draft-ietf-manet-dymo-00.txt   draft-ietf-manet-dymo-01.txt 
Mobile Ad hoc Networks Working I. Chakeres Mobile Ad hoc Networks Working I. Chakeres
Group E. Belding-Royer Group E. Belding-Royer
Internet-Draft UC Santa Barbara Internet-Draft UC Santa Barbara
Expires: July 5, 2005 C. Perkins Expires: November 9, 2005 C. Perkins
Nokia Nokia
January 2005 May 8, 2005
Dynamic MANET On-demand Routing Protocol (DYMO) Dynamic MANET On-demand (DYMO) Routing
draft-ietf-manet-dymo-00 draft-ietf-manet-dymo-01
Status of this Memo Status of this Memo
This document is an Internet-Draft and is subject to all provisions This document is an Internet-Draft and is subject to all provisions
of Section 3 of RFC 3667. By submitting this Internet-Draft, each of Section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of author represents that any 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 is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with which he or she become aware will be disclosed, in accordance with
RFC 3668. RFC 3668.
skipping to change at page 1, line 37 skipping to change at page 1, line 37
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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. The list of http://www.ietf.org/ietf/1id-abstracts.txt. The list of
Internet-Draft Shadow Directories can be accessed at 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 July 5, 2005. This Internet-Draft will expire on November 9, 2005.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
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 quick use by mobile nodes in wireless multihop networks. It offers
adaptation to dynamic conditions, low processing and memory overhead, adaptation to changing network topology and determines unicast routes
low network utilization, and determines unicast routes between nodes between nodes within the network.
within the network.
Table of Contents Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 6 3. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 6
3.1 Conceptual Data Structures . . . . . . . . . . . . . . . . 6 3.1 Route Table Entry . . . . . . . . . . . . . . . . . . . . 6
3.1.1 Route Table Entry . . . . . . . . . . . . . . . . . . 6 3.2 DYMO Message Elements . . . . . . . . . . . . . . . . . . 7
3.2 DYMO Message Elements . . . . . . . . . . . . . . . . . . 6 3.2.1 Generic DYMO Element Structure . . . . . . . . . . . . 7
3.2.1 Fixed Portion of DYMO Elements . . . . . . . . . . . . 6 3.2.2 Routing Element (RE) . . . . . . . . . . . . . . . . . 9
3.2.2 Routing Element (RE) . . . . . . . . . . . . . . . . . 7 3.2.3 Route Error (RERR) . . . . . . . . . . . . . . . . . . 11
3.2.3 Route Error (RERR) . . . . . . . . . . . . . . . . . . 8 3.2.4 Unsupported-element Error (UERR) . . . . . . . . . . . 12
3.2.4 Unsupported-element Error (UERR) . . . . . . . . . . . 8
3.3 Field Descriptions . . . . . . . . . . . . . . . . . . . . 8
4. Detailed Operation . . . . . . . . . . . . . . . . . . . . . . 12
4.1 Sequence Numbers . . . . . . . . . . . . . . . . . . . . . 12
4.1.1 Maintaining a Sequence Number . . . . . . . . . . . . 12
4.1.2 Incrementing a Sequence Number . . . . . . . . . . . . 12
4.1.3 Sequence Number Rollover . . . . . . . . . . . . . . . 12
4.1.4 Actions After Sequence Number Loss . . . . . . . . . . 12
4.2 DYMO Routing Table Operations . . . . . . . . . . . . . . 12
4.2.1 Creating or Updating a Route Table Entry from
Routing Element Information . . . . . . . . . . . . . 12
4.2.2 Route Table Entry Timeouts . . . . . . . . . . . . . . 13
4.3 DYMO General Processing . . . . . . . . . . . . . . . . . 13
4.3.1 DYMO Control Packet Processing . . . . . . . . . . . . 13
4.3.2 Generic Element Pre-processing . . . . . . . . . . . . 14
4.3.3 Processing Unsupported DYMO Elements . . . . . . . . . 14
4.3.3.1 Generating an Unsupported-element Error . . . . . 14
4.3.4 Generic Element Post-processing . . . . . . . . . . . 15
4.3.5 DYMO Control Packet Transmission . . . . . . . . . . . 15
4.4 Routing Element . . . . . . . . . . . . . . . . . . . . . 15
4.4.1 Routing Element Creation . . . . . . . . . . . . . . . 15
4.4.2 Appending Additional Routing Information to an
Existing Routing Element . . . . . . . . . . . . . . . 15
4.4.3 Routing Element Processing . . . . . . . . . . . . . . 16
4.5 Route Discovery . . . . . . . . . . . . . . . . . . . . . 16
4.6 Route Maintenance . . . . . . . . . . . . . . . . . . . . 17
4.6.1 Link Breaks . . . . . . . . . . . . . . . . . . . . . 17
4.6.2 Updating Route Lifetimes . . . . . . . . . . . . . . . 17
4.6.3 Extending Route Lifetimes . . . . . . . . . . . . . . 17
4.6.4 Route Error Generation . . . . . . . . . . . . . . . . 18
4.6.5 Route Error Processing . . . . . . . . . . . . . . . . 18
4.7 Routing Prefix . . . . . . . . . . . . . . . . . . . . . . 19
4.8 Internet Attachment . . . . . . . . . . . . . . . . . . . 19
4.9 Multiple Interfaces . . . . . . . . . . . . . . . . . . . 19
4.10 Packet Generation Limits . . . . . . . . . . . . . . . . . 20
5. Configuration Parameters . . . . . . . . . . . . . . . . . . . 21 4. Detailed Operation . . . . . . . . . . . . . . . . . . . . . . 13
4.1 Sequence Numbers . . . . . . . . . . . . . . . . . . . . . 13
4.1.1 Maintaining a Sequence Number . . . . . . . . . . . . 13
4.1.2 Incrementing a Sequence Number . . . . . . . . . . . . 13
4.1.3 Sequence Number Rollover . . . . . . . . . . . . . . . 13
4.1.4 Actions After Sequence Number Loss . . . . . . . . . . 13
4.2 DYMO Routing Table Operations . . . . . . . . . . . . . . 13
4.2.1 Creating or Updating a Route Table Entry from a
Routing Element Block . . . . . . . . . . . . . . . . 13
4.2.2 Route Table Entry Timeouts . . . . . . . . . . . . . . 14
4.3 General DYMO Processing . . . . . . . . . . . . . . . . . 15
4.3.1 DYMO Control Packet Processing . . . . . . . . . . . . 15
4.3.2 Generic Element Pre-processing . . . . . . . . . . . . 15
4.3.3 Processing Unsupported DYMO Element Types . . . . . . 15
4.3.3.1 Generating an Unsupported-element Error . . . . . 16
4.3.4 Generic Element Post-processing . . . . . . . . . . . 16
4.3.5 DYMO Control Packet Transmission . . . . . . . . . . . 16
4.4 Routing Element . . . . . . . . . . . . . . . . . . . . . 17
4.4.1 Routing Element Creation . . . . . . . . . . . . . . . 17
4.4.2 Routing Element Processing . . . . . . . . . . . . . . 17
4.4.3 Appending Additional Routing Information to an
Existing Routing Element . . . . . . . . . . . . . . . 18
4.5 Route Discovery . . . . . . . . . . . . . . . . . . . . . 18
4.6 Route Maintenance . . . . . . . . . . . . . . . . . . . . 19
4.6.1 Active Link Monitoring . . . . . . . . . . . . . . . . 19
4.6.2 Updating Route Lifetimes . . . . . . . . . . . . . . . 19
4.6.3 Route Error Generation . . . . . . . . . . . . . . . . 19
4.6.4 Route Error Processing . . . . . . . . . . . . . . . . 20
4.7 Routing Prefix . . . . . . . . . . . . . . . . . . . . . . 20
4.8 Internet Attachment . . . . . . . . . . . . . . . . . . . 21
4.9 Multiple Interfaces . . . . . . . . . . . . . . . . . . . 21
4.10 Packet Generation Limits . . . . . . . . . . . . . . . . . 22
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 5. Configuration Parameters . . . . . . . . . . . . . . . . . . . 23
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
7. Security Considerations . . . . . . . . . . . . . . . . . . . 23 7. Security Considerations . . . . . . . . . . . . . . . . . . . 25
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.1 Normative References . . . . . . . . . . . . . . . . . . . 25 9.1 Normative References . . . . . . . . . . . . . . . . . . . 27
9.2 Informative References . . . . . . . . . . . . . . . . . . 25 9.2 Informative References . . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 27
Intellectual Property and Copyright Statements . . . . . . . . 27 Intellectual Property and Copyright Statements . . . . . . . . 29
1. Overview 1. Overview
The Dynamic MANET On-demand (DYMO) routing protocol enables dynamic, The Dynamic MANET On-demand (DYMO) routing protocol enables reactive,
reactive, multihop routing between participating nodes wishing to multihop routing between participating nodes that wish to
communicate. The basic operations of the protocol are route communicate. The basic operations of the DYMO protocol are route
discovery and management. During route discovery the originating discovery and management. During route discovery the originating
node causes dissemination of a Routing Element (RE) throughout the node initiates dissemination of a Route Request (RREQ) throughout the
network to find the target node. During dissemination each network to find the target node. During this dissemination process,
intermediate node creates a route to the originating node. When the each intermediate node records a route to the originating node. When
target node receives the RE it responds with RE unicast toward the target node receives the RREQ, it responds with a Route Reply
originating node. During propagation each node creates a route to (RREP), unicast toward the originating node. Each node that receives
the target node. When the originating node is reached routes have the RREP records a route to the target node, and then the RREP is
been established between the originating node and the target node in unicast toward the originating node. When the originating node
both directions. receives the RREP, routes have then been established between the
originating node and the target node in both directions.
