Add extra new Stackwise virtual link (SVL)

[TariqAlmouti72833]

Dears

I currently have 2 x C9500-24Y4C connected via 1 x 10GB Stackwise-virtual link (SVL) and it's up and running.

I would like to add a second SVL 10GB link for redundancy and greater throughput. 

If I go with adding the port and configure it, should I need to restart the switch to make the new link run? and am I gonna face any downtime or network interruption? or it will go smoothly with no interruption on the network?

Regards

[Reza Sharifi]

Hi,

You should be able to add a second port to the Porchannel and there is no need to reboot. That said, I would have a maintenance window and do it during off hours just in case something unexpectedly goes wrong.

HTH

[Francesco Molino · Accepted solution]

Hi

Never added a link afterwards and i would have thought there’s no need to reboot but FAQ official doc says differently:
After StackWise Virtual conversion, any addition to or removal from SVL or fast hello connection will require both stack members to reload to make the configuration effective.

https://www.cisco.com/c/dam/en/us/products/collateral/switches/catalyst-3850-series-switches/q-and-a-c67-738577.pdf

[heleros]

You have to reload both switch to activate a additional port.
But the Cisco TAC told me with the command redundancy force-switchover you are able to add a Stackwise Link or DAD Link without any outage, but i didn't try it yet.

[Reza Sharifi]

Thanks for the feedback!

Let us know if it works without reloading both switches. It is absurd and such a bad design if you have to reload both switches simply because you are adding an extra link to the SVL.

HTH   

[Francesco Molino]

Yeah i would be interested to know it that works. I hope so and this will means the doc isn’t to explicit.

[hans.goes]

Situation : 

2 x Cisco 9500-16X

Active SVL on Te1/0/15 <> Te2/0/15

Tried to add second SVL on Te1/0/14 <> Te2/0/14 via redundant fiber-route :

CSW(config)#int te2/0/14
CSW(config-if)# stackwise-virtual link 1
WARNING: All the extraneous configurations will be removed for TenGigabitEthernet2/0/14 on reboot
INFO: Upon reboot, the config will be part of running config but not part of start up config.

CSW(config-if)#int te1/0/14
CSW(config-if)# stackwise-virtual link 1
WARNING: All the extraneous configurations will be removed for TenGigabitEthernet1/0/14 on reboot

I tried rebooten switch 2 first but the Te1/0/14 stayed in SHUTDOWN

Te1/0/14                       admin down     down     StackWise-Virtual Link #1 (MER1 > SER2 fiber 3/4 > MER2)
Te1/0/15                       down           down     StackWise-Virtual Link #1 via MER1 Fiber

CSW(config)#int te1/0/14
CSW(config-if)#no shut
                                 ^
% Invalid input detected at '^' marker.

I also tried to reboot switch 1, no luck again.

Therefor I had to reboot both members at once :

CSW#   reload

System configuration has been modified. Save? [yes/no]: yes
Building configuration...
Compressed configuration from 21280 bytes to 9750 bytes[OK]Reload command is being issued on Active unit, this will reload the whole stack
Proceed with reload? [confirm]

After it came back :

*Sep 30 2020 13:12:55.312 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet2/0/14, changed state to up
*Sep 30 2020 13:12:55.318 UTC: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/0/14, changed state to up
*Sep 30 2020 13:12:55.317 UTC: %NIF_MGR-6-PORT_LINK_UP: Switch 1 R0/0: nif_mgr: Port 14 on front side stack link 0 is UP.
*Sep 30 2020 13:12:55.317 UTC: %NIF_MGR-6-PORT_CONN_PENDING: Switch 1 R0/0: nif_mgr: Port 14 on front side stack link 0 connection is PENDING.
*Sep 30 2020 13:12:55.311 UTC: %NIF_MGR-6-PORT_LINK_UP: Switch 2 R0/0: nif_mgr: Port 14 on front side stack link 0 is UP.
*Sep 30 2020 13:12:55.311 UTC: %NIF_MGR-6-PORT_CONN_PENDING: Switch 2 R0/0: nif_mgr: Port 14 on front side stack link 0 connection is PENDING.
*Sep 30 2020 13:12:56.311 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet2/0/14, changed state to up
*Sep 30 2020 13:12:56.318 UTC: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/14, changed state to up
*Sep 30 2020 13:13:00.715 UTC: %NIF_MGR-6-PORT_CONNECTION_STATUS_CHANGE: Switch 2 R0/0: nif_mgr: PORT lpn:14 changed state from Pending to Ready.
*Sep 30 2020 13:13:00.715 UTC: %NIF_MGR-6-PORT_CONN_READY: Switch 2 R0/0: nif_mgr: Port 14 on front side stack link 0 connection is READY.
*Sep 30 2020 13:13:01.707 UTC: %NIF_MGR-6-PORT_CONNECTION_STATUS_CHANGE: Switch 1 R0/0: nif_mgr: PORT lpn:14 changed state from Pending to Ready.
*Sep 30 2020 13:13:01.707 UTC: %NIF_MGR-6-PORT_CONN_READY: Switch 1 R0/0: nif_mgr: Port 14 on front side stack link 0 connection is READY.

[heleros]

You have to reboot the switch via redundancy force-switchover. Only this command works to add a additional SVL Link and you have to do it twice.

There is a outage of 1sec/1Ping. If you reboot the whole Stack, then you have an outage of 10min.

[loizosko]

did anybody try the redundancy force-switchover?

[MARTIN THEINER]

I´m going to test it tomorrow.

We previously wanted to use 40Gig, but we had the 40/100 bidi which only goes 100 meters... so we had to step back to 10 gig.

Therefor I changed both links on the first box to 10 gig.

Afterwards i did the same on the second box, but only one of both links was correctly added to the running-config.

So i added the second link on the second box again... and now we have the same situation.

I´ll keep u updated