Re: Exit-Graceful Restart Condition

[Acee Lindem <[e-mail]>]

Padma Pillay-Esnault wrote:

> sujay wrote:
>
>> Hi All,
>>
>> Considering RFC3623, Graceful Restart for OSPF V2 I have a problem;
>>
>> Ex:
>>
>>  (network)---- DUT ---- RTA
>>
>> (All in the same area)
>>
>> Assume DUT undergoes a Graceful-Restart, it sends out grace LSA's to
>> RTA and other routers in the 'network'
>>
>> At the instant RTA recvs the Grace-LSA it also goes down.
>>
>> Is there a way in the RFC 3623 specified as to how DUT could Detect 
>> this topology change and Exit GR *before* grace period expiry??
>>  
>>
> I do not think the RFC covers this case. You are in a double failure 
> situation.
>
> I can think of a simple solution. When DUT reacquires its router-lsa. 
> It can determine its previous
> neighbors. It can then decide that if within DeadRouterInterval that 
> neighbor did not  respond
> to hellos to abort GR. This would be equivalent to the normal 
> situation when a router goes down and its
> neigbors takes DeadInterval to bring down their adjacency

I agree completely with Padma. One point, if RTA comes back up and 
originates a new router LSA
then the DUT will detect the inconsistency (as specified in RFC 3623) 
with it's pre-restart LSA and
terminate graceful restart. 


>
> Padma.
>
>> For other routers in the network RTA is still reachable and traffic 
>> Will be eventually dropped.
>>
>> Kindly correct me,
>>
>> Regds,
>> Ashok/Sujay
>>
>>  
>>
>