Use Case 3: Changing VSF link speed

The sequence to change the VSF link speed is as follows:

Prerequisites
VSF requires that all ports in all VSF links in the VSF stack must be of the same speed. VSF supports two port speeds, 1G and 10G, and up to 8 ports can be added to a VSF link. There is no default port speed defined. When a VSF link is first configured, the global port speed is automatically set to the interface speed of the port on the link.

  • There is no restriction on the ports which can be added to a VSF link. Ports which do not match the global port speed can be added to a VSF link, but only ports matching the configured global port speed will be up.

  • On a running VSF stack, the current applicable port speed is shown as part of the show vsf command output. 
    Switch(config)# show vsf
VSF Domain ID      : 164423
MAC Address        : b05ada-9694e3
VSF Topology       : Chain
VSF Status         : Active
Uptime             : 0d 5h 37m
VSF MAD            : None
VSF Port Speed     : 1G
Software Version   : WC.16.03.0003
Procedure
  1. Add ports of the desired link speed to each link of the stack.
    Once this is done, the show vsf link detail output would be similar to: 
    VSF Member: 1     Link: 1

Port     State
-------- ----------------------------
1/1      Up   : Connected to port 4/1
1/25     Error: Port speed mismatch

VSF Member: 1     Link: 2

Port     State
-------- ---------------------------
1/2      Up   : Connected to port 2/2
1/26     Error: Port speed mismatch      


VSF Member: 2     Link: 1

Port     State
-------- ----------------------------
2/1      Up   : Connected to port 3/1
2/25     Error: Port speed mismatch
  2. Connect the ports of the new speed (1/25, 1/26, etc.). Since the ports are kept disabled, it is safe to make the connections at this point. The link will not come up. All links must have ports of both speeds, otherwise the link will fail to come up when the port speed is changed.
  3. Execute the command indicating the target speed: vsf port speed <1G/10G>. This will trigger a reboot of the whole stack. On reboot, the stack will form using the ports which match the new VSF port speed. Ports which do not match will be kept disabled. The output of show vsf link detail after the reboot would be as follows: 
    VSF Member: 1     Link: 1

Port     State
-------- --------------------------
1/1      Error: Port speed mismatch      
1/25     Up   : Connected to 4/25

VSF Member: 1     Link: 2

Port     State
-------- --------------------------
1/2      Error: Port speed mismatch      
1/26     Up   : Connected to 2/26


VSF Member: 2     Link: 1

Port     State
-------- --------------------------
2/1      Error: Port speed mismatch      
2/25     Up   : Connected to 3/25
  4. Disconnect the unused ports (1/1, 1/2 etc.). This is a safety measure to avoid accidentally creating a network loop when executing the next step.
  5. Unconfigure the unused ports from the VSF link, using the command no vsf member 1 link 1 1/1 etc. Once this step is completed, the output of show vsf link detail would be as follows: 
    VSF Member: 1     Link: 1

Port     State
-------- ---------------------
1/25     Up: Connected to 4/25

VSF Member: 1     Link: 2

Port     State
-------- --------------------
1/26     Up: Connected to 2/26


VSF Member: 2     Link: 1

Port     State
-------- ---------------------
2/25     Up: Connected to 3/25

    The ports which have been removed from VSF links can now be used as regular Ethernet ports.