[42741] in North American Network Operators' Group
how are backups implemented?
daemon@ATHENA.MIT.EDU (Ratul Mahajan)
Thu Sep 20 04:52:32 2001
Date: Thu, 20 Sep 2001 01:51:54 -0700 (PDT)
From: Ratul Mahajan <ratul@cs.washington.edu>
To: <nanog@merit.edu>
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[posting this message after having looked for answers elsewhere including
the archives, but found no satisfactory answers]
i wanted to ask the operations community about how backups are typically
implemented. i am more interested in backup implementations, in which a
failure would expose a different origin AS (this would exclude prepending
based backups).
1. when a network is multihomed, and one of the links fails, would you
expect a smooth transition (as seen in the bgp tables of a remote AS) from
one origin AS to another (modulo convergence effects)?
2. can a failure (anywhere in the network) ever expose another origin AS
for some AS's while it stays the same for some? i guess it can, when the
network is being persistently announced from both origins, and under
normal scenario one origin could be hidden from some AS's. would this also
hold for a routing table as rich as routeviews?
3. can a failure ever cause more-specifics with a different (from the
origin of the less-specific) origin AS to appear (again, as seen from a
remote AS)? this might depend on how backups are implemented - so what i
am asking is, is this a common/possible case?
thanks,
-- ratul
