Nexus 7K is not load balancing

Muhammed AKYUZ · ‎08-06-2012

Hi,

we have Nexus 7K on production. 7K chasis is not load balancing with non-cisco devices with etherchannel or LACP..

I have tried all load balancing algorithms but it does help.

# sh port-channel traffic

ChanId Port Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst

------ --------- ------- ------- ------- ------- ------- -------

1 Eth2/1 50.15% 50.21% 34.98% 4.81% 52.15% 30.64% >>>>>>> N7K connection

1 Eth1/1 49.84% 49.78% 65.01% 95.18% 47.84% 69.35%

------ --------- ------- ------- ------- ------- ------- -------

2 Eth10/1 87.92% 49.37% 50.00% 50.00% 66.66% 100.00%

2 Eth10/2 12.07% 50.62% 50.00% 50.00% 33.33% 0.0%

------ --------- ------- ------- ------- ------- ------- -------

7 Eth10/7 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

------ --------- ------- ------- ------- ------- ------- -------

8 Eth10/8 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

------ --------- ------- ------- ------- ------- ------- -------

9 Eth2/2 52.00% 49.82% 78.72% 63.22% 100.00% 47.71% >>>>>>> FEX

9 Eth2/3 47.99% 50.17% 21.27% 36.77% 0.0% 52.28%

------ --------- ------- ------- ------- ------- ------- -------

12 Eth103/1/2 12.31% 99.99% 49.98% 56.72% 52.27% 28.89% >>>>>>> SERVER...

12 Eth103/1/1 87.68% 0.00% 50.01% 43.27% 47.72% 71.10%

------ --------- ------- ------- ------- ------- ------- -------

13 Eth2/6 51.51% 48.70% 68.10% 36.94% 100.00% 51.19%

13 Eth2/7 48.48% 51.29% 31.89% 63.05% 0.0% 48.80%

------ --------- ------- ------- ------- ------- ------- -------

16 Eth10/40 0.01% 1.88% 0.21% 23.34% 17.22% 23.33%

16 Eth10/41 99.98% 1.28% 0.22% 55.01% 0.62% 34.23% >>>>> HP BLADE SERVER

16 Eth10/42 0.00% 96.83% 99.56% 21.63% 82.14% 42.42%

------ --------- ------- ------- ------- ------- ------- -------

90 Eth10/46 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

------ --------- ------- ------- ------- ------- ------- -------

91 Eth10/44 100.00% 100.00% 100.00% 100.00% 0.0% 100.00%

------ --------- ------- ------- ------- ------- ------- -------

99 Eth10/48 100.00% 100.00% 100.00% 100.00% 100.00% 100.00%

------ --------- ------- ------- ------- ------- ------- -------

I check the load balancing path, it says different ports.. but not..

NX2-TEST# sh port-channel load-balance forwarding-path interface po10 dst-ip 192.168.30.2 src-ip 192.168.30.243 module 1

Missing params will be substituted by 0's.

Module 1: Load-balance Algorithm: src-dst ip

RBH: 0x6 Outgoing port id: Ethernet103/1/1

NX2-TEST# sh port-channel load-balance forwarding-path interface po10 dst-ip 192.168.30.2 src-ip 192.168.30.102 module 1

Missing params will be substituted by 0's.

Module 1: Load-balance Algorithm: src-dst ip

RBH: 0x2 Outgoing port id: Ethernet103/1/2

NX2-TEST# clear counters

robert.horrigan · ‎08-06-2012

My guess would be because this is double-sided VPC and the traffic should not cross the peer link of either vpc pair.

Muhammed AKYUZ · ‎08-06-2012

we are not using double sided vpc. it is regular vpc, but is not related to VPC also. it is regular etherchannel on a single Nexus chasis.

Lee Smitherman · ‎08-07-2012

Hi,

Im not sure if im missing something as not familiar with the nexus range, however Etherchannel does not load balance in the sence of 50/50(2 links), 25/25/25/25(4 Links) etc. Its a best effort depending on the method selected, packet by packet. As a very example, if only two nodes talk over a channel to one server, chances are all that traffic will go down one interface, even if the algorithm does work out that each node will use different links in the channel, one may be transmitting megabytes of data, and the other only bytes.

Lee.