Maximum switches in Ring topology

[abdulkarim041]

Hi,

How many maximum switches we can install in ring topology with STP?

 BR

Muhammad Jasim Abdul Karim

[Julio E. Moisa]

Hi

You should take in consideration the diameter, STP timers, I should not recommend more than 7.

Regards 

[abdulkarim041]

Hi,

Can I deploy 20 switches in one ring?

BR

Abdul Karim

[Karsten Iwen]

I would not expect that you'll get a definitive answer like "X  Switches". It is still Spanning-Tree with its design-limitations. But typically it scales much better than originally specified, especially with some tuning.

In a situation like this I would also ask myself if my aproach to the problem is right. STP is not designed for Rings. Although Cisco-propriatary, REP could be a better fit for your problem as it is designed for these kind of ring-topologies.

[Joseph W. Doherty]

Using 802.1D, according to Max Spanning Tree (STP) Diameter , the answer is 18.  Note cautions in the text using 18.

If you're planning on using 802.1s or 802.1w, maximum will likely vary and seems perhaps larger can be supported.

As Karsten suggested, REP (see Resilient Ethernet Protocol Overview ) would likely be a better choice, but not as widely supported on all Cisco switches as STP variants.  It seems a bit difficult to nail down the maximum number of nodes it supports in a ring, which seems to vary (a lot) by what's recommended (neighborhood of 22) and what some have successfully achieved (neighborhood of 100).