Loopback Tests on the AccessBuilder 400/500/600 and OfficeConnect Remote 510, 520 and 530
This document explains the procedure to run loopback tests on ISDN Ports of the AB400, AB500 and OfficeConnect 510, 520, and 530 ISDN bridge routers.
The document also explains how to run loopback tests on the
WAN port on the AB500 and OfficeConnect 530.
An AB500 is used in the following examples.
An ISDN loopback entails placing on outbound call on one B channel and answering the call on the other B channel.
First check the configuration of SPIDS (if applicable), Directory Numbers, and network type on the
ISDN Parameters Screen. The ISDN Parameters screen is reached by entering CO IS PA
V05.02b Lab2 ISDN PARAMETERS 5ESS ISDN Down
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Network Type : USA (AT&T 5ESS Custom)
(Service Profile Identifiers - USA Only)
SPID 1 :0198212330
Directory Number 1 :9821233
SPID 2 :0198212340
Directory Number 2 :9821234
Multiple Subscriber Numbers Sub Addresses
Lan MSN : Lan SA :
Voice MSN : Voice SA :
Send MSN : Disabled Send SA : Disabled
Check MSN : Disabled Check SA : Disabled
SA Type : NSAP (default)
Report Busy : Disabled
Answer Voice as Data : Disabled
Maximum Call Duration : 60 minutes
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^G - Main menu
^E - Submit ^L - Prev menu
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Enter Ctrl-E and type SAVE to submit and save any changes.
Go to the Port Configuration Screen before placing a loop back call. The Port Configuration screen is reached by entering CO PO.
Place a call from one B channel to the other using the call command.
Example: Call 9821234
The Port Configuration Screen would appear as follows on a successful loopback call. Both ISDN ports show Loopback! and the state of both ports is UP. The AB500 will drop the call after about 30 seconds.
V05.02b Lab2 PORT CONFIGURATION 5ESS ISDN Ok
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Page No. 1 of 1
No. Name Type Phys. Rx(%) Tx(%) LZC(/) State
LAN1 LAN Port No. 1 ETHERNET AUI 00 00 DOWN
WAN1 HDLC Link 1 HDLC None 00 00 DOWN
[ISDN1 LOOPBACK! ISDN ISDN 00 00 1.0 UP ]
ISDN2 LOOPBACK! ISDN ISDN 00 00 1.0 UP
VOICE Voice Port VOICE Analogue On Hook
MNGR Manager Port AUTODETECT V.24 00 06 UP
EXam - Examine Port Stats EDit - Edit ISDN Port TYpe - Change Port Type
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^G - Main menu
^L - Prev menu
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(co po) Enter command :
Request for call placed OK
IF the loopback call fails, highlight the ISDN1 port on the Port Configuration Screen and enter EX to examine the port. In the top right corner of the screen the last number dialed and often a cause code relating to the failed call is displayed. See the manual for a further explanation of cause codes. There may be a problem with either the ISDN line or the configuration on the AB/500. Be sure the Network Type is correct, SPIDs are entered correctly and Directory Numbers entered without an area code.
The configuration on the WAN port may need to be changed before running a Loopback on the WAN port.
Proceed to the Port Configuration screen by entering CO PO. Set the port Type to Fast or PPP and then edit the WAN Port as follows:
V05.02b Lab2 PORT CONFIGURATION 5ESS ISDN Down
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Page No. 1 of 1
No. Name Type Phys. Rx(%) Tx(%) LZC(/) State
[LAN1 LAN Port No. 1 ETHERNET AUI 00 00 DOWN]
WAN1 Unconfigured NONE None 00 00
ISDN1 AUTO HDLC/PPP 1 ISDN ISDN 00 00 DOWN
ISDN2 AUTO HDLC/PPP 2 ISDN ISDN 00 00 DOWN
VOICE Voice Port VOICE Analogue On Hook
MNGR Manager Port AUTODETECT V.24 00 06 UP
EXam - Examine Port Stats EDit - Edit Ethernet Port
-------------------| Please save new Configuration (SAVE) |--------------------
^G - Main menu
^L - Prev menu
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(co po) Enter command : TYpe
Enter Type of NOne, PPp or FAst ? Fast (or PPp)
(co po) Enter command : EDit
V05.02b Lab2 EDIT HDLC PORT 5ESS ISDN Down
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Port Number :WAN1 Backup Bridge MAC :000000000000
Port Name :HDLC Link 1
Remote Bridge Name:
Port IP Address :10.0.0.1
Port IP Mask :255.0.0.0 Demand Threshold :80%
Port Hop Count :1
Demand Period :5
Port IPX Network :FFFFFFFE
IPX Frame Type :802.2 Idle Threshold :2%
STP Priority :128 Idle Period :20
Line Speed(bits/s):64000 Demand Priority :0
Compression :DISABLED
Scramble :DISABLED Backup Priority :0
Backup/Demand Mode:NONE Backup Alert :ENABLED
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^G - Main menu
^E - Submit ^L - Prev menu
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Highlight the choice for Compression and change the setting to DISABLED The Line Speed should be set to match the speed that the line is being clocked at, though if it is mismatched it will not keep the WAN Port from coming up. Enter Ctrl-E to submit changes and then type "SAVE" to save the configuration.
First perform a loopback to the local DSU/CSU by placing the local DSU/CSU into a DTE loopback or local loopback. The DSU/CSU will loop traffic received on its DTE port back to the AB500. The AB500 constantly sends HDLC frames on the link. This traffic will be looped back to the AB500 and can be monitored by examining the WAN port. If the AB500, the Cable and the DSU/CSU are all working properly the RX and TX statistics should be incrementing in step with each other and the error categories should ideally all be zero or at least at very low levels.
If there are a significant number of errors, or TX and RX counters are far off from each other there could be a problem with either the Cable, AB500 or the DSU/CSU. Swap components to isolate the problem.
View the Wan Ports Stats by highlighting the WAN port on the port configuration screen and typing EXam.
V05.02b Lab2 Wan Port Stats 5ESS ISDN Down
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Status : Up In Signals : DSR:DCD:CTS
Physical : None Out Signals : DTR:RTS
RX COUNTERS TX COUNTERS
Octets : 24386 Octets : 24548
Frames : 5908 Frames : 5926
RX ERRORS TX ERRORS
Missed Frames : 0 Discarded Frames : 0
CRC Errors : 0 Underrun Errors : 0
Overflows : 0 CTS Lost Errors : 0
Frames Too Long : 0
Alignment Errors : 0
Abort Sequences : 0
DPLL Errors : 0 Rx Clock Glitch : 0
CD Lost Errors : 0 Tx Clock Glitch : 0
CLear - Clear Statistics
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^G - Main menu
^L - Prev menu
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( co po ex ) Enter command :
If the local loopback is successful and there is still a problem on the WAN link, further testing could be done by running the same local loopback on the AB500 and CSU/DSU on the remote end. IF local loopbacks at each end are successful one knows that both the AB500's are working correctly. A network Loop can be performed to further test the leased line. Place the local DSU/CSU into its normal operational mode. Set the remote DSU/CSU into a Network Loopback mode. Traffic from the local AB500 will traverse the leased line and be looped back by the remote DSU/CSU. Examine the Wan Port Stats again on the AB500. A large number of errors or difference between the TX and RX statistics may indicate a line problem.
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