Troubleshooting guide

B-13
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
Step 4 Test Cisco ITP-L ports and hardware by conducting a loop test of the signal link, excluding connectivity
to the distant-end SS7 node and the LAN switch.
If the test does not discover an MTP1 problem, the MTP1 problem likely resides within the STP node or
the connection to the STP node.
Step 5 If the problem is within the Cisco ITP-L, replace the unit.
MTP2 Communication Problems
The next two sections describe the procedures for identifying and solving MTP2 communication
problems.
Identifying MTP2 Communication Problems
MTP2 standardizes SS7 signaling link alignment. MTP2 communication problems