STP on L2/L3 switches

[AkbarAliSheikh]

Hi All,

Can  someone advise me if i can setup STP on a 3560X switch working as L2/L3  same time? There are VLANs configured on the ports and the switch is  using EIGRP for routing.

Thank you all in advance.

[Giuseppe Larosa · Accepted solution]

Hello Akbar,

you can and you should use an STP flavor on your multilayer switch, because STP manages link redundancy at OSI layer 2, it does a different job that it is not performed by an IP routing protocol like EIGRP.

To make an example it is STP and its safety measures like Bpduguard that allows to avoid to melt down the network if by user error two switch ports are connected together.

PVST+ should be enough, configure your switch to be the primary root bridge for all Vlans, and use Bpduguard on all user facing ports.

Hope to help

Giuseppe

[Joseph W. Doherty · Accepted solution]

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Posting

Like Giuseppe, I too would recommend keeping STP active in case of accidental L2 loops.

You can make portfast and bpduguard the default for ordinary edge switchports with these two global commands:

spanning-tree portfast default

spanning-tree portfast bpduguard default

[Jon Marshall]

STP should already be running unless you explicitly disabled it.

If you did and you reenable it and you have multiple switches be aware that you amy experience a short outage while STP converges.

Jon