate the information that a route is
a particular destination, or set of destinations. not available for one or more particular IP addresses.
RERR creation and processing are described in Section 5.5.3 and RERR creation and processing are described in Section 5.5.
Section 5.5.4.
A RERR requires the following information: A RERR requires the following information:
IP.DestinationAddress IP.DestinationAddress
The IP address of the packet destination. The IP address is set to LL_ALL_MANET_ROUTERS.
UDP.DestinationPort
The UDP destination port is set to TBD.
MsgHdr.HopLimit MsgHdr.HopLimit
The remaining number of hops this message may traverse. The remaining number of hops this message is allowed to traverse.
AddBlk.Unreachable.Address AddBlk.UnreachableNode.Address
The IP address of an Unreachable Node. Multiple Unreachable The IP address of an UnreachableNode. Multiple unreachable
Addresses may be included. If a SeqNum for this address is not addresses may be included in a RERR.
included, it is assumed to be unknown.
A Route Error may optionally include the following information: A Route Error may optionally include the following information:
AddTLV.Unreachable.SeqNum AddTLV.UnreachableNode.SeqNum
The DYMO sequence number of the Unreachable Node. The last known DYMO sequence number of the unreachable node. If a
SeqNum for an address is not included, it is assumed to be
AddTLV.Node.Ignore unknown. This case occurs when a node receives a message to
If the information associated with Node.Address should not be used forward for which it does not have any information in its routing
to invalidate routes, this flag is set. table.
Example IPv4 RERR Example IPv4 RERR
0 1 2 3 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 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 Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IP.DestinationAddress=LL_ALL_MANET_ROUTERS | | IP.DestinationAddress=LL_ALL_MANET_ROUTERS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 12, line 25 skipping to change at page 12, line 25
UDP Header UDP Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Port=TBD | | Destination Port=TBD |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ...
Message Header Message Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RERR-type | Resv |0|0|1| msg-size=16 | | RERR-type | Resv |0|0|1| msg-size=16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-hoplimit | msg-hopcnt | msg-tlv-block-size=0 | | msg-hoplimit | msg-hopcnt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
... ...
Address Block Message Body
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Number Addrs=1 |0|HeadLength=0 | Unreachable.Addr : | msg-tlv-block-size=0 |Number Addrs=1 |1|HeadLength=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Unreachable.Addr (cont) | TLV-blk-size=0 | | Unreachable.Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV-blk-size=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 Figure 2
5. Detailed Operation 5. Detailed Operation
5.1. DYMO Sequence Numbers 5.1. DYMO Sequence Numbers
DYMO sequence numbers allow nodes to judge the freshness of routing DYMO sequence numbers allow nodes to judge the freshness of routing
information, and ensure loop freedom. 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 a each node in the network to maintain its own DYMO DYMO requires that each node in the network to maintain its own DYMO
sequence number (OwnSeqNum), a 16-bit unsigned integer. The sequence number (OwnSeqNum), a 16-bit unsigned integer. The
circumstances for a node to incrementing its OwnSeqNum are described circumstances for a node to incrementing its OwnSeqNum are described
in Section 5.3. in Section 5.3.
5.1.2. Incrementing a Sequence Number 5.1.2. Incrementing OwnSeqNum
When a node increments its OwnSeqNum (as described in Section 5.3) it When a node increments its OwnSeqNum (as described in Section 5.3) it
MUST do so by treating the sequence number value as if it was an MUST do so by treating the sequence number value as an unsigned
unsigned number. The sequence number zero (0) is reserved and is number. A node starts with its OwnSeqNum equal to one (1). The
used in several DYMO data structures to represent an unknown sequence sequence number zero (0) is reserved.
number.
5.1.3. Sequence Number Rollover 5.1.3. OwnSeqNum Rollover
If the sequence number has been assigned to be the largest possible If the sequence number has been assigned to be the largest possible
number representable as a 16-bit unsigned integer (i.e., 65535), then number representable as a 16-bit unsigned integer (i.e., 65535), then
the sequence number MUST be set to 256 when incremented. Setting the the sequence number is set to 256 when incremented. Setting the
sequence number to 256 allows other nodes to detect that the number sequence number to 256 allows other nodes to detect that the number
has rolled over and the node has not lost its sequence number. has rolled over and the node has not lost its sequence number.
5.1.4. Actions After Sequence Number Loss 5.1.4. Actions After OwnSeqNum Loss
A node can maintain its sequence number in persistent storage, A node should maintain its sequence number in persistent storage,
between reboots. between reboots.
If a node's OwnSeqNum is lost, it must take certain actions to avoid If a node's OwnSeqNum is lost, it must take certain actions to avoid
creating routing loops. To prevent this possibility after OwnSeqNum creating routing loops. To prevent this possibility after OwnSeqNum
loss a node MUST wait for at least ROUTE_DELETE_PERIOD before fully loss a node MUST wait for at least ROUTE_DELETE_TIMEOUT before fully
participating in the DYMO routing protocol. If a DYMO control participating in the DYMO routing protocol. If a DYMO control
message is received during this waiting period, the node SHOULD message is received during this waiting period, the node SHOULD
process it normally but MUST not transmit or retransmit any DYMO process it normally but MUST not transmit or retransmit any DYMO
messages. If a data packet is received for forwarding to another messages. If a data packet is received for forwarding to another
destination during this waiting period, the node MUST generate a RERR destination during this waiting period, the node MUST generate a RERR
message indicating that this route is not available and reset its message indicating that this route is not available and reset its
waiting period. RERR generation is described in Section 5.5.3. At waiting timeout. At the end of the waiting period a node sets its
the end of the waiting period a node sets its OwnSeqNum to one (1). OwnSeqNum to one (1).
The longest a node must wait is ROUTE_AGE_MAX_TIMEOUT. At the end of
the maximum waiting period a node sets its OwnSeqNum to one (1) and
begins participating.
5.2. DYMO Routing Table Operations 5.2. DYMO Routing Table Operations
5.2.1. Judging New Routing Information's Usefulness 5.2.1. Judging Routing Information's Usefulness
Given a routing table entry (Route.SeqNum, Route.HopCnt, and Given a route table entry (Route.SeqNum, Route.HopCnt, and
Route.ValidTimeout) and new routing information for a particular node Route.Broken) and new routing information for a particular node in a
in a RM (Node.SeqNum, Node.HopCnt, and RM message type - RREQ/RREP), RM (Node.SeqNum, Node.HopCnt, and RM message type - RREQ/RREP), the
the quality of the new routing information is evaluated to determine quality of the new routing information is evaluated to determine its
its usefulness. The following comparisons are performed in order: usefulness. Incoming routing information is 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 information is stale. Using stale routing information is not the information is stale. Using stale routing information is not
allowed, since doing so might result in routing loops. allowed, since doing so might result in routing loops.
2. Loop-prone (Node.SeqNum - Route.SeqNum < 0)
If Node.SeqNum == Route.SeqNum the information maybe loop-prone,
additional information must be examined. If Route.HopCnt is 2. Loop-possible
unknown or set to zero (0), then the routing information is loop- If Node.SeqNum == Route.SeqNum the information may cause loops if
prone. Likewise, if Node.HopCnt is unknown or set to zero (0), used; in this case additional information must be examined. If
then the routing information is loop-prone. If Node.HopCnt > Route.HopCnt or Node.HopCnt is unknown or zero (0), then the
Route.HopCnt + 1, then the routing information is loop-prone. routing information is loop-possible. If Node.HopCnt >
Using loop-prone routing information is not allowed, since doing Route.HopCnt + 1, then the routing information is loop-possible.
so might result in routing loops. Using loop-possible routing information is not allowed, otherwise
routing loops may be formed.
