Teamed nics on 2 (trunk-)stacked 2960G (redundancy)

ernieveder · ‎03-04-2009

Hello,

We have a couple of linux servers that we want to interconnect using switches. We need 3 VLANs of which only the production VLAN needs redundancy and load balancing. And it should easily be expandable with more servers.

Our proposed setup contains of 2 stacked HP 2960G-24TC-L (stacked using 2 trunked connections). Each server has 1 teamed pair of nics with one nic going to switch-1 and the other to switch-2. These 2 ports should be trunked (trunked over 2 stacked switches). This should be the default VLAN. Next to that each server connects 2 more nics for both other VLANs (1 per VLAN, no specialities here).

My question is if this is going to work and if this is matching our needs? Can ports on 2 stacked 2960G be configured as trunked ports to serve a teamed set of nics for load balancing and redundancy?

And is our proposed setup a proper way to achieve our goals?

Thanks for listening and feedback,

Ernie

P.S. I already learned that the HP ProCurves are not able to tackle this.

andrew.prince · ‎03-04-2009

Ernie,

See the below 2960G config guide for ether channels/port trunking:-

http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_25_see/configuration/guide/swethchl.html

And for load balancing:-

http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_25_see/configuration/guide/swethchl.html#wp1275731

HTH>

ernieveder · ‎03-04-2009

Thanks for your swift response.

I did indeed read these sections and I was under the impression that Cisco's EtherChannels might do the trick. However what is still unclear to me, if you can spread an EtherChannel-group and/or a group of trunked ports over 2 stacked switches. Most examples deal with trunked ports within 1 switch. Can you confirm the ability to trunk ports over stacked switches or even better point me to the exact text-parts in the manual, since I am having trouble digging this out. Thanks.

andrew.prince · ‎03-04-2009

OK - to answer your question, that is not possible.

Each etherchannel is unique to the switch. You cannot have an etherchannel configured on both switches that is part of an overal bigger etherchannel.

Etherchannel groups layer 2 switch/physical ports into a virtual group. The swirtch port have to be physically on the device you are configuring.

In the case of a stack - well the normall rules do not apply....although they are physically seperate switches, in a stack they are 1 logical - so in theory yes you can do it.

HTH>

ernieveder · ‎03-04-2009

So, EtherChannels are out.

Is there another way to solve this in a setup like this? Or does proper redundancy and load-balancing need a multitude of switches and thus a higher budget?

andrew.prince · ‎03-04-2009

Errrm did you miss the last bit of my post

"In the case of a stack - well the normall rules do not apply....although they are physically seperate switches, in a stack they are 1 logical - so in theory yes you can do it" ???