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New Member

STP Configuration

Hi,

I have the following design, Core_A (Cat65) and Core_B(Cat65),3 Access Switches, AS_A, AS_B, AS_C. AS_C is using 3Com.

- AS_A is connected to Core_A and Core_B via Gi0/1 and Gi0/2 using fiber.

- Both Core have been configure with a Vlan 200, and Core_A is the root bridge.

- AS_B uses 3 UTP cross cables, one to AS_A and two to Both Core.

- AS_C connect to AS_B using a cross cable.

Base on the above design, how do i force AS_B to chose AS_A as the root path to Core? If AS_A is down, AS_B will chose one of the UTP path to Core_A?

Many thanks!!!

Merry Christmas!

2 REPLIES

Re: STP Configuration

Hi,

you can increase the STP cost on the AS_B ports connecting to the core switches, e.g.

I suppose you are running IOS on AS_B.

Use

sh spanning-tree vlan 200

and check the current values.

Then go to the AS_B config and use

spanning-tree vlan 200 cost xxx

command for each interface connecting to the core.

The value xxx has to be big enough to change the interface to STP blocking stage.

Finally both lines to the core will become blocking while the line to AS_A will become forwarding.

Regards,

Milan

New Member

Re: STP Configuration

thanks Milan!

br.

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