(Node.SeqNum == Route.SeqNum) AND
((Node.HopCnt is unknown)
OR (Route.HopCnt is unknown)
OR (Node.HopCnt > Route.HopCnt +1))
3. Inferior 3. Inferior
If Node.SeqNum == Route.SeqNum the information may be inferior, If Node.SeqNum == Route.SeqNum the information may be inferior;
additional information must be examined. If the route is valid additional information must be examined. If Node.HopCnt >= to
(by examining Route.ValidTimeout and the current time), then the Route.HopCnt, the current route is not Broken, and the message is
new information is inferior if Node.HopCnt > Route.HopCnt. If the a RREQ, then the new information is inferior. If Node.HopCnt >
route is valid, then the new information is also inferior if Route.HopCnt + 1, the current route is not Broken and the message
Node.HopCnt == Route.HopCnt AND this RM is a RREQ. is RREP, then the new information is inferior. Inferior routes
will not cause routing loops if introduced, but should not be used
since better information is already available.
4. Fresh (Node.SeqNum == Route.SeqNum) AND
(Route.Broken == false) AND
((Node.HopCnt > Route.HopCnt) AND (RM is RREQ))
OR ((Node.HopCnt > Route.HopCnt + 1) AND (RM is RREP)))
4. Superior
Routing information that does not match any of the above criteria Routing information that does not match any of the above criteria
is loop-free and better than the information existing in the is loop-free and better than the information existing in the
routing table. Only this type of information is used to update routing table. This type of information is used to update the
the routing table. routing table. For completeness, the following other cases are
possible:
5.2.2. Updating a Route Table Entry with Fresh Routing Information (Node.SeqNum - Route.SeqNum > 0) OR
((Node.SeqNum == Route.Seqnum)
AND ((Node.HopCnt == Route.HopCnt + 1)
OR (Node.HopCnt == Route.HopCnt))
AND (((Route.Broken == true) AND (RM is RREQ))
OR ((Route.Broken == false) AND (RM is RREP)))) OR
((Node.HopCnt < Route.HopCnt + 1) AND (Route.Broken == false))
If fresh routing information is received, the routing table entry is 5.2.2. Creating or Updating a Route Table Entry with New Routing
populated with the following information: 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.SeqNum is set to the Node.SeqNum, 2. the Route.SeqNum is set to the Node.SeqNum,
3. the Route.NextHopAddress is set to the node that transmitted this 3. the Route.NextHopAddress is set to the node that transmitted this
DYMO packet (IP.SourceAddress), DYMO RM packet (i.e., the IP.SourceAddress),
4. the Route.NextHopInterface is set to the interface that this DYMO 4. the Route.NextHopInterface is set to the interface that this DYMO
packet was received on, packet was received on,
5. the Route.ValidTimeout is set to the current time + 5. if known, the Route.HopCnt is set to the Node.HopCnt,
ROUTE_VALID_TIMEOUT,
6. the Route.HopCnt is set to the Node.HopCnt,
7. the Route.Prefix is set to the Node.Prefix, 6. if known, the Route.Prefix is set to the Node.Prefix.
8. the Route.IsInternetGateway is set if address is an Internet Fields without known values are not populated with any value.
Gateway.
Unknown values are set to zero (0). Previous timers for this route table entry are removed. A timer for
the minimum delete timeout (ROUTE_AGE_MIN) is set to
ROUTE_AGE_MIN_TIMEOUT. A timer to indicate a recently learned route
(ROUTE_NEW) is set to ROUTE_NEW_TIMEOUT. A timer for the maximum
delete timeout (ROUTE_AGE_MAX). ROUTE_AGE_MAX is set to
Node.AddTLV.MaxAge if included; otherwise, ROUTE_AGE_MAX is set to
ROUTE_AGE_MAX_TIMEOUT. The usage of these timers and others are
described in Section 5.2.3.
If a valid route exists to Node.Address at this point, the route can At this point, a forwarding route should be installed. Afterward,
be used to send any queued data packets and to fulfill any the route can be used to send any queued data packets and forwarding
outstanding RREQ. any incoming data packets for Route.Address. This route also
fulfills any outstanding route discovery attempts for Node.Address.
5.2.3. Route Table Entry Timeouts 5.2.3. Route Table Entry Timeouts
Before using a routing table entry its timeouts must be examined. 5.2.3.1. Minimum Delete Timeout (ROUTE_AGE_MIN)
If the current time is after Route.DeleteTimeout the corresponding When a node transmits a RM, other nodes expect the transmitting node
routing table entry MUST be deleted. to have a forwarding route to the RM originator. After updating a
route table entry, it should be maintained for at least
ROUTE_AGE_MIN. Failure to maintain the information might result in
lost messages/packets, or in the worst case scenario several
duplicate messages.
If the current time is later than a routing entry's After the ROUTE_AGE_MIN timeout a route can safely be deleted.
Route.ValidTimeout, the route is stale and cannot be used to route
packets. The information in invalid entries is still used for
filling fields in outgoing RM with last known values.
5.3. Routing Message 5.2.3.2. Maximum Delete Timeout (ROUTE_AGE_MAX)
5.3.1. RREQ Creation Sequence number information is time sensitive, and must be deleted
after a time in order to avoid conflicts due to reboots and
rollovers. When a node has lost its sequence number (e.g, due to
daemon reboot or node replacement) the node must wait until routing
information associated with its IP address and sequence number are no
longer maintained by other nodes in the network to ensure loop-free
routing.
When a node creates a RREQ it SHOULD increment its OwnSeqNum by one After the ROUTE_AGE_MAX timeout a route must be deleted. All
(1) according to the rules specified in (Section 5.1.2). information about the route is deleted upon ROUTE_AGE_MAX timeout.
If a forwarding route exists it is also removed.
Fist, the node adds the AddBlk.Target.Address to the RM. 5.2.3.3. New Information Timeout (ROUTE_NEW)
If a previous value of the Target.SeqNum is known (from an existing As time progresses the likelihood that a route remains intact
routing table entry), it SHOULD be placed in AddTLV.Target.SeqNum. decreases, if the network nodes are mobile. Maintaining and using
If a Target.SeqNum is not included, it is assumed to be unknown by old routing information can lead to many DYMO messages and excess
processing nodes and only the target is allowed to respond. A route discovery delay.
Target.SeqNum of zero (0) MAY be set to indicate that any node with
valid routing information about this destination can respond to this
RREQ if the node is so enabled, though the process for doing so is
not described in this document.
Similarly, if a previous value of the Target.HopCnt is known, it After the ROUTE_NEW timeout if the route has not been used, a timer
SHOULD be placed in AddTLV.Target.HopCnt. Otherwise, the HopCnt is for deleting the route (ROUTE_DELETE) is set to ROUTE_DELETE_TIMEOUT.
not included and assumed unknown by processing nodes.
These AddTLVs associated with the target SHOULD be set to maximum 5.2.3.4. Recently Used Timeout (ROUTE_USED)
protocol efficiency, but they may be omitted to reduce message size.
