From PVST to RPVST in cisco switches

[13jobsp90]

Next week our infra is planning to move from PVST mode (currently all switches are in PVST) to RPVST all are cisco switches. Our infra is like this we have 2 core switches both in hsrp protocol and from there 2 distribution switches from there it goes to several access switches. These access switches are of cascaded connection (no stacking) through copper cable. All the vlans are passed in all the switches in infra because we connect differenet end devices in same switches likes ip camera, ipphone, wifi AP, PCs. All of them are in different vlans configured.So my question is before starting this activity what all things I should keep in mind because I dont want to have any network disruption in the live environment (like vlan priority, root port etc). I have only limited knowledge based on STP, loopguard,bpdu etc. Pls help me.

NOTE: All the access switches are cisco 2960 model, Core & distribution switches are 4506 model.

[Joseph W. Doherty]

You might take special note, on the web page reference Paul provided of:

• Spanning Tree from PVST+ to Rapid-PVST Migration Configuration Example (ZIP - 45 KB)

[13jobsp90]

I have done this activity before I started off with an edge switch. But immediately after changing to RPVST in cbs 350 some of the vlans got down hence its connected end devices got offline. What must be the possible reasons for this? Since it got down I have to rollback to PVST immediately. Pls help me.

[MHM Cisco World]

cbs350 it bugs, these switch family is full of bugs

MHM

[13jobsp90]

Are you sure it is due to CBS 350? I am asking before changing to RPVST what all basic  things needs to be for each access switches like loopguard, bpdu, portfast, root bridge for each vlan etc like that?

[MHM Cisco World]

Believe me cbs have a lot of bugs' the only solution if link is down when connect pvst SW to r-pvst SW and one of SW is cbs is open tac.

Sorry I cant help ypu with issue.

Goodluck 

MHM

[MHM Cisco World]

I will share some details about loop guard and root guard' 

I will share details in this post and your other post.

Thanks 

MHM

[paul driver]

Hello
As I have stated you need to understand your switching topology before migration, if your unsure then I would suggest you do not proceed

What pre-change activity did/have you preformed?
Possibly map out your switching topology, it should not be that hard to do, starting from the cores switch's and working your way downstream, taking note of the vlans, stp port states/costs, switch interconnects, bridge priorities etc...

So when you begin the migration you have a good understanding of how the migration will respond to the changes yoo make, Also if you start at the access layer, you should only cause stp change to the immediate connected upstream switches towards the primary root switch, from distribution again the same affect and lastly when changing the stp roots (secondary first) well at this point they should not effect the edge switches at all.