In order to react quickly to changes in the network topology nodes In order to react to changes in the network topology nodes maintain
should maintain their routes and monitor their links. When a packet their routes and monitor their links. When a packet is received for
is received for a route that is no longer available the source of the a route that is no longer available the source of the packet is
packet should be notified. A Route Error (RERR) is sent to the notified. A Route Error (RERR) is sent to the packet source to
packet source to indicate the current route is broken. Once the indicate the current route is broken. Once the source receives the
source receives the RERR, it will re-initiate route discovery if it RERR, it re-initiates route discovery if it still has packets to
still has packets to deliver. deliver.
In order to enable extension of the base specification, DYMO defines In order to enable extension of the base specification, DYMO defines
the handling of unsupported extensions. By defining default a generic element structure and handling of future extensions. By
handling, future extensions are handled in a predetermined understood defining a fixed structure and default handling, future extensions
fashion. are handled in a predetermined fashion.
DYMO uses sequence numbers to ensure loop freedom [3]. DYMO uses sequence numbers as they have been proven to ensure loop
freedom [3]. Sequence numbers enable nodes to determine the order of
DYMO route discovery packets, thereby avoiding use of stale routing
information.
All DYMO packets are transmitted via UDP on port TBD. All DYMO packets are transmitted via UDP on port TBD.
2. Terminology 2. Terminology
IPBroadcastAddress
Transmit the packet to the IP Limited Broadcast address, IP Destination Address (IPDestinationAddress)
255.255.255.255 (IPv4) or FF:FF:FF:FF:FF:FF (IPv6).
IPDestinationAddress
The destination of a packet, indicated by examining the IP The destination of a packet, indicated by examining the IP
header. header.
IPSourceAddress
IP Source Address (IPSourceAddress)
The source of a packet, indicated by examining the IP header. The source of a packet, indicated by examining the IP header.
MANETcast
Transmit the packet to all MANET nodes within reception range. DYMOcast
In a simple implementation MANETcast packets are sent to the Packet transmission to all MANET routers within reception
IPBroadcastAddress. MANETcast SHOULD preform duplicate range. DYMOcast packets should be sent with an
suppression. IPDestinationAddress of IPv4 TBD (IPv6 TBD), the
DYMOcastAddress.
Routing Element (RE)
A DYMO message element that is used to distribute routing
information.
Route Invalidation
Disabling the use of a route, causing it to be unavailable for
forwarding data.
Route Reply (RREP)
Upon receiving a RREQ, the target node generates a Route Reply
(RREP). A RREP is a RE with a unicast IPDestinationAddress,
indicating that this RE is to be unicast hop-by-hop toward the
TargetAddress.
Route Request (RREQ)
A node generates a Route Request (RREQ) to discover a valid
route to a particular destination (TargetAddress). A RREQ is
simply a RE with the DYMOcastAddress in the
IPDestinationAddress field of the IP packet. Also, the A-bit
is set to one (A=1) to indicate that the TargetNode must
respond with a RREP.
Valid Route Valid Route
A known route where the RouteValidTimeout is larger than the A known route where the Route.ValidTimeout is greater than the
current time. current time.
3. Data Structures 3. Data Structures
3.1 Conceptual Data Structures 3.1 Route Table Entry
3.1.1 Route Table Entry The route table entry is a conceptual data structure.
o RouteAddress Implementations may use any internal representation that conforms to
o RouteDeleteTimeout the semantics of a route as specified in this document.
o RouteHopCnt o Route.DestAddress
o RouteIsGateway o Route.DeleteTimeout
o RouteNextHopAddress o Route.HopCnt
o RouteNextHopInterface o Route.IsGateway
o RoutePrefix o Route.NextHopAddress
o RouteSeqNum o Route.NextHopInterface
o RouteValidTimeout o Route.Prefix
o Route.SeqNum
o Route.ValidTimeout
These fields are defined as follows:
Route Node Address (Route.DestAddress)
The IP address of the node associated with the routing table
entry.
Route Delete Timeout (Route.DeleteTimeout)
If the time current is after Route.DeleteTimeout the
corresponding routing table entry MUST be deleted.
Route Hop Count (Route.HopCnt)
The number of intermediate node hops before reaching the
Route.DestAddress.
Route Is Gateway (Route.IsGateway)
1-bit selector indicating whether the Route.DestAddress is a
gateway.
Route Next Hop Address (Route.NextHopAddress)
The IP address of the next node on the path toward the
Route.DestAddress.
Route Next Hop Interface (Route.NextHopInterface)
The interface used to send packets toward the
Route.DestAddress.
Route Prefix (Route.Prefix)
6-bit field that specifies the size of the subnet reachable
through the Route.DestAddress, see Section 4.7. The definition
of the Prefix field is different for gateways; entries with
Route.IsGateway set to one (1).
Route Sequence Number (Route.SeqNum)
The sequence number of the Route.DestAddress.
Route.ValidTimeout
The time at which a route table entry is scheduled to be
invalidated. The routing table entry is no longer considered
valid if the current time is after Route.ValidTimeout.
3.2 DYMO Message Elements 3.2 DYMO Message Elements
3.2.1 Fixed Portion of DYMO Elements 3.2.1 Generic DYMO Element Structure
All DYMO message elements must conform to the fixed data structure All DYMO message elements MUST conform to the fixed data structure
below. below.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ElemType |T|I| Res | ElemTTL | ElemLen | | Type | Len | TTL |I|Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. ElemTargetAddress . . NotifyAddress (Only Types with M-bit set) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. ElemNotifyAddress (Only ElemTypes with M-bit set) . . TargetAddress (for non-DYMOcastAddress IPDestinationAddresses).
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . . .
. ElemData . . Data .
. ElemType-Specific Payload . . Type-Specific Payload .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
Element Type (Type)
0 0
0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| Type | = |M| H | |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 2
The Type field identifies the element as well as the handling
by nodes that do not implement or understand the element. The
most significant bit, the M-bit, denotes whether the element
requires notification via an Unsupported-element Error (UERR)
when the element is not understood or handled by a particular
node. The next two bits, H-bits, identify how the Type is to
be handled by nodes not implementing the Type, regardless of
UERR delivery. Section 4.3.3 describes the handling behavior
based on the Type.
I-bit (I)
1-bit selector indicating whether the element has been ignored
by some node that has relayed this element. If I=1 the element
has been ignored.
Reserved (Reserved, Reservd, Res, R)
Reserved bits. These bits are set to zero (0) during element
creation and ignored during processing.
