Hi Peter -----Original Message----- From: Peter Psenak [mailto:ppse...@cisco.com] Sent: Thursday, April 02, 2015 3:48 PM To: Santanu Kar; ospf@ietf.org; sprev...@cisco.com; cfils...@cisco.com; han...@juniper.net; rob.sha...@bt.com; wim.henderi...@alcatel-lucent.com Cc: penchala.re...@ipinfusion.com Subject: Re: PHP route determination in draft-ietf-ospf-segment-routing-extensions-03
Santanu, On 4/2/15 11:34 , Santanu Kar wrote: > Hi Peter > > I think, considering we are using Ext Prefix LSA in 'Area-Flooding' > scope, A should do PHP for 20.1.1.0/24 if C has advertised it. I do not see why would you do PHP, if B is not advertising the SID. > If A doesn’t pop for 20.1.1.0/24, and give the packet to B, it will > drop it, since PHP is enabled by default for all nodes. why would it drop? B will get the packet with the label that corresponds to 20.1.1.0/24. [SANTANU] Since PHP is enabled globally, B may not expect a label packet for 20.1.1.0/24 as it expects it to be POPed in penultimate node. So B may choose not to install any POP entry for 20.1.1.0/24. In that case packet will be dropped. regards, Peter > > Regards > Santanu > > -----Original Message----- > From: Peter Psenak [mailto:ppse...@cisco.com] > Sent: Thursday, April 02, 2015 1:08 PM > To: Santanu Kar; ospf@ietf.org; sprev...@cisco.com; > cfils...@cisco.com; han...@juniper.net; rob.sha...@bt.com; > wim.henderi...@alcatel-lucent.com > Subject: Re: PHP route determination in > draft-ietf-ospf-segment-routing-extensions-03 > > 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. >> SANTANU> 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. >> > -- . _______________________________________________ OSPF mailing list OSPF@ietf.org https://www.ietf.org/mailman/listinfo/ospf
