[c-nsp] Etherchannel load balancing

[Billy Guthrie]

When you configure an etherchannel bundle, the frames are distributed 
across the individual bundled links deterministically; however, the load 
is not balanced equally across all the links. You may or may not know, 
but the frames are forwarded on a specific link due to the hashing 
algorithm that is used. The algorithm can use destination IP address, 
source IP address, or a combination of both source and destination IP 
addresses, source and destination MAC addresses, or TCP and UDP port 
numbers. The hashing algorithm computes a binary pattern that selects a 
link number in a bundle to carry each frame.

Document may or may not help:
http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a0080094714.shtm


Good Luck
Billy


Ivan Šimko wrote:
> Hi all
>
> I've got two switches 3560
> group with 2xFE on both switches and inteconnected together.
> port channel is L2
> 2 VRFs - ivan, mark
> 4 VLANs:
> - vlan 100 VRF "ivan" for interconnection between swtiches
> - vlan 11 VRF "ivan" for customer's connection
>
> - vlan 200 VRF"mark" for interconnection between switches
> - vlan 12 VRF "mark" for customer's connection
>
> ports 12 and 13 as trunks
> - interconnection between switches
>
> OSPF runs over SVIs of 100 and 200.
>
> I'm strugling with load balancing:
> when I setup port channel load balancing dst-ip switch does correct
> balancing between interconnected vlans but not for customers' vlans.
> - vlan 100 would use port 12 - switch interconnection
> - vlan 200 would use port 13 - switch interconnection
> - vlan 11 would use port 13 - customer 1
> - vlan 12 would use port 13 - customer 2
>
> when I setup port channel load balancing src-dst-ip switch does correct
> balance for customers' vlans but not for interconnected vlans.
> - vlan 100 would use port 13
> - vlan 200 would use port 13
> - vlan 11 would use port 12
> - vlan 12 would use port 13
>
> Result is not full bandwidth used for both customers' traffic resp. only 100
> Mbps.
>
>
> Any ideas how to sort it out?
>
> thanks
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