Default Spanning Tree on Cisco IOS switches

Dilan77
Dilan77 used Ask the Experts™
on
Hi All

I've been searching the Cisco site for a definative answer as to what the default STP method is running on IOS switches such as the 2950 and 3550. Some people say it's PVST+, others CST.

Does anyone know, or better still, have a link to where this is answered?

Thanks
 
 
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Instructor
Top Expert 2015
Commented:
PVST over ISL trunks and PVST+ over 802.1q trunks.

Same thing, basically.
Top Expert 2009
Commented:
I second donjohnston's comment.

Speaking from experience with these switches, it's PVST+.

Here is a portion from this "http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00801a6baa.html" that confirms.  The link is for the 2950 switch but the same applies to the 3550.

Spanning-Tree Modes and Protocols

The switch supports these spanning-tree modes and protocols:

PVST+—This spanning-tree mode is based on the IEEE 802.1D standard and Cisco proprietary extensions. It is the default spanning-tree mode used on all Ethernet, Fast Ethernet, and Gigabit Ethernet port-based VLANs. The PVST+ runs on each VLAN on the switch up to the maximum supported, ensuring that each has a loop-free path through the network.

Author

Commented:
Thanks guys...

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial