Re: Additional unknown interfaces on WS-C3850-24XS which do not exist

msue24 · ‎01-10-2023

Hello everyone,

i currently face a weird problem on a WS-C3850-24XS (16.09.07 - CAT3K_CAA-UNIVERSALK9 - INSTALL).
The switch has 24 Te Ports but when running a sh ver it shows 34 Ports.
Sh ip int br shows this:

Switch#sh ip int br
Interface IP-Address OK? Method Status Protocol
Vlan1 unassigned YES NVRAM administratively down down
Vlan22 x.x.x.x YES NVRAM up up
GigabitEthernet0/0 unassigned YES NVRAM down down
Te1/0/1 unassigned YES unset up up
Te1/0/2 unassigned YES unset up up
Te1/0/3 unassigned YES unset up up
Te1/0/4 unassigned YES unset up up
Te1/0/5 unassigned YES unset up up
Te1/0/6 unassigned YES unset up up
Te1/0/7 unassigned YES unset up up
Te1/0/8 unassigned YES unset up up
Te1/0/9 unassigned YES unset up up
Te1/0/10 unassigned YES unset up up
Te1/0/11 unassigned YES unset up up
Te1/0/12 unassigned YES unset up up
Te1/0/13 unassigned YES unset administratively down down
Te1/0/14 unassigned YES unset administratively down down
Te1/0/15 unassigned YES unset administratively down down
Te1/0/16 unassigned YES unset administratively down down
Te1/0/17 unassigned YES unset administratively down down
Te1/0/18 unassigned YES unset administratively down down
Te1/0/19 unassigned YES unset administratively down down
Te1/0/20 unassigned YES unset administratively down down
Te1/0/21 unassigned YES unset administratively down down
Te1/0/22 unassigned YES unset up up
Te1/0/23 unassigned YES unset up up
Te1/0/24 unassigned YES unset up up
Te1/1/1 unassigned YES unset down down
Te1/1/2 unassigned YES unset down down
Te1/1/3 unassigned YES unset down down
Te1/1/4 unassigned YES unset down down
Te1/1/5 unassigned YES unset down down
Te1/1/6 unassigned YES unset down down
Te1/1/7 unassigned YES unset down down
Te1/1/8 unassigned YES unset down down
Fo1/1/1 unassigned YES unset down down
Fo1/1/2 unassigned YES unset down down
Port-channel1 unassigned YES unset up up
Port-channel10 unassigned YES unset up up
Port-channel44 unassigned YES unset up up
Port-channel45 unassigned YES unset up up

I know about modules, virtual ethernet interfaces and i also know that the interface does not change when installing a different SFP module. The weird thing about this is that normally it should show Gi and Te interfaces, but in my case eight Te ports are shown twice. SFP modules were never changed.

I can not ignore this since our monitoring system does an environment check which fails because of this phenomenon.
Does anybody have an idea on how to fix this issue?

Mark Elsen · ‎01-10-2023

- Check if you can use "no interface Te1/1/1" in the running config (meaning as an example-only and or as a test) , also check if this is not related to stacking and or interfaces belonging to another stack switch member. For the rest use show inventory and or show tech , scrutinize the outputs and check if that can bring additional insights,

M.

-- Let everything happen to you
   Beauty and terror
      Just keep going
     No feeling is final
Reiner Maria Rilke (1899)

Leo Laohoo · ‎01-10-2023

Downgrade the firmware (to like 16.6.X) and those "provisioning" interfaces will disappear.

Those "provisioning" interfaces are there so people can "pre-provision" the ports.

msue24 · ‎01-12-2023

Thank you for your answers.
I did the things mentioned above except the downgrade because this problem appeared only recently and before did not occur on the same firmware.
The switch was never provisioned and the "no interface" command does not work because it tells me that "physical interfaces can not be removed". The switch never was a stack member. Show inventory or sh int status do not contain these interfaces.
Here is the output of sh switch detail:

Switch/Stack Mac Address : xxxx.xxxx.xxxx - Local Mac Address
Mac persistency wait time: Indefinite
H/W Current
Switch# Role Mac Address Priority Version State
-------------------------------------------------------------------------------------
*1 Active xxxx.xxxx.xxxx 1 V02 Ready

Stack Port Status Neighbors
Switch# Port 1 Port 2 Port 1 Port 2
--------------------------------------------------------
1 DOWN DOWN None None

And here is the output of sh inv:

NAME: "c38xx Stack", DESCR: "c38xx Stack"
PID: WS-C3850-24XS-E , VID: V02 , SN: xxx

NAME: "Switch 1", DESCR: "WS-C3850-24XS-E"
PID: WS-C3850-24XS-E , VID: V02 , SN: xxx

NAME: "Switch 1 - Power Supply A", DESCR: "Switch 1 - Power Supply A"
PID: PWR-C1-715WAC , VID: V03 , SN: xxx

NAME: "Te1/0/1", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR , VID: V02 , SN: xxx

NAME: "Te1/0/2", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR , VID: V02 , SN: xxx

NAME: "Te1/0/3", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR , VID: V02 , SN: xxx

NAME: "Te1/0/4", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR , VID: V02 , SN: xxx

NAME: "Te1/0/5", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR , VID: V02 , SN: xxx

NAME: "Te1/0/6", DESCR: "SFP-10GBase-LR"
PID: SFP-10G-LR , VID: V02 , SN: xxx

NAME: "Te1/0/7", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/8", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/9", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/10", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/11", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/12", DESCR: "1000BaseLX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/21", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/22", DESCR: "1000BaseSX SFP"
PID: GLC-SX-MMD , VID: V01 , SN: xxx

NAME: "Te1/0/23", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

NAME: "Te1/0/24", DESCR: "1000BaseSX SFP"
PID: , VID: , SN: xxx

alessandro.s · ‎01-13-2023

Seems that at some point C3850-NM-8-10G was inserted and then removed as i don't see it in showe inventory output but the interfaces remains stuck in the config

Mark Elsen · ‎01-13-2023

- Check if that remains so after a reload ,

M.

-- Let everything happen to you
   Beauty and terror
      Just keep going
     No feeling is final
Reiner Maria Rilke (1899)

msue24 · ‎01-18-2023

So I did a reload but unfortunately it did not solve the problem.

msue24 · ‎01-18-2023

The switch is not modular which makes things even more weird. I already mentioned i can't ignore this problem because of the failing environment check.

Mark Elsen · ‎01-18-2023

- Try if (config) # no interface Te1/1/1 (e.g.)
can work,

M.

-- Let everything happen to you
   Beauty and terror
      Just keep going
     No feeling is final
Reiner Maria Rilke (1899)

Georg Pauwen · ‎01-18-2023

Hello,

just a thought, but check if 'vstack' (smart install) is enabled, and if you don't need it, disable it (no vstack) and reboot the switch...

j.a.m.e.s · ‎02-25-2025

I had a similar issue on a stack of WS-C3850-24XUW-S running ios-xe 16.12.09.

Even though the stack was provisioned correctly:

switch 1 provision ws-c3850-24xu
switch 2 provision ws-c3850-24xu

For some reason there was a phantom interface which showed "connected" but wouldn't send CDP/OSPF etc.

Te2/0/31 Uplink to CORE-2 connected routed full 10G SFP-10GBase-SR <- Should be Te2/1/3 !!

In the end, I did just edited the config, uploaded it to flash, did a copy flash:/newconfig.txt nvram:startup-config then reload on the stack.

Seems to be working now.