Hello and ACK

auos

If router (A) send Update as reliably multicast and an ACK is not received from a neighbor, the packet will be retransmitted as a unicast to that unresponding neighbor. If an ACK is not received after 16 of these unicast retransmissions, the neighbor will be declared dead.

Ok, my question is during the waiting for receiving an ACK, is there no any Hello message is send from router (A) to unresponding neighbor. In other word why the hello message does not recognize that neighbor is dead.

BR,
Auos.

dtlokee

A couple of factors to think about. First what are the hello and dead timers for an EIGRP neighbor and what values will control the retransmission of a Update packet if an acknowledgement is not received. Then compare the time of retransmissions to the dead timer. It's another way to declare a neighbor dead.

adam-b

Im curious how often these updates are sent? If it is every second then this would correspond nicely with the default hold timer of fifteen seconds.

dtlokee

It's based on the "retransmission time out" which is determined on a per neighbor basis.

adam-b

dtlokee wrote: »

It's based on the "retransmission time out" which is determined on a per neighbor basis.

thanks for clarifying.