Element Time to Live (TTL)
6-bit field that identifies the maximum number of times the
element is to be retransmitted. The TTL field operates similar
to IPTTL (MaxCount) and is decremented at each hop. When TTL
reaches zero (0) the element is dropped.
Element Length (Len)
12-bit field that indicates the size of the element in bytes,
including the fixed portion.
Element Notify Address (NotifyAddress)
The node to send a UERR if the Element Type is unsupported or
not handled by the processing node. The NotifyAddress field is
only present if the Type field has the M-bit is set to one (1).
Element Target Address (TargetAddress)
The node that is the ultimate destination of the element. This
field is only required if the IPDestinationAddress is not the
DYMOcastAddress. During hop-by-hop transmission of a DYMO
packet the IPDestinationAddress is filled with the
Route.NextHopAddress of the route table entry associated with
the TargetAddress.
Element Data (Data)
Type-specific payload.
3.2.2 Routing Element (RE) 3.2.2 Routing Element (RE)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ElemType |T|I| Res | ElemTTL | ElemLen | | Type | Len | TTL |I|A| Res |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. ElemTargetAddress .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ElemTargetSeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|G| Prefix1 | Res | REHopCnt1 | . TargetAddress .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. RENodeAddress1 . | TargetSeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RENodeSeqNum1 | | THopCnt |Res| .
+-+-+-+-+-+-+-+-+ .
. .
. Routing Element Blocks (1 or more) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|G| PrefixN | Res | REHopCntN |
Figure 3
A-bit (A)
1-bit selector indicating whether this RE requires a RREP by
the TargetAddress. If A=1 a RREP is required. The
instructions for generating a RREP are described in
Section 4.4.2.
Element Target Address (TargetAddress)
The node that is the ultimate destination of the Routing
Element.
Target Sequence Number (TargetSeqNum)
The sequence number of the ultimate destination of this Routing
Element. If the Sequence Number is unknown for this particular
Route.DestAddress then TargetSeqNum is set to zero (0).
Target Hop Count (THopCnt)
6-bit field that identifies the number of intermediate nodes
through which a packet traversed on the route to this
particular TargetAddress the last time a route was available.
The THopCnt is the Route.HopCnt of the TargetAddress, stored in
the routing table of the RREQ originator. If the hop count
information is not available at the originating node then the
THopCnt is set to zero (0).
Routing Element Block (REBlock)
Data structure that describes routing information related to a
particular IP address, RENodeAddress.
Routing Element Block (REBlock)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|G| Prefix |Reservd| REHopCnt |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. Additional RENodeAddressN (if needed) . . RENodeAddress .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional RENodeSeqNumN (if needed) | | RENodeSeqNum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ElemType: 1. Nodes MUST implement the Routing Element. Figure 4
G-bit (G)
1-bit selector to indicate whether the RENodeAddress is a
gateway. If G=1 RENodeAddress is a gateway. For more
information on gateway operation see Section 4.8.
Prefix Size (Prefix)
6-bit field that specifies the size of the subnet reachable
through the associated node, see Section 4.7. The
definition of Prefix is different for gateways.
Routing Element Block Hop Count (REHopCnt)
6-bit field that identifies the number of intermediate nodes
through which the associated REBlock has passed.
Routing Element Node Address (RENodeAddress)
The IP address of the node associated with this REBlock.
Routing Element Node Sequence Number (RENodeSeqNum)
The sequence number of the node associated with this
REBlock.
3.2.3 Route Error (RERR) 3.2.3 Route Error (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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ElemType |T|I| Res | ElemTTL | ElemLen | | Type | Len | TTL |I|Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. ElemTargetAddress .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. UNodeAddress1 . . UNodeAddress1 .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UNodeSeqNum1 | | UNodeSeqNum1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. Additional UNodeAddress (if needed) . . Additional UNodeAddressN (if needed) .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Additional UNodeSeqNum (if needed) | | Additional UNodeSeqNumN (if needed) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
ElemType: 2. Nodes not implementing RERR will ignore the element Figure 5
and continue.
Unreachable Node Address (UNodeAddress)
The IP address of the unreachable node.
Unreachable Node Sequence Number (UNodeSeqNum)
The sequence number of the unreachable node, if known;
otherwise, zero (0). RERR generation is described in
Section 4.6.3.
3.2.4 Unsupported-element Error (UERR) 3.2.4 Unsupported-element Error (UERR)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ElemType |T|I| Res | ElemTTL | ElemLen | | Type | Len | TTL |I|Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. ElemTargetAddress . . TargetAddress .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. UElemTargetAddress . . UElemTargetAddress .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. UERRNodeAddress . . UERRNodeAddress .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UElemType | | UElemType |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
ElemType: 3. Nodes not implementing UERR will ignore the element Figure 6
and continue.
3.3 Field Descriptions
A-bit (A)
1-bit selector indicating whether this RE requires an answer RE
by the ElemTargetAddress. If A=1 an answer is required. The
instructions for generating an answer RE are described in
Section 4.4.3.
Element Data (ElemData)
ElemType-specific payload.
Element Length (ElemLen)
12-bit field that indicates the size of the element in bytes,
including the fixed portion.
Element Notify Address (ElemNotifyAddress)
The node to send a UERR if the ElemType is unsupported. The
ElemNotifyAddress field is only present if the ElemType has the
M-bit is set to one (1).
Element Target Address (ElemTargetAddress)
The node that is the ultimate destination of the element.
Element Time to Live (ElemTTL)
6-bit field that identifies the maximum number of times the
element is to be retransmitted. The ElemTTL field operates
similar to IPTTL (MaxCount) and is decremented at each hop.
When ElemTTL reaches zero (0) the element is dropped.
Element Type (ElemType)
0 0 Element Target Address (TargetAddress)
0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8 The node that is the ultimate destination of the element,
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ NotifyAddress.
| ElemType | = |M| H | |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
The ElemType field identifies the element as well as the Unsupported-element Target Address (UElemTargetAddress)
handling by nodes that do not implement or understand the Address of the destination of the element that caused
element. The MSB bit, M-bit, denotes whether the element generation of this UERR; TargetAddress from the offending fixed
requires notification via an Unsupported-element Error (UERR) DYMO element.
when the element is not understood or handled by a particular
node. The next two bits, H-bits, identify how the ElemType
MUST be handled by nodes not implementing the ElemType,
regardless of UERR delivery. Section 4.3.3 describes the
handling behavior based on the ElemType.
G-bit (G)
1-bit selector to indicate whether the RENodeAddress1 is a
gateway. If G=1 RENodeAddress1 is a gateway. For more
information on gateway operation see Section 4.8.
I-bit (I)
1-bit selector indicating whether the element has been ignored.
If I=1 the element has been ignored. For a description of
processing for unsupported elements by ElemType see
Section 4.3.3.
Prefix Size (Prefix)
6-bit field that specifies the size of the subnet reachable
through the associated node, see Section 4.7. The definition
of Prefix is different for gateways.
Routing Element Block Hop Count (REHopCnt)
6-bit field that identifies the number of intermediate nodes
the associated RE block has passed through.
Routing Element Node Address (RENodeAddress)
The IP address of the node that appending its RENodeAddress.
Routing Element Node Sequence Number (RENodeSeqNum)
The sequence number of the node appending its RENodeSeqNum.
Reserved (Res, R)
Reserved bits. These bits are set to zero (0) during element
creation and ignored during processing.
Route Node Address (RouteNodeAddress)
The IP address of the node associated with the routing table
entry.
Route Delete Timeout (RouteDeleteTimeout)
The corresponding routing table entry MUST be deleted if the
current time is after RouteDeleteTimeout.
Route Hop Count (RouteHopCnt)
The number of intermediate node hops before reaching the
RouteNodeAddress.
Route Is Gateway (RouteIsGateway)
1-bit selector indicating whether the RouteNodeAddress is a
gateway.
Route Next Hop Address (RouteNextHopAddress)
The IP address of the next node on the path toward the
RouteNodeAddress.
Route Next Hop Interface (RouteNextHopInterface)
The interface to send packets toward the RouteNodeAddress.
