DROther/BDR graceful restart question

[Ramesh Kandula <ramesh.kandula at SPIRENTCOM.COM>]

Hi All,

Suppose a DROther router restarts gracefully on a broadcast network. 
Before restart it has adjacencies with DR and BDR. According to clause in
 
2.2.1 (RFC 3623), it is supposed to wait till it forms adjacencies with 

BDR and DR before exiting restart mode.

However there is no way for it to determine who the BDR was before restar
t 
using the pre-restart router lsa (and/or pre-restart network lsa). Or am 
I 
missing something? Actually why is it necessary to wait (i.e for exiting 

restart mode) till it forms an adjaceny with BDR? Isn't it enough for it 

wait till it forms an adjacency with DR?

A similar issue arises with BDR restart as well. According to the same 

clause it is supposed to wait till it forms adjacencies with all the 
routers on the network. However it has no way of determining that it was 

the BDR using just the pre-restart lsas.

Thanks,
Ramesh