[nsp] PVST+ BPDU frame format

[Even Glemmestad]

Afaik, BPDUs sent from a Cisco over .1q trunks are not PVST BPDUs; when
Cisco uses a .1q trunk it uses normal STP on the link. I have created
connections between Cisco and 3rd-party switches using PVST+ on the
Cisco end, and STP on the 3rd-party end, running a .1q link in between.
The result, without any other configuration than setting the trunk mode
to dot1q, was that the BPDUs sent across the .1q trunks were normal STP
BPDUs for VLAN1, and interpreted correctly by the 3rd-party switches.

Best regards,
Even Glemmestad [CCNP,MCSE-2k,MCSE-NT,CNA,LCP,OCA]
Email even at supras.nu


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Clinton Work
Sent: 28. mars 2004 23:39
To: cisco-nsp at puck.nether.net
Subject: [nsp] PVST+ BPDU frame format


I'm trying to find a reference for the PVST+ BPDU frame format. I'm sure
that its similar to a 802.1d BPDU, but I can't find anything on
Cisco/Google. I'm
trying to troubleshoot a STP problem on a Etherchannel 802.1q trunk
between
a Catalyst 6500 (CatOS) and 7600 (Native IOS). Neither NAI Sniffer nor
Ethereal can decode the PVST+ BPDUs.

===================================
Clinton Work                clinton at scripty.com
Airdrie, AB



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