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

John E Drake <jdrake@juniper.net> Tue, 05 April 2011 14:04 UTC

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From: John E Drake <jdrake@juniper.net>
To: =?iso-8859-1?Q?Andr=E1s_Cs=E1sz=E1r?= <Andras.Csaszar@ericsson.com>, "Bhatia, Manav (Manav)" <manav.bhatia@alcatel-lucent.com>, "curtis@occnc.com" <curtis@occnc.com>
Date: Tue, 5 Apr 2011 07:04:02 -0700
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> <8DCD771BDA4A394E9BCBA8932E83929720E74AF217@ESESSCMS0363.eemea.ericsson.se>
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Subject: Re: [OSPF] draft-kini-ospf-fast-notification-01
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We actually implemented this in IBM's Nways products in the early/mid nineties and found it wasn't worth the trouble.  It had no measurable effect on network performance and the protocols necessary to terminate the broadcast were messy and error prone.

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> -----Original Message-----
> From: ospf-bounces@ietf.org [mailto:ospf-bounces@ietf.org] On Behalf Of
> András Császár
> Sent: Tuesday, April 05, 2011 6:09 AM
> To: Bhatia, Manav (Manav); curtis@occnc.com
> Cc: ospf@ietf.org
> Subject: Re: [OSPF] draft-kini-ospf-fast-notification-01
> 
> > 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
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