[c-nsp] Configuring Ethernet Channel on a Cisco 7513

[Joe Maimon]

Jon Lewis wrote:

>On Sun, 13 Feb 2005, Oliver Boehmer (oboehmer) wrote:
>
>  
>
>>>But, I want to know if is necessary to apply Ethernet channel config
>>>in the switch where the router is connected?, and if is necessary how
>>>to configure it?.  The switch is a catalyst 3550.
>>>      
>>>
>>Yes, you need to configure the neighboring switch as well, take a look
>>at
>>http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/1214ea1/3550sc
>>g/swethchl.htm.
>>    
>>
>
>I'll add to this that hopefully your traffic from switch to router is from
>many different sources.  AFAIK, the 3550's default etherchannel behavior
>is to load share the member interfaces based on packet source IP.  If one
>IP is sending 80mbit/s to the 7500, that's all going to end up on one
>of the ethernets.  It's been my experience that the routers do a much
>better job of reasonably equal load sharing across etherchannel members
>than the 3550 is capable of.
>
>  
>
IIRC you have a choice on the switch of per-mac source or destination 
balancing. This makes for interesting scenarios when certain pairs of 
macs generate the bulk of traffic.