[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Reestablish adjacencies after Graceful-Restart



This question is a bit long, backdated and maybe, queer. But it is a bit critical for me.
It is regarding RFC 3623 (Graceful OSPF Restart), Section 2.2. "When to Exit Graceful Restart", Point 1 "Router X has reestablished all its adjacencies".
 
I am trying to identify the corresponding event from RFC 2328 for Router X. Is it one of the following:
a> Upon installation of an LSA in the database [RFC2328, Sec 13.2] [and thereby tracing the database for all the relevant LSAs which indicate the previous adjacencies],
     or
b> State of neighbor Y changing to Full; [and thereby tracing the database ...]
     or
c> Implementation specific
 
Let me explain this with a simplified example:
 
            X ----- lan ----- Y
 
In the topology, we have two routers, X and Y; and Y happens to be the DR in the network segment.
 
Now Router X restarts. After 'T' seconds, Router X becomes fully adjacent with Router Y.
 
At this point, three scenarios are possible:
1> X had received all the relevant LSAs (i.e. router-LSAs of X, Y and Network-LSA of Y) BEFORE becoming fully adjacent with Y.
     Hence, the graceful-restart exit event has already been fired BEFORE X became fully adjacent with Y.
2> X had received all the relevant LSAs BEFORE becoming fully adjacent with Y;
     but graceful-restart exit event gets fired EXACTLY when X became fully adjacent with Y.
3> X had completed receiving all the relevant LSAs AFTER becoming fully adjacent with Y;
     Hence, the graceful-restart exit event gets fired sometime AFTER X became fully adjacent with Y.
 
Thanks,
Debopam