Troubleshooting the T1 or E1 Interface Module

You can use the following methods to troubleshoot the T1 or E1 interface modules:

  • Bit Error Rate Testing (BERT)

  • Loopback

Overview of BERT

Bit Error Rate Testing (BERT) is used to test the integrity of the physical line.

The interface contains on board BERT circuitry. With this circuitry, the interface software can send and detect a programmable pattern that is compliant with CCITT/ITU O.151, O.152, O.153 pseudo-random, and repetitive test patterns. BERTs allow you to test cables and signal problems in the field.

The bit error rate (BER) is determined by comparing the erroneous bits received with the total number of bits received. You can display and analyze the total number of error bits transmitted and the total number of bits received on the link. You can retrieve error statistics anytime during the BERT.

Both the total number of bits and the error bits received are available for analysis. You can select the testing period from 1 minute to 24 hours and you can also retrieve the error statistics anytime during the BERT test.

Running a BERT Test

When running a BERT test, the system expects to receive the same pattern that it transmits. To help ensure this, two common options are available:

  • Use a loopback somewhere in the link or network

  • Configure remote testing equipment to transmit the same BERT test pattern at the same time.

The BERT runtime engine can be kept running until the interval completes or can be stopped by unconfiguring it anytime.

Types of BERT

BERT is supported in two directions:

  • Line - supports BERT in TDM direction

  • System - supports BERT in PSN direction

BERT engines uses different BERT patterns for transmission for each mode. The supported BERT patterns on each card is described.

BERT Restrictions

  • BERT is not supported on the following modes:

    • T3—Framing M-13, non-channelized

    • E3—Framing G832, channelized

  • When the BERT is initiated with pattern 0s and 1s from the local end and the loopback local is applied from the far end, then the BERT syncing does not happen. Since the BERT process is asserted as LOS alarms for all 0s and AIS alarms for all 1s BERT patterns. Whereas the BERT syncing behaves properly when the BERT is initiated from both the local and the far end.

    For all 1s on T3 or E3, the BERT behaviour is not asserted as AIS and the BERT syncing happens as usual.

  • In the unframed mode, BERT sync is not stable and may generate alarms until Cisco IOS XE Fuji 16.9.4.


    Note


    Framing type should be similar in all routers end to end.


  • System BERT is not supported for any pattern in framed SATOP for releases earlier to Cisco IOS XE 17.13.1.

    Starting with Cisco IOS XE 17.13.1, system BERT is supported for any pattern in the framed SAToP on T1/E1 interface module.

  • System BERT is not configurable, without cem-group configuration.

  • Path modes, unframed modes, and concatenation modes are not supported.

  • The default BERT pattern supported is PRBS. The QRSS pattern is supported only on T1 or E1 level and the STS-1E path level for pattern 2^20-O151.

BERT Restrictions for Cisco IOS XE Bengaluru 17.4.1 release

  • When the BERT is initiated from the local end and the loopback local is applied from the far end, then BERT syncing does not happen. Since the BERT process is asserted as LOS alarms for all 0s and AIS alarms for all 1s BERT patterns. Whereas the BERT syncing behaves properly when the BERT is initiated from both the local and the far end.

BERT for SAToP

BERT is supported for both unframed and framed modes.

Configuring BERT for SAToP

Before You Begin

Before you run BERT test, you must configure card type and controller.

To run a BERT on T1/E1 interface, perform the following tasks in global configuration mode.
 
enable
configure terminal
controller t10/1/1
bert pattern 2^11 interval 5 direction line/system
exit

Note


To terminate a BERT test during the specified test period, use the no bert command.


Verifying BERT Configuration for SAToP

Use the following command to verify the BERT configuration for T1/E1 interfaces:


