Subject: (IPng 7261) lifetime in router renumbering messages

From: JINMEI Tatuya / 神明達哉<[email-masked]>
Date: Wed, 03 Mar 1999 21:09:50 +0900

Hi,

We are now implementing router renumbering in the KAME project and
have a question about how to use lifetime fields in router renumbering
messages.

There are two lifetime fields in a use-prefix part; Valid Lifetime and
Preferred Lifetime. For these fields, the specification says as
follows.

    Additional information for each Use-Prefix is included in the Prefix
    Control Operation: the valid and preferred lifetimes to be included
    in Router Advertisement Prefix Information Options [ND], and either
    the L and A flags for the same option, or an indication that they
    are to be copied from the prefix that matched the Match-Prefix.

It seems that the specification only says that how these fields are
used in corresponding Router Advertisements, but do the lifetimes have
an effect on a router which receives router renumbering messages? For
example, should a router decrement the lifetime and delete the
corresponding prefix when the lifetime expired? Or should the router
just copy the lifetime to the corresponding field of succeeding router
advertisement messages (and should not apply the lifetimes to its own
prefixes)? Or is the semantics completely implementation dependent?

IMO, the specification does not intend that a router use the lifetimes
for its own prefixes and addresses. However, it may be convenient
since we can omit RR messages that cause explicit deletion. We would
like to know whether it is allowed or not.

Thanks in advance,

					JINMEI, Tatuya
					Comm. and Info. Systems Research Labs.
					Toshiba R&D Center
					[email-masked]
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