Subject: OSPF Link State Advertisement

From: Ameya Pandit <[email-masked]>
Date: Mon, 16 Jun 2003 13:03:01 +0000

Hello,

I have a query on link State Acknowledgements (LSAck). We know that when a
router receives a link state advertisement (LSA) it sends a LSAck for the
received LSA. I understand that it is possible to couple different
acknowledgements together. However, my question is: how do we determine the
'ifIndex' of the interface on which the router sends the LSAck for the
currently received LSA.
Is there any way we can find out the interface on which the LSAck was sent
knowing the details in the
received LSA (viz. Seq, Checksum et. al.). ?? .  In other words, i need to
know the
interface on which the LSA was received.

More specifically, I have a requirement where in my Network Management
Software needs to know the ifIndex (and eventually the neighbor that sent
(forwarded) the LSA) of the interface on which the LSAck was generated for
the LSA. I have the details of the LSA. I checked the OSPF MIB however there
was no way to get the ifIndex on which the LSA was received.

Any guidance would be helpful.

Regards
-Ameya

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---

From: Don Goodspeed <[email-masked]>
Date: Mon, 16 Jun 2003 14:06:57 -0400

Ameya,

Remember that LSA are global, but a LS-Ack is acknowledging receipt
from a specific neighbor (or a specific DR on a LAN segment), not
for the LSA in general.  Therefore, the interface associated with
that neighbor and/or DR should always be known.

-don

==========================================
Hello,

Regards
-Ameya

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