Foreign Agent Error Extension for Mobile IPv4
RFC 4636
Document | Type |
RFC - Proposed Standard
(October 2006; Errata)
Updates RFC 3344
Was draft-ietf-mip4-faerr (mip4 WG)
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Author | Charles Perkins | ||
Last updated | 2020-01-21 | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4636 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Margaret Cullen | ||
Send notices to | (None) |
Network Working Group C. Perkins Request for Comments: 4636 Nokia Research Center Category: Standards Track October 2006 Foreign Agent Error Extension for Mobile IPv4 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 Internet Society (2006). Abstract This document specifies a new extension for use by Foreign Agents operating Mobile IP for IPv4. Currently, a foreign agent cannot supply status information without destroying the ability for a mobile node to verify authentication data supplied by the home agent. The new extension solves this problem by making a better place for the foreign agent to provide its status information to the mobile node. Perkins Standards Track [Page 1] RFC 4636 FA Error Extension October 2006 1. Introduction This document specifies a new non-skippable extension for use by Foreign Agents operating Mobile IP for IPv4 [4]. The new extension option allows a foreign agent to supply an error code without disturbing the data supplied by the Home Agent within the Registration Reply message. In this way, the mobile node can verify that the Registration Reply message was generated by the Home Agent even in cases where the foreign agent is required by protocol to insert new status information into the Registration Reply message. 2. Terminology The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [1]. Other terminology is used as already defined in [4]. 3. FA Error Extension Format The format of the FA Error Extension conforms to the Short Extension format specified for Mobile IPv4 [4]. The FA Error Extension is not skippable. 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 | Sub-Type | Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 45 Length 2 Sub-Type 0 Status A status code used by the foreign agent to supply status information to the mobile node. Perkins Standards Track [Page 2] RFC 4636 FA Error Extension October 2006 4. Operation and Use of the FA Error Extension The FA Error Extension is only valid for use within Mobile IPv4 Registration Reply messages. The FA Error Extension is not skippable. A mobile node that cannot correctly interpret the contents of the FA Error Extension MUST NOT use the care-of address provided in the Registration Reply message, until another Registration Request message has been sent and a successful Registration Reply message received. Status codes allowable for use within the FA Error Extension are within the range 64-127. The currently specified codes are as follows: 64 reason unspecified 65 administratively prohibited 66 insufficient resources 68 home agent failed authentication 71 poorly formed Reply 77 invalid care-of address 78 registration timeout as defined in RFC 3344 [4] for use by the Foreign Agent. Status codes for use with the FA Error extensions must not be differently defined for use in the Code field of Registration Reply messages. When a foreign agent appends a FA Error Extension to the Registration Reply as received from the Home Agent, it has to update the UDP Length field in the UDP header [5] to account for the extra 4 bytes of length. This document updates the Mobile IP base specification [4] regarding the procedures followed by the foreign agent in the case that the home agent fails authentication. Instead of modifying the "status" field of the Registration Reply to contain the value 68, now the foreign agent should append the Foreign Agent Error Extension containing the status value 68. 5. Mobile Node Considerations If a mobile node receives a successful Registration Reply (status code 0 or 1), with a FA Error Extension indicating that the foreign agent is not honoring said Registration Reply, the mobile node SHOULD then send a deregistration message to the home agent. In this way,Show full document text