Router# show controllers t1 0/1/1 

T1 0/1/1 is up.
  Applique type is ASR903-48T1E1-CE
  Cablelength is short 110
   DSX1 BERT pattern     : 2^11
   DSX1 BERT direction   : Line
   DSX1 BERT sync        : no sync
   DSX1 BERT sync count  : 0
   DSX1 BERT interval    : 5
   DSX1 BERT time remain : 2
   DSX1 BERT total errs  : 0
   DSX1 BERT total k bits: 0
   DSX1 BERT errors (last): 0
   DSX1 BERT k bits (last): 0
   Last clearing of BERT counters never
  No alarms detected.                                                           
  alarm-trigger is not set                                                      
  Soaking time: 3, Clearance time: 10                                           
  AIS State:Clear  LOS State:Clear  LOF State:Clear                             
  Framing is ESF, FDL is ansi, Line Code is B8ZS, Clock Source is Line.         
  BER thresholds:  SF = 10e-3  SD = 10e-6                                       
  Data in current interval (230 seconds elapsed):                               
   Near End                                                                     
     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 Unavailable Secs 
     0 Path Failures, 0 SEF/AIS Secs                                            
   Far End                                                                      
     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 Unavailable Secs 
     0 Path Failures                                                            
  Data in Interval 1:                                                           
   Near End                                                                     
     0 Line Code Violations, 0 Path Code Violations                             
     0 Slip Secs, 0 Fr Loss Secs, 14 Line Err Secs, 0 Degraded Mins             
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 15 Unavailable Secs
     1 Path Failures, 0 SEF/AIS Secs                                            
   Far End Data                                                                 
     0 Line Code Violations, 0 Path Code Violations                             
     0 Slip Secs, 4 Fr Loss Secs, 2 Line Err Secs, 0 Degraded Mins              
     4 Errored Secs, 0 Bursty Err Secs, 4 Severely Err Secs, 0 Unavailable Secs 
     0 Path Failures                                                            
  Total Data (last 1 15 minute intervals):                                      
   Near End                                                                     
     0 Line Code Violations, 0 Path Code Violations,                            
     0 Slip Secs, 0 Fr Loss Secs, 14 Line Err Secs, 0 Degraded Mins,            
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 15 Unavailable Secs
     1 Path Failures, 0 SEF/AIS Secs                                            
   Far End                                                                      
     0 Line Code Violations, 0 Path Code Violations,                            
     0 Slip Secs, 4 Fr Loss Secs, 2 Line Err Secs, 0 Degraded Mins,             
     4 Errored Secs, 0 Bursty Err Secs, 4 Severely Err Secs, 0 Unavailable Secs 
     0 Path Failures 

You can view the results of a BERT test at the following times:

  • After you terminate the test using the no bert command

  • After the test runs completely

  • Anytime during the test (in real time)

Framed SAToP System BERT

Table 1. Feature History
Feature Name Release Information Description
Framed SAToP System BERT

Cisco IOS XE 17.13.1

You can configure SATOP system BERT with framing under CEM circuits on T1 or E1 interfaces and verify if the BERT is stable and transmitted end-to-end.

System BERT is used between PEs on the core side. This feature is supported only on the 48-port T1/E1 Interface module. You can run a maximum of 16 BERTs at a time.


Note


For NCS 4200 series routers, the framed SAToP system BERT is supported only on the NCS 4202 router with NCS4200-3GMS Interface Module.


Restrictions for Framed SAToP System BERT

  • Framing change is not allowed while bert is running

Configuring Framed SAToP System BERT

You can configure the framed SAToP system BERT in the following scenarios:

  • Scenario 1: PE1—core—PE2

    CEM system BERT is configured on both PE1 and PE2.

  • Scenario 2: PE1—core—PE2

    CEM system BERT is configured on PE1 and loopback local is configured on PE2.

Scenario 1: PE1—CORE—PE2
  1. Configure system BERT on PE1.

  2. Configure system BERT on PE2.

  3. Configure cross-connect on core.

Configure System BERT on PE1


PE1#config terminal
PE1(config)#controller T1 0/4/35
PE1(config-controller)#bert pattern 3-in-24 interval 40 direction system
PE1(config)#end

Configure System BERT on PE2


PE1#config terminal
PE1(config)#controller T1 0/3/17
PE1(config-controller)#bert pattern 3-in-24 interval 40 direction system
PE1(config)#end

Configure Cross Connect on Core

Ensure that the cross connection is UP before configuring BERT.

Scenario 2: PE1—core—PE2
  1. Configure system BERT on T1 at the PE1 side.

