Mobility Header Home Agent Switch Message
RFC 5142
Network Working Group B. Haley
Request for Comments: 5142 Hewlett-Packard
Category: Standards Track V. Devarapalli
Azaire Networks
H. Deng
China Mobile
J. Kempf
DoCoMo USA Labs
January 2008
Mobility Header Home Agent Switch Message
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.
Abstract
This document specifies a new Mobility Header message type that can
be used between a home agent and mobile node to signal to a mobile
node that it should acquire a new home agent.
Haley, et al. Standards Track [Page 1]
RFC 5142 Home Agent Switch Message January 2008
Table of Contents
1. Introduction ....................................................2
2. Terminology .....................................................3
3. Scenarios .......................................................3
3.1. Overloaded .................................................3
3.2. Load Balancing .............................................3
3.3. Maintenance ................................................3
3.4. Functional Load Balancing ..................................3
3.5. Home Agent Renumbering .....................................4
4. Home Agent Switch Message .......................................4
5. Home Agent Operation ............................................6
5.1. Sending Home Agent Switch Messages .........................6
5.2. Retransmissions ............................................7
5.3. Mobile Node Errors .........................................7
6. Mobile Node Operation ...........................................8
6.1. Receiving Home Agent Switch Messages .......................8
6.2. Selecting a Home Agent .....................................9
7. Operational Considerations ......................................9
8. Protocol Constants .............................................10
9. IANA Considerations ............................................10
10. Security Considerations .......................................10
11. References ....................................................11
11.1. Normative References .....................................11
11.2. Informative References ...................................11
Acknowledgments ...................................................11
1. Introduction
RFC 3775 [RFC3775] contains no provision to allow a home agent to
inform a mobile node that it needs to stop acting as the home agent
for the mobile node. For example, a home agent may wish to handoff
some of its mobile nodes to another home agent because it has become
overloaded or it is going offline.
This protocol describes a signaling message, called the Home Agent
Switch message, that can be used to send a handoff notification
between a home agent and mobile node.
The Home Agent Switch message does not attempt to solve all general
problems related to changing the home agent of a mobile node. In
particular, this protocol does not attempt to solve:
o The case where the Home Address of a mobile node must change in
order to switch to a new home agent. This operation should be
avoided using this message.
Haley, et al. Standards Track [Page 2]
RFC 5142 Home Agent Switch Message January 2008
o Determining when a home agent should actively move mobile nodes
to another home agent. This decision should be made by a
backend protocol, for example, as described in [hareliability].
2. Terminology
The key words "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 [RFC2119].
3. Scenarios
Here are some example scenarios where a home agent signaling message
would be useful.
3.1. Overloaded
There are a number of reasons a home agent might be considered
overloaded. One might be that it is at, or near, its limit on the
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