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New Member

Etherchannel/trunks

Hello,

I'm trying to create an etherchannel between our cores using 4 x 10GB ports.  I have built the edge switches (3750G's) for the users workstations and I have created multiple trunks to the cores for redundancy I just need to link the cores, however I'm not sure of how the spanning tree might go onec the ehterchannel is up and ideas?  One of the ports on the edge stack has gone into blocking mode already.

Diagram is attached, the green links are the trunk and the red will be the etherchannel.

Thanks

3 REPLIES
Cisco Employee

Re: Etherchannel/trunks

You need to make sure which switch is the spanning-tree root. Assuming 6500 on the left is already configured as the root for all VLAN's, then spanning tree shouldn't reconverge when the etherchannel is configured. However, using protection machanism (root guard, loop guard, storm-control etc.) is always a good idea to avoid spanning-tree loop, etc.

Regards,

jerry

New Member

Re: Etherchannel/trunks

root guard, loop guard,  storm-control - in what area would I use these please?

Thanks

Cisco Employee

Re: Etherchannel/trunks

Please take a look at this link

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/configuration/guide/stp_enha.html#wp1036858

Root guard should be on the root bridge's ports (designated port) to prevent it becomes root port.

Storm control is really used to suppress broadcast during spanning loop.

Regards,

jerry

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