  2. Apply loopback local on PE2.

  3. Configure cross-connect on core.


PE1#show run | s 0/4/35
controller T1 0/4/35
 threshold sd-ber 6
 threshold sf-ber 3
 framing esf
 linecode b8zs
 cablelength short 110
 no snmp trap link-status
  cem-group 0 framed
interface CEM0/4/35
 no ip address
 cem 0

Configure System BERT on PE1


PE1#config terminal
PE1(config)#controller T1 0/4/35
PE1(config-controller)#bert pattern 3-in-24 interval 40 direction system
PE1(config)#end

Apply Loopback Local on PE2


PE2(config-controller)#controller T1 0/4/0                                   
PE2(config-controller)#loopback local
PE2(config-controller)#end

Configure Cross Connect on Core

Ensure that the cross connection is UP before configuring BERT.

Verifying Framed SAToP System BERT

Use the following show commands to verify the framed SAToP system BERT configuration:

Scenario 1: PE1—CORE—PE2

Verify the configuration on PE1


PE1#show xconnect all
Legend:    XC ST=Xconnect State  S1=Segment1 State  S2=Segment2 State
  UP=Up       DN=Down            AD=Admin Down      IA=Inactive
  SB=Standby  HS=Hot Standby     RV=Recovering      NH=No Hardware

XC ST  Segment 1                         S1 Segment 2                         S2
------+---------------------------------+--+---------------------------------+--
UP pri mpls 2.2.2.2:500                  UP   ac CE0/4/35:0(SATOP T1)  UP

PE1#show controller T1 0/4/35 | sec BERT
   DSX1 BERT test result: (running)
   DSX1 BERT pattern     : 3-in-24
   DSX1 BERT direction   : System
   DSX1 BERT sync        : sync
   DSX1 BERT sync count  : 1
   DSX1 BERT interval    : 100
   DSX1 BERT time remain : 01:39:52
   DSX1 BERT total errs  : 0
   DSX1 BERT total k bits: 10759
   DSX1 BERT errors (last): 0
   DSX1 BERT k bits (last): 10759
   Last clearing of BERT counters never

Verify the configuration on PE2


PE1#show xconnect all
Legend:    XC ST=Xconnect State  S1=Segment1 State  S2=Segment2 State
  UP=Up       DN=Down            AD=Admin Down      IA=Inactive
  SB=Standby  HS=Hot Standby     RV=Recovering      NH=No Hardware

XC ST  Segment 1                         S1 Segment 2                         S2
------+---------------------------------+--+---------------------------------+--
UP pri mpls 3.3.3.3:500                  UP   ac CE0/3/17:0(SATOP T1)  UP

PE1#show controller T1 0/3/17 | sec BERT
   DSX1 BERT test result: (running)
   DSX1 BERT pattern     : 3-in-24
   DSX1 BERT direction   : System
   DSX1 BERT sync        : sync
   DSX1 BERT sync count  : 1
   DSX1 BERT interval    : 100
   DSX1 BERT time remain : 01:39:52
   DSX1 BERT total errs  : 0
   DSX1 BERT total k bits: 10759
   DSX1 BERT errors (last): 0
   DSX1 BERT k bits (last): 10759
   Last clearing of BERT counters never

Scenario 2: PE1—CORE—PE2

Verify the configuration on PE1


PE1#show xconnect all
Legend:    XC ST=Xconnect State  S1=Segment1 State  S2=Segment2 State
  UP=Up       DN=Down            AD=Admin Down      IA=Inactive
  SB=Standby  HS=Hot Standby     RV=Recovering      NH=No Hardware

XC ST  Segment 1                         S1 Segment 2                         S2
------+---------------------------------+--+---------------------------------+--
UP pri mpls 2.2.2.2:500                  UP   ac CE0/4/35:0(SATOP T1)  UP

PE1#show controller T1 0/4/35 | sec BERT
   DSX1 BERT test result: (running)
   DSX1 BERT pattern     : 3-in-24
   DSX1 BERT direction   : System
   DSX1 BERT sync        : sync
   DSX1 BERT sync count  : 1
   DSX1 BERT interval    : 100
   DSX1 BERT time remain : 01:39:52
   DSX1 BERT total errs  : 0
   DSX1 BERT total k bits: 10759
   DSX1 BERT errors (last): 0
   DSX1 BERT k bits (last): 10759
   Last clearing of BERT counters never

BERT for CESoPSN

BERT is supported at the TDM side and pseudowire side. BERT can be used either at NxDS0 or DS1 but not together.

