E1 up serial protocol down

Unanswered Question
Feb 11th, 2009

Hi guys, I have a problem with a configuration, I have a C3745, a E1 card used before and a new 12 Digital Modems. I need to configure these Digital modules but if I configure the serial X/X:15 with a ppp encapsulation, the serial protocol goes down!!!!, on the other hand if I configure the hdlc encapsulation, serial is OK. Some help, do i need to talk with my service provider about this?

Thanks a lot guys


I have this problem too.
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Paolo Bevilacqua Wed, 02/11/2009 - 12:40

1st, which E1 card do you have ? Check show diag to know.

2nd, which Digital modems do you have? Again, show diag will tell you.

3nd, unless you receive digital calls, encapsulation on serial doesn't matter. You want PPP on group-async that controls the modems.

david-lima Wed, 02/11/2009 - 16:21

Hi Paolo, thanks for your mail,

1. High Density Voice NM-HDV2-1T1/E1 Port adapter

2- Digital Modems Port adapter, 12 ports

3. A have 10 remote users that need that they dial into my network.

I have these relevant configuration.

controller E1 2/0

pri-group timeslots 1-31

interface Serial2/0:15

no ip address

encapsulation ppp

isdn switch-type primary-net5

isdn incoming-voice modem

isdn calling-number 2623122

interface Group-Async0

ip unnumbered GigabitEthernet0/0

encapsulation ppp

dialer in-band

dialer idle-timeout 1500

dialer-group 1

async dynamic routing

async mode dedicated

peer default ip address pool dialin

keepalive 10 3

ppp authentication pap

group-range 1/0 1/11

line 1/0 1/11

modem Dialin

modem autoconfigure type default

transport input all

autoselect during-login

autoselect ppp


SA_RAS#sh inter s2/0:15

Serial2/0:15 is up, line protocol is down



Paolo Bevilacqua Thu, 02/12/2009 - 01:29

Hi, do you have PVDM2-12DM ? please check show diag.

Then check circuit status with "show controllers E1"

david-lima Thu, 02/12/2009 - 05:16

Hi Paolo, thanks again for your time, these are the show controlller/inter seri

SA_RAS#sh controllers e1

E1 2/0 is up.

Applique type is Channelized E1 - balanced

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20040802, FPGA: 255, spm_count = 0

Framing is CRC4, Line Code is HDB3, Clock Source is Line.

Current port master clock:recovered from controller 2/0

Data in current interval (362 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Total Data (last 1 15 minute intervals):

0 Line Code Violations, 6 Path Code Violations,

1 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,

1 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

SA_RAS#sh inter s2/0:15

Serial2/0:15 is up, line protocol is down

Hardware is DSX1

MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation PPP, loopback not set

Keepalive set (10 sec)

Last input 00:00:02, output never, output hang never

Last clearing of "show interface" counters 00:06:55

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 48 kilobits/sec

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

184 packets input, 552 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

184 packets output, 552 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions



david-lima Thu, 02/12/2009 - 10:25

Thanks a lot for you time Paolo,

If we can, we'll try with another NM according to the hardware requirements.

All the best


david-lima Tue, 04/21/2009 - 06:30

Hi Paolo, finally I get a NM-PRI-2CE1U only for a test, to configure my digital modems that are in my Cisco 3825. Just one question, does the NM-PRI-2CE1U modelule will need DSP? if yes, can I use the DSP of the PVDM2-32?

Thanks again,

All the best


david-lima Tue, 04/21/2009 - 10:53

Hi Paolo, again thanks for your time, I'm going to install the NM in a few hours, this last one please, if the NM-2CE1U does not work with PVDM2, it means that this particular NM can work without PVDMs?

Thanks a lot

Best regards.



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