Route Prefix (RoutePrefix)
6-bit field that specifies the size of the subnet reachable
through the RouteNodeAddress, see Section 4.7. The definition
of the Prefix field is different for gateways.
Route Sequence Number (RouteSeqNum)
The sequence number of the RouteNodeAddress.
RouteValidTimeout
The routing table entry is no longer considered valid if the
current time is after RouteValidTimeout.
T-bit (T)
1-bit selector indicating how the element must be transmitted.
If T=0 the element is unicast toward the ElemTargetAddress.
Otherwise, if T=1 the element is MANETcast.
Unreachable Node Address (UNodeAddress)
The IP address of the unreachable node.
Unreachable Node Sequence Number (UNodeSeqNum)
The sequence number of the unreachable node, if known;
otherwise, zero (0).
Unsupported-element Node Address (UERRNodeAddress) Unsupported-element Node Address (UERRNodeAddress)
The IP address of the node that generated the UERR. The IP address of the node that created the UERR.
Unsupported-element Target Address (UElemTargetAddress)
Address of the destination of the element that caused delivery
of the UERR.
Unsupported-element Type (UElemType) Unsupported-element Type (UElemType)
The ElemType that required generation of the UERR. The Type that required generation of the UERR.
4. Detailed Operation 4. Detailed Operation
4.1 Sequence Numbers 4.1 Sequence Numbers
4.1.1 Maintaining a Sequence Number 4.1.1 Maintaining a Sequence Number
DYMO requires each node in the network maintain its own sequence DYMO requires each node in the network to maintain its own sequence
number (OwnSeqNum). The circumstances for a node to change its number (OwnSeqNum). The circumstances for a node to change its
OwnSeqNum are described in Section 4.4.1. OwnSeqNum are described in Section 4.4.1.
4.1.2 Incrementing a Sequence Number 4.1.2 Incrementing a Sequence Number
When a node increments its OwnSeqNum (as proscribed in Section 4.4.1 When a node increments its OwnSeqNum (as described in Section 4.4.1
and Section 4.4.3) it MUST do so by treating the sequence number and Section 4.4.2) it MUST do so by treating the sequence number
value as if it were an unsigned number. The sequence number zero (0) value as if it was an unsigned number. The sequence number zero (0)
is reserved and is used in several DYMO data structures to represent is reserved and is used in several DYMO data structures to represent
an unknown sequence number. an unknown sequence number.
4.1.3 Sequence Number Rollover 4.1.3 Sequence Number Rollover
To accomplish sequence number rollover, if the sequence number has If the sequence number has been assigned to be the largest possible
been assigned to be the largest possible number representable as a number representable as a 32-bit unsigned integer (i.e., 4294967295),
32-bit unsigned integer (i.e., 4294967295), then the sequence number then the sequence number MUST be set to one (1) when incremented.
when incremented MUST be set to one (1).
4.1.4 Actions After Sequence Number Loss 4.1.4 Actions After Sequence Number Loss
If a node's OwnSeqNum is lost it MUST NOT participate in the MANET If a node's OwnSeqNum is lost, it must take certain actions to avoid
network (forward any data or issue any DYMO control packets) until it creating routing loops. To prevent this possibility after sequence
is sure that all other nodes have deleted any sequence number number loss a node MUST wait for at least ROUTE_DELETE_PERIOD before
information about it. If RouteDeleteTimeout is set to transmitting any DYMO packet other than RERR generated by this node.
ROUTE_DELETE_TIMEOUT + the current time (as described in If a DYMO control packet is received during this period, the node
Section 4.2.1), nodes should avoid participation for at least SHOULD process it normally but MUST not retransmit any DYMO control
ROUTE_DELETE_TIMEOUT after sequence number loss. packets. If a data packet is received during this waiting period the
node MUST send a RERR message to the IPSourceAddress with the
UNodeSeqNum set to zero (0) and restart its waiting period before
transmitting any DYMO control packets except RERR generated by this
node.
4.2 DYMO Routing Table Operations 4.2 DYMO Routing Table Operations
4.2.1 Creating or Updating a Route Table Entry from Routing Element 4.2.1 Creating or Updating a Route Table Entry from a Routing Element
Information Block
While processing a RE, as described in Section 4.4.3, a node checks While processing a RE, as described in Section 4.4.2, a node checks
its routing table for an entry to the RENodeAddress using its routing table for an entry to the RENodeAddress using
longest-prefix matching. In the event that there is no corresponding longest-prefix matching. In the event that no matching entry is
entry for the node, an entry is created. found, an entry is created.
The routing information about RENodeAddress contained in the RE block
is considered stale if:
o the result of subtracting the RouteSeqNum from RENodeSeqNum is If a matching entry is found, the routing information about
RENodeAddress contained in this REBlock is considered stale if:
o the result of subtracting the Route.SeqNum from RENodeSeqNum is
less than zero (0) using signed 32-bit arithmetic, OR less than zero (0) using signed 32-bit arithmetic, OR
o the result of subtracting the RouteSeqNum from RENodeSeqNum is o the result of subtracting the Route.SeqNum from RENodeSeqNum is
equal to zero (0) using signed 32-bit arithmetic AND the REHopCnt equal to zero (0) using signed 32-bit arithmetic AND the REHopCnt
is greater than RouteHopCnt. is greater than Route.HopCnt.
If the information is stale and this RE block is the first node in
the RE (RENodeAddress1) this DYMO packet dropped. Otherwise, the
RENodeAddress and RENodeSeqNum are removed from this RE.
If the route information for RENodeAddress is not stale, then the If there exists a valid route AND the result of subtracting the
following actions occur to the route table entry for RENodeAddress: Route.SeqNum from RENodeSeqNum is equal to zero (0) using signed
o the RouteDeleteTimeout is set to the current time + 32-bit arithmetic AND the REHopCnt is equal to the Route.HopCnt in
this REBLock the information is not stale, but the routing
information SHOULD be disregarded and no routing update should occur.
If the information in this REBLock is stale or disregarded and this
REBlock is the first node in the RE this DYMO packet MUST be dropped.
For other REBlocks containing stale or disregarded routing
information, the REBlock is simply removed from this RE and the RELen
adjusted. Removing stale and disregarded REBlocks ensures that
unused information is not propagated further.
If the route information for RENodeAddress is not stale or
disregarded, then the following actions occur to the route table
entry for RENodeAddress:
1. the Route.HopCnt is set to the REHopCnt,
2. the Route.IsGateway is set to the G-bit,
3. the Route.DeleteTimeout is set to the current time +
ROUTE_DELETE_TIMEOUT, ROUTE_DELETE_TIMEOUT,
o the RouteNextHopAddress is set to the node that transmitted this 4. the Route.NextHopAddress is set to the node that transmitted this
DYMO packet (IPSourceAddress), DYMO packet (IPSourceAddress),
o the RouteNextHopInterface is set to the interface that this DYMO 5. the Route.NextHopInterface is set to the interface that this DYMO
packet was received on, packet was received on,
o the RoutePrefix is set to Prefix, 6. the Route.Prefix is set to Prefix,
o and the RouteSeqNum is set to the RENodeSeqNum. 7. the Route.SeqNum is set to the RENodeSeqNum,
o the RouteValidTimeout is set to the current time + ROUTE_TIMEOUT, 8. and the Route.ValidTimeout is set to the current time +
ROUTE_TIMEOUT.
If a valid route exists to RENodeAddress, the route can be used to If a valid route exists to RENodeAddress, the route can be used to
send any queued data packets and to fulfill any outstanding route send any queued data packets and to fulfill any outstanding route
requests. requests.
4.2.2 Route Table Entry Timeouts 4.2.2 Route Table Entry Timeouts
If the current time is later than a routing entry's If the current time is later than a routing entry's
RouteValidTimeout, the route is stale and it is not be used to route Route.ValidTimeout, the route is stale and it is not be used to route
packets. packets. The information in invalid entries may still be useful for
generating RREQ messages.
If the current time is later than a routing entry's If the current time is after Route.DeleteTimeout the corresponding
RouteDeleteTimeout, the route MUST be deleted. routing table entry MUST be deleted.