Next, the node adds AddBlk.Orig.Address to the RM and the When a route is used to forward data packets, this timer is set to
AddTLV.Orig.SeqNum (OwnSeqNum) in an address block TLV. The expire after ROUTE_USED_TIMEOUT. This operation is also discussed in
Orig.Address is this node's primary addresses/identifier. The Section 5.5.2.
Orig.Address must be a routable IP address.
Other AddTLVs for the originator SHOULD be set to maximum protocol If a route has not been used recently, then a timer for ROUTE_DELETE
efficiency, but they may be omitted to reduce message size. is set to ROUTE_DELETE_TIMEOUT.
The MsgHdr.HopCnt is set to zero (0). The MsgHdr.HopLimit SHOULD be 5.2.3.5. Delete Information Timeout (ROUTE_DELETE)
set to NET_DIAMETER, but MAY be set smaller. For RREQ, the
MsgHdr.HopLimit MAY be set in accordance with an expanding ring
search as described in [RFC3561] to limit the RREQ propagation to a
subset of the network and possibly reduce route discovery overhead.
5.3.2. RREP Creation As time progresses the likelihood that old routing information is
useful decreases, especially if the network nodes are mobile.
Therefore, old information should be deleted.
When a node creates a RREP in response to a RREQ, it MUST increment After the ROUTE_DELETE timeout, the routing table entry should be
its OwnSeqNum under the following conditions: deleted. If a forwarding route exists, it should also be removed.
o Target.SeqNum is not included in the message, OR 5.3. Routing Messages
o Target.SeqNum is zero (0), OR 5.3.1. RREQ Creation
o Target.SeqNum - OwnSeqNum > 0 (using 16-bit signed arithmetic), OR When a node creates a RREQ it SHOULD increment its OwnSeqNum by one
(1) according to the rules specified in Section 5.1.2. Incrementing
OwnSeqNum will ensure that all nodes with existing routing
information to consider this new information fresh. If the sequence
number is not incremented, certain nodes might not consider this
information useful if they have better information already.
o Target.SeqNum == OwnSeqNum AND Target.HopCnt is unknown, OR First, the node adds the AddBlk.TargetNode.Address to the RM.
o Target.SeqNum == OwnSeqNum AND Orig.HopCnt is unknown, OR If a previous value of the TargetNode.SeqNum is known (from a routing
table entry), it should be placed in AddTLV.TargetNode.SeqNum. If a
TargetNode.SeqNum is not included, it is assumed to be unknown by
processing nodes.
o Target.SeqNum == OwnSeqNum AND Target.HopCnt (the last know hop Similarly, if a previous value of the TargetNode.HopCnt is known, it
count value) < Orig.HopCnt (the number of hops traversed by this should be placed in AddTLV.TargetNode.HopCnt. Otherwise, the
RREQ to reach the target). AddTLV.TargetNode.HopCnt is not included and assumed unknown by
processing nodes.
First, the node adds the AddBlk.Target.Address to the RM. The These AddTLVs associated with the target node should be set to
Target.Address is copied from the incoming RREQ AddBlk.Orig.Address. improve protocol efficiency, but they may be omitted.
Next, the node adds the AddBlk.Orig.Address to the RM and the Next, the node adds AddBlk.OrigNode.Address to the RM and the
AddTLV.Orig.SeqNum (OwnSeqNum) in an address block TLV. The AddTLV.OrigNode.SeqNum (OwnSeqNum) in an address block TLV. The
Orig.Address is copied from the incoming RREQ AddBlk.Target.Address. OrigNode.Address is this node's primary addresses/identifier, and it
must be a routable IP address. This information will be used by
nodes to create a route toward the OrigNode and enable delivery of a
RREP.
Other AddTLVs for the originator and target SHOULD be set to maximum Other AddTLVs for the OrigNode should be set to improve protocol
protocol efficiency, but they may be omitted to reduce message size. efficiency, but they may be omitted. If OrigNode.HopCnt is included
it is set to zero (0).
The MsgHdr.HopCnt is set to zero (0). The MsgHdr.HopLimit should be
set to NET_DIAMETER, but may be set smaller. For RREQ, the
MsgHdr.HopLimit may be set in accordance with an expanding ring
search as described in [RFC3561] to limit the RREQ propagation to a
subset of the network and possibly reduce route discovery overhead.
The IP.DestinationAddress for RREQ is set to the
LL_ALL_MANET_ROUTERS.
5.3.2. RREP Creation
When a node creates a RREP in response to a RREQ, it increments its
OwnSeqNum by one (1) according to the rules specified in
Section 5.1.2. If OwnSeqNum is not incremented the routing
information might be considered stale. In this case, the RREP would
not reach the originating node.
Note: We are currently discussing and investigating mechanisms to
avoid incrementing the sequence number before issuing a route reply.
An update to this behavior will likely happen in the next revision.
Avoiding incrementation of the sequence number when issuing a RREP is
an important mechanism to reduce the unnecessary devaluing of good
routing information, and the ability to issue intermediate node
replies. Further when intermediate node replies are coupled with
expanding ring search, route discovery cost can be further reduced.
The node then adds the AddBlk.TargetNode.Address to the RREP. The
TargetNode.Address is copied from the incoming RREQ
AddBlk.OrigNode.Address.
Next, the node adds the AddBlk.OrigNode.Address to the RREP and the
AddTLV.OrigNode.SeqNum (OwnSeqNum) in an address block TLV. The
OrigNode.Address is copied from the incoming RREQ
AddBlk.TargetNode.Address.
Other AddTLVs for the OrigNode and TargetNode should be set to
improve protocol efficiency, but they may be omitted. If
OrigNode.HopCnt is included it is set to zero (0).
The MsgHdr.HopCnt is set to zero (0). The MsgHdr.HopLimit is set to The MsgHdr.HopCnt is set to zero (0). The MsgHdr.HopLimit is set to
NET_DIAMETER. NET_DIAMETER.
The IP.DestinationAddress for RREP is set to the IP address of the
Route.NextHopAddress for the route to the RREP TargetNode.
5.3.3. RM Processing 5.3.3. RM Processing
When a RM is received the MsgHdr.HopLimit is decremented by one (1) When a RM is received the MsgHdr.HopLimit is decremented by one (1)
and MsgHdr.HopCnt is incremented by one (1). and MsgHdr.HopCnt is incremented by one (1).
For each address in the RM that includes AddTLV-HopCnt information For each address (except the TargetNode) in the RM that includes
except the target and those addresses tagged with the AddTLV-Ignore, AddTLV.HopCnt information, the AddTLV.HopCnt information is
the AddTLV-HopCnt information is incremented by one (1). incremented by one (1).
Next, this node checks whether its routing table has an entry to the Next, this node checks whether its routing table has an entry to the
AddBlk.Orig.Address using longest-prefix matching [RFC1812]. If a AddBlk.OrigNode.Address using longest-prefix matching [RFC1812]. If
route does not exist, the new routing information is considered fresh a route does not exist, the new routing information is considered
and a new route table entry is created and updated as described in fresh and a new route table entry is created and updated as described
Section 5.2.2. If a routing table entry exists, the new node's in Section 5.2.2. If a route table entry does exists, the new node's
information is compared with the route table entry following the information is compared with the route table entry following the
procedure described in Section 5.2.1. If the new node's routing procedure described in Section 5.2.1. If the new node's routing
information is considered fresh, the route table entry is updated as information is considered superior, the route table entry is updated
described in Section 5.2.2. as described in Section 5.2.2.
