Need recommend spanning-tree mode pvst and mstp?

[rechard_hk]

Dear all Experts,

I would like all of you recommend me with protocol should i apply on my system spanning-tree mode pvst or mstp ?

Currently i have 3850-X 2 unit connecting with Stacking. and i have Access switch 2960 around 10 unit.

from Access switch 2960 i connect two link to 3850-X.  by default the protocol PVST come with switch. should we change to mstp ?

Which ones better for apply?

Best Regards,

Rechard

[Peter Paluch]

Hi Rechard,

MSTP is the standardized solution that will work nicely with hundreds or thousands of VLANs and will provide seamless compatibility and interoperability with switches from different vendors. However, running MSTP successfully requires deeper knowledge about its operation - I personally wouldn't recommend just turning it on and hoping for the best.

In general, if your network has only a handful of VLANs (say, 10 or 20 at most) and all switches are Cisco switches then I recommend running Rapid PVST (spanning-tree mode rapid-pvst). If you intend to use lots of VLANs (50 and more), or if your network is going to include switches from different vendors, I recommend considering MSTP.

Running legacy PVST which is the default (and what you have right now) will work but will not provide you with rapid convergence properties - a change to the topology will result into reconverging in 30-50 seconds. Running Rapid PVST should bring this time down to below 1 second.

If you run Rapid PVST or MSTP, you should also configure all your switches with the spanning-tree portfast default global configuration command. This will make all access ports behave as so-called edge ports. This is extremely important for Rapid PVST and MSTP that specifically protect edge ports from being influenced by reconvergence processes inside the network. If the access ports were not configured as edge ports, they could get blocked for 30 seconds each time a reconvergence occurred in your network - certainly, you do not want that to happen.

Best regards,
Peter

[Joseph W. Doherty]

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Posting

BTW, if you use port fast (and I agree with Peter, you do), you might also want to pair it with bpduguard.

[rechard_hk]

Dear Peter,

Thank you for your advice and more detail on this.

i don't have any experience on Rapid-pvst, i will check on rapid-pvst and i will apply this protocol to my system.

Do you have any sample command or document on this ?

if we use Rapid-pvst, Do we need apply all cisco ( Core-switch and access switch )? 

Best Regards,

Rechard

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Cisco's rapid-pvst will inter-operate with Cisco's pvst, you only need to change the global command.  However, it's best if all the devices are migrated to it (the inter-operation assists in migration, i.e. all devices don't have to be changed at the same time).  Also, again, as Peter noted, you also want to enable portfast.