LACP between 2 Nexus 2000 with the same Parent Nexus 5000/7000

[robert.lian]

Hi Guys,

I tried to build a port channel between 2 interfaces from 2 different fex with the same Parent switch but failed to do so. 

The parent switch which i have tested is the Nexus 7010 and 5020.

N7K-01(config)# int e101/1/1,e102/1/1

N7K-01(config-if-range)# channel-group 2000 force mode active

command failed: port not compatible [Members in multiple FEX]

on the Nexus 7000, im using NX-OS 6.0.2.

Is this a normal behavior on the Nexus? I can't seem to find this documented on Cisco website.

[robert.lian]

For the Nexus 5000. below is the error i get

int eth 103/1/1 - 2

N5K-01(config-if)# channel-group 2000

command failed: port not compatible [All HIF member ports not in same pinning group]

[mipetrin]

Hi Robert,

That depends on the exact topology you have setup.

Could you describe your topology a little more in detail. As in, how many Nexus 7Ks or 5Ks are you testing with connectivity to the two Nexus 2000s that you have. It would seem that you are only using a single 7k/5k which is then connected to the two Nexus 2Ks. From this, you are then attempting to create a port-channel on the N2k ports towards a server. Is that correct?

Are you attempting to make use of vPC?

Thanks,

Michael

[robert.lian]

Hi Michael,

Yes i'm using a single N7K/N5K which is connected to two Nexus 2Ks.

I'm not using VPC for the server connection.

With this setup, Can the N2K build a LACP port with 2 different FEX to the server?

[mipetrin · Accepted solution]

Hi Robert,

That particular design with the Nexus 7000 is not supported.

In regards to the Nexus 5000 design, the N2K doesn't need to have vPC configured unless it is dual homed. As I understand, you are trying to setup a port-channel from 2 different N2Ks to the single server, this it NOT possible, unless you make use of vPC across two N5Ks and have each N2K single homed to one N5K.

Have a look through the following blog by Jeremy Waldrop which explains the topologies available:

http://jeremywaldrop.wordpress.com/2011/06/30/cisco-nexus-50007000-fex-topologies/

Nexus 5000 - Supported vPC Topologies

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/layer2/513_n1_1/b_Cisco_n5k_layer2_config_gd_rel_513_N1_1_chapter_01001.html#d12422e301a1635

Thanks,

Michael

[robert.lian]

Thanks Michael

[emresumengen]

Hi Michael,

I was wondering if there was a workaround (or a solution, whether it's directly supported by Cisco TAC or not) for this.

As the documentation states, I guess Cisco believes it's not worth implementing (as it says "This topology does not provide a good high availability solution because the server loses the connectivity to the network when the Cisco Nexus 5000 Series device fails." in

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/mkt_ops_guides/513_n1_1/n5k_enhanced_vpc.html#wp1162010.

But, in fact, having NO redundancy is never a better alternative than a limited redundancy, which is the case if you connect your server to a single FEX, which is single-homed to a Nexus 5500. As you can guess, a power or hardware problem in the FEX itself can get the server(s) disconnected, which is a very unwelcome situation in a datacenter.

Or, at least, are there any plans to implement this feature, in future releases? (As far as I can see, NX-OS v6 didn't bring any news on this front.)