Re: [OSPF] draft-kini-ospf-fast-notification-01

András Császár <Andras.Csaszar@ericsson.com> Tue, 05 April 2011 13:07 UTC

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From: András Császár <Andras.Csaszar@ericsson.com>
To: "Bhatia, Manav (Manav)" <manav.bhatia@alcatel-lucent.com>, "curtis@occnc.com" <curtis@occnc.com>
Date: Tue, 05 Apr 2011 15:08:53 +0200
Thread-Topic: [OSPF] draft-kini-ospf-fast-notification-01
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References: Your message of "Tue, 05 Apr 2011 05:29:16 +0530." <7C362EEF9C7896468B36C9B79200D8350CFCF67253@INBANSXCHMBSA1.in.alcatel-lucent.com> <201104050225.p352PaCS029256@harbor.orleans.occnc.com> <7C362EEF9C7896468B36C9B79200D8350CFCF67274@INBANSXCHMBSA1.in.alcatel-lucent.com>
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Subject: Re: [OSPF] draft-kini-ospf-fast-notification-01
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> I believe the idea is quite simple - 
> Flooding a changed LSA in HW (data plane) is faster than 
> doing it in SW (not matter how optimized the latter is) or 
> your control plane.

That's the main purpose, yes.

You could combine this with something else: OSPF could pre-calc/pre-download potential new LSAs to the dataplane anticipating local failures. 

Whenever a local failure really happens, dataplane notices it by LoS or BFD, then can immediately disseminate the changed LSA using FN. So, in addition to the per-hop CP processing of LSAs, you could also spare some time with originating an LSA:
- failure trigger reaching/processed by CP
- OSPF originating a new LSA
- OSPF sending the LSU packet down to DP

Cheers,
András