Spanning-Tree Questions

[skribbla]

just a couple quick qsns.. does the "spanning-tree portfast trunk" command cause the associated port to go into fowarding and skip the first stages of the STA???
and how do i force a port into becoming the root port?? i have a setup where my main wireless link (GX) plugs into a 3560 switch and a mesh access point also plugs into the switch (both are trunk links), both links go to our Data Center.. i am trying to make the mesh port the alternate route hence block it and the main wireless gx port the root route (hehe).. but it keeps going the other way. i have tried changing bandwidth, priority and cost still the same. Your help will be greatly appreciated.

 

[vipergg]

Yes it does , only use this on a server attached trunk . To set spanning tree use "spanning-tree vlan XX root primary" command to make the switch root for that vlan. Use the "spanning-tree vlan XX root secondary " for a back up link .

 

[rbradely]

to force a port into becoming the root port you need to change it's port-priority for the vlan.

Switch(config-if)# spanning-tree [vlan vlan-list] port-priority port-priority

The value of port-priority can range from 0 to 255 and defaults to 128. A lower port priority value indicates a more preferred path toward the Root Bridge.

 

[VinceWhirlwind]

...and you shouldn't have "spanning-tree portfast trunk" on any of the switchports to either of these devices.

 

[rbradely]

You can speed up convergence on these ports by using:

switchport mode trunk
switchport nonegotiate

and if you are using RSTP add:

spanning-tree link-type point-to-point