Network Working Group Naiming Shen
Internet Draft Redback Networks
Expiration Date: December 2003 June 2003
Link Name and Sequence Options for IPv6 Neighbor Discovery
draft-shen-ipv6-nd-name-seq-options-00.txt
1. Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet- Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
2. Abstract
To facilitate network troubleshooting and management in IPv6
environment, two new options for IPv6 Neighbor Discovery messages
are proposed in this document. The Link-Name option is used in
Router Advertisement message, and the Sequence-Number option is
used in Neighbor Solicitation and Neighbor Advertisement messages.
3. Introduction
The Router Advertisement message in Neighbor Discovery for IPv6 [1]
currently has defined options with source link-layer address,
MTU and prefix information. It is obvious that, by inspecting
a link-local address of the neighbor from diagnostics information
is less clear than symbolic names. This draft proposes a mechanism
allowing Router Advertisement message to include a Link-Name
option.
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Internet Draft IPv6 ND Link-Name and Seq-Num June 2003
When Neighbor Advertisement message is received from a neighbor,
and if the Neighbor Solicitation messages were retransmitted, it
is useful from troubleshooting point of view to learn which
Neighbor Solicitation message the Neighbor Advertisement message
replied to and what is the round trip delay for this address
resolution, similar to the sequence number and round-trip time
scheme used in ICMP request/reply implementation.
4. Link-Name Option
The Link-Name option MAY be included in Router Advertisement
message. A typical Link-Name can be a combination of router name,
virtual router identifier and interface name of the link.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Link-Name String ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Fields:
Type Link-Name [TBD: IANA]
Length 6 (including the type and length fields, total 48
bytes)
Link-Name String
This field identifies the symbolic name of the link
of the router. The string is null-terminated if the
name is less than 46 bytes.
The option MUST be silently ignored for other Neighbor Discovery
messages.
5. Sequence-Number Option
The Sequence-Number option MAY be included in Neighbor Solicitation
message and Neighbor Advertisement message. The sequence number
is maintained for each cache entry and is increased by one for each
Neighbor Solicitation sent for the entry. A Neighbor Advertisement
message only include this option when responding to the Neighbor
Solicitation message, and it SHOULD simply copy the Sequence-Number
Option from the Neighbor Solicitation packet unchanged.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Sequence-Number |
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Internet Draft IPv6 ND Link-Name and Seq-Num June 2003
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NS User Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Fields:
Type Sequence-Number [TBD: IANA]
Length 1 (8 bytes including the type and length fields)
Sequence-Number
A 16-bit unsigned integer in network byte order.
NS User Data
A 32-bit unsigned integer in network byte order. This
value has only local significance to the sender of
the Neighbor Solicitation packet. For example, it
can be a timestamp in milliseconds.
The option SHOULD only be used in Neighbor Solicitation message
when the source address is not an unspecified address. The
Neighbor Advertisement SHOULD relay the option back to the
sender of the Neighbor Solicitation packet when responding to
the Neighbor Solicitation. This option SHOULD not be used in
unsolicited Neighbor Advertisement message.
6. Security Considerations
This extension does not introduce any security issues.
7. Acknowledgments
TBD.
8. References
[1] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery
for IP Version 6 (IPv6)", RFC 2461, December 1998.
9. Author Information
Naiming Shen
Redback Networks, Inc.
300 Holger Way
San Jose, CA 95134
e-mail: naiming@redback.com
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