Re: [OSPF] draft-ietf-ospf-two-part-metric : Max metric handling

"Acee Lindem (acee)" <acee@cisco.com> Thu, 08 October 2015 09:33 UTC

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From: "Acee Lindem (acee)" <acee@cisco.com>
To: Shraddha Hegde <shraddha@juniper.net>, "draft-ietf-ospf-two-part-metric@ietf.org" <draft-ietf-ospf-two-part-metric@ietf.org>
Thread-Topic: draft-ietf-ospf-two-part-metric : Max metric handling
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Date: Thu, 8 Oct 2015 09:33:03 +0000
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Cc: OSPF WG List <ospf@ietf.org>
Subject: Re: [OSPF] draft-ietf-ospf-two-part-metric : Max metric handling
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Hi Shraddha,
Since RFC 2328 and RFC 5340 don’t explicitly call out the case of 0xffff, I don’t see why this should be handled. Perhaps, we should state both metric SHOULD be set to 0xffff in the stub router case.
Thanks,
Acee

From: Shraddha Hegde <shraddha@juniper.net<mailto:shraddha@juniper.net>>
Date: Tuesday, October 6, 2015 at 5:58 AM
To: "draft-ietf-ospf-two-part-metric@ietf.org<mailto:draft-ietf-ospf-two-part-metric@ietf.org>" <draft-ietf-ospf-two-part-metric@ietf.org<mailto:draft-ietf-ospf-two-part-metric@ietf.org>>
Cc: OSPF WG List <ospf@ietf.org<mailto:ospf@ietf.org>>
Subject: draft-ietf-ospf-two-part-metric : Max metric handling

Authors,

As per my understanding of the draft, SPF calculation uses sum of metric from the interface cost and the network to router cost advertised by the neighbor.
Handling of MAX metric is not described in the draft.  Since the metric will be sum of 2 16 bit numbers it can exceed the normal 0xffff metric value and the draft should talk about how to handle these cases.

Rgds
Shraddha