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New Member

Cisco 3750x BRP Priority

I have 2 3750s connected via flexstack. Its working good no issues.

I have 8 2960s (each in stack of 4).

Each stack of 2960s, is connected via a port-channel to my 3750. But, I have a backup port-channel to my second 3750, just in case my first 3750 goes down.

I dont want to have both connections up, I just want it so that in case one of the connections goes down, the secondary one takes over.

Isnt that done thru spanning-tree cost?


This is my setup:

3750

The primary Connection:

interface Port-channel2
description Uplink to ETHSW05
snmp trap mac-notification change added
snmp trap mac-notification change removed
spanning-tree guard loop
spanning-tree cost 15

The backup port-channel

interface Port-channel4

description BRP to ETHSW05

snmp trap mac-notification change added

snmp trap mac-notification change removed

spanning-tree guard loop

spanning-tree cost 1

Is my setup correct? Cause at the moment, both port-channels shows as up. Basically, I just want 2 2GB connections to each stack, one of them being a backup in case the first fails.

Thanks for the help...

Everyone's tags (3)
6 REPLIES
VIP Super Bronze

Re: Cisco 3750x BRP Priority

In a case when you have 2 portchannels to the same switch, the second portchannel will be in blocking mode, but the interfaces are still in up and up mode.  So, STP blocks one of them.

HTH

New Member

Cisco 3750x BRP Priority

Thank you.

So my configuration is correct?

Thanks...

Hall of Fame Super Blue

Cisco 3750x BRP Priority

Pick a vlan that is allowed on both both port channel interfaces and then do -

sh spanning-tree vlan

and you should see it being blocked on one of the switches. You should do this on he 2960s.

Jon

Hall of Fame Super Blue

Cisco 3750x BRP Priority

Hi Reza

Forgot to reply when i saw you in another post. Hope all is well with you

Jon

VIP Super Bronze

Cisco 3750x BRP Priority

Hi Jon,

All is well, thanks.

Good to see you are back after a long pause.

Have you recovered completely from your bike injury?

Reza

Hall of Fame Super Blue

Re: Cisco 3750x BRP Priority

Reza

Have you recovered completely from your bike injury?

Pretty much yes although i do still get the odd twinge every now and then.

Glad to see your'e still active and i am learning more about VSS every time i read one of your posts.

Jon

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