Subject: MASC comments

From: Dave Thaler <[email-masked]>
Date: Mon, 29 Nov 1999 19:52:25 -0800 (PST)

I don't know if Jeremy is on this list now or not, but he gave me two
comments at IETF on MASC that I'd like some quick discussion of.

Paraphrased (in my own words, not his), the comments were:
1) "Need a way to say I'm going away permanently."
   I'm not sure whether he was asking for a way to withdraw prefixes in use
   or what.  My guess is that the WITHDRAW message might be able to be
   used for this purpose.

2) "Need to fix having to wait 1 1/2 days after a partition to
   get more addresses.  For example, need a way to have a 2-hour 
   maintenance window, and then continue working fine."
   Pavlin, can you answer this?

Thanks,
-Dave

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From: Pavlin Ivanov Radoslavov <[email-masked]>
Date: Mon, 29 Nov 1999 20:26:01 -0800

> comments at IETF on MASC that I'd like some quick discussion of.

I guess you mean Jeremy Hall, so I am cc to him, because it doesn't
seem that he is on the list.

>    or what.  My guess is that the WITHDRAW message might be able to be

Yes, the WITHDRAW message can be used. Because the WITHDRAW will be
in affect for as long as it will be kept in the memory of the MASC
servers, and because WITHDRAW's Holdtime field specifies how long to
be kept there, setting the WITHDRAW's Holdtime no shorter than the
corresponding previously allocated prefix's lifetime
(PREFIX_MANAGED) will have in practice the effect of canceling that
allocation. Note that both the PREFIX_MANAGED and WITHDRAW will be
kept by the appropriate MASC servers (parents, siblings, etc.) until
they expire, and a MASC server needs to interpretate both of them to
conclude that the particular prefix can be reused before it has
really expired. The spec doesn't specify this behavior (of reusing
withdrawn prefixes), but doesn't forbid it either. Should it be
added to the spec, or should it be left to some other document
("MASC operations" or whatever)?

>    Pavlin, can you answer this?

Section 5.1 says:

" A MASC node which is not in a top-level domain can initiate a claim
   toward a parent MASC domain if and only if it currently has an
   established connection with at least one node in that parent domain."

Hence, if there is partitioning between the parent and the child
domain, the child MASC node cannot initiate a claim, but needs to
wait until the partitioning is healed. The motivation for this
behavior is for robustness, but if necessary it could be specified
as "SHOULD", and allow (by configurable option) a child to claim
from its parent even if its connection to the parent is
down.

However, if the child has already initiated a claim, and then the
connection to the parent goes down, the claim timer will continue
running and will not be reset by the fact that the connection is
down. So, even if there is a N-hour maitenance window, the pending
claims will not be affected.

Jeremy, does this answer your original questions or I have
misunderstood something.

Pavlin