Etherchannel load balancing on 4506 switch

[karmisevicg]

Hi there,

I use etherchannels to connect Compaq ProLiant servers and access layer switches (Cisco 2950T-24s) to Catalyst 4506 w/ Sup IV. It's my understanding that mac source address balancing is used when you connect etherchannel to single mac address (i.e. ProLiant server) and destination mac address load balancing is used to connect to devices with multiple mac addresses (switches). However, on 4506 switch load balancing is configured in the global mode and affects all the etherchannels. How should I configure load balancing? What does port-channel load-balance src-dst-mac is used for?

TIA

[donewald]

The src-dst-mac will use both scr and dst, as a pair, to do load sharing. For example if MAC A was talking to MAC B it would take one path. If MAC A talks to MAC C it would take another. If MAC D talks to MAC B it would take yet another. Gives a bit more granularity than source or destination together.

You are correct in the fact that load balancing for your channels is configured and applied to all channels. You'll need to, based on your traffic patterns, pick the best for you in your environment. Here's a link that talks about it a bit more.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat4000/12_18a/config/channel.htm

Hope this helps you,

Don