cisco 5400 T.38 Fax Relay Troubleshooting

3. Check for SLIPs and Other Errors on Digital Interfaces

If there are any T1 or E1 digital connections used by the routers that perform fax relay, make sure that they are error free. Fax relay is very sensitive to errors on digital interfaces, especially slips. The errors will not be noticeable on voice calls but they can cause faxes to fail.

show controller T1(E1) 1/0 Command

vnt-3660-23c#show contr t1 1/0


T1 1/0 is up.

Applique type is Channelized T1

Cablelength is long gain36 0db

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20010805, FPGA: 15

Framing is ESF, Line Code is B8ZS, Clock Source is Line.


Data in current interval (132 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

 

The T1 or E1 controllers at both origination and termination gateways should be error free. If errors occur, repeat the show controller (T1 , E1 , and 1/0 will vary) command several times within the call to see if the number of errors increases. The most common problem of slips is a synchronization problem that results in clocking errors.

In packet voice networks, it is usually sufficient to confirm that the router clocks from the line. If it does not, ensure the clock source line command is entered at the controller level, but in VoATM or TDM networks, where a clocking hierarchy is established and the routers need to pass clock through the network, additional considerations need to be made. The Clocking Plan document provides more information about synchronous clocking.

 

 

Router#show controllers E1 7/1 brief
E1 7/1 is up.
  Applique type is Channelized E1 - balanced
  No alarms detected.
  alarm-trigger is not set
  Version info of slot 7:  HW: 517, PLD Rev: 1
  Framer Version: 0x8

Manufacture Cookie Info:
 EEPROM Type 0x0001, EEPROM Version 0x01, Board ID 0x0A,
 Board Hardware Version 2.5, Item Number 73-5268-02,
 Board Revision B0, Serial Number JAE071404C8,
 PLD/ISP Version <unset>,  Manufacture Date 4-Apr-2003.

  Framing is CRC4, Line Code is HDB3, Clock Source is Line.
  Data in current interval (416 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     76 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     76 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
  Total Data (last 42 15 minute intervals):
     0 Line Code Violations, 0 Path Code Violations,
     6675 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
     6675 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
Router#

 

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