Best practices regarding EtherChannel

[Nikos Nicolaides]

Hi,

I was wondering in a typical 20/80 network in which 80% gets outside the VLAN, what is the best load-balancing algorithm ?

souce destination port

source destination IP

source destination MAC

I would say that the best case scenario is the port, after the IP and then the MAC for the following reasons. If you choose src dest MAC, and you have multiple users hitting a file server in this VLAN , the source MAC will be the MAC address of the server and destination will be the gateway.

However, if you put IP address, the souce will be servers IP but destination will be users IP address.

The same goes for port only better; if you are having one client opening multiple sockets to one server, then it can load share based on the souce port of the client.

Is the theory correct or did i got it wrong?

Regards,

Nicos

[Joseph W. Doherty · Accepted solution]

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Posting

Really depends on what's normal traffic flows.  Using IP ports as "better" is assuming multiple sockets between two hosts, but if there were multiple hosts hitting the same server, it's possible the port number would have multiple hits as the server considers the combination of IP address and port as unique but if the hash only considers source destination port, you might have poorer distribution than source destination IP.

[Nikos Nicolaides]

Hmm, thats what i thought. A couple more questions though:

• is the etherchannel algorithm more cpu intensive as we go deeper in to the packet
• Does it cause any downtime when i change the algorithm?

[JohnTylerPearce · Accepted solution]

It does not cause any down time to change the algorithm. I have done this before without any down time in a live network.

Joseph is 100% correct, it all depends on your traffic flow. For me I did src-dst-ip. That was the best choice for my network enviornment. This is also a test command to help you out. 'test etherchannel load-balance' or something like that I forget of the top of my head. If I could have used ports in the algorithm I would have done that.

[Nikos Nicolaides]

OK, thanks