Is RSTP part of PVSTP? Cisco 2960 Switches (Cisco Support Community Subscription Update)

[YumeNoKira]

My client has asked me to run rapid spanning tree on his cisco switches.

The first one is a WS-CS2960G-24TC-L  running 12.2(25)SED and C2960-LANBASEK9-M.

The second one is also a WS-C2960G-24TC-L running 12.2(35)SE5 and C2960-LANBASE-M.

The only configuration lines that i found on both devices relatives to spanning-tree are the following ones.

spanning-tree mode pvst
spanning-tree extend system-id

With my limited knowledge and experience in cisco switches i can only tell that they are running per vlan spanning tree. However i always assumed from what i've red on the subject that RSTP was an improvement included in PVST. Now i am confused because i have seen a list on plateform which support RSTP  ( https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24062-146.html ) and CISCO 2960 switches are not among them.

I am told i will be given a diagram of the targeted architecture by thursday, i will post it here. In the meantime i would like to know if RSTP is a reliable solution on my platforms or not.

[Jon Marshall]

They are not the same thing. 

On the switch in configuration mode - 

"spanning-tree mode ?" 

and it will show you which versions of STP the switch supports but only change it out of hours. 

Jon

[Joseph W. Doherty]

To add to Jon's post, the command you want to find (use) is:

spanning-tree mode rapid-pvst

BTW, pvst and rapid-pvst will inter-operate, but ideally, you'll want all the switches on rapid.

[YumeNoKira]

The vlan are meant to be kept, in that case giving up on pvst for rstp is not appropriate is it ? I'm assuming that rstp does not handle vlan or does it ?

[Jon Marshall]

The version of RSTP on the switches are per vlan so you should be okay.

Jon

[Joseph W. Doherty]

Adding to Jon's post, again ;)

STP vs. rapid-STP are the underlying algorithms. STP, I believe, predates VLANs, and on some vendors equipment they only support STP or rapid-STP for all VLAN instances. (Sometimes this is known as "common" STP.)

One of Cisco's early "enhancements" was to support STP per VLAN (allowing different STP topologies per VLAN, PVST - Per-VlanSTp, also allowing different physically redundant link usage). When rapid STP came out, Cisco again implemented it per VLAN.

[syrehan]

This should clear things out for you:

https://supportforums.cisco.com/t5/lan-switching-and-routing/pvst-rstp-and-rapid-pvst/td-p/1459012

[YumeNoKira]

Thank you all for your replies. Turns out the client want to add some devices to my switches, 4 additional switchs (2 Dell 2 HP). I advised against trying to implement spanning tree between devices from different constructors.

[Joseph W. Doherty]

Mixing vendor switches, and their STP implementations, can sometimes be done. The problem often is (rapid or not) Cisco's per-VLAN STP vs. other vendor's common STP. Sometimes the only solution between different vendors is using MST.