Nexus Admin account and Jumbo Frame setup

Hi Guys,

For some reasons we have lost the local admin password to our nexus platform, but can login using a TACACS account. Is that a way to reset the Admin password on the Nexus platform without doing password-recovery? Can I just overwrite the admin password with the command - username admin password Cisco123

Also, I want to enable jumbo frame support across the Nexus platform, N5Ks and N7Ks. Do I have to change it on the class-map with regards to the N5Ks an enable it on the N7K using the system jumbo size 9216 and that is all, or do I also need to change it on the individual / port-channel interfaces?
Finally, will such change cause any downtime?

Thanks for your help



  • RE: Admin account - just use the 'username admin password <password> role network-admin command.  No downtime.

    RE: Jumbo Frames:

    N5K:  Change in class-map, although when looking at the port (sh int x/y) it will still show as 1500mtu.  You need to use sh queuing int x/y

    N7K:  For M-Series cards/ports, you can change on a per interface basis.

             For F-Series, system-jumbo mtu & directly on ports for 9216 bytes.  If you want anything other than 9216 on F-Series card  (e.g 8900) you need to change in class-map.

    Should not cause any downtime.


  • Thanks Dominic

    That is very kind of you to take the time out to read and respond.

    That answers my question neatly and takes for the verification pointers.

    Thank you once again.


  • Say Dominic, are you sure you can set MTU via class-map on an F-series module?  My understanding is that you can only set either the system-jumbo or default values via the 'mtu' command, as you say, but those are your only two options.

    I tried configuring a policy-map in the 7K and couldn't find an option for it.

  • QoS on  F line cards resemble QoS on N5Ks. So it is definitely possible to change MTU via system policy under N7K.

    You have to be in admin/default VDC for this. 


    For MTU specific it will be policy-map type network-qos.

    You can either copy existing templates or create a new one. 

    Please refer to this guide




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