BERT is supported on following controllers:

  • T1—NxDS0, DS1

  • T3—NxDS0, DS1 (channelised), clear channel DS3.

  • OCX—NxDS0, DS1 (channelised),DS3(channelised), clear channel DS3,STS1,STS-nc,VT-1.5,VT1.5 T1

Configuring BERT for CESoPSN

Before You Begin

Before you run BERT test, you must configure card type and controller.

To run a BERT on T1/E1 interface for CESoPSN, perform the following tasks in global configuration mode.
 
enable
configure terminal
controller t10/1/1
bert pattern 2^11 interval 5 direction line/system timeslots value speed
exit

Note


To terminate a BERT test during the specified test period, use the no bert command.


Verifying BERT Configuration for CESoPSN

Use the following command to verify the BERT configuration for CESoPSN on T1 interfaces:

Router# show controllers t1 0/1/32
T1 0/1/32 is up
  Applique type is NCS4200-48T1E1-CE
  Cablelength is short 110
   DS0 Bert enabled on the following timeslots : 1-2
   Speed : 64 kpbs
   DSX1 BERT test result: (running)
   DSX1 BERT pattern     : 2^15
   DSX1 BERT direction   : Line
   DSX1 BERT sync        : sync
   DSX1 BERT sync count  : 1
   DSX1 BERT interval    : 1
   DSX1 BERT time remain : 00:00:55
   DSX1 BERT total errs  : 0
   DSX1 BERT total k bits: 512
   DSX1 BERT errors (last): 0
   DSX1 BERT k bits (last): 512
   Last clearing of BERT counters never
 No alarms detected.                                                           
  alarm-trigger is not set                                                      
  Soaking time: 3, Clearance time: 10                                           
  AIS State:Clear  LOS State:Clear  LOF State:Clear                             
  Framing is ESF, FDL is ansi, Line Code is B8ZS, Clock Source is Line.         
  BER thresholds:  SF = 10e-3  SD = 10e-6                                       
  Data in current interval (230 seconds elapsed):                               
   Near End                                                                     
     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 Unavailable Secs 
     0 Path Failures, 0 SEF/AIS Secs                                            
   Far End                                                                      
     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 Unavailable Secs 
     0 Path Failures                                                            
  Data in Interval 1:                                                           
   Near End                                                                     
     0 Line Code Violations, 0 Path Code Violations                             
     0 Slip Secs, 0 Fr Loss Secs, 14 Line Err Secs, 0 Degraded Mins             
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 15 Unavailable Secs
     1 Path Failures, 0 SEF/AIS Secs                                            
   Far End Data                                                                 
     0 Line Code Violations, 0 Path Code Violations                             
     0 Slip Secs, 4 Fr Loss Secs, 2 Line Err Secs, 0 Degraded Mins              
     4 Errored Secs, 0 Bursty Err Secs, 4 Severely Err Secs, 0 Unavailable Secs 
     0 Path Failures                                                            
  Total Data (last 1 15 minute intervals):                                      
   Near End                                                                     
     0 Line Code Violations, 0 Path Code Violations,                            
     0 Slip Secs, 0 Fr Loss Secs, 14 Line Err Secs, 0 Degraded Mins,            
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 15 Unavailable Secs
     1 Path Failures, 0 SEF/AIS Secs                                            
   Far End                                                                      
     0 Line Code Violations, 0 Path Code Violations,                            
     0 Slip Secs, 4 Fr Loss Secs, 2 Line Err Secs, 0 Degraded Mins,             
     4 Errored Secs, 0 Bursty Err Secs, 4 Severely Err Secs, 0 Unavailable Secs 
     0 Path Failures 

You can view the results of a BERT test at the following times:

  • After you terminate the test using the no bert command

  • After the test runs completely

  • Anytime during the test (in real time)

Loopback on T1 or E1 Interfaces

You can use the following loopback on the T1 or E1 interfaces. Loopback is supported on both unframed and framed modes.

Restrictions

  • Framing type should be maintained same in all routers end to end .

  • AIS alarm is not transmitted to the connected peer port with loopback local line configuration until Cisco IOS XE 16.9.4 Fuji Release.