4.3 DYMO General Processing 4.3 General DYMO Processing
4.3.1 DYMO Control Packet Processing 4.3.1 DYMO Control Packet Processing
A DYMO packet may consist of multiple DYMO elements. Each element is A DYMO packet may consist of multiple DYMO elements. Each element is
processed individually and in sequence, from first to last. An processed individually and in sequence, from first to last. An
incoming DYMO packet MUST be completely processed prior to any DYMO incoming DYMO packet MUST be completely processed prior to any DYMO
packet transmissions, resulting from the contained DYMO elements. packet transmissions.
The length of IP addresses (32-bits for IPv4 and 128-bits for IPv6) The length of IP addresses (32-bits for IPv4 and 128-bits for IPv6)
inside DYMO elements is dependent on the IP packet header. For inside DYMO elements is dependent on the IP packet header. For
example, if the IP header is IPv6 then all DYMO elements contained in example, if the IP header is IPv6 then all DYMO elements contained in
the payload use IPv6 addresses. the payload use IPv6 addresses.
Unless specific element processing requires dropping the DYMO packet, Unless specific element processing requires dropping the DYMO packet,
it is retransmitted after processing. it is retransmitted after processing, according to the method
described in Section 4.3.5.
4.3.2 Generic Element Pre-processing 4.3.2 Generic Element Pre-processing
Each element in a DYMO packet undergoes pre-processing before the Each element in a DYMO packet undergoes pre-processing before the
element specific processing occurs. The ElemTTL is decremented by element specific processing occurs. During pre-processing, the TTL
one (1). is decremented by one (1).
4.3.3 Processing Unsupported DYMO Elements 4.3.3 Processing Unsupported DYMO Element Types
This section describe the processing for unsupported DYMO ElemTypes. This section describes the processing for unsupported DYMO element
For unsupported DYMO elements, the ElemType field identifies the Types. The Type field identifies the handling by nodes that do not
handling by nodes that do not implement or understand the element. implement, support or understand a particular Element Type. The most
The most significant bit (M-bit) indicates whether an significant bit (M-bit) indicates whether an Unsupported-element
Unsupported-element Error (UERR) SHOULD be sent to the Error (UERR) SHOULD be sent to the NotifyAddress. The next two bits
ElemNotifyAddress. The next two bits (H-bits) identify how the (H-bits) identify how the element should be handled.
element should be handled.
0 0 0 0
0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8 0 1 2 3 4 5 6 7 8
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
| ElemType | = |M| H | | | Type | = |M| H | |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
If the M-bit is set is this DYMO element, a UERR is sent to the If the M-bit is set in a DYMO element being processed by a node that
ElemNotifyAddress. This is accomplished by following the does not support this Element Type a UERR SHOULD be sent to the
instructions in Section 4.3.3.1. NotifyAddress. This is accomplished by following the instructions in
Section 4.3.3.1.
Regardless of whether or not a UERR is sent in response to this Regardless of whether or not a UERR is sent in response to this
unsupported ElemType, the processing node MUST also examine the unsupported Element Type, the processing node MUST also examine the
H-bits to determine how this unsupported element is handled. If : H-bits to determine how this unsupported element is handled. The
o H == 00: Processing for this ElemType MUST skip the element and unsupported element Type MUST be handled as follows:
continue, as if the packet did not contain this element. o If H == 00 skip the element and continue as if the packet did not
o H == 01: Processing for this ElemType MUST remove the element
(using the ElemLen) from the packet and continue, as if the packet
did not include this element.
o H == 10: Processing for this ElemType MUST set the ignored bit
(I-bit), skip this element and continue, as if the packet did not
contain this element. contain this element.
o H == 11: Processing for this ElemType dictates that the packet o If H == 01 remove the unsupported element (using the Len field)
MUST be dropped. from the packet and continue as if the packet did not include this
element.
o If H == 10 set the ignored bit (I-bit) skip this element and
continue, as if the packet did not contain this element.
o If H == 11 drop the packet without processing any other DYMO
elements.
4.3.3.1 Generating an Unsupported-element Error 4.3.3.1 Generating an Unsupported-element Error
The ElemTargetAddress in the UERR is set to the ElemNotifyAddress When an unsupported element type is received with the M-bit set, the
from the unsupported element. The UElemTargetAddress is set to the processing node SHOULD generate an Unsupported-element Error (UERR).
ElemTargetAddress from the unsupported element. The UERRNodeAddress The TargetAddress is set to the NotifyAddress. The
is set to the generating nodes IP address. The UElemType is the IPDestinationAddress is set to the Route.NextHopAddress toward the
ElemType from the unsupported element. The ElemTTL is set to NotifyAddress. The UElemTargetAddress is set to the TargetAddress
NET_DIAMETER. The UERRNodeAddress is set to the address of the node from the unsupported element. The UERRNodeAddress is set to the node
generating this UERR. The ElemLen is set to the total number of address generating this UERR. The UElemType is the Type from the
bytes in this UERR. The T-bit is set to zero (T=0). The element is unsupported element. The TTL SHOULD be set to NET_DIAMETER, but MAY
then processed as described in Section 4.3.4. be set smaller. The Len is set to the total number of bytes in this
UERR. The element is then processed as described in Section 4.3.4.
4.3.4 Generic Element Post-processing 4.3.4 Generic Element Post-processing
If the ElemTTL is zero (0) AND this element is the first element this If the first element TTL is zero (0) the DYMO packet is dropped after
DYMO packet is dropped after processing of all elements in the DYMO processing of all elements. If the TTL of the first element is
packet. If the ElemTTL is zero (0) AND this is NOT the first greater than zero the DYMO packet is re-transmitted after processing
element, this element is removed from the packet. If the ElemTTL is of all elements. If the TTL of any element is zero (0) after
larger than zero (0), this element is re-transmitted in a DYMO packet processing it MUST be removed from the DYMO packet prior to
after all elements have been processed. transmission.
4.3.5 DYMO Control Packet Transmission 4.3.5 DYMO Control Packet Transmission
DYMO packet transmission is controlled by the T-bit in the first DYMO packet transmission and re-transmission is controlled by the
element. If T=0 the element is unicast toward the ElemTargetAddress IPDestinationAddress. If the IPDestinationAddress is a unicast
via a routing table lookup. If the RouteNextHopAddress for the address, the packet IPDestinationAddress is replaced by the
ElemTargetAddress is not known the packet is dropped. If T=1 the Route.NextHopAddress from a route table lookup for the TargetAddress.
element is MANETcast. If a route for the TargetAddress is unknown or invalid the packet is
dropped and a RERR SHOULD be generated.
For all DYMO packets the IPTTL (IPMaxCount) SHOULD be set to 1 For all currently defined DYMO packets the IPTTL (IPMaxCount) SHOULD
(IPTTL=1). be set to 1 (IPTTL=1), since all DYMO packet communications are
between direct neighbors.
4.4 Routing Element 4.4 Routing Element
4.4.1 Routing Element Creation 4.4.1 Routing Element Creation
When a node creates a RE, it first increments its OwnSeqNum by one When a node creates a RE it MUST increment its OwnSeqNum by one
according to the rules specified in Section 4.1.2. Then it sets the according to the rules specified in Section 4.1.2, except under the
RENodeAddress1 to its own address. The RENodeSeqNum1 is the node's following conditions: The RE being created is a RREP AND either the
OwnSeqNum. The node may advertise a prefix using the Prefix field, o TargetSeqNum is less than OwnSeqNum OR
as described in Section 4.7. Otherwise, the Prefix field is set to o TargetSeqNum is equal to OwnSeqNum AND the and THopCnt is less
zero (0). This node may advertise it is a gateway by setting the than or equal to HopCnt.
G-bit, as described in Section 4.8. Otherwise, the G-bit is set to Then the node sets the RENodeAddress1 to its own address. The
zero (0). The ElemTTL is set to NET_DIAMETER. RENodeSeqNum1 is the node's OwnSeqNum. The node may advertise a
prefix using the Prefix field, as described in Section 4.7.
