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AMA event- Migrating Existing Networks to Cisco ACI

Nexus 5020 running NX-OS ver4.1(3)N2(1)

Hi Guys,

I am trying to configure double sided vPC from a pair of N5K (N5020 with NX-OS version 4.1(3)N2(1)) to a pair of Nexus 7K in a double sided or back-to-back vPC fashion.

For some reasons, whenever I complete the config and apply, everything seem fine and after 10mins or so one of the N5K falls apart, reboots and Bridge Assurance kicks in and starts blocking ports.

I have this same setup and configuration on some other locations which works fine.

The only difference is that the NX-OS version on the other sites is different from this particular site running 4.1(3)N2(1).

Can someone tell me if its not possible to run double-sided (back-to-back) vPC from the N5Ks to the N7Ks when running on this version 4.1(3)N2(1)  and the only solution is to upgrade to the latest code?

Thanks for any feedback.

Cisco Employee

Nexus 5020 running NX-OS ver4.1(3)N2(1)

Hi Luke,

AFAIK double-sided vPC has always been supported. I would look into upgrading to a more recent version of NX-OS, as that version is really old. I have a few customers right now running this same scenerio and I have moved them to 5.1 and 5.2 trains. If you want to send me your configurations I can take a look and see if I notice anything off, but I would imagine this will be resolved with an upgrade if you have the exact same setup working on a later version of NX-OS.




Nexus 5020 running NX-OS ver4.1(3)N2(1)

Hi Ant,

Thanks for your feedback. I actually double checked and can see that the other site where the double-sided vPC work is running the same version of code of 4.1(3)N2(1).

I will look to upgrade this site though to the latest version. Is there anything I need to be aware of from moving from version 4.1(3)N2 to 5.2.1.N1.4? Can I upgrade direct or do I have to upgrade to a previous code before upgrading to the latest one?



Cisco Employee

Nexus 5020 running NX-OS ver4.1(3)N2(1)

Hi Luke,

Unfortunately its not possible to directly upgrade. From looking into a bit here is an upgrade path option (there are others if you want to investigate):

4.1(3)N2(1) to 4.2(1)N1(1) - Disruptive Upgrade

4.2(1)N1(1) to 5.0(3)N1(1c) - ISSU

5.0(3)N1(1c) to 5.2(1)N1(4) - ISSU

Here is some documentation on upgrading:

Some Caveats on ISSU:

- Cannot be STP root

- No L3 card, which the N5020 doesnt support anyway.

- No fast timers for LACP




Nexus 5020 running NX-OS ver4.1(3)N2(1)

May I add this:

If you want to keep the downtime as little as possible, verify the master/slave state of your node regarding your FEX.

If you have a host dual homed on two FEXs and FEXs have the same master, you will experience a reboot of your FEXs at the same time.

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