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)
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Authors | Andrew McDonald , Jukka Manner | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized 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 brevity. +----------+-------------------------+------------------------------+ | Value | IPv4 RAO Meaning | IPv6 RAO Meaning | +----------+-------------------------+------------------------------+Show full document text