Nexus Port-channel loadbalancing

[manumohan200]

Hi All,

I have a customer with two Datacenters in two locations connected through Dark Fibre. There are two Dark Fibre links for redundancy. The connectivity is like below:

N7K-DC1---(1/1) <----------------------------Dark Fibre-------------------->(1/1)---N7K-DC2

N7K-DC1---(1/2) <----------------------------Dark Fibre-------------------->(1/2)---N7K-DC2

Both the Dark Fibres are bundled into one port-channel. The traffic between these two sites are always having same source-destination IP pairs( since this is a OTV traffic). Because of this, all the traffic is passing through 1/1 in both the Data Centers as this is the link chosen by the Etherchannel load balancing algorithm by both the Nexus devices.  The second link is not at all used. Since the customer is unneccesary paying for the second link, I am thinking of some options to load-balance the traffic.

I am planning the below connectivity.

N7K-DC1---(1/1) <----------------------------Dark Fibre-------------------->(1/2)---N7K-DC2

N7K-DC1---(1/2) <----------------------------Dark Fibre-------------------->(1/1)---N7K-DC2

With this, DC1 will send the traffic through one link and return traffic will come through the other link.

Is my thinking right, or I am missing here something?

Thanks,

Manu

[Reza Sharifi]

Hi,

It should not make any difference whether you connect port 1/1 to 1/1 or 1/1 to 1/2.  If the traffic is coming from the same IP source, it will always use the same link, but if the traffic is coming from different IP sources, than the traffic should be load balance across both links.  What happens if you disconnect one of the physical ports in the portchannel? would the other port start forwarding packets?

HTH