From: Bob Sinclair (bob@bobsinclair.net)
Date: Sun Apr 15 2007 - 19:36:27 ART
Gregory Gombas wrote:
> Thanks for the clarification Bob.
>
> Yes I was able to observe the differences between global bpdufilter
> and interface level bpdufilter and it works as you described.
>
> As far as differences between 3550 and 3560 with regards to portfast,
> I was not able to replicate your scenario:
Hi Greg,
YUP! I retested and found exactly the result you have; the 3550 DID
disable portfast with receipt of a bpdu without any extra bpdufilter
configuration.
Here is where I think I went wrong in my previous test: the portfasted
port was a DESIGNATED port, and so did not receive any bpdus (they only
send once roles are determined.) I should have tested on a root port
to keep it simple!
When I added the global bpdufilter, the designated port stopped sending
bpdus. After 20 seconds, the other side sent a bpdu claiming to be
root. This triggered the portfast disable on the portfasted side, it
stopped filtering and sent a bpdu to override the inferior one sent.
So, by testing on a designated port, adding the global bpdufilter
caused the other side to eventually send a bpdu. DOH!
As I always tell my students: believe none of what you hear and only
half of what you "see."
Thanks! :-)
--Bob Sinclair CCIE 10427 CCSI 30427 www.netmasterclass.net
This archive was generated by hypermail 2.1.4 : Tue May 01 2007 - 08:28:35 ART