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Re: [OSPF] PHP route determination in draft-ietf-ospf-segment-routing-extensions-03

Peter Psenak <ppsenak@cisco.com> Thu, 02 April 2015 07:38 UTC

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Date: Thu, 02 Apr 2015 09:38:19 +0200
From: Peter Psenak <ppsenak@cisco.com>
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To: Santanu Kar <santanu.kar@ipinfusion.com>, ospf@ietf.org, sprevidi@cisco.com, cfilsfil@cisco.com, hannes@juniper.net, rob.shakir@bt.com, wim.henderickx@alcatel-lucent.com
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Subject: Re: [OSPF] PHP route determination in draft-ietf-ospf-segment-routing-extensions-03
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Santanu,

If B is not advertising a SID for 20.1.1.0/24, then A will not do PHP.

regards,
Peter


On 4/2/15 08:39 , Santanu Kar wrote:
> SANTANU> Iactually wanted to highlight the non-ABR cases here. Consider
> the3routers below,in same area.
>
>   A -----10.1.1.0/24----- B ------20.1.1.0/24 -----C
>
> In thecontext of A, the route of 20.1.1.0/24 <http://20.1.1.0/24> is a
> PHP route. Now the Prefix Segment for prefix 20.1.1.0/24
> <http://20.1.1.0/24> can be advertised by bothB, as well as by C towards
> A. The case I am considering here is, C has advertised the prefix
> segment of 20.1.1.0/24 <http://20.1.1.0/24> to Afirst.Stillwhen A is
> calculating label for20.1.1.0/24 <http://20.1.1.0/24>,it should take it
> as PHP. Howeverthe text in draft states "upstream neighbor of the
> Prefix-SID originator MUST pop the Prefix-SID". Here A is not the
> upstream neighbor of C.
>

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