Brocade VDX 6720 vLAG

[Tim12]

NOS Version: 4.1.3d

The server is connected by two links to two switches Brocade VDX6720. There is a problem with load balancing in vLAG. If connect the server to one switch, then there are no problems with load balancing. Traffic is distributed evenly.

sh int tengi 1/0/41

Rate info:
    Input 326.962956 Mbits/sec, 49440 packets/sec, 3.27% of line-rate
    Output 666.638788 Mbits/sec, 92225 packets/sec, 6.67% of line-rate

sh int tengi 2/0/41

Rate info:
    Input 324.905664 Mbits/sec, 44864 packets/sec, 3.25% of line-rate
    Output 8.917360 Mbits/sec, 3498 packets/sec, 0.09% of line-rate

[Russ]

Hi,

How can I verify the load-balance policy in place for a port-channel?

[Tim12]

The problem is still relevant

[Tim12]

Yes I know. 90% of the outgoing traffic is on the rbridge-id 1.The rest of the outgoing traffic to rbridge-id 2. If disable port 1/0/41, all traffic goes to 2/0/41 and if turn it back on, then all traffic also goes back to port 1/0/41. The stack between the switches is assembled from two ports 1/0/59 - 60 and 2/0/59 - 60. Traffic through ISL ports is also evenly distributed.

[joergkost]

Do you know where the outgoing traffic for this port-channel is originated from?

On the VDX6720 I have often seen that VLAG traffic could be biased on  the rbridge member. That means, that  traffic for a port-channel comes into e.g. rbridge-id 1, it won’t spread to member interfaces on a different rbridge as long as the link is working. A typical sign for this is a traffic empty ISL port.  I am not sure if this was a design thing or a protocol limitation.