If the routing information for the originator is not fresh then this After processing the OrigNode's routing information, then each
RM must be discarded and no further processing of this message is address that is not the TargetNode should be considered for creating
performed. and updating routes. Creating and updating routes to other nodes can
eliminate RREQ for those IP destinations, in the event that data
needs to be forwarded to the IP destination(s) in the near future.
If the originator's routing information was considered fresh, then For each of the additional addresses considered, if the routing table
each address that is not the target and is not flagged with the does not have a matching route using longest-prefix matching, then a
Ignore address-block-tlv SHOULD considered for creating and updating route is created and updated as described in Section 5.2.2. If a
routes. If routing table space is limited, only the routing route table entry exists, the new node's information is compared with
information about the originator is required. Creating and updating the route table entry following the procedure described in
routes for other locations can eliminate RREQ for those destination, Section 5.2.1. If the new node's routing information is considered
in the event that data needs to be forwarded to these destinations in superior, the route table entry is updated as described in
the near future. Section 5.2.2.
For each of these addresses considered, if the routing table does not If the routing information for an AdditionalNode.Address is not
have a matching route using longest-prefix matching, then a route is considered superior, then it is removed from the RM. Removing this
created and updated as described in Section 5.2.2. If a routing information ensures that the information is not propagated.
table entry exists, the new node's information is compared with the
route table entry following the procedure described in Section 5.2.1.
If the new node's routing information is considered fresh, the route
table entry is updated as described in Section 5.2.2.
If the routing information for an Node.Address is not considered At this point, if the routing information for the OrigNode was not
fresh, then if MUST be removed from the RM. Removing this superior then this RM should be discarded and no further processing
information ensures that non-fresh information is not propagated. of this message is performed.
If this node is the target AND this RM is a RREQ, this node responds If the receiving node is the TargetNode AND this RM is a RREQ, then
with a RREP. This node creates a new RREP as described in this node responds with a RREP. The procedure for creating a new
Section 5.3.2. RREP is described in Section 5.3.2.
After processing a RM or creating a new RM, a node MAY append After processing a RM or creating a new RM, a node can append
additional routing information to the RM, according to the process additional routing information to the RM, according to the procedure
described in Section 5.3.4. The additional routing information will described in Section 5.3.4. The additional routing information can
help reduce route discoveries at the expense of increased message help reduce route discoveries at the expense of increased message
size. size.
If this RM's MsgHdr.HopLimit is greater than one (1), this node is If this RM's MsgHdr.HopLimit is greater than one (1), this node is
not the target, AND this RM is a RREQ, then the current RM (altered not the TargetNode, AND this RM is a RREQ, then the current RM
by the process defined above) SHOULD be sent to the (altered by the procedure defined above) is sent to the
LL_ALL_MANET_ROUTERS IP.DestinationAddress. LL_ALL_MANET_ROUTERS IP.DestinationAddress.
If this RM's MsgHdr.HopLimit is greater than one (1), this node is If this RM's MsgHdr.HopLimit is greater than one (1), this node is
not the target, AND this RM is a RREP, then the new RM SHOULD be sent not the TargetNode, AND this RM is a RREP, then the current RM is
to the Route.NextHopAddress for the RREP's Target.Address. sent to the Route.NextHopAddress for the RREP's TargetNode.Address.
If this node is the target, the current RM's information is not If no forwarding route exists to Target.Address, then a RERR is
issued to the originator of the RREP.
If this node is the TargetNode of the RM, the current RM is not
retransmitted. retransmitted.
5.3.4. Adding Additional Routing Information to a RM 5.3.4. Adding Additional Routing Information to a RM
Appending routing information will alleviate route discovery attempts Appending routing information can alleviate route discovery attempts
to the nodes whose information is included, if other nodes use this to the nodes whose information is included, if other nodes use this
information to update their routing tables. information to update their routing tables.
Nodes MAY append routing information to a RM, if the node believe Nodes can append routing information to a RM, and should if the node
that this additional routing information will alleviate future RREQ. believes that this additional routing information will alleviate
This option should be administratively controlled. future RREQ. This option should be administratively configured.
Prior to appending their own address to a RM, a node MUST increment
its OwnSeqNum as defined in Section 5.1.2. Then the node appends its
IP address (AddBlk-Address) and OwnSeqNum (AddTLV-SeqNum). It MAY
also append other information to its address, such as prefix and/or
that it is an Internet Gateway. If included, the Node.HopCnt is set
to one (1).
Routing information about other nodes MAY also be added. If this
information is included, it must be flagged with the
AddTLV.AdditionalNode.IsOffPath.
Note an address may appear only once in a message's address blocks. Prior to appending its own address to a RM, a node should increment
Prior to adding any address, the message is searched for existing its OwnSeqNum as defined in Section 5.1.2. If OwnSeqNum is not
entries. If an existing entry exists, this entry will have the incremented the appended routing information might not be considered
information as this node's routing table information (created or fresh, when received by nodes with existing routing information.
updated while processing the RM) and therefore no update is Incrementation of the sequence number when appending information to
necessary. an RM in transit should be administratively configured.
In the event a newly appended address already has an AddTLV-Ignore If included the Node.HopCnt for this node is included, it is set to
flag set, it is removed. zero (0). Additional information about the address(es) can also be
appended, such as a PREFIX_LENGTH AddTLV.
5.4. Route Discovery 5.4. Route Discovery
A node creates a RREQ (described in Section 5.3.1) to discover a A node creates and sends a RREQ (described in Section 5.3.1) to
route to a particular destination (target). The discover a route to a particular destination (TargetNode) for which
IP.DestinationAddress for this RREQ is set to the it does not currently have a forwarding route.
LL_ALL_MANET_ROUTERS. Then the RM is transmitted.
After issuing a RREQ, the originating node waits for a route to be After issuing a RREQ, the OrigNode waits for a route to be created to
created to the target. If a route is not found within RREQ_WAIT_TIME the TargetNode. If a route is not created within RREQ_WAIT_TIME,
milliseconds, this node MAY again try to discover a route by issuing this node may again try to discover a route by issuing another RREQ.
another RREQ.
To reduce congestion in a network, repeated attempts at route To reduce congestion in a network, repeated attempts at route
discovery for a particular target SHOULD utilize a binary exponential discovery for a particular target node should utilize an exponential
backoff. The first time a node issues a RREQ, it waits backoff.
RREQ_WAIT_TIME milliseconds for a route to the target. If a route is
not found within that time, the node MAY send another RREQ. If a
route is not found within two (2) times the current waiting time,
another RREQ may be sent, up to a total of RREQ_TRIES. For each
additional attempt, the waiting time for the previous RREQ is
multiplied by two (2) so that the waiting time conforms to a binary
exponential backoff.
Data packets awaiting a route SHOULD be buffered. This buffer SHOULD For example, the first time a node issues a RREQ, it waits
have a fixed limited size and discard older data packets first. RREQ_WAIT_TIME for a route to the target node. If a route is not
found within that time, the node MAY send another RREQ. If a route
is not found within two (2) times the current waiting time, another
RREQ may be sent, up to a total of RREQ_TRIES. For each additional
attempt, the waiting time for the previous RREQ is multiplied by two
(2) so that the waiting time conforms to a binary exponential
backoff.
