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Problem Description:


This document is about the most common cause of the CRIT Error LED on the ASR1000 platform. In practice this error is usually encountered when the router is being configured for the first time and the connections have been configured but not brought up yet. An example of the ominous indicator LED is shown to the left.

Frequently it is found that there is a port that is in a hot state but is disconnected or down/down for some reason. In other words, the interface has been configured and had the default shutdown cleared, but for some reason the interface is still down. (Reasons include fiber disconnected, other end admin down, transceiver not inserted yet, etc.)


This scenario can be easily verified by looking for the following symptoms:

Compare the running configuration show run of the device with the interface status while paying special attention to the interfaces not configured with shutdown.  Then compare that with the current state of interfaces on the router show interface

show runshow interfaces

*output removed preceding*

interface GigabitEthernet0/0/0

  ip address

  negotiation auto


interface GigabitEthernet0/0/1

  no ip address


  negotiation auto


*output removed following*

GigabitEthernet0/0/0 is down, line protocol is down

*output deleted*


GigabitEthernet0/0/1 is administratively down, line protocol is down






*output deleted*

Then perform a show facility-alarms status which, in this scenario, will show something like:

router#show facility-alarm status
System Totals  Critical: 1  Major: 0  Minor: 0

Source              Severity      Description [Index]
------              --------      -------------------
GigabitEthernet0/0/0       CRITICAL      Physical Port Link Down [1]
xcvr container 0/0/1       INFO          Transceiver Missing [0]
xcvr container 0/0/2       INFO          Transceiver Missing [0]

This critical facility alarm is what is causing the system status.  Please note that this behavior is intentional, not a bug.  The ASR series is used primarily by ISPs who need to know immediately if an interface is disconnected for any reason. (ie someone in the datacenter accidentally bumping a cable, etc.) For an ISP any disconnect could cause an outage for hundreds or thousands of customers, hence it is critical.


Now that you know what is causing the alarm in this case you basically have two choices.  You can place the interface that is causing the status into admin down until you turn up the interface and place it into testing or production. (ie in config-interface perform shutdown) This is preffered. You could also just ignore the error, although I wouldn't suggest it unless you're going to be turning up the interface in the next couple minutes.  If you have another critical issue you won't know the difference, via the LED indicators in any case.

Finally, clearing the alarms with clear facility-alarm most likely won't work unless the state of the interface(s) has changed either to admin down or up/up because the alarm will just be thrown again in a couple of seconds.  When the interface(s) are in a preferred state this alarm (LED indicator) should clear automatically.

Joseph Dworak


Mark DeLong

Your awesome dude! Thx!

Hi, this apply for ASR900 series too?

Paul Stafford

IT SURE DOES!  I had the same light and when I admin shut the unused interfaces, my CRIT LED went out!

Thanks for the note,


Excellent article, thank you. 


So I am checking this on ASR1001X router


ASR1001X#sh facility-alarm status
System Totals Critical: 1 Major: 0 Minor: 0

Source Time Severity Description [Index]
------ ------ -------- -------------------
xcvr container 0/0/1 Nov 22 2017 08:00:06 CRITICAL Transceiver Missing - Link Down [1]
xcvr container 0/0/2 Mar 08 2018 13:11:51 INFO Transceiver Missing [0]
xcvr container 0/0/4 Mar 08 2018 13:11:55 INFO Transceiver Missing [0]
xcvr container 0/0/5 Mar 01 2018 00:43:02 INFO Transceiver Missing [0]
xcvr container 0/0/6 May 19 2017 00:34:01 INFO Transceiver Missing [0]



Critical says that port 1 is down 


check port connectivity  and is up and connected 

ASR1001X# sh int gig 0/0/1
GigabitEthernet0/0/1 is up, line protocol is up


I guess I may try to clear the the alarms , but why this is not cleared itself 




There is something more to this - I have two ASR1001,  both configured he same, i have a bridge-domain on gi0/0/0 and gi0/0/1 as BDI100 with rj45 modules (connected to an active/passive firewall pair, in which inactive also has ethernet ports, so there will never be more than one of the two active) 

on my router-1, port 0 is active, port 1 is inactive. show facility shows port 1 as critical, no fault-light

on my router-2, port 0 is inactive, port 1 is active. show facility shows port 0 as critical, has fault-light

so if a fault light is shown due to a port in "no shut" but has no connection - then why does not my router-1 have this?

They both run the same xos version.




O my word ...! Thank you so much for this.


I am wondering though, what does "transceiver not inserted" means, something physical ...?


Thanks for the amazing write up!


Quick question... what does "Transceiver Missing" under Description [Index] mean? when you use the command show facility-alarm, status? Thanks

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