IANA Considerations for the IPv4 and IPv6 Router Alert Options
RFC 5350
| Document | Type |
RFC - Proposed Standard
(September 2008; No errata)
Was draft-manner-router-alert-iana (individual in int area)
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5350 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Jari Arkko | ||
| Send notices to | (None) | ||
Network Working Group J. Manner
Request for Comments: 5350 TKK
Updates: 2113, 3175 A. McDonald
Category: Standards Track Siemens/Roke
September 2008
IANA Considerations for the IPv4 and IPv6 Router Alert Options
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2008).
Abstract
This document updates the IANA allocation rules and registry of IPv4
and IPv6 Router Alert Option Values.
Table of Contents
1. Introduction ....................................................2
2. Use of the Router Alert Option Value Field ......................2
3. IANA Considerations .............................................4
3.1. IANA Considerations for IPv4 Router Alert Option Values ....4
3.2. IANA Considerations for IPv6 Router Alert Option Values ....5
4. Security Considerations .........................................5
5. Acknowledgements ................................................6
6. References ......................................................6
6.1. Normative References .......................................6
6.2. Informative References .....................................6
Manner & McDonald Standards Track [Page 1]
RFC 5350 IANA Considerations for Router Alert September 2008
1. Introduction
The IP Router Alert Option is defined for IPv4 in [RFC2113]. A
similar IPv6 option is defined in [RFC2711]. When one of these
options is present in an IP datagram, it indicates that the contents
of the datagram may be interesting to routers. The Router Alert
Option (RAO) is used by protocols such as the Resource Reservation
Protocol (RSVP) [RFC2205] and IGMP [RFC3376].
Both the IPv4 and IPv6 options contain a two-octet Value field to
carry extra information. This information can be used, for example,
by routers to determine whether or not the packet should be more
closely examined by them.
There can be up to 65536 values for the RAO. Yet, currently there is
only a registry for IPv6 values. No registry or allocation policies
are defined for IPv4.
This document updates the IANA registry for managing IPv4 and IPv6
Router Alert Option Values, and removes one existing IPv6 Router
Alert Option Value.
2. Use of the Router Alert Option Value Field
One difference between the specifications for the IPv4 and IPv6
Router Alert Options is the way values for the Value field are
managed. In [RFC2113], the IPv4 Router Alert Option Value field has
the value 0 assigned to "Router shall examine packet". All other
values (1-65535) are reserved. Neither a management mechanism (e.g.,
an IANA registry) nor an allocation policy are provided for the IPv4
RAO values.
The IPv6 Router Alert Option has an IANA-managed registry
[IANA-IPv6RAO] containing allocations for the Value field.
In [RFC3175], the IPv4 Router Alert Option Value is described as a
parameter that provides "additional information" to the router in
making its interception decision, rather than as a registry managed
by IANA. As such, this aggregation mechanism makes use of the Value
field to carry the reservation aggregation level. For the IPv6
option, IANA has assigned a set of 32 values to indicate reservation
levels. However, since other registrations have already been made in
that registry, these values are from 3-35 (which is actually a set of
33 values).
Although it might have been desirable to have the same values used in
both the IPv4 and IPv6 registries, the initial allocations in
[RFC2711] and the aggregation-level allocations in [RFC3175] have
Manner & McDonald Standards Track [Page 2]
RFC 5350 IANA Considerations for Router Alert September 2008
made this impossible. The following table shows the allocations in
the IPv6 registry and the values used in the IPv4 registry, where the
latter have been deduced from [RFC2113] and [RFC3175] with the
assumption that the number of aggregation levels can be limited to 32
as in the IPv6 case. Entries for values 6 to 31 have been elided for
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