Subject: RE: [mobile-ip] Issues pertaining to "Mobility Support in IPv6" v 13

From: "Shahrier, Sharif M." <[email-masked]>
Date: Tue, 17 Apr 2001 15:59:35 -0400

I would like to discuss a couple of issues relating to the "Mobility Support
in IPv6" draft v13.0. It is regarding to failure/reconfiguration of home
agent router while the MN is away from its home agent. It is stated that the
dynamic home agent address discovey procedure was to be used to dynamically
discover the IP address of a home agent. 

As an alternative, a dual home agent router system can be used, to form a
2MR system. One of the routers is the "shadow" of the other and is only used
as backup. If the "primary" one fails or is reconfigured, the "shadow"
router could be switched into operation. From my previous knowledge, 2MR
systems are quite fail-safe and is deployed in many fault tolerant systems. 

I was wondering how people felt about the 2MR approach.

Another problem that I didn't see being discussed is the failure of home
agent's link when the MN is away from its home agent. Link failure or
reconfiguration is just as important as home agent failure. I believe  that
this needs to be explicitly spelled out  in the draft together with a
solution.

Could people comment on this as well.

Sharif.

---

From: Jim Bound <[email-masked]>
Date: Tue, 17 Apr 2001 19:25:34 -0400 (EDT)

I would argue that I agree with you about it should be mentioned. I don't
agree that it needs to be spelled out at all to move this draft forward to
PS.  Anymore than we had to have DHCP failover spelled out to move DHCP
forward to PS and many other pieces of work.  

This should be a seperate work item and draft dealing with failover in
general and possibly an opportunity to join forces with MANET work.

This is exactly the kind of thing that MUST NOT hold up MIPv6 going to PS
and code started.  If during PS we learn we can solve this and it should
have it included fine.  But its not needed for PS or get this stuff widely
implemented for testing (it is implemented by early coder adopters but we
need it implemented by suppliers now).

regards,
/jim