See inline

Ahmed

On 11/28/2017 8:04 AM, Alexander Vainshtein wrote:
Ahmed and all,
Two points:
1. From my POV your description of forwarding behavior when the link S-->F fails is incomplete: the top label in the stack may be poppoed, but it is not "forgotten", and the next exposed label is looked up by S in the context label space that is F-specific. I.e., if S has two downstream neighbors, F and G, and both links S-->F and S-->G fail, lookup of the next exposed label for packets with ToS being S label for F and S label for G will yield different results.

#Ahmed: I do not understand what is not clear. The draft says in sections 5.3.1 and 5.3.2 "Confirm that the next segment is in the SRGB of F" and "the active segment is a prefix SID for a neighbor F" and "Confirm that the next segment is an adjacency SID of F".

In my previous email I said 'node "S" knows the SRGB of node "F" as well as all adjacency SIDs of node "F"'

So it is quite clear that the checks done on the new top label is within the context of the next-hop "F"

2. From my POV draft-hegde-spring-node-protection-for-sr-te-paths provides roughly equjvalent behavior, but it is much more clear when it comes to describibg the DP mechanisms involved. (IMHO and FWIW calling a spae by its name is greatly preferable in most cases.)
#Ahmed: thanks for pointing out that draft-hegde-spring-node-protection-for-sr-te-paths overlaps with draft-bashandy-rtgwg-segment-routing-ti-lfa :)


My 2c


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    On Tue, Nov 28, 2017 at 6:04, Ahmed Bashandy (bashandy)
    <[email protected]> wrote:
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