Trouble configuring new T1 for WAN

[Skymander]

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 moved to a new T1 at a remote office 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.

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

Am I missing anything? Thanks for your help.

 

[david902]

up/down is a layer 2 issue,

encapsulations correct ?
what kind of T1 did you get ?


show logging for events
show interface for errors.

 

[Skymander]

Thanks for the reply David.

This is an integrated T1 with 8 (0-7) channels dedicated to data.

I believe PPP is the correct encapsulation. It is the same we use for another wan connection to a different remote location. Both T1s go direct (not point to point or frame relay).

Here is the interface status for the main office:

show interface Serial0/3/1
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

I just turned on logging (again) and did "debug serial interface" and will post the results for this and the interface status for the remote office in just a few moments.

 

[Skymander]

Here is the debug log for the main router:

debug serial interface
Serial network interface debugging is on

*Feb 24 21:07:14.760: Serial0/3/1: attempting to restart
*Feb 24 21:07:14.760: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE
*Feb 24 21:07:14.760: DTE idb->dte_interface = DTE
*Feb 24 21:07:14.760: Dscc4(Serial0/3/1): DCD is up.

*Feb 24 21:07:33.596: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE
*Feb 24 21:07:33.596: DTE idb->dte_interface = DTE
*Feb 24 21:07:33.596: Dscc4(Serial0/3/1): DCD is up.

*Feb 24 21:07:44.760: Serial0/3/1: attempting to restart
*Feb 24 21:07:44.760: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE
*Feb 24 21:07:44.760: DTE idb->dte_interface = DTE
*Feb 24 21:07:44.760: Dscc4(Serial0/3/1): DCD is up.

And it just keeps repeating that over and over every 10 seconds. That's not normal right?

Will post the remote office in a few minutes (waiting for an email as we cannot access the site right now from here).

 

[Skymander]

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

debug serial interface
*Feb 24 21:20:58.194: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE

*Feb 24 21:20:58.194: DTE idb->dte_interface = DTE
*Feb 24 21:20:58.194: Dscc4(Serial0/2/0): DCD is up.

*Feb 24 21:21:48.370: gt96k_mbrd_serial_mode_reg_init:: was DTE, now set to DTE

*Feb 24 21:21:48.370: DTE idb->dte_interface = DTE
*Feb 24 21:21:48.370: Dscc4(Serial0/2/0): DCD is up.

 

[Skymander]

Anyone see any mistakes I made in the configuration?

 

[david902]

do you have a controller interface ?

usually channelized T1s are configured this way

i.e. soemthing like this
(framing and line code from your provider)

controller T1 0/1/0
framing esf
linecode b8zs
channel-group 0 timeslots 1-8

interface Serial0/1/0:0
ip address 5.6.7.9 255.255.255.252

 

[Skymander]

Yes, I do have a T1 contoller interface (2 actually) but not for 0/2/0.

controller T1 0/0/0
framing esf
linecode b8zs
channel-group 1 timeslots 1-8

controller T1 0/0/1
framing esf
linecode b8zs
channel-group 1 timeslots 1-8

Is this our problem? And how do we fix it?

 

[Skymander]

I just verified that esf and b8zs is correct

 

[Skymander]

We do not have this plugged into the T1 interface though. It is plugged into a serial port that goes through a CSU/DSU modem which appears to be working well.

 

[TripTek]

I'm not a Cisco master, but at first glance it appears
interfaces at both ends are configured DTE.
I believe one should be DTE, the other DCE.

 

[TripTek]

Please ignore my first response. (assuming the CSU is DCE and is providing
the clocking)

An edit post feature would be nice...

I've noticed LCP is listen, not open.
If memory serves, this indicates that the ppp link is not established.

Authentication ok? (username and password)