From: Marko Milivojevic (markom@markom.info)
Date: Thu Nov 27 2008 - 19:27:09 ARST
On Thu, Nov 27, 2008 at 19:50, Scott Morris
<smorris@internetworkexpert.com> wrote:
> You could do passive for the interface (in router ospf config), or on the
> interface itself you can use "no routing dynamic"
>
> I'm not sure I'd consider either to be particularly "graceful" though.
They actually are... at least much more than simply shutting down the
interfaces ;-).
It takes time for neighbors and LSA's to be cleared from the tables
and run SPF to recalculate paths and update RIB. If you are using
boxes with separate forwarding plane, it takes even longer! At the
same time, CEF table is intact and router keeps forwarding traffic out
the interfaces on which you disabled OSPF. When recalculation is
finished and CEF is updated, traffic will shift traffic to alternative
interfaces, or alternative routers altogether.
I use this all the time when upgrading backbone nodes.
-- Marko CCIE #18427 (SP) My network blog: http://cisco.markom.info/Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Mon Dec 01 2008 - 08:18:32 ARST