Data packets awaiting a route should be buffered. This buffer should
have a fixed limited size (BUFFER_SIZE_PACKETS or BUFFER_SIZE_BYTES)
and older data packets should be discarded first.
If a route discovery has been attempted RREQ_TRIES times without If a route discovery has been attempted RREQ_TRIES times without
receiving a route to the target, all data packets destined for the receiving a route to the target node, all data packets destined for
corresponding target are dropped from the buffer and a Destination the corresponding target node are dropped from the buffer and a
Unreachable ICMP message SHOULD be delivered to the application. Destination Unreachable ICMP message should be delivered to the
application.
5.5. Route Maintenance 5.5. Route Maintenance
A RERR MUST be issued if a data packet is received and it cannot be A RERR MUST be issued if a data packet is received and it cannot be
delivered to the next hop, RERR generation is described in delivered to the next hop when no forwarding route exists; RERR
Section 5.5.3. A RERR MAY be issued immediately after detecting a generation is described in Section 5.5.3.
broken link of an active route to quickly notify nodes that a link
break occurred and certain routes are no longer available. If a In addition to inability to deliver a data packet, A RERR should be
route has not been used, a RERR SHOULD NOT be generated unless issued immediately after detecting a broken link of an forwarding
generation is expected to reduce future traffic. route to quickly notify nodes that a link break occurred and that
certain routes are no longer available. If the route with the broken
link has not been used recently (indicated by ROUTE_USED), the RERR
should not be generated.
5.5.1. Active Link Monitoring 5.5.1. Active Link Monitoring
Nodes MUST monitor links on active routes that are being used. This Nodes MUST monitor next hop links on forwarding routes. This
may be accomplished by one or several mechanisms. Including: monitoring can be accomplished by one or several mechanisms,
including:
o Link layer feedback o Link layer feedback
o Neighborhood discovery [I-D.ietf-manet-nhdp] o Neighborhood discovery [I-D.ietf-manet-nhdp]
o Route timeout o Route timeout
o Other monitoring mechanisms or heuristics o Other monitoring mechanisms or heuristics
Upon detecting a link break the detecting node MUST set the Upon detecting a link break (or an unreachable next hop) the
Route.ValidTimeout to the current time for all active routes detecting node must remove the affected forwarding routes (those with
utilizing the broken link. an unreachable next hop). The node also flags these routes as
Broken. For each broken route a timer for ROUTE_DELETE is set to
ROUTE_DELETE_TIMEOUT.
5.5.2. Updating Route Lifetimes during Packet Forwarding 5.5.2. Updating Route Lifetimes during Packet Forwarding
To avoid route timeouts for active routes, a node SHOULD update the To avoid removing forwarding routes that are being used, a node
Route.ValidTimeout for the IP.SourceAddress to be the current time + SHOULD set a timeout (ROUTE_USED) to ROUTE_USED_TIMEOUT for the route
ROUTE_VALID_TIMEOUT upon receiving a data packet. This route's to the IP.SourceAddress upon receiving a data packet. If a timer for
Route.Used bit is also set, if implemented. ROUTE_DELETE is set, it is removed.
To avoid route timeouts for active routes, a node SHOULD update the To avoid removing forwarding routes that are being used, a node
Route.ValidTimeout for the IP.DestinationAddress to be the current SHOULD set a timeout (ROUTE_USED) to ROUTE_USED_TIMEOUT for the route
time + ROUTE_VALID_TIMEOUT upon successfully transmitting a packet to to the IP.DestinationAddress upon sending a data packet. If a timer
the next hop. This route's Route.Used bit is also set. for ROUTE_DELETE is set, it is removed.
5.5.3. Route Error Generation 5.5.3. Route Error Generation
When a data packet is received for a destination without a valid When a data packet is received for a destination without a valid
routing table entry, a RERR MUST be generated. When a RREP is being route table entry, a RERR MUST be generated. When a RREP is being
transmitted and no active route to the target exists, a RERR MUST be transmitted and no forwarding route to the TargetNode exists, a RERR
generated. A RERR informs the IP.SourceAddress that the route does MUST be generated. A RERR informs the IP.SourceAddress or
not exist, is no longer available, or is now invalid. RREP.OrigNode.Address that the route does not exist, and a route is
not available through this node.
In a new RERR, the address of first unreachable node When creating a new RERR, the address of first unreachable node
(IP.DestinationAddress from the data packet) is inserted. If a value (IP.DestinationAddress from the data packet or
for the unreachable node's SeqNum (AddTLV-SeqNum) is known, it SHOULD RREP.TargetNode.Address) is inserted. If a value for the unreachable
be placed in the RERR. The MsgHdr.HopLimit is set to NET_DIAMETER. node's SeqNum (AddTLV.UnreachableNode.SeqNum) is known, it should be
The MsgHdr.HopCnt is set to one (1). placed in the RERR. The MsgHdr.HopLimit is set to NET_DIAMETER. The
MsgHdr.HopCnt is set to one (1).
Additional unreachable nodes that required the same unavailable link Additional UnreachableNodes that require the same unavailable link
(routes with the same Route.NextHopAddress and (routes with the same Route.NextHopAddress and
Route.NextHopInterface) MAY be added to the RERR. The SeqNum if know Route.NextHopInterface) may be added to the RERR. The SeqNum if
SHOULD also be included. Appending unreachable node information known should also be included. Appending UnreachableNode information
notifies each processing node of additional routes that are no longer notifies each processing node of additional routes that are no longer
available. available. This option should be administratively configured.
If SeqNum information is not known or not included all nodes If SeqNum information is not known or not included in the RERR, all
processing the routing information will assume their routing nodes processing the RERR will assume their routing information
information associated with the unreachable node is no longer valid. associated with the UnreachableNode is no longer valid.
The RERR is sent to the IP.DestinationAddress LL_ALL_MANET_ROUTERS. The RERR is sent to the IP.DestinationAddress LL_ALL_MANET_ROUTERS.
Sending the RERR to the LL_ALL_MANET_ROUTERS address notifies the Sending the RERR to the LL_ALL_MANET_ROUTERS address notifies nearby
maximum number of nodes of the broken link. nodes that might depend on the now broken link.
The packet or message that forced generation of this RERR is The packet or message that forced generation of this RERR is
discarded. discarded.
5.5.4. Route Error Processing 5.5.4. Route Error Processing
When a node processes a RERR, it processes each unreachable node When a node processes a RERR, it processes each UnreachableNode's
address. It sets the Route.ValidTimeout to the current time for each information. The processing node removes the forwarding route and
Address found using longest prefix matching that meet all of the sets the broken flag for each UnreachableNode.Address found using
following conditions: longest prefix matching that meet all of the following conditions:
1. The Route.NextHopAddress is the same as the RERR 1. The Route.NextHopAddress is the same as the RERR
IP.SourceAddress. IP.SourceAddress.
2. The Route.NextHopInterface is the same as the interface on which 2. The Route.NextHopInterface is the same as the interface on which
the RERR was received. the RERR was received.
3. The Route.SeqNum is zero (0), unknown, OR the Node.SeqNum is zero 3. The Route.SeqNum is zero (0), unknown, OR the
(0), unknown, OR Node.SeqNum - Route.SeqNum <= 0 (using signed UnreachableNode.SeqNum is zero (0), unknown, OR
16-bit arithmetic). UnreachableNode.SeqNum - Route.SeqNum <= 0 (using signed 16-bit
arithmetic).
