2960S redundancy for Trunk

[Tippey]

Hello, 

Ive done a fair bit of searching this morning and am not able to find anything which covers which im looking for.

We currently have a trunk port with a few VLANS which we will be adding more to over the next few weeks.

My main query is setting up some for of redundancy for the trunk port so that if it ever fails it will fail over to a secondary trunk (which is not yet setup)

Is this at all possible? Lots of what i have seen use commands which are not in use for the software:

C2960S Software (C2960S-UNIVERSALK9-M), Version 12.2(55)SE8, RELEASE SOFTWARE (fc2)

[Seb Rupik]

Hi there,

For trunk link redundancy you have two options:

Etherchannel - and an additional uplink and bundle it with the existing one to create an etherchannel. Both links will be in a forwarding state and traffic will be balanced across them.

STP blocked - like the above, except not bundled together. If the primary link fails STP will reconverge the topology and the second uplink will begin forwarding.

I would recommend you implement an etherchannel,

cheers,

Seb.

[Martin L]

agree. etherchannels are way to go

[Joseph W. Doherty]

Just to clarify a point on the use of an Etherchannel; ideally you have a stack of 2960Ss with an Etherchannel link running to different switch stack members. Even if the port, ASIC or a whole stack member fails, the trunk will remain up and functional. Any traffic on the failed link will move to the remaining Etherchannel link(s) very quickly.

The STP approach doesn't require a stack to function. Its fail over time, compared to the Etherchannel, will be much slower. Ideally you would want to use a "rapid"/fast STP variant.

BTW, possibly another approach would be to use Cisco's Flex Link.