Re: Question about EtherChannel

wooying · ‎02-19-2011

All

I have a Cisco 4006 (old school) and I am trying to setup etherchannel over 4 port. The issue I am having is flapping, it see's two IP addres on the same MAC address. The reason for this is bonding, so all 4 ports are bonded, but I have two servers that need to send a heartbeat between the two server hence the second IP, and the other IP address to send/recieve. Any suggestion on getting around this?

IAN WHITMORE · ‎02-19-2011

I have this argument all the time with server administrators. A heartbeat should be on a cross-over cable between the two servers, not over the LAN. Oh well, so be it. So it's on the LAN...right, what to do.

One option is to use another network card on each server if it's available.

Or instead of bonding the 4 NICs, what about using 3? Is it really necessary to use all 4? Is there really that much traffic?

Monitor the server / switch porta for traffic usage. If the are ethernet ports have you thought about upgrading to fiber? And leave the copper for heartbeat?

I eventually got them to see the error of their ways and now they put crossovers. You don't won't servers switching node for a switch failure if you have desgined it properly.

For instance you should have two switches. Eacher server with one or more interfaces bonded to each switch and a crossover inbetween. There you have a redundant configuration for network failure and for server failure.

Regards,

Ian

wooying · ‎02-19-2011

Ian, thanks for your quick reply, the heartbeat also act as a failure (HA) between the two servers as well. I wanted to bond all 4 to get maximum speed, I think your right I might have to bond two set of NIC's and set it up that way or use LACP? Any thought's on LACP instead? Fiber instead of copper would be nice but it is not feasible at this time. Again thanks for your reply.

IAN WHITMORE · ‎02-19-2011

LACP (industry standard) or PAgP (Cisco propietary) are just the protocols Cisco use to create and communicate over the etherchannel. If you are load balancing to a server and it supports it, you should use LACP cos it won't support PAgP. Otherwise you should just turn the channel-group ON and be done with it.

Regards,

Ian

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