Each unreachable node that did not result in a change to Each UnreachableNode that did not result in a broken route is removed
Route.ValidTimeout is removed from the RERR, since propagation of from the RERR, since propagation of this information will not result
this information will not result in any benefit. Any information in any benefit. Any other information (AddTLVs) associated with the
associated with the removed addresses is also removed. removed address(es) is also removed.
If no unreachable node addresses remain, no further processing is If no UnreachableNode addresses remain in the RERR, no other
performed. processing is required and the RERR is discarded.
If this RERR's MsgHdr.HopLimit is greater than one (1) and at least If this RERR's MsgHdr.HopLimit is greater than one (1) and at least
one unreachable node address remains in the RERR, then the RERR is one unreachable node address remains in the RERR, then the updated
sent to the IP.DestinationAddress LL_ALL_MANET_ROUTERS. RERR is sent to the IP.DestinationAddress LL_ALL_MANET_ROUTERS.
Addresses marked with AddTLV-Ignore should remain in the RERR.
5.6. General DYMO Packet and Message Processing
5.6.1. Receiving Packets
When a packet is received, its PktTLV are first examined. Next each
message is examined and processed in order.
Each message's headers are first examined. Next, the MsgTLV are
examined. Finally, each message is processed according to its
MsgHdr.type.
5.6.2. Processing Unknown Message and TLV Types
To allow future extensions, DYMO uses bits from the semantics fields
of PktTLV, Message, MsgTLV, and AddTLV [I-D.ietf-manet-packetbb].
Note [I-D.ietf-manet-packetbb] does not currently support this
functionality.
The semantic bits have the following names and characteristics for 5.6. Unknown Message & TLV Types
nodes that do not understand the type.
Remove If a message with an unknown type is received, the message is
If the Semantics.Remove-bit is set, this information SHOULD be discarded.
removed from the message.
Discard If a message contains TLVs of an unknown type, a node ignores these
If the Semantics.Discard-bit is set, this message SHOULD not be during processing. The processing node can remove these TLVs from
processed further and it should not be propagated. In the case of any resulting transmitted messages. The behavior for unknown TLV
PktTLVs if the Semantics.Discard-bit is set, no messages from the types should be administratively configured.
packet should be processed or propagated.
5.7. Network Addresses 5.7. Advertising Network Addresses
Any node MAY advertise a network address by using a Prefix tlv Any node can advertise a network address by using a PREFIX_LENGTH TLV
[I-D.ietf-manet-packetbb]. Any nodes (other than the advertising [I-D.ietf-manet-packetbb]. Any nodes (other than the advertising
node) within the advertised Prefix SHOULD NOT participate in the node) within the advertised prefix SHOULD NOT participate in the DYMO
MANET and these nodes MUST be reachable by forwarding packets to the protocol directly and these nodes MUST be reachable by forwarding
node advertising connectivity. For example, A.B.C.1 with a prefix packets to the node advertising connectivity. Nodes other than the
length of 24 indicates all nodes with the matching A.B.C.X are advertising node that do participate in DYMO must forward the DYMO
control packets to the advertising node. For example, A.B.C.1 with a
prefix length of 24 indicates all nodes with the matching A.B.C.X are
reachable through the node with address A.B.C.1. reachable through the node with address A.B.C.1.
The meaning of the Prefix field is altered for theroute to an
Internet gateway; Route.IsInternetGateway is one (1). If the route
refers to an Internet gateway, its Prefix in association with the IP
address indicates that all nodes outside that subnet are reachable
via the Internet gateway node. For example, a route to a Internet
gateway with IP address A.B.C.1 and a prefix of 24 indicates that all
nodes with an IP address NOT matching A.B.C.X are reachable via this
node.
5.8. Simple Internet Attachment and Gatewaying 5.8. Simple Internet Attachment and Gatewaying
Simple Internet attachment consists of a network of MANET nodes Simple Internet attachment consists of a network of MANET nodes
connected to the Internet via a single Internet gateway node. The connected to the Internet via a single Internet gateway node. The
gateway is responsible for responding to RREQs for targets outside gateway is responsible for responding to RREQs for target nodes
its configured MANET subnet, as well as delivering packets to outside its configured DYMO prefix, as well as delivering packets to
destinations outside the MANET. destinations outside the MANET.
/--------------------------\ /--------------------------\
/ Internet \ / Internet \
\ / \ /
\------------+-------------/ \------------+-------------/
MANET Subnet | A.B.C.X Gateway's |
Advertised | A.B.C.X
Prefix |
+-----+-----+ +-----+-----+
| MANET | | DYMO |
/------| Internet |------\ /------| Internet |------\
/ | Gateway | \ / | Gateway | \
/ | A.B.C.1 | \ / | A.B.C.1 | \
| +-----------+ | | +-----------+ |
| MANET | | DYMO Region |
| | | |
| +------------+ | | +------------+ |
| | MANET Node | | | | DYMO Node | |
| | A.B.C.2 | | | | A.B.C.2 | |
| +------------+ | | +------------+ |
| +------------+ | | +------------+ |
| | MANET Node | | | | DYMO Node | |
| | A.B.C.3 | | | | A.B.C.3 | |
\ +------------+ / \ +------------+ /
\ / \ /
\-------------------------/ \-------------------------/
Figure 3: Simple Internet Attachament Example Figure 7: Simple Internet Attachament Example
MANET nodes wishing to be reachable from nodes in the Internet MUST DYMO nodes wishing to be reachable from nodes in the Internet MUST
have IP addresses within the gateway's configured and advertised have IP addresses within the gateway's configured and advertised
MANET subnet. Given a node with a globally routeable address or prefix. Given a node with a globally routeable address or care-of
care-of address handled by the gateway, the gateway is responsible address handled by the gateway, the gateway is responsible for
for routing and forwarding packets received from the Internet routing and forwarding packets received from the Internet destined
destined for nodes inside its MANET subnet. for nodes inside its MANET.
Since many nodes may commonly wish to communicate with the gateway, When nodes within the MANET want to send messages to nodes in the
the gateway SHOULD indicate to nodes that it is a gateway by using Internet, they simply issue RREQ for those IP.DestinationAddresses.
the gateway tlv in any RM transmitted. The Internet Gateway tlv The gateway is responsible for responding to RREQ on behalf of the
indicates to nodes in the MANET that the Node.Address is attached to Internet destinations and maintaining their associated sequence
the Internet and is capable of routing data packets to all nodes numbers.
outside of the configured MANET subnet, defined by the Node.Address
and Node.Prefix fields. For an Internet gateway and other nodes that maintain the sequence
number on behalf of other nodes, these routers must be
administratively configured to know the IP addresses for which they
must generate DYMO messages and maintain OwnSeqNum.
5.9. Multiple Interfaces 5.9. Multiple Interfaces
It is likely that DYMO will be used with multiple wireless DYMO will often be used with multiple interfaces; therefore, the
interfaces; therefore, the particular interface over which packets particular interface over which packets arrive must be known whenever
arrive must be known whenever a packet is received. Whenever a new a packet is received. Whenever a new route is created, the interface
route is created, the interface through which the Route.Address can through which the Route.Address can be reached is also recorded in
be reached is also recorded in the route table entry. the route table entry.
