ISDN Layer 1 Status

Hi Guys!

If your anything like me, you thought that an ISDN output like below:

#show isdn status
Global ISDN Switchtype = primary-net5
ISDN Serial0/0/1:15 interface
        dsl 0, interface ISDN Switchtype = primary-net5
    Layer 1 Status:
        DEACTIVATED


Meant that there was some sort of cabling problem, I always assumed Layer 1 deactivated means there is a cabling problem and that is that, but alas no! It can mean a few things, Check out the output below:



#show controller e1 0/0/1
E1 0/0/1 is down.
  Applique type is Channelized E1 - balanced
  Description: ### E1 Outside Line ###
  Transmitter is sending TS16 LOMF Alarm.
  Receiver has loss of multi-frame in TS16.

The above output shows that you can see a little bit of info about what Alarms the E1 Can see, this is another way of accomplishing more troubleshooting, From the output above we can see it is upset with the framing in some way, so let's change the framing:



controller e1 0/0/1
   framing no-crc4

Now let's check the status:
 

#show isdn status
Global ISDN Switchtype = primary-net5
ISDN Serial0/0/1:15 interface
        dsl 0, interface ISDN Switchtype = primary-net5
    Layer 1 Status:
        ACTIVE
    Layer 2 Status:
        TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED


Hooray!!! Another way to effectively troubleshoot E1 Lines.