Etherchannel to 3com switch

[firemtngems]

Has anyone configured a C2960 to etherchannel to a 3com 4924 super stack? What I have on my 2960 is this:

Interface Port-channel1

switchport mode trunk

!

!

interface GigabitEthernet0/23

switchport mode trunk

channel-group 1 mode on

!

interface GigabitEthernet0/23

switchport mode trunk

channel-group 1 mode on

!

and the 3com's ports a set to Aggregated Links on two ports.

Thanks,

Mike

[Roberto Salazar]

Not sure how you configure 3Com but mode "on" on cisco as you have it, should be the right way as 3com will not understand PaGP (desirable).

Please rate all posts.

[firemtngems]

Right, I want to avoid PaGP and LACP, I just want to force it on since it is a simple deployment. I was hoping a 3com person would chime in with some advice.

Thanks,

Mike

[scottmac]

If the 3COM doesn't support pagp or lacp, then you will not be able to do link aggregation.

If the 3COM has some proprietary aggregation scheme, then (being proprietary) it won't work on the Cisco.

Any other collection of parallel connections to the same broadcast domain(s) will either cause a L2 loop, or spanning tree will shut down the extra links.

(or the links just won't come up when the other side can't be identified)

Good Luck

Scott

[mchoo2005]

I think the root cause of your problem is you should use "active" instead of "on". channel-group with "on" basically tells your Catalyst to use EtherChannel, which is Cisco proprietary. The "active" keyword should force the Catalyst to use LACP protocol instead. If you like, you can throw in "channel-protocol lacp" interface configuration command as well for good measure.

[firemtngems]

In http://www.cisco.com/en/US/products/ps6406/products_configuration_guide_chapter09186a00805a75e0.html

it states:

"EtherChannel on mode can be used to manually configure an EtherChannel. The on mode forces a port to join an EtherChannel without negotiations. The on mode can be useful if the remote device does not support PAgP or LACP. In the on mode, a usable EtherChannel exists only when the switches at both ends of the link are configured in the on mode."

I was thinking that it would be easier to set up in a manual fashion. Maybe, since the 3com seems to support LACP I should use it to establish the link. My problem is I don't have a test switch to use so if enabling the link caused any SPT issues, the villagers will come to storm the castle.

If anyone has set it up with 3com, please tell me of your experience.

Thanks,

Mike

[mchoo2005]

Mate... I'm sure EtherChannel is Cisco proprietary. I can't remember the exact article/document that states this.

Why don't you give the command a go and see the result? Sometimes we can't wholly trust technical doc (Cisco or otherwise).

BTW, I have also used a 3Com SuperStack 4924 (it's the one with 24-port 10/100/1000, plus 2 modules at the back, right?), which I'm sure can support LACP.