No cable is connected, but interface status is up

[paranengmoose]

Hi I have a Cisco ASR router with tengig interfaces.

Those tengig interfaces always remain up/up even though no cable is plugged and the switch on the other side shutdown the interface.

Is this a normal behavior of ASR?

How can I make the interface change its status when a cable is unplugged?

[Leo Laohoo · Accepted solution]

There is a known bug between an ASR and 3850/3650 and the behaviour is very similar to what you're seeing. Let me see if I can find the Bug ID for it.

[paranengmoose]

Hi Leo,

thank you for the quick reply.

I will really appreciate if you can find the BUG ID for me.

Thank you

[Reza Sharifi]

Hi,

Does it change if you issue "sh" and "no sh" on the interface?

HTH

[Georg Pauwen]

Hello,

the below bug might apply:

CSCvf63836

ASR1001X SFP-10G-SR link status is still up after remove the fiber cable

Symptom:
ASR1001X Tengiga interface using SFP-10G-SR link status is still up after remove the fiber cable

Conditions:
- remote fiber calbe SFP-10G-SR form chassis
- insert SFP-10G-SR and fiber cable. The Tengiga interface become up
- remote tx fiver cable after rx fiber cable
- Tengiga interface link is still up.

Workaround:
- "shutdown" command

[Leo Laohoo]

This should be the one.

[paranengmoose]

Hi Leo,

does it mean I will have to manually shutdown the tengig interface even after a cable is unplugged?

[Mark Malone]

yes as per the workaround in the bug id George posted

Workaround:
- "shutdown" command

[Georg Pauwen]

Hello,

shutting down the interface manually is indeed the recommended workaround...

[paranengmoose]

Hi George,

I think it means the ASR has no ability to detect any cable unplug or a switch failure on the other side.

No matter what happens, the interfaces will stay up/up all the time.

Am I right?

[Georg Pauwen]

Yes, that is the bug...

[paranengmoose]

Thank you very much, George.

That was very helpful.

Does Cisco usually release any patch or upgrade to fix this kind of bug?

It doesn't make sense to let the product miss the basic functionalities...

[Leo Laohoo]

---

@paranengmoose wrote:

Does Cisco usually release any patch or upgrade to fix this kind of bug?

It doesn't make sense to let the product miss the basic functionalities...

---

Unless the bug is deemed to be of certain level, details in the Bug ID is rarely updated.  It is better to raise a TAC case and get TAC to provide you with the latest advisory then to "wait" for the Bug ID to be updated.

[iashaan55]

Maybe you should upgrade to latest IOS-XE. There is no such issue with the latest OS

[burleyman]

I think sometimes the more TAC cases that get opened on a bug the more likely they will work on it sooner, just a guess.

Mike