What is L2 and L3 etherchannel default load balancing method?

[SubnetWarrior]

Hello experts, 

Please your insight and enlighment about etherchannel load balance.

To be quick, what is default load balance method for layer 2 etherchannel? what is default load balance method for layer 3 etherchannel?

Can layer 3 etherchannel using mac source/dest as load balance? can layer 2 etherchannel using ip source/dest as load balance?

If the layer 3 etherchannel can using mac as load balance, by what that etherchannel link can differ the mac address? as we know layer 3 can only view ip address. For example my edge switch is L3 switch and it is not default gateway for the PCs/Servers. Can layer 3 etherchannel in my edge switch load balance by mac address? There is no information about PCs/Servers mac address in my edge switch since this edge it's not default gateway (can not view the PCs/Servers ARP).

I'm sory for the very basic question but this answers will clear all my doubts about etherchannel load balance.

[marce1000]

  - FYI : https://www.cisco.com/c/en/us/support/docs/lan-switching/etherchannel/12023-4.html

 M.

[Giuseppe Larosa]

Hello @SubnetWarrior ,

in addition to the link provided we can say that load balancing depends more on the type of traffic going over the bundle then on the type of etherchannel.

In other words a L2 port channel can use IP addresses of IPv4 flows to perform load balancing it is not restricted to check MAC addresses only.

For a non IP flow not routable the use of MAC addresses may be the only way to perform load balancing.

What algorythms are available is platform dependent but the above is generally true.

An important note is that the choice of the load balancing method is platform wide it cannot be done per single port channel

Hope to help

Giuseppe

[Joseph W. Doherty]

Default and available load balancing options vary per platform.  Same options for L2 or L3 Etherchannel as load balancing doesn't care which.  (The latter is because the switches that offer Etherchannel load balancing are often "smart" or "enhanced" meaning even for L2 switching they offer L3 features.)