Loopback

Description

loopback local line

Loops the outgoing transmit signal back to the receive signal. This is done using the diagnostic loopback feature in the interface module’s framer. Set the clock source command to internal for this loopback mode.

loopback network line

Loops the incoming signal back in the interface module using the line loopback mode of the framer. The framer does not reclock or reframe the incoming data. All incoming data is received by the interface module driver.

Loopback network line is supported on E1 interface.


Note


Starting Cisco IOS Release 16.8.1, the following loopback commands are not supported.

  • loopback diag

  • loopback local

  • loopback local payload


Configuring Loopback

Before You Begin

Before you configure loopback, you must configure the controller and the CEM.

To set a loopback local on the T1 interface, perform the following tasks in global configuration mode:
 
enable
configure terminal
controller t1 0/1/1
loopback local line
exit
To set a loopback diag on the T1 interface, perform the following tasks in global configuration mode:
 
enable
configure terminal
controller t1 0/1/1
loopbackdiag
exit
To set a loopback local on the E1 interface, perform the following tasks in global configuration mode:
 
enable
configure terminal
controller e1 0/1/1
loopback local 
exit
To set a loopback network on the E1 interface, perform the following tasks in global configuration mode:
 
enable
configure terminal
controller e1 0/1/1
loopback network line
exit

Note


To remove a loopback, use the no loopback command.



Note


Network payload configuration is not supported on the port configured with SAToP. To configure loopback network payload when SAToP is configured, you need to remove the CEM configuration and then configure the loopback.


Loopback Remote on T1 Interfaces

The remote loopback configuration attempts to put the far-end T1 into a loopback.

The remote loopback setting loops back the far-end at line or payload, using IBOC (in-band bit-orientated CDE) or the ESF loopback codes to communicate the request to the far-end.

For releases later than Cisco IOS XE Fuji 16.8.x, we recommend that you use ESF loopback codes with ESF framing and IBOC loopback codes with SF framing.

Restrictions for Loopback Remote

  • E1 loopback remote is not supported until Cisco IOS XE 16.9.4 Fuji Release. Starting from Cisco IOS XE Fuji 16.9.5 release, E1 loopback remote is supported.

  • Loopback remote is not supported when cem-group is configured under T1 until Cisco IOS XE 16.9.4 Fuji Release.

  • IBOC loopcode configuration is not supported when CESoP or SATOP (framed or unframed) is configured.

  • ESF loopcode configuration is not supported when SAToP is configured.

Configuring Loopback Remote on a T1 Interface Module

To set T1 loopback remote iboc fac1/fac2/csu for DS1, perform the following tasks in global configuration mode:

enable
configure terminal
controller t1 0/1/1
loopback remote iboc {fac1 | fac2 | csu}
exit

To set T1 loopback remote esf line csu/payload on the DS1 interface, perform the following tasks in global configuration mode:

enable
configure terminal
controller t1 0/1/1
loopback remote esf {line csu | payload}
exit

Note


loopback remote esf line niu is not supported.


Verifying the Loopback Remote Configuration

Use the following command to check the loopback remote configuration:

router# show running-config | sec 0/1/1
controller T1 0/1/10
 threshold sd-ber 6
 threshold sf-ber 3
 framing sf
 linecode b8zs
 cablelength short 110
 loopback remote iboc fac1


Use the following command to verify the loopback remote configuration:

