Joe Lau writes: Regarding the new text on section 10.6.1 List of Home
Network Prefixes

  "If there are multiple home agents, differences in the advertisements
   sent by different home agents can lead to an inability to use a
   particular home address when changing to another home agent.  In
   order to ensure that the mobile nodes get the same information from
   different home agents, it is desired that all the home agents on the
   same link be configured in the same manner.

   To support this, the home agent monitors prefixes advertised by
   itself and other home agents routers on the home link.  Observed
   differences SHOULD be logged."

I believe the "Observed differences SHOULD be logged" is more than what
RFC 2467 has already specified in 6.2.7 Router Advertisement Consistency.

Can we make the text more specific or is that the text really meant 
"any difference" on the prefixes SHOULD be logged.

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Vijay Devarapalli responds to Joe Lau:

> I believe the "Observed differences SHOULD be logged" is more than what
> RFC 2467 has already specified in 6.2.7 Router Advertisement Consistency.

I guess you meant 2461. I think RFC 2461 talks about differences 
in advertisements sent out by two routers regarding the same 
prefix. for example one router could advertise the prefix with 
lifetime 100 seconds. another router could advertise the same 
prefix with lifetime 120 seconds. such differences should be 
logged.

> Can we make the text more specific or is that the text really meant
> "any difference" on the prefixes SHOULD be logged.

MIPv6 talks about logging differences in the sets of prefixes
advertised by different home agents on the same home link. the
current MIPv6 spec recommends that the all Home Agents advertise
the same set of prefixes.

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Joe Lau responds to Vijay Devarapalli:

> MIPv6 talks about logging differences in the sets of prefixes
> advertised by different home agents on the same home link. the
> current MIPv6 spec recommends that the all Home Agents advertise
> the same set of prefixes.

Adding your "text" to the spec will be helpful.  Is it too late?

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Jari Arkko writes: I'm not quite sure what text change you two agreed
on, but here's how I think the text should be changed:

   To support this, the home agent monitors prefixes advertised by
   itself and other home agents routers on the home link.  Observed
   differences SHOULD be logged.

=>

   To support this, the home agent monitors prefixes advertised by itself
   and other home agents on the home link. In addition to the consistency
   checks specified in Section 6.2.7 of RFC 2461 [ref], home
   agents SHOULD log differences in the sets of prefixes advertised by
   the different home agents.

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Erik Nordmark responds to Joe Lau: How about adding something like this:

	In RFC 2461 it is acceptable for two routers to advertise different
	sets of prefixes on the same link. For Home Agents such differences 
	should be detected since a mobile node only communicates with
	one home agent at a time and the mobile node needs to know the
	full set of prefixes assigned to the home link.
	All other comparisons of router advertisements are as specified
	in RFC 2461.

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Jari Arkko responds to Erik Nordmark: The text that I crafted had the
same intent, I think, but I have now take in your text...

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Markku Savela responds to Erik Nordmark: I would prefer that "single
home agent at time" limitation is not "hard coded" into the
specification. I accept that support may be optional.

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Jari Arkko responds to Markku Savela: Its not hardcoded. You can
indeed have multiple home agents, on different networks.

I fixed the proposed text to "... one home agent on a given home
link at a time ..."

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