4.4.2 Appending Additional Routing Information to an Existing Routing Otherwise, the Prefix field is set to zero (0). The node may
Element advertise it is a gateway by setting the G-bit if it is a gateway, as
described in Section 4.8. Otherwise, the G-bit is set to zero (0).
After processing a RE, a node MAY append its IP address and OwnSeqNum The TTL SHOULD be set to NET_DIAMETER, but MAY be set smaller. For
to the RE. Appending its own routing information may alleviate some the case of RREQ, the TTL MAY be set in accordance with an expanding
route discovery procedures to this node from other nodes that process ring search as described in [2].
this RE.
If this node plans to append its IP address to the RE, it first 4.4.2 Routing Element Processing
increments its OwnSeqNum as defined in Section 4.1.2. Then this node
appends its IP address and OwnSeqNum to the RE. The ElemLen is also
adjusted accordingly.
4.4.3 Routing Element Processing After general DYMO element pre-processing (Section 4.3.2), the
REHopCnt for the first REBlock is incremented by one (1). A route to
the first REBlock is then created or updated, as described in
Section 4.2.1. If this REBlock does not result in a valid route the
packet MUST be dropped.
After general DYMO element pre-processing, the ElemHopCnt is Each additional REBlock SHOULD be processed. For each REBlock the
incremented by one. A route to RENodeAddress1 is then created or REHopCnt is incremented by one (1), then a route is created or
updated using the associated RENodeSeqNum, G-bit, Prefix, and updated as defined in Section 4.2.1. Each REBlock resulting in a
REHopCnt, as defined in Section 4.2.1. valid route entry may alleviate a future route discovery. Any
REBlocks that do not result in a valid route update or that are not
processed MUST be removed from the RE.
Each RENodeAddress, RENodeSeqNum, G-bit, Prefix, and REHopCnt block If this node is the TargetAddress AND the A-bit is set (A=1), this
MAY be processed. First the REHopCnt is incremented, then a route is node MUST respond with a RREP. The target node creates a new RE as
created or updated as defined in Section 4.2.1. Each RENodeAddress described in Section 4.4.1. The TargetAddress in the new RE is set
block resulting in a valid route entry may alleviate a future route to the RENodeAddress1 from the RE currently being processed. The
discovery. Any unprocessed RENodeAddress blocks MUST be removed from THopCnt is the hop count for the TargetAddress. The A-bit is set to
the RE. (A=0). The IPDestinationAddress is set to the Route.NextHopAddress
for the TargetAddress. The TargetSeqNum is set to Route.SeqNum for
the TargetAddress. Then the new RE undergoes post-processing,
according to Section 4.3.4.
If this node is the ElemTargetAddress AND the A-bit is set (A=1), After processing a RE, a node MAY append its routing information to
this node MUST reciprocate with a RE. This node creates a new RE as the RE, according to the process described in Section 4.4.3. The
described in Section 4.4.1. The ElemTargetAddress in the new RE is additional routing information will reduce route discoveries to this
set to the RENodeAddress1 from the RE currently being processed. The node.
T-bit is set to zero (T=0) and the A-bit is set to (A=0). Then the
new RE undergoes post-processing, according to Section 4.3.5.
If this node is not the ElemTargetAddress the current RE SHOULD be If this node is not the TargetAddress, the current RE SHOULD be
handled according to Section 4.3.4. handled according to Section 4.3.4.
If this node is the ElemTargetAddress the current packet and any If this node is the TargetAddress, the current packet and any
additional elements are processed, but this packet is not additional elements are processed, but this packet is not
retransmitted. retransmitted.
4.4.3 Appending Additional Routing Information to an Existing Routing
Element
Appending routing information will alleviate route discovery attempts
to this node from other nodes that process the resultant RE. Nodes
SHOULD append a REBlock to RE processed.
Prior to appending a REBlock to a RE, a node MUST increment its
OwnSeqNum as defined in Section 4.1.2. Then it appends its IP
address, OwnSeqNum, Prefix and G-bit to the RE in a REBlock. The
REHopCnt is set to zero (0). The RE Len is also adjusted according
to the number of REBlocks in the RE.
4.5 Route Discovery 4.5 Route Discovery
A node generates a Route Request (RREQ) to discover a valid route to A node generates a Route Request (RREQ) to discover a valid route to
a particular destination (ElemTargetAddress), other than itself. A a particular destination (TargetAddress). A RREQ is a RE with the
RREQ is simply a RE with the T-bit set (T=1) to indicate that this RE A-bit is set to one (A=1) to indicate that the TargetNode must
is to be MANETcast. Also, the A-bit is set to one (A=1) to indicate respond with a RREP. If a sequence number is known for the
that the TargetNode must respond with a RE. If a sequence number is TargetAddress it is placed in the TargetSeqNum field. Otherwise,
known for the ElemTargetAddress it is placed in the ElemTargetSeqNum TargetSeqNum is set to zero (0). Similarly, if a hop count is known
field. Otherwise, ElemTargetSeqNum is set to zero (0). for the TargetAddress it is placed in the THopCnt field. Otherwise,
the THopCnt is set to zero (o). The IPDestinationAddress is set to
Before sending the RREQ, the generating node buffers its the DYMOcastAddress. Then the RE is then transmitted according to
RENodeAddress and RENodeSeqNum in its RE Table. The RE is then the procedure defined in Section 4.3.5.
transmitted according to the procedure defined in Section 4.3.5.
After issuing the RREQ, the node waits for a route to be created to After issuing a RREQ, the originating node waits for a route to be
the TargetNode. If a route is not received within RREQ_WAIT_TIME created to the TargetNode. If a route is not received within
milliseconds, this node MAY again try to discover a route by issuing RREQ_WAIT_TIME milliseconds, this node MAY again try to discover a
another RREQ. route by issuing 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 TargetNode SHOULD utilize a binary discovery for a particular TargetNode SHOULD utilize a binary
exponential backoff. The first time an node issues a RREQ, it waits exponential backoff. The first time a node issues a RREQ, it waits
RREQ_WAIT_TIME milliseconds for a route to the TargetNode. If a RREQ_WAIT_TIME milliseconds for a route to the TargetNode. If a
route is not found within that time, the node may send another RREQ. route is not found within that time, the node MAY send another RREQ.
If a route is not found within 2*RREQ_WAIT_TIME, another RREQ may be If a route is not found within two (2) times the current waiting
sent, up to a total of RREQ_TRIES. For each additional attempt, the time, another RREQ may be sent, up to a total of RREQ_TRIES. For
waiting time for the previous RREP is multiplied by 2 so that the each additional attempt, the waiting time for the previous RREQ is
waiting time conforms to a binary exponential backoff. multiplied by two (2) so that the waiting time conforms to a binary
exponential backoff.
Data packets waiting for a route SHOULD be buffered. Data packets awaiting for a route SHOULD be buffered.
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 TargetNode, all data packets destined for receiving a route to the TargetNode, all data packets destined for
the corresponding TargetNode SHOULD be dropped from the buffer and a the corresponding TargetNode SHOULD be dropped from the buffer and a
Destination Unreachable ICMP message SHOULD be delivered to the Destination Unreachable ICMP message SHOULD be delivered to the
application. application.
4.6 Route Maintenance 4.6 Route Maintenance
4.6.1 Link Breaks 4.6.1 Active Link Monitoring
Nodes SHOULD monitor links to active neighbors. This may be Nodes MUST monitor links on active routes. This may be accomplished
accomplished by one or several mechanisms. Such as: by one or several mechanisms. Including:
o Link layer feedback o Link layer feedback
o Hello messages o Hello messages
o Neighbor discovery o Neighbor discovery
o Route timeout o Route timeout
Upon detecting a link break the valid routes utilizing the broken Upon detecting a link break the detecting node MUST set the
link MUST set their RouteValidTimeout to the current time. Route.ValidTimeout to the current time for all routes active routes
utilizing the broken link.
A RERR MAY be issued after detecting a broken link of an active A RERR MUST be issued if a data packet is received and it cannot be
route. RERR Generation is described in Section 4.6.4. delivered to the next hop. RERR generation is described in
Section 4.6.3. A RERR SHOULD be issued after detecting a broken link
of an active route to quickly notify nodes that a link break occurred
and a route or routes are no longer available.