router# show controller t1 0/1/1
T1 0/1/1 is up (NIU FAC1 Line Loopback with IBOC)
  Currently in Inband Remotely Line Looped
  Applique type is ASR900-48T1E1-CE
  Cablelength is short 110
  Receiver has no alarms.
  alarm-trigger is not set
Soaking time: 3, Clearance time: 10                                           
  AIS State:Clear  LOS State:Clear  LOF State:Clear                             
  Framing is ESF, FDL is ansi, Line Code is B8ZS, Clock Source is Line.         
  BER thresholds:  SF = 10e-3  SD = 10e-6                                       
  Data in current interval (230 seconds elapsed):                               
   Near End                                                                     
     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 Unavailable Secs 
     0 Path Failures, 0 SEF/AIS Secs                                            
   Far End                                                                      
     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 Unavailable Secs 
     0 Path Failures                                                            
  Data in Interval 1:                                                           
   Near End                                                                     
     0 Line Code Violations, 0 Path Code Violations                             
     0 Slip Secs, 0 Fr Loss Secs, 14 Line Err Secs, 0 Degraded Mins             
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 15 Unavailable Secs
     1 Path Failures, 0 SEF/AIS Secs                                            
   Far End Data                                                                 
     0 Line Code Violations, 0 Path Code Violations                             
     0 Slip Secs, 4 Fr Loss Secs, 2 Line Err Secs, 0 Degraded Mins              
     4 Errored Secs, 0 Bursty Err Secs, 4 Severely Err Secs, 0 Unavailable Secs 
     0 Path Failures                                                            
  Total Data (last 1 15 minute intervals):                                      
   Near End                                                                     
     0 Line Code Violations, 0 Path Code Violations,                            
     0 Slip Secs, 0 Fr Loss Secs, 14 Line Err Secs, 0 Degraded Mins,            
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 15 Unavailable Secs
     1 Path Failures, 0 SEF/AIS Secs                                            
   Far End                                                                      
     0 Line Code Violations, 0 Path Code Violations,                            
     0 Slip Secs, 4 Fr Loss Secs, 2 Line Err Secs, 0 Degraded Mins,             
     4 Errored Secs, 0 Bursty Err Secs, 4 Severely Err Secs, 0 Unavailable Secs 
     0 Path Failures 

User-defined Remote Loopback on T1 Interfaces

Table 2. Feature History
Feature Name Release Information Description
User-defined Remote Loopback on T1 Interfaces

Cisco IOS XE 17.13.1

You can customize the loopback codes on T1 in a 16-bit format in contrast to the standard 6-bit loop code on the 48-port T1 interface module.

For this release, you can configure the custom code only in the transmit direction (Tx) with ESF framing. The user-defined loop codes are supported only on the T1 controllers of 48-port T1/E1 Interface module .

The list of supported loop codes are:

  • 0xFF48, 0xFF24, 0xD3D3, 0x3F02, 0x9393, 0xD5D5, 0xD5D6, and 0x6767

  • 0xDBDB, 0xC741, 0xC754, 0xC743, 0xC742, 0xFF1E, 0xC541, and 0x12FF

  • 0x5F5F, 0x56D7, 0x56D8, 0x56DF, 0x56FB, 0xD5D6, 0xD5D5, and 0x5688

  • 0x5687, 0xC564, 0x9393, 0x24FF, 0xC741, 0xC742, 0xC743, and 0xC744

  • 0xC745, 0xC746, 0xC747, 0xC748, 0xC749, 0xC74A, 0xC74B, and 0xC74C

  • 0xC74D, 0xC74E, 0xC74F, 0xC750, 0xC751, 0xC752, 0xC753, and 0xC754

Configuring User-defined Remote Loopback on T1 Interfaces

You can configure a T1 remote loopback with ESF framing and 16-bit custom code on PE router.


PE1#config terminal
PE1(config)#controller T1 0/4/47
PE1(config-controller)#loopback remote esf line custom_code 0x9393
PE1(config-controller)#end

You can verify the remote loopbackconfiguration using the following show command:


PE1#show run | sec 0/4/47
 controller T1 0/4/47
 threshold sd-ber 6
 threshold sf-ber 3
 framing esf
 linecode b8zs
 cablelength short 110
 loopback remote esf line custom_code 0x9393
 no snmp trap link-status

Verifying User-defined Remote Loopback on T1 Interfaces

Use the following show commands to verify the user-defined remote loopback:


PE1#show controller T1 0/4/47
T1 0/4/47 is up (Far End Line Loopback with ESF BOC Custom Code)
  Currently in FDL Custom Code Remotely Line Looped
  Applique type is NCS4200-48T1E1-CE
  Cablelength is short 110
  Receiver has no alarms.
  alarm-trigger is not set
  Soaking time: 3, Clearance time: 10
  Framing is ESF, Line Code is B8ZS, Clock Source is Line.
  BER thresholds:  SF = 10e-3  SD = 10e-6
  Data in current interval (870 seconds elapsed):
   Near End

PE1#show facility-alarm status | i 0/4/47
T1 0/4/47                  May 10 2023 14:13:54   MINOR         LOOPBACK_REMOTE_FDL_CUSTOM_COD Loopback Remote Line FDL Custom Code Alarm [22]