10 GIG Etherchannel

[mbaylis]

Hi,

I'm using cisco ws-x6704-10ge blades in 3 6509 switches running sup-720's.

I have a query regarding etherchannel.

1) we have an existing 2 gig etherchannel link between the 3 switches. This existing etherchannel I would like to use as a backup to the new 10 gig etherchannel. Is there any config i need to do to the existing etherchannel to enable the 10 gig link to be used first instead of the 2 gig?

2) are there any restrictions in using 2 backbone etherchanels on the same switches?

3) If you have 2 Layer 2 etherchannels on the same switch 1 x 2gig backbone and 1 x 10gig (as a backbone to another switch) Which Etherchannel does the switch use to send traffic accross?

Thanks in advance

[Amit Singh]

Hi,

1. Nope, no special config is required on the existing etherchannel.

2. No restrictions as such.

3. It will use both the ether-channels to send the traffic accross. Etherchannel is implemented in hardware, and uses a hash based on source/destination MAC and/or IP and port # to decide what link each packet will take.Etherchannel supports load balancing based on individual or combination of MAC/IP/Port info. You might be able to influence the flow of traffic indirectly by choosing the right load balancing method by studying the physical interface stats.

More about all this here:

http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a008045296f.html

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009437d.shtml

http://cisco.com/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a0080160a03.html#wp1020436

HTH,Please rate if it does.

-amit singh

[mbaylis]

Thanks for that amit.

What affects will there be on spanning tree if both etherchannels coexist on the 3 switches? Will 1 port channel block? Can't get my head around how both will work without spanning tree problems. Thanks

[Amit Singh]

If you have two ether-channels, one of them will be blocked by STP

-amit singh