4.6.2 Updating Route Lifetimes 4.6.2 Updating Route Lifetimes
To avoid route timeouts for active sources, after receiving a packet To avoid route timeouts for active routes, a node MUST update the
a node MAY update the RouteValidTimeout to the IPSourceAddress to be Route.ValidTimeout to the IPSourceAddress to be the current time +
the current time + ROUTE_TIMEOUT. ROUTE_TIMEOUT upon receiving a data packet. The Route.DeleteTimeout
MUST also be updated to the current time + ROUTE_DELETE_TIMEOUT.
4.6.3 Extending Route Lifetimes
To avoid route timeouts for active routes, an originating node MAY To avoid route timeouts for active routes, a node SHOULD update the
periodically send a RE with the T-bit set to zero (0), the A-bit set Route.ValidTimeout to the IPDestinationAddress to be the current time
to one (A=1) and the ElemTargetAddress set to the target node's + ROUTE_TIMEOUT upon successfully transmitting a packet to the next
address (RouteAddress). The resultant DYMO packet transmissions and hop. The Route.DeleteTimeout SHOULD also be updated to the current
RE processing (Section 4.2.1) will update the lifetime of routes to time + ROUTE_DELETE_TIMEOUT.
the originating node and target node (RouteAddress) at all
intermediate nodes, if a valid route still exists.
4.6.4 Route Error Generation 4.6.3 Route Error Generation
When a non-DYMO 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 Route Error (RERR) SHOULD be generated by this routing table entry, a Route Error (RERR) MUST be generated by this
node. A RERR informs the source that the current route is no longer node. A RERR informs the source that the current route is no longer
available in a more timely manner than RouteValidTimeout. available.
In the RERR, the ElemTargetAddress is the node that sent the non-DYMO In the RERR, the UNodeAddress1 field is the address of the
packet, the IPSourceAddress. The UNodeAddress1 field is the address unreachable node (IPDestinationAddress) from the data packet. If the
of the unreachable node (IPDestinationAddress) from the non-DYMO UNodeSeqNum is known, it is placed in the RERR; otherwise, zero (0)
packet. If the UNodeSeqNum is known, it is placed in the RERR; is placed in the UNodeSeqNum field of the RERR. The TTL SHOULD be
otherwise zero (0) is placed in the this field of the RERR. The set to NET_DIAMETER, but may be set smaller. The
ElemTTL is set to NET_DIAMETER. The T-bit is set to one (T=1). IPDestinationAddress is set to the DYMOcastAddress.
Additional unreachable nodes utilizing the same invalid link (routes Additional unreachable nodes that required the same unavailable link
with the same RouteNextHopAddress and RouteNextHopInterface) as the (routes with the same Route.NextHopAddress and
UNodeAddress1 MAY be appended to the RERR. For each unreachable node Route.NextHopInterface) as the UNodeAddress1 SHOULD be appended to
their UNodeAddress and UNodeSeqNum are appended. The ElemLen is set the RERR. For each unreachable node the UNodeAddress and UNodeSeqNum
accordingly. are appended. The Len is set accordingly.
The RERR is then processed as described in Section 4.3.5. The RERR is then processed as described in Section 4.3.5.
4.6.5 Route Error Processing 4.6.4 Route Error Processing
When a node processes a RERR after generic element pre-processing, it When a node processes a RERR after generic element pre-processing
SHOULD set the RouteValidTimeout to the current time for each route (Section 4.3.2), it SHOULD set the Route.ValidTimeout to the current
to a UNodeAddress that meet all of the following conditions: time for each route to a UNodeAddress that meets all of the following
The RouteNextHopAddress is the same as the RERR IPSourceAddress. conditions:
The RouteNextHopInterface is the same as the interface this RERR 1. The Route.NextHopAddress is the same as the RERR IPSourceAddress.
was received. 2. The Route.NextHopInterface is the same as the interface on which
The UNodeSeqNum is zero (0) OR if the result of subtracting the RERR was received.
RouteSeqNum from UNodeSeqNum is less than or equal to zero using 3. The UNodeSeqNum is zero (0) OR the result of subtracting
signed 32-bit arithmetic Route.SeqNum from UNodeSeqNum is less than or equal to zero using
signed 32-bit arithmetic.
If any route's RouteValidTimeout is set to the current time, this Each UNodeAddress that did not result in a change to
RERR MAY be handled as described in Section 4.3.4. Otherwise, the Route.ValidTimeout SHOULD be removed from the RERR.
RERR is dropped.
Prior to RERR element post processing a node MAY remove UNodeAddress, Prior to generic post processing a node MAY remove any UNodeAddressN,
UNodeSeqNum pairs to decrease the element size. UNodeSeqNumN pairs except UNodeAddress1 to decrease the element size.
If at least one UNodeAddress remains and at least one route remains
in the RERR it SHOULD be handled as described in Section 4.3.4 to
continue notification of nodes effected by the broken link.
Otherwise, the RERR is dropped.
4.7 Routing Prefix 4.7 Routing Prefix
Any node can advertise connectivity to a subset of nodes within its Any node can advertise connectivity to a subset of other nodes within
address space by using the prefix field in RE. The nodes within the its address space by using the prefix field in RE. The nodes within
advertised prefix SHOULD NOT participate in the MANET, and MUST be the advertised prefix SHOULD NOT participate in the MANET and MUST be
reachable by forwarding packets to the node advertising connectivity. reachable by forwarding packets to the node advertising connectivity.
For example, 192.168.1.1 with a prefix of 16 indicates all nodes with For example, 192.168.1.1 with a prefix of 16 indicates all nodes with
the prefix 192.168.X.X are reachable through 192.168.1.1. the prefix 192.168.X.X are reachable through 192.168.1.1.
If the G-bit is set the meaning of the prefix field is altered. For The meaning of the prefix field is altered for routes to the gateway;
a gateway the prefix in association with the IP address indicates Route.IsGateway is one (1). If the G-bit is set the prefix in
that nodes outside the subnet are reachable via the gateway node. association with the IP address indicates that all nodes outside the
For example, a gateway with IP address 192.168.1.1 and a prefix of 16 subnet are reachable via the gateway node. For example, a route to a
indicates all nodes with the IP address NOT matching 192.168.X.X are gateway with IP address 192.168.1.1 and a prefix of 16 indicates that
reachable through 192.168.1.1. all nodes with an IP address NOT matching 192.168.X.X are reachable
via this route.
4.8 Internet Attachment 4.8 Internet Attachment
Basic Internet attachment consists of a stub network of MANET nodes Internet attachment consists of a network of MANET nodes connected to
connected to the Internet via a single gateway node. The gateway is the Internet via a gateway node. The gateway is responsible for
responsible for responding to RREQs for TargetNodes outside its responding to RREQs for TargetNodes outside its configured MANET
configured MANET subnet, as well as delivering packets to subnet, as well as delivering packets to destinations outside the
destinations outside the MANET subnet. MANET subnet.
MANET nodes wishing to be reachable from nodes in the Internet MUST MANET nodes wishing to be reachable from nodes in the Internet MUST
have IP addresses within the gateway's configured MANET subnet. have IP addresses within the gateway's configured MANET subnet.
Given a node with a globally route-able address or care-of address Given a node with a globally routeable address or care-of address
handled by the gateway, the gateway is responsible for performing handled by the gateway, the gateway is responsible for routing and
route discovery for packets received from the Internet destined for forwarding packets received from the Internet destined for nodes
nodes inside its MANET subnet. inside its MANET subnet.
Since many nodes may commonly wish to communicate with the gateway, Since many nodes may commonly wish to communicate with the gateway,
the gateway SHOULD indicate to nodes that it is a gateway by setting the gateway SHOULD indicate to nodes that it is a gateway by setting
the gateway bit (G-bit) in the RE. The G-bit flag indicates to nodes the gateway bit (G-bit) in any RE created or processed. The G-bit
in the MANET that the RENodeAddress is attached to the Internet and flag indicates to nodes in the MANET that the RENodeAddress is
is capable of routing data packets to all nodes outside of the attached to the Internet and is capable of routing data packets to
configured MANET subnet, described by the RENodeAddress and Prefix all nodes outside of the configured MANET subnet, described by the
fields. RENodeAddress and Prefix fields.