When multiple interfaces are available, a node transmitting a packet When multiple interfaces are available, a node transmitting a packet
with IP.DestinationAddress set to LL_ALL_MANET_ROUTERS SHOULD send with IP.DestinationAddress set to LL_ALL_MANET_ROUTERS SHOULD send
the packet on all interfaces that have been configured for DYMO the packet on all interfaces that have been configured for DYMO
operation. operation.
5.10. Packet Generation Limits 5.10. Packet/Message Generation Limits
To avoid congestion, a node SHOULD NOT transmit more than RATE_LIMIT To avoid congestion, a node's rate of packet/message generation
control messages per second. RREQ packets SHOULD be discarded before should be limited. The rate and algorithm for limiting messages is
RREP or RERR packets. left to the implementor and should be administratively configured.
Messages should be discarded in the following order of preferences
RREQ, RREP, and finally RERR.
6. Configuration Parameters 6. Configuration Parameters and Other Administrative Options
Suggested Parameter Values Suggested Parameter Values
+------------------------+-------------------------+ +------------------------------+------------------------+
| Name | Value | | Name | Value |
+------------------------+-------------------------+ +------------------------------+------------------------+
| NET_DIAMETER | 10 | | NET_DIAMETER | 10 hops |
| RATE_LIMIT | 10 | | NET_TRAVERSAL_TIME | 1000 milliseconds |
| ROUTE_VALID_TIMEOUT | 5000 milliseconds | | ROUTE_TIMEOUT | 5 seconds |
| ROUTE_DELETE_TIMEOUT | 5 * ROUTE_VALID_TIMEOUT | | ROUTE_AGE_MIN_TIMEOUT | NET_TRAVERSAL_TIME |
| ROUTE_DELETE_PERIOD | 6 * ROUTE_VALID_TIMEOUT | | ROUTE_AGE_MAX_TIMEOUT | 60 seconds |
| ROUTE_RREQ_WAIT_TIME | 1000 milliseconds | | ROUTE_NEW_TIMEOUT | ROUTE_TIMEOUT |
| RREQ_TRIES | 3 | | ROUTE_USED_TIMEOUT | ROUTE_TIMEOUT |
+------------------------+-------------------------+ | ROUTE_DELETE_TIMEOUT | 2 * ROUTE_TIMEOUT |
| ROUTE_RREQ_WAIT_TIME | 2 * NET_TRAVERSAL_TIME |
Table 1 | RREQ_TRIES | 3 tries |
| UNICAST_MESSAGE_SENT_TIMEOUT | 1 second |
+------------------------------+------------------------+
Table 2
These suggested values work well for small and medium well connected These suggested values work well for small and medium well connected
networks with infrequence topology changes. For larger networks or networks with infrequent topology changes. These parameters should
networks with frequent topology changes the default DYMO parameters be administratively configured for the network where DYMO is used.
should be adjusted using either experimentally determined values or Ideally, for networks with frequent topology changes the DYMO
dynamic adaptation. For example, in networks with infrequent parameters should be adjusted using either experimentally determined
topology changes ROUTE_VALID_TIMEOUT may be set to a much larger values or dynamic adaptation. For example, in networks with
value. infrequent topology changes ROUTE_USED_TIMEOUT may be set to a much
larger value.
It is assumed that all nodes in the network share the same parameter In addition to the parameters above several administrative options
settings. Different parameter values for ROUTE_VALID_TIMEOUT or exist. The following table enumerates several of the options and
ROUTE_DELETE_TIMEOUT in addition to arbitrary packet delays may suggested values.
result in frequent route breaks or in extreme cases routing loops.
Suggested Options Settings
+-------------------------------------+----------------------------+
| Name | Value |
+-------------------------------------+----------------------------+
| RESPONSIBLE_ADDRESSES | Self or Prefix |
| DYMO_INTERFACES | User Specified |
| INCLUDE_INFORMATION | Yes-SeqNum,HopCnt,Prefix |
| APPEND_ADDRESS | Yes - RREQ & RREP |
| APPEND_OWN_ADDRESS_INCREMENT_SEQNUM | Yes for RREQ |
| GENERATE_RERR_IMMEDIATELY | No |
| RERR_INCLUDE_ALL_UNREACHABLES | Yes |
| UNKNOWN_TYPE_HANDLING | Ignore |
| BUFFER_SIZE_PACKETS | 50 packets |
| BUFFER_SIZE_BYTES | 1500 * BUFFER_SIZE_PACKETS |
+-------------------------------------+----------------------------+
Table 3
7. IANA Considerations 7. IANA Considerations
DYMO requires a UDP port number to carry protocol packets - TBD. DYMO requires a UDP port number to carry protocol packets - TBD.
DYMO also requires the link-local multicast address DYMO also requires the link-local multicast address
LL_ALL_MANET_ROUTERS; IPv4 TBD, IPv6 TBD. LL_ALL_MANET_ROUTERS; IPv4 TBD, IPv6 TBD [I-D.chakeres-manet-iana].
This section also specifies several messages types, message tlv- This section specifies several messages types, message tlv-types, and
types, and address tlv-types. address tlv-types.
Future types will be allocated using standard actions as described in Future types will be allocated using standard actions as described in
[RFC2434]. [RFC2434].
7.1. DYMO Message Type Specification 7.1. DYMO Message Type Specification
The following address block TLV.
DYMO Message Types DYMO 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 2 Table 4
7.2. Packet TLV Type Specification 7.2. Packet TLV Type Specification
Packet TLV Types Packet TLV Types
+-------------------+------+--------+-------------------------------+ +-------------------+------+--------+-------------------------------+
| Name | Type | Length | Value | | Name | Type | Length | Value |
+-------------------+------+--------+-------------------------------+ +-------------------+------+--------+-------------------------------+
| Unicast Response | TBD | 10 - | Indicates to the processing | | Unicast Response | 10 - | 0 | Indicates to the processing |
| Request | | TBD | node that the previous hop | | Request | TBD | | node that the previous hop |
| | | | (IP.SourceAddress) expects a | | | | | (IP.SourceAddress) expects a |
| | | | unicast message within | | | | | unicast message within |
| | | | UNICAST_MESSAGE_SENT_TIMEOUT. | | | | | UNICAST_MESSAGE_SENT_TIMEOUT. |
| | | | Any unicast packet will serve | | | | | Any unicast packet will serve |
| | | | this purpose, and it MAY be | | | | | this purpose, and it MAY be |
| | | | an ICMP REPLY message. If a | | | | | an ICMP REPLY message. If a |
| | | | message is not sent, then the | | | | | message is not sent, then the |
| | | | previous hop may assume that | | | | | previous hop may assume that |
| | | | the link is unidirectional | | | | | the link is unidirectional |
| | | | and may blacklist this node. | | | | | and may blacklist the link to |
| | | | this node. |
+-------------------+------+--------+-------------------------------+ +-------------------+------+--------+-------------------------------+
Table 3 Table 5
7.3. Address Block TLV Specification 7.3. Address Block TLV Specification
Address Block TLV Specification Overview Address Block TLV Types
+----------------------+------+--------+----------------------------+ +----------------+------+---------+---------------------------------+
| Name | Type | Length | Value | | Name | Type | Length | Value |
+----------------------+------+--------+----------------------------+ +----------------+------+---------+---------------------------------+
| DYMOSeqNum | 10 - | 16 | The DYMO sequence num | | DYMOSeqNum | 10 - | 16 bits | The DYMO sequence num |
| | TBD | bits | associated with this | | | TBD | | associated with this address. |
| | | | address. The sequence | | | | | The sequence number may be the |
| | | | number may be the last | | | | | last known sequence number. |
| | | | known sequence number. | | HopCount | 11 - | 8 bits | The number of hops traversed by |
| HopCount | 11 - | 8 bits | The number of hops | | | TBD | | the information associated with |
| | TBD | | traversed by the | | | | | this address. |
| | | | information associated | | MaxAge | 12 - | Any | The maximum number of |
| | | | with this address. | | | TBD | length | milliseconds that the |
| IsInternetGateway | 12 - | 0 bits | Usde to indicate that this | | | | | associated routing information |
| | TBD | | node is an Internet | | | | | can be kept before being |
| | | | Gateway | | | | | deleted. |
| IsOriginator | 13 - | 0 bits | Used to indicate that this | +----------------+------+---------+---------------------------------+
| | TBD | | node is the Originator of |
| | | | the RM. |
| IsTarget | 14 - | 0 bits | Used to indicate this node |
| | TBD | | is the target of the DYMO |
| | | | message |
| Ignore | 15 - | 0 | Used to indicate that this |
| | TBD | | addresses should not be |
| | | | processed normally; |
| | | | instead it should be |
| | | | ignored. |
+----------------------+------+--------+----------------------------+
Table 4 Table 6
8. Security Considerations 8. Security Considerations
Currently, DYMO does not specify any special security measures. Currently, DYMO does not specify any special security measures.
