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Problem setting up new T1

Posted on 2011-02-25
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Last Modified: 2012-05-11
Hi all, I am more of a software engineer than a networking guy but I dabble enough in routing to get the job done (normally) for minor things.

Recently we had a dry pair go bad to one of our remote offices and we installed a new T1 and I figured it would be easy to copy the config to a new interface and everything would work - not so much. Here is my setup:

Main Office Router -> CSU/DSU (Adtran) -> T1 -> CSU/DSU (Adtran) -> Remote Office Router

We know the adtran units are working because our phone admin is able to use them for his 4 digit dialing. However, both the routers are showing: "Serial0/* is up, line protocol is down" and I'm not sure why.

This is an integrated T1 with 8 channels dedicated to data.

Here is the configs for the interfaces:

Main Router:

interface Serial0/3/1
 description To Remote Office
 bandwidth 512
 ip address 192.168.11.1 255.255.255.252
 encapsulation ppp

Remote Router:

interface Serial0/2/0
 description To Main
 bandwidth 512
 ip address 192.168.11.2 255.255.255.252
 encapsulation ppp

Here is the interface status for the main office:

Serial0/3/1 is up, line protocol is down
  Hardware is GT96K Serial
  Description: To Remote Office
  Internet address is 192.168.11.1/30
  MTU 1500 bytes, BW 512 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation PPP, LCP Listen, loopback not set
  Keepalive set (10 sec)
  Last input never, output 00:00:31, output hang never
  Last clearing of "show interface" counters 14:32:23
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 384 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     10431 packets output, 146034 bytes, 0 underruns
     0 output errors, 0 collisions, 2788 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

Here is the interface status on the remote router:

Serial0/2/0 is up, line protocol is down
  Hardware is GT96K Serial
  Description: Main Lot New
  Internet address is 192.168.11.2/30
  MTU 1500 bytes, BW 512 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation PPP, LCP Listen, loopback not set
  Keepalive set (10 sec)
  Last input never, output 00:00:05, output hang never
  Last clearing of "show interface" counters 21:21:33
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/1/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 384 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     15330 packets output, 214620 bytes, 0 underruns
     0 output errors, 0 collisions, 1534 interface resets
    0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

Am I missing anything? Thanks for your help.
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Question by:skymander
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8 Comments
 
LVL 1

Author Comment

by:skymander
ID: 34983691
Some more information:

The old T1 used to be plugged in to a T1 interface on the remote router. Here is the old interface config:

controller T1 0/0/0
 framing esf
 linecode b8zs
 channel-group 1 timeslots 1-24

interface Serial0/0/0:1
 description To Main Lot Old
 bandwidth 1536
 ip address 192.168.11.2 255.255.255.252
 encapsulation ppp
!

We installed a new WIC card wich is now Serial0/2/0 on the remote router and plugs directly into the Adtran CSU/DSU which was configured by our telco.
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Accepted Solution

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tjdabomb earned 250 total points
ID: 34983703
typically, serial up, line down is a clocking, framing or encapsulation problem
0
 
LVL 1

Author Comment

by:skymander
ID: 34983732
How would I troubleshoot that? I have tried manually setting the clocking on the interface. But from what I understand that is ignored if an external CSU/DSU is employed.

The framing and encapsulation should both be handled by the CSU/DSU too right?
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LVL 24

Expert Comment

by:rfc1180
ID: 34983864
> I have tried manually setting the clocking on the interface. But from what I understand that is ignored if an external CSU/DSU is employed.

https://supportforums.cisco.com/docs/DOC-6085

>How would I troubleshoot that?

http://www.cisco.com/en/US/tech/tk713/tk628/technologies_tech_note09186a00800a758d.shtml
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Author Comment

by:skymander
ID: 34984884
We made sure one of the DSU units is set to be the clock source. Framing is set appropriately on both sides. Loopback test worked between the two DSU units.

The line protocol is still down. Any other ideas? Do the configs looks ok for the interfaces?
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LVL 9

Expert Comment

by:tjdabomb
ID: 34985030
you addressed two of the three issues (clocking, framing), it seems.  encapsulation may still be the issue.  Try debug commands =  Router-->debug ppp event or debug ppp packet.  It will give you an idea where is a root of problem.
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LVL 1

Author Comment

by:skymander
ID: 34986146
Hi guys, turns out we had a defective WIC. After replacing it everything worked fine... Thanks so much for your help!
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LVL 9

Expert Comment

by:tjdabomb
ID: 34999381
The truth is ALWAYS in the WIC.  ;)
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