Question about MESH and RSTP.

[Ville Leinonen_1]

Hi,

I wonder how RSTP switches see's MESHed 5308xl "domain" one switch or many swithces?

If i asume right Link B is being blocked if i raise that link priority 8-16?

How stp root is selected for this enviroment?

I attach picture for example network configuration.

Best regards,

Ville

[Stuart Teo]

sw2 and sw4 must both run rstp and mesh. either link A or link B will be blocked depending on the port cost you set for the ports in sw2, sw4 and where the root is.

root is elected using root priority as usual.

[Ardon]

Hi Ville,

All of you Meshed Switches should also run (R)STP not only the Edge ones.

From the Advanced Traffic Management Guide Jan 2005 page 7-6:
"The spanning-tree configuration must be the same for all switches in the
mesh (enabled or disabled). If spanning tree is enabled in the mesh, it
must be the same version on all switches in the mesh: 802.1D, 802.1w, or
802.1s. If there are any 1600M/2400M/2424M/4000M/8000M switches in the
mesh, then only 802.1D STP can be used."

Indeed a Mesh is seen as one Switch in terms of Spanning Tree.

In your topology if Core 1 becomes STP Root (Priority 0) then indeed Link B will be Blocked. In your drawing I see the link between Sw5 and Sw6 as BLK which I think means Blocked so probably Core 1 is already Root.

Regards, Ardon