STP-Settings

[Ibrahim Jamil]

Hi Netpro

i have 2960 switch connected via two uplinks <LINK A  towards CORE-1 and LINK B to CORE-2 , both link are equal , STP Chosen LINK A as primary while LINK B as secondary , how can play with stp and Make LINK B the Primary while LINK A the secondary?

thanks

ibrahim

[Giuseppe Larosa]

Hello Ibrahim,

you would like to make LINK B The root port to achieve this you can increase the STP cost (that is calculated on the rx side in STP) on LINK A (on the c2960 switch I mean) port using

interface type x/y

spanning-tree cost X

where X must be greater the the cost to reach the STP root bridge ( core1 i guess) via LINK B.

for example X can be 20.

configured in this way the STP cost is modified for all vlans ( I suppose you are using PVST+ or Rapid PVST)

the STP cost can be modified per vlan or group of vlans with

spanning-tree vlan Y cost X

Hope to help

Giuseppe

[Ibrahim Jamil]

Hi Giuseppe

am still using PVST ,

regarding the Cost , both Link are equal , 1G Each, so to play with cost in this regard

thanks

Ibrahim

[glen.grant]

On core 2 use  "spanning tree vlan X root primary"  command.