4.9 Multiple Interfaces 4.9 Multiple Interfaces
It is likely that DYMO will be used with multiple wireless It is likely that DYMO will be used with multiple wireless
interfaces; therefore, the particular interface over which packets interfaces; therefore, the particular interface over which packets
arrive must be known whenever a packet is received. Whenever a new arrive must be known whenever a packet is received. Whenever a new
route is created, the interface through which the RouteAddress can be route is created, the interface through which the Route.DestAddress
reached is also recorded into the route table entry. can be reached is also recorded into the route table entry.
When multiple interfaces are available, a node transmitting a When multiple interfaces are available, a node transmitting a
MANETcast packet SHOULD send the packet on all interfaces that have DYMOcast packet SHOULD send the packet on all interfaces that have
been configured for operation in the MANET. been configured for operation in the MANET.
4.10 Packet Generation Limits 4.10 Packet Generation Limits
To avoid congestion, a node SHOULD NOT transmit more than RATE_LIMIT To avoid congestion, a node SHOULD NOT transmit more than RATE_LIMIT
control messages per second. control messages per second. RREQ packets SHOULD be discarded before
RREP or RERR packets.
5. Configuration Parameters 5. Configuration Parameters
Here are some suggested parameter values for DYMO: Here are some default parameter values for DYMO:
Parameter Name Suggested Value Parameter Name Suggested Value
--------------------------- --------------- --------------------------- ---------------
NET_DIAMETER 10 NET_DIAMETER 10
RATE_LIMIT 10 RATE_LIMIT 10
ROUTE_TIMEOUT 3000 milliseconds ROUTE_TIMEOUT 3000 milliseconds
ROUTE_DELETE_TIMEOUT 5*ROUTE_TIMEOUT ROUTE_DELETE_TIMEOUT 5*ROUTE_TIMEOUT
RREQ_WAIT_TIME 1000 milliseconds RREQ_WAIT_TIME 1000 milliseconds
RREQ_TRIES 3 RREQ_TRIES 3
These parameters work well for small well-connected networks with
moderate network topology changes.
For other networks these DYMO parameters SHOULD be adjusted using For large networks or networks with frequent topology changes the
either dynamic adaptation or experimentally determined values. For default DYMO parameters should be adjusted using either
example in static networks, ROUTE_TIMEOUT may be set to a much larger experimentally determined values or dynamic adaptation. For example,
value. in networks with infrequent topology changes ROUTE_TIMEOUT may be set
to a much larger value.
It is assumed that all nodes in the network share the same parameter
settings. Different parameter values for ROUTE_TIMEOUT or
ROUTE_DELETE_TIMEOUT in addition to arbitrary packet delays may
result in frequent route breaks or routing loops.
6. IANA Considerations 6. IANA Considerations
DYMO defines a ElemType field for each element within a packet sent DYMO defines a Type field for each element within a packet sent to
to port TBD. A new registry will be created for the values for this port TBD. A new registry will be created for the values for this
ElemType field, and the following values will be assigned: Type field, and the following values will be assigned:
ElemType Value Type Value
-------------------------------- ----- -------------------------------- -----
Routing Element (RE) 1 Routing Element (RE) 1
Route Error (RERR) 2 Route Error (RERR) 2
Unsupported-element Error (UERR) 3 Unsupported-element Error (UERR) 3
Future values of the ElemType and ErrType will be allocated using Future values of the Type will be allocated using standard actions as
standard actions as described in [1]. described in [1]. For future Types with the M-bit set NotifyAddress
MUST be included. Similarly for future Types that are unicast
hop-by-hop (packets not sent to the DYMOcastAddress), these Types
MUST include the TargetAddress field.
7. Security Considerations 7. 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 elements must be protected by the use of authentication attacks, DYMO elements must be protected by the use of authentication
skipping to change at page 23, line 25 skipping to change at page 25, line 25
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 Element (AH) is mechanism used for this purpose, IPsec Authentication Element (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, RE messages SHOULD be authenticated to avoid creation In particular, RE 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 less for delivery to the destination. RERR messages, while slightly less
dangerous, SHOULD be authenticated in order to prevent malicious dangerous, SHOULD be authenticated in order to prevent malicious
nodes from disrupting active routes between communicating nodes. nodes from disrupting active routes between communicating nodes.
DYMO does not make any assumption about the method by which addresses If the mobile nodes in the ad hoc network have pre-established
are assigned to the mobile nodes except that they are presumed to security associations, the purposes for which the security
have unique IP addresses. Therefore, no special consideration, other associations are created should include that of authorizing the
than what is natural because of the general protocol specifications, processing of DYMO control packets. Given this understanding, the
can be made about the applicability of IPsec authentication elements mobile nodes should be able to use the same authentication mechanisms
or key exchange mechanisms. However, if the mobile nodes in the ad based on their IP addresses as they would have used otherwise.
hoc network have pre-established security associations, it is
presumed that the purposes for which the security associations are
created include that of authorizing the processing of DYMO control
packets. Given this understanding, the mobile nodes should be able
to use the same authentication mechanisms based on their IP addresses
as they would have used otherwise.
8. Acknowledgments 8. Acknowledgments
DYMO is an decedent of the design of previous MANET reactive DYMO is a descendant of the design of previous MANET reactive
protocols. Special thanks to the authors of AODV [2] and DSR [4]. protocols, especially AODV [2] and DSR [4]. Changes to previous
The authors of AODV and DSR include Charlie Perkins, Elizabeth MANET reactive protocols stem from research and implementation
Belding-Royer, Samir Das, David Johnson, David Maltz, Yih-Chun Hu and experiences. Thanks to Luke Klein-Berndt for reviewing of DYMO, as
Jorjeta Jetcheva. Much of the DYMO protocol also stems from research well as several specification suggestions.
and implementation of MANET reactive-routing protocols. To mention a
few major contributors Sung-Ju Lee, Mahesh Marina, Erik Nordstrom,
Yves Prelot, J.J. Garcia-Luna-Aceves, Marc Mosko, Manel Guerrero
Zapata, Philippe Jacquet, and Chris Shiflet. Also, special thanks to
Luke Klein-Berndt for extensive implementation and testing of AODV,
early reviewing of DYMO, as well as several technical discussions.
9. References 9. References
9.1 Normative References 9.1 Normative References
[1] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [1] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", RFC 2434, BCP 26, October 1998. Considerations Section in RFCs", RFC 2434, BCP 26, October 1998.
[2] Perkins, C., Belding-Royer, E. and S. Das, "Ad hoc On-demand [2] Perkins, C., Belding-Royer, E. and S. Das, "Ad hoc On-demand
Distance Vector (AODV) Routing", RFC 3561, July 2003. Distance Vector (AODV) Routing", RFC 3561, July 2003.
9.2 Informative References 9.2 Informative References
[3] Perkins, C. and E. Belding-Royer, "Ad hoc On-Demand Distance [3] Perkins, C. and E. Belding-Royer, "Ad hoc On-Demand Distance
Vector (AODV) Routing", February 1999. Vector (AODV) Routing", Proceedings of the 2nd IEEE Workshop on
Mobile Computing Systems and Applications, New Orleans, LA, pp.
90-100, February 1999.
[4] Johnson, D. and D. Maltz, "Dynamic Source Routing in Ad-hoc [4] Johnson, D. and D. Maltz, "Dynamic Source Routing (DSR) in Ad
Wireless Networks", August 1996. hoc Networks", In Mobile Computing, Chapter 5, pp. 153-181,
1996.
Authors' Addresses Authors' Addresses
Ian Chakeres Ian Chakeres
University of California Santa Barbara University of California Santa Barbara
Dept. of Electrical and Computer Engineering Dept. of Electrical and Computer Engineering
Santa Barbara, CA 93106 Santa Barbara, CA 93106
USA USA
Phone: +1-805-893-8981 Phone: +1-805-893-8981
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/