C3850-48XS-S switch stacking

[scarr6]

We have 2 3850-XS-S switches configured for stackwise virtual but the stacking isn't working.

switch 1 provision ws-c3850-48xs
switch 2 provision ws-c3850-48xs
stackwise-virtual
 domain 1

interface TenGigabitEthernet1/0/45
stackwise-virtual link 1
!
interface TenGigabitEthernet1/0/46
stackwise-virtual link 1
!
interface TenGigabitEthernet1/0/47
stackwise-virtual link 1
!
interface TenGigabitEthernet1/0/48
stackwise-virtual link 1
!



interface TenGigabitEthernet2/0/45
stackwise-virtual link 1
!
interface TenGigabitEthernet2/0/46
stackwise-virtual link 1
!
interface TenGigabitEthernet2/0/47
stackwise-virtual link 1
!
interface TenGigabitEthernet2/0/48
stackwise-virtual link 1
!

MLSUDSC01#show switch
Switch/Stack Mac Address : 009a.d21d.ec00 - Local Mac Address
Mac persistency wait time: Indefinite
 H/W Current
Switch# Role Mac Address Priority Version State
-------------------------------------------------------------------------------------
*1 Active 009a.d21d.ec00 1 V02 Ready
 2 Member 0000.0000.0000 0 V02 Removed

MLSUDSC01#show stackwise-virtual switch 1
Stackwise Virtual Configuration:
--------------------------------
Stackwise Virtual : Enabled
Domain Number : 1

Switch Stackwise Virtual Link Ports
------ ---------------------- ------
1 1 TenGigabitEthernet1/0/45
 TenGigabitEthernet1/0/46
 TenGigabitEthernet1/0/47
 TenGigabitEthernet1/0/48

MLSUDSC01#show stackwise-virtual switch 2
Stackwise Virtual Configuration:
--------------------------------
Stackwise Virtual : Enabled
Domain Number : 1

Switch Stackwise Virtual Link Ports
------ ---------------------- ------


MLSUDSC01#show stackwise-virtual link
Stackwise Virtual Link(SVL) Information:
----------------------------------------
Flags:
------
Link Status
-----------
U-Up D-Down
Protocol Status
---------------
S-Suspended P-Pending E-Error T-Timeout R-Ready
-----------------------------------------------
Switch SVL Ports Link-Status Protocol-Status
------ --- ----- ----------- ---------------
1 1 TenGigabitEthernet1/0/45 U R
 TenGigabitEthernet1/0/46 U R
 TenGigabitEthernet1/0/47 U R
 TenGigabitEthernet1/0/48 U R

MLSUDSC01#show stackwise-virtual neighbors
Stackwise Virtual Link(SVL) Neighbors Information:
--------------------------------------------------
Switch SVL Local Port Remote Port
------ --- ---------- -----------
1 1 TenGigabitEthernet1/0/45
 TenGigabitEthernet1/0/46
 TenGigabitEthernet1/0/47
 TenGigabitEthernet1/0/48

MLSUDSC01#show stackwise-virtual dual-active-detection
Dual-Active-Detection Configuration:
-------------------------------------
Switch Dad port Status
------ ------------ ---------

MLSUDSC01#show stackwise-virtual
Stackwise Virtual Configuration:
--------------------------------
Stackwise Virtual : Enabled
Domain Number : 1

Switch Stackwise Virtual Link Ports
------ ---------------------- ------
1 1 TenGigabitEthernet1/0/45
 TenGigabitEthernet1/0/46
 TenGigabitEthernet1/0/47
 TenGigabitEthernet1/0/48


MLSUDSC01#show version
...
Switch Ports Model SW Version SW Image Mode
------ ----- ----- ---------- ---------- ----
* 1 68 WS-C3850-48XS 16.6.1 CAT3K_CAA-UNIVERSALK9 BUNDLE

Switch 2 always shows as 'removed'.

Connecting to console port on switch 2 returns the following:

MLSUDSC01>show switch
Switch/Stack Mac Address : 00a3.d11f.7a80 - Local Mac Address
Mac persistency wait time: Indefinite
                                             H/W   Current
Switch#   Role    Mac Address     Priority Version  State
-------------------------------------------------------------------------------------
 1       Member   0000.0000.0000     0              Provisioned
*2       Active   00a3.d11f.7a80     1      V02     Ready

Any ideas what is wrong would be greatly appreciated.

[Reza Sharifi]

I have never done this on 3850s but I think you need to assign switch 2 for interfaces 2/0/45-48

stackwise-virtual link 2

and test again.

HTH 

[Leo Laohoo · Accepted solution]

Is global MTU set to 9115?

[scarr6]

Hi Leo

Checked and the system MTU was indeed set to a higher value.

I set the MTU to 9115, rebooted the switch stack and the stack came up perfectly.

MLSUDSC01#show switch
Switch/Stack Mac Address : 009a.d21d.ec00 - Local Mac Address
Mac persistency wait time: Indefinite
                                             H/W   Current
Switch#   Role    Mac Address     Priority Version  State
-------------------------------------------------------------------------------------
*1       Active   009a.d21d.ec00     1      V02     Ready
 2       Standby  00a3.d11f.7a80     1      V02     Ready

Thanks for your suggestion!