Need to increase bandwidth between 2 6500 Chassis

david-flores · ‎12-01-2008

Currently I have 2 Gigabit connections between my 2 6509 switches that are at the core. One is forwarding, the other is blocking. The primary forwarding one is beginning to average around 45% to 55% utilization. I need to start to balance this load, I was considering configuring etherchannel, PAgP, or LACP, which is my best option in this situation.

Mark Yeates · ‎12-01-2008

David,

Etherchannel sounds like it will definitely be the right solution for you. Since you are going to use Cisco products you could go either way using LACP or PAgP, and still load balance. Here is a configuration guide to help you.

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.1E/native/configuration/guide/channel.html

HTH,

Mark

david-flores · ‎12-01-2008

Thanks for the link, so is one method preferred over the other in this situation?

Mark Yeates · ‎12-01-2008

I would not say that one should be preferred over the other. When I have customers that have mixed vendor equipment networks I will usually suggest LACP because it is an IEEE standard and can be used across many vendors. Just to keep things simple I will use LACP across the network. Both PAgP and LACP are very similar feature wise.

HTH,

Mark

Joseph W. Doherty · ‎12-01-2008

BTW:

Don't forget, if you enable a Etherchannel, you might need to change the hash algorithm to obtain the best usage of multiple links for your topology.

david-flores · ‎12-01-2008

What exactly does that mean, is that mentioned in the above posted link?

Jon Marshall · ‎12-01-2008

David

It's all to do with how the switch uses all links to transmit the traffic. The 6500 switches can use src/dst mac-address, src/dst IP address, src/dst port so you have the full set of options.

The same src and dst will always use the same link so you need to choose which one ie. mac-addresss, IP address, ports that would give you the most variation and hence use the most links -

http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a0080094714.shtml

Jon