Routing protocols, however, are prime targets for impersonation Routing protocols, however, are prime targets for impersonation
attacks. In networks where the node membership is not known, it is attacks. In networks where the node membership is not known, it is
difficult to determine the occurrence of impersonation attacks, and difficult to determine the occurrence of impersonation attacks, and
security prevention techniques are difficult at best. However, when security prevention techniques are difficult at best. However, when
the network membership is known and there is a danger of such the network membership is known and there is a danger of such
attacks, DYMO messages must be protected by the use of authentication attacks, DYMO messages must be protected by the use of authentication
skipping to change at page 27, line 11 skipping to change at page 28, line 48
cryptographically strong message digests or digital signatures. cryptographically strong message digests or digital signatures.
While DYMO does not place restrictions on the authentication While DYMO does not place restrictions on the authentication
mechanism used for this purpose, IPsec Authentication Message (AH) is mechanism used for this purpose, IPsec Authentication Message (AH) is
an appropriate choice for cases where the nodes share an appropriate an appropriate choice for cases where the nodes share an appropriate
security association that enables the use of AH. security association that enables the use of AH.
In particular, RM messages SHOULD be authenticated to avoid creation In particular, RM messages SHOULD be authenticated to avoid creation
of spurious routes to a destination. Otherwise, an attacker could of spurious routes to a destination. Otherwise, an attacker could
masquerade as that destination and maliciously deny service to the masquerade as that destination and maliciously deny service to the
destination and/or maliciously inspect and consume traffic intended destination and/or maliciously inspect and consume traffic intended
for delivery to the destination. RERR messages, while slightly less for delivery to the destination. RERR messages SHOULD be
dangerous, SHOULD be authenticated in order to prevent malicious authenticated in order to prevent malicious nodes from disrupting
nodes from disrupting active routes between communicating nodes. active routes between communicating nodes.
If the mobile nodes in the ad hoc network have pre-established If the mobile nodes in the ad hoc network have pre-established
security associations, the purposes for which the security security associations, the purposes for which the security
associations are created should include that of authorizing the associations are created should include that of authorizing the
processing of DYMO control packets. Given this understanding, the processing of DYMO control packets. Given this understanding, the
mobile nodes should be able to use the same authentication mechanisms mobile nodes should be able to use the same authentication mechanisms
based on their IP addresses as they would have used otherwise. based on their IP addresses as they would have used otherwise.
9. Acknowledgments 9. Acknowledgments
DYMO is a descendant of the design of previous MANET reactive DYMO is a descendant of the design of previous MANET reactive
protocols, especially AODV [RFC3561] and DSR [Johnson96]. Changes to protocols, especially AODV [RFC3561] and DSR [Johnson96]. Changes to
previous MANET reactive protocols stem from research and previous MANET reactive 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 DYMO. Additional thanks to Luke Klein-
Berndt, Pedro Ruiz, Fransisco Ros, Koojana Kuladinithi, Ramon Berndt, Pedro Ruiz, Fransisco Ros, Koojana Kuladinithi, Ramon
Caceres, and Thomas Clausen for reviewing of DYMO, as well as several Caceres, Thomas Clausen, Christopher Dearlove, and Seung Yi for
specification suggestions. reviewing of DYMO, as well as several specification suggestions.
10. References 10. References
10.1. Normative References 10.1. Normative References
[I-D.ietf-manet-packetbb]
Clausen, T., "Generalized MANET Packet/Message Format",
draft-ietf-manet-packetbb-02 (work in progress),
July 2006.
[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.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434, IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998. October 1998.
[RFC3513] Hinden, R. and S. Deering, "Internet Protocol Version 6 [RFC3513] Hinden, R. and S. Deering, "Internet Protocol Version 6
(IPv6) Addressing Architecture", RFC 3513, April 2003. (IPv6) Addressing Architecture", RFC 3513, April 2003.
[RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On-
Demand Distance Vector (AODV) Routing", RFC 3561, Demand Distance Vector (AODV) Routing", RFC 3561,
July 2003. July 2003.
10.2. Informative References 10.2. Informative References
[I-D.ietf-manet-nhdp] [I-D.chakeres-manet-iana]
Clausen, T., Dearlove, C., and J. Dean, "MANET Chakeres, I., "MANET IANA Needs",
Neighborhood Discovery Protocol", draft-ietf-manet-nhdp-00 draft-chakeres-manet-iana-01 (work in progress),
(work in progress), June 2006. September 2006.
[I-D.ietf-manet-packetbb] [I-D.ietf-manet-nhdp]
Clausen, T., Dearlove, C., Dean, J., and C. Adjih, Clausen, T., "MANET Neighborhood Discovery Protocol
"Generalized MANET Packet/Message Format", (NHDP)", draft-ietf-manet-nhdp-00 (work in progress),
draft-ietf-manet-packetbb-01 (work in progress),
June 2006. June 2006.
[Johnson96] [Johnson96]
Johnson, D. and D. Maltz, "Dynamic Source Routing (DSR) in Johnson, D. and D. Maltz, "Dynamic Source Routing (DSR) in
Ad hoc Networks", In Mobile Computing, Chapter 5, pp. 153- Ad hoc Networks", In Mobile Computing, Chapter 5, pp. 153-
181, 1996. 181, 1996.
[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
skipping to change at page 29, line 24 skipping to change at page 31, line 24
Email: ian.chakeres@gmail.com Email: ian.chakeres@gmail.com
Charlie Perkins Charlie Perkins
Nokia Research Center Nokia Research Center
313 Fairchild Drive 313 Fairchild Drive
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
Phone: +1-650-625-2986 Phone: +1-650-625-2986
Fax: +1-650-625-2502 Fax: +1-650-625-2502
Email: charlie.perkins@nokia.com Email: charles.perkins@nokia.com
Intellectual Property Statement Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
 End of changes. 199 change blocks. 
623 lines changed or deleted 706 lines changed or added

This html diff was produced by rfcdiff 1.33. The latest version is available from http://tools.ietf.org/tools/rfcdiff/