Circular links in switch setup

Installing and Using OpenWrt Network and Wireless Configuration
1

Not strictly an OpenWRT question here, but I know that the knowledgable people here will help!

Am I right in thinking that it's OK to set up circular links between switches (that is to say, if I have 3 switches, connect A to B, B to C and C to A) so long as Spanning Tree Protocol is enabled?

In this scenario, it would create a fault tolerant situation where if the link from B to C failed, STP would automatically re-route packets via switch A (B to A to C)?

Does STP handle this all automatically?

2

STP is implemented in software kernel bridges, it's not part of hardware switches. So you'd need to set it up so any potential loop goes through a software bridge with STP enabled.

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3

Yes, that is the exact scenario why STP was created. However, the failover functionality may not be as fast as you would expect.

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4

Yup. I've actually explicitly disabled STP for a bunch of VPNs using tap bridges because STP causes significant initialization delays in just bringing the connection up.

5

Sure, but in terms of enabling it on an L2 managed switch.. this should be a no-brainer right?

Also this switch supports RSTP (Rapid STP) which I think is designed to make these delays significantly shorter.