draft-ietf-mip6-ha-switch-05.txt   draft-ietf-mip6-ha-switch-06.txt 
Mobile IPv6 B. Haley Mobile IPv6 B. Haley
Internet Draft Hewlett-Packard Internet Draft Hewlett-Packard
Document: draft-ietf-mip6-ha-switch-05.txt V. Devarapalli Document: draft-ietf-mip6-ha-switch-06.txt V. Devarapalli
Intended status: Standards Track Azaire Networks Intended status: Standards Track Azaire Networks
Expires: May 16, 2008 H. Deng Expires: June 4, 2008 H. Deng
China Mobile China Mobile
J. Kempf J. Kempf
DoCoMo USA Labs DoCoMo USA Labs
November 16, 2007 December 4, 2007
Mobility Header Home Agent Switch Message Mobility Header Home Agent Switch Message
draft-ietf-mip6-ha-switch-05.txt draft-ietf-mip6-ha-switch-06.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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3.5 Home Agent Renumbering.....................................4 3.5 Home Agent Renumbering.....................................4
4. Home Agent Switch Message......................................4 4. Home Agent Switch Message......................................4
5. Home Agent Operation...........................................6 5. Home Agent Operation...........................................6
5.1 Sending Home Agent Switch Messages.........................6 5.1 Sending Home Agent Switch Messages.........................6
5.2 Retransmissions............................................7 5.2 Retransmissions............................................7
5.3 Mobile Node Errors.........................................7 5.3 Mobile Node Errors.........................................7
6. Mobile Node Operation..........................................8 6. Mobile Node Operation..........................................8
6.1 Receiving Home Agent Switch Messages.......................8 6.1 Receiving Home Agent Switch Messages.......................8
6.2 Selecting a Home Agent.....................................8 6.2 Selecting a Home Agent.....................................8
7. Operational Considerations.....................................9 7. Operational Considerations.....................................9
8. Procotol Constants.............................................9 8. Procotol Constants............................................10
9. IANA Considerations............................................9 9. IANA Considerations...........................................10
10. Security Considerations.......................................9 10. Security Considerations......................................10
11. References...................................................10 11. References...................................................10
11.1 Normative References.....................................10 11.1 Normative References.....................................10
11.2 Informative references...................................10 11.2 Informative references...................................10
Acknowledgments..................................................10 Acknowledgments..................................................11
Author's Addresses...............................................10 Author's Addresses...............................................11
1. Introduction 1. Introduction
RFC 3775 [RFC3775] contains no provision to allow a home agent to 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 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 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 some of its mobile nodes to another home agent because it has become
overloaded or it is going offline. overloaded or it is going offline.
This protocol describes a signaling message, called the Home Agent This protocol describes a signaling message, called the Home Agent
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(the computed prefix is different), the mobile node SHOULD select one (the computed prefix is different), the mobile node SHOULD select one
its home network prefix first, if available, followed by home agents its home network prefix first, if available, followed by home agents
with other prefixes. Choosing a home agent with a different prefix with other prefixes. Choosing a home agent with a different prefix
might require a change of the home address for the mobile node, which might require a change of the home address for the mobile node, which
could cause a loss of connectivity for any connections using the could cause a loss of connectivity for any connections using the
current home address. current home address.
7. Operational Considerations 7. Operational Considerations
This document does not specify how an operator might use the Home This document does not specify how an operator might use the Home
Agent Switch message in its network. However, it might be the case Agent Switch message in its network. However, the following
that a home agent provides service for many thousands of mobile requirements are placed on the usage:
nodes. Care should be taken to reduce the signaling overhead on the
network required for handing off many mobile nodes to an alternate
home agent.
In general, switching the home agent of a mobile node should only be o The use of this message needs to take into account possible
done when absolutely necessary, since it might cause a service signaling overhead, congestion, load from the mechanism
disruption if switch to a new home agent fails, and the mobile node itself, and the resulting registration to another home agent.
has to perform home agent discovery. A home agent may provide service for thousands, if not
millions, of mobile nodes. Careless application of the Home
Agent Switch message may cause the new home agent, or some
other parts of the network, to suffer. As a result, it is
REQUIRED that applications of this message either employ a
feedback loop between resources of the new home agent and the
sending of additional Home Agent Switch messages, or apply a
maximum rate at which mobile nodes can be informed of the
switch that is far below the designated capacity of new
registrations that the set of home agents can process. If no
other information is available, this maximum rate should
default to MAX-HA-SWITCH-TRANSMIT-RATE.
If this message is being used for load-balancing between a set of o In general, switching the home agent of a mobile node should
home agents, they should all be configured with the same set of only be done when absolutely necessary, since it might cause
prefixes so a home agent switch does not require a change of the home a service disruption if the switch to a new home agent fails,
address for a mobile node. That operation is not recommended and the new home agent is itself under an overload condition, or
should be avoided. the network connection of the new home agent is congested.
Similarly, the path characteristics via the new home agent
may be different, which may cause temporary difficulties for
end to end transport layer operation.
o If this message is being used for load-balancing between a set
of home agents, they should all be configured with the same
set of prefixes so a home agent switch does not require a
change of the home address for a mobile node. That operation
is NOT RECOMMENDED and should be avoided.
8. Procotol Constants 8. Procotol Constants
INITIAL-HA-SWITCH-TIMEOUT 5 seconds INITIAL-HA-SWITCH-TIMEOUT 5 seconds
MAX-HA-SWITCH-TIMEOUT 20 seconds MAX-HA-SWITCH-TIMEOUT 20 seconds
MAX-HA-SWITCH-TRANSMIT-RATE 1 per second
9. IANA Considerations 9. IANA Considerations
A new Mobility Header type is required for the following new message A new Mobility Header type is required for the following new message
described in Section 4: described in Section 4:
(TBD) Home Agent Switch message (TBD) Home Agent Switch message
10. Security Considerations 10. Security Considerations
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