On 23/02/18 05:48 , Mahendra Singh Negi wrote:
Dear Authors,

Amidst implementing conflict resolution for OSPF SR ( we
came across this issue.





1.Prefix conflict occurs at RT1 and RT2.

2.Both RT1 and RT2 resolve the conflict and download corresponding Label
for SID:1 (SID:1 wins conflict resolution).

3.Both RT1 and RT2 advertise inter-area Extended Prefix Opaque LSA for
prefix in area a1 with SID:1.



   (If an OSPF router advertises multiple Prefix-SIDs for the same
prefix, topology and algorithm, all of them MUST be ignored.)

which router advertises multiple Prefix-SIDs for the same prefix in your example?

4.Now at RT1, user *changes the  SID configuration value to 4*, and
still SID 1 wins the conflict resolution as in area a1 RT2 has not
flushed or updated SID:1, and SID:1 is forever in LSDB.

I don't understand the above. Why would that happen?


*How to fix the issue?*

a)think ABRs should advertise all the SIDs to leaking areas and MUST
condition mentioned highlighted in yellow above be relaxed(i.e. update
inter-area segment routing section accordingly) and let each node run

b) On SID configuration change, RT1 Flushes the SID:1 and waits for
SID:1 flushing out from the LSDB and then originates with new SID:4.(How
long to wait is decided locally).

I prefer (a), if you please provide your opinion on this.We are under
development, highly appreciate prompt  responses.



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