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B-12
Cisco PGW 2200 Softswitch Release 9.8 Operations, Maintenance, and Troubleshooting Guide
OL-0800-14
Appendix B Troubleshooting Cisco ITP-L Signaling
Troubleshooting Cisco ITP-L-to-STP Signaling Links
MTP1 Communication Problems
The next two sections describe the procedures for identifying and solving MTP1 communication
problems. The initial indication of signaling problems may change in T1 (or E1) status. Check for alarms
on the T1 (or E1) interface before performing any of the following procedures.
Identifying MTP1 Communication Problems
MTP1 standardizes SS7 signaling link physical connectivity. When an MTP1 problem occurs, there is a
physical connection break or a virtual break (something that causes the symptoms of a physical
connection break, such as no power to a card slot) in the signaling link path. A break is identified when
no Message Signaling Unit (MSU), Fill-In Signaling Unit (FISU), or Link Status Signaling Unit (LSSU)
traffic can be sent or received over the SS7 link. MTP1 communication problems are normally the result
of either a hardware failure, a cabling problem, or a physical interface problem.
Figure B-2 Physical Layer, MTP1 Communication Problems
Resolving MTP1 Communication Problems
If monitoring the SS7 link with a protocol analyzer reveals no MSU, FISU, or LSSU message traffic,
complete the following steps:
Step 1 Ensure that power is on to the Cisco ITP-L.
Step 2 Check to ensure that the STP signal link cabling is connected correctly to the Cisco ITP-L.
Step 3 Disconnect the Cisco ITP-L from both the STP and the LAN switch for offline testing. Connect two
recommended SS7 protocol analyzers, one to the STP interface the other to the IP interface.
One SS7 protocol analyzer must be equipped to send SS7 test messages to (or receive SS7 test messages
from) the Cisco ITP-L over the V.35 interface. The other SS7 protocol analyzer sends SS7 test messages
to (and receives SS7 test message from) the Cisco ITP-L over the IP interface.
Caution Do not leave the Cisco ITP-L connected to the LAN switch, and thus the Cisco PGW 2200 Softswitch,
while injecting SS7 test messages into the Cisco ITP-L. The Cisco PGW 2200 Softswitch might not
properly recognize the SS7 test messages that the protocol analyzer sends, which could cause error
conditions between the Cisco PGW 2200 Softswitch and the Cisco Media Gateway.