25G SFP28 with or without FEC

Recently hit an issue between a Universal 5420 switch running EXOS in a stack connected to VSP 7432 switches. Normal practice to use different slots for the uplinks ie 1:52 and 2:52 in a LAG. I noticed 2:52 was not coming up.

On slot 1, the Master switch, Forward Error Correction was ON and this matched FEC settings on the VSP 7432 interfaces (100G channelized to 4 x 25 with breakout cable).

The default for EXOS should be that FEC is disabled. Disabling FEC on the VSP 7432 side brought the link up on 2:52. Disabled FEC on 1:52 allowed all ports to be active.

Bottom line, FEC must match both ends for the link to come up. I have raised a ticket as to why slot 1 would enable FEC on its ports but not on backup or standby switch ports.

Extending Premier License on New Extreme Hardware

Extend the Factory Default Premier Trial License

Use the following procedure to extend the Factory Default Premier Trial License on your switch.

You can run the extend-time-period command up to three times to extend the evaluation license in 30-day increments for an additional 90 days.


  1. Enter Privileged EXEC mode:


  2. Extend the trial software license on your device:




    You must reboot your switch after each license extension.


    Extend the trial license period for 30-days:

    Are you sure you want to reset the box to apply changes? (y/n) y

VOSS Configuring SNMPv3


snmp-server view ALL 1
snmp-server group HOMELAB “” auth-priv read-view ALL write-view ALL notify-view ALL
snmp-server user snmpuser group HOMELAB md5 authcred des privcred
snmp-server host v3 authpriv snmpuser
snmp-server sender-ip

Note: Empty string for GlobalRouter VRF.

# Show snmp-server commands

show snmp-server
show snmp-server group
show snmp-server user
show snmp-server view

no snmp-server view ALL 1
no snmp-server group HOMELAB
no snmp-server user snmpuser
no snmp-server host v3 snmpuser

Note: To remove the host address the “authpriv” should not be included.

5520-VIM-4YE module


Does the 5520-VIM-4YE support 1G connections along with 10G and 25G?


No. The 5520-VIM-4YE only supports 10G and 25G port speeds. If 1G and 10G is required you can use the 5520-VIM-4XE instead.


In Fabric Engine, you must use the sys vim-speed command to set the speed to 10G or
25G for 5520-VIM-4YE. The default is 25G. A reboot is not necessary after setting the speed.
In Switch Engine, use the configure ports partition command with 4×25 or 4×10.

Example,  for 5520-48p with 5520-VIM-4YE

configure ports partition 57 4x10G

The show ports partition-template command will confirm configuration in place.

YouTube Channel Open today


I thought why not have a go at creating some videos to compliment the posts I publish on my blog, so I’ve created a YouTube channel and uploaded a couple of videos to get started.

My videos use GNS3 and simulated switches to help demonstrate something useful from an Extreme Networks experience with operating systems such as EXOS or VOSS.

Please check it out and subscribe if you like them and I will create some more.




Change Default SNMP v2c Community in VOSS

For security hardening change the default SNMP v2c communities of public (read only) and private (read write).

Under global configuration mode:

no snmp-server community public

no snmp-server community private

snmp-server community NewRead group readgrp index first secname readview

snmp-server community NewWrite group v1v2grp index second secname initialview

Type show snmp-server community and see the list of indexes in the Community Table (first, second etc…) as there may be others as well created for VRFs.

VSP Premier License

Generate a license .XML file on the support portal using a valid voucher ID and match against the switch base MAC address and serial number (type show sys-info command).

Copy .XML file to /intflash and then type load-license command from configuration mode. This will install the premier license. Type show license command to confirm license is in place and type save config.

On the portal the license files can be seen against the customer and switch type under assets. In the event of a replacement switch the license file can be edited with a new base MAC and serial number.