Les, >From what you describe in section 3.3.8, all the SIDs attached to prefixes are >fed into the database. The example I am talking about,
1.prefix 1.1.1.1 advertised from node A with no SID 2.Prefix 1.1.1.1 advertised from node B with SID 10 3. Prefix 1.1.1.1 advertised from node C with SID 10 The advertisements 2 and 3 are fed into the mapping database and 1 isn't. The conflict resolution does not detect any conflict with the above advertisements and For prefix 1.1.1.1 /SID 10 is chosen. All this is fine but the problem is in programming the forwarding plane. Lets say for a certain node E in the network node A is the nexthop for 1.1.1.1. How would node E program its forwarding plane? Node E should recognize the conflict between node A, Node B and C and program the SID 10 with a pop and forward instead of looking into the P and E flags of the SID 10? This is good enough detail, that should be explained in the draft instead of leaving it to the Imagination of implementers. Rgds Shraddha From: Les Ginsberg (ginsberg) [mailto:ginsb...@cisco.com] Sent: Wednesday, May 3, 2017 11:47 PM To: Shraddha Hegde <shrad...@juniper.net>; draft-ietf-spring-conflict-resolut...@ietf.org Cc: spring@ietf.org Subject: RE: Mail regarding draft-ietf-spring-conflict-resolution Shraddha - There is a misunderstanding on your part. It would be good if you read Section 3.3.8. Guaranteeing Database Consistency again. In short, it does not matter whether you do or do not advertise a prefix SID for a prefix which you own. What matters is that all routers populate the mapping entry database consistent w Section 3.3.8 and that each router applies the conflict resolution rules in a consistent manner. Then all routers will be using the same prefix/SID pair in forwarding. Les From: Shraddha Hegde [mailto:shrad...@juniper.net] Sent: Wednesday, May 03, 2017 9:58 AM To: draft-ietf-spring-conflict-resolut...@ietf.org<mailto:draft-ietf-spring-conflict-resolut...@ietf.org> Cc: spring@ietf.org<mailto:spring@ietf.org> Subject: Mail regarding draft-ietf-spring-conflict-resolution Hi Authors, When there are multiple anycast IP addresses assigned to different nodes and one or more nodes do not advertise a Prefix SID for that anycast address but other nodes advertise a prefix-sid, there is a possibility of different implementations behaving differently with respect to programming the labelled routes. This scenario should be considered as a prefix conflict and the behavior should be addressed in the draft. I suggest to update section 3.2.1 with the relevant text to describe the behavior. Rgds Shraddha
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