Subject: Re: Extended Hitless OSPF Restart

From: "Naidu, Venkata" <[email-masked]>
Date: Wed, 26 Jun 2002 18:00:39 -0400

Acee,

  Here is what I think.

-> This not what I've implemented. A router acting as a helper will exit
-> helper mode when:
->
->     1. The inactivity timer expires.

  No, any hello related, packet exchange timers related, to
  that interface, should not bring down helper mode.

->     2. The interface goes down (which will also cause an LSA
-> change).

  Do you mean, operational state of interface going down?
  In other words, forwarding plane on that interface goes down ?

->     3. Certain sequence mismatch conditions (but not the
-> obvious ones that occur
->        naturally during graceful restart).

  Again, any change in the LSDB which the restart router
  might want to know, should trigger helper exit.

  More precisely, some changes in LSAs might not affect
  forwarding plane at all. In all those cases, there is no
  need to exit from helper mode.

--
Venkata.

---

From: Acee Lindem <[email-masked]>
Date: Wed, 26 Jun 2002 15:07:02 -0700

>   In other words, forwarding plane on that interface goes down ?

Yes.

>   need to exit from helper mode.

Sequence mismatch is a neighbor event. What I'm saying is that
if there is an error in the database exchange after the initial
unexpected transition from full to exchange start, I will exit
helper mode and restart the database exchange.

--
Acee