11-09-2007 06:45 AM - edited 03-03-2019 07:28 PM
If an OSPF router receives from its OSPF neighbor an OSPF packet other than Hello packet (i.e. LSA, LSAck), is dead interval reset anyway?
Regards
Stefano
11-09-2007 06:53 AM
What "other" OSPF packet can it be ?
11-09-2007 06:56 AM
Any OSPF packet other than Hello: LSA, LSU, LSR, LSAck
Stefano
11-09-2007 07:09 AM
AFAIK, there isn't any other packet.
11-09-2007 07:08 AM
All OSPF packets like LS Request, Update, & Acknowledgement are a part of Hello packet only. They are not exchanged as separate packets. However for identification, each packet type contains its own header format within a HELLO. And ofcourse everytime a HELLO is received, the timer gets reset.
Happy Diwali.
11-09-2007 10:12 AM
That's not what I'm inferring from my book, Routing TCP/IP Vol I. There are separate and distinct packets for each type. Only the HELLO has what is needed to keep the neigborship up. (the hello and dead intervals, options, network mask)
All packets have the same header and in the header there is a field for a type code (1 - 5) to distinguish what type of packet it is.
So I would answer the original question as no, the dead interval would not get reset each time any packet is received, only when it receives a HELLO.
It wouldn't be to hard to lab this up. set the hello and dead intervals to something high, then create a loopback and advertise it into OSPF and sh ip ospf ne to see when the dead timer is to expire and if it got reset after the new LSAs advertising the new loopback network.
11-09-2007 11:12 AM
Yes... IOS resets the dead interval for all OSPF packets received. I seem to remember a time when this wasn't so, and a discussion about changing it, but the current code always resets the dead timer, and I can't track down anything about it ever being different, so....
HTH.
:-)
Russ
11-09-2007 11:54 AM
Yes it does..I even simulated it to confirm
Narayan
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: