Hi Nanaraya,
Acknowledgements are generally sent as multicasts in OSPF except in
response to the reciept of duplicate LSAs. When the neighbour adjacency
is going up there are no explicit ACKs sent. If you need to send explicit ACKs
then what purpose does it serve to re-issue the LSR list upon the reciept
of the LSUs you requested for. Secondly, we would have to then send
a direct ACK back to the neighbour, which is not done. We cannot
multicast the ACK to all the routers on the LAN this time !

What do you say ?

Regards,
Manav

----- Original Message -----
From: <nanarayaCISCO.COM>
To: <OSPFDISCUSS.MICROSOFT.COM>
Sent: Friday, September 14, 2001 9:58 AM
Subject: Re: (Reply) ospf novice question - II

> Hi,
>
> Manav :
> You mentioned that during the database exchange process, we don't have
> to explicitly ACK the LSUs.
> I feel just removing the LSA from the LSRequest list does not indicate
> to the sending neighbour that we have received the update.
> I feel the LSAs in the LSUs should be ACKed irrespective of whether they
> are received during the database exchange process or when the neighbour
> state is FULL. This is because, all LSUs are handled by section 13.
> During database exchange process, step 13-(5)(b) is executed. So, when a
> LSU is received during the database exchange process, it still goes
> through the above step 13 and it might result in an ACK.
> Please correct me if I am wrong.
>
> Zhang :
> Your point(4) related to BadLSReq event will only happen if a router
> receives a LSA that is older or same as what it already has and the LSA
> is present its LSRequest list. What it means is that either the router
> is requesting for something it already has or the neighbour router has

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