Switch Meshing

Operating Notes for Switch Meshing

Figure 14-17. Connecting a Switch Mesh Domain to Non-Meshed Devices

STP or RSTP should be configured on non-mesh devices that use redundant links to interconnect with other devices or with multiple switch mesh domains. For example:

Non-Mesh Switch

STP

Block

STP

Block

Mesh Domain

 

Mesh Domain

 

 

 

 

Non-Mesh Switch

Figure 14-18. Interconnecting Switch Mesh Domains with Redundant Links

In the above case of multiple switch meshes linked with redundant trunks there is the possibility that STP or RSTP will temporarily block a mesh link. This is because it is possible for STP or RSTP to interpret the cost on an external trunked link to be less than the cost on a meshed link. However, if this condition occurs, the meshed switch that has a blocked link will automat­ ically increase the cost on the external (non-meshed) link to the point where STP or RSTP will block the external link and unblock the meshed link. This process typically resolves itself in approximately 30 seconds.

14-21