Etherchannell vs. Network Fault Tolerance vs. NIC teaming

[Jan Rolny]

Hi all,

I tried to understand what I need to configure on cisco switch if I want failover two NICs on single server but did not find simple answer for that. Somebody recommends to configure etherchannell and somebody suggest load balancing.

Please see attached picture.

Two NICs on server are configured in team mode (or bonding) so in case that active link will fail I will be still able to ping to server without interruption.

Is there something what I must configure on switch side to make this work properly?

I do not want load balance this NICs and also I do not want to improve performance in bandwidth, just switch active/standby link between NICs. NICs are members of the same VLAN.

Thank you for answers.

Have a nice day,

Jan.

[Collin Clark]

Jan,

From my experience the teaming on NIC's is flakey. What we did to increase stablility was to etherchannel between the server and switch. We preferred to trunk, but setting as access should work too.

Hope it helps.

[Jan Rolny]

Hi Collin,

thank you for answer. What i do not understand is why to configure etherchannell? Because what I know so etherchannell was designed to incerase bandwidth and not failover, right?

Regarding trunk configuration is it enought to configure port like this:

# switchport mode trunk

without encapsulation right?

Thank you,

Jan.

[Collin Clark]

Etherchannel does increase bandwidth but it also provides failover. If you have two links in an etherchannel and one of the links goes down, the etherchannel stays up because there is still a valid link. You get the best of both worlds. However if you two links don't expect 200Mb as there are some tweaks/limitations on how it balances the load on the links, but that is another discussion. The trunk command you have is correct. Make sure your server NIC supports 802.1q. Newer switches don't support ISL, but depending on the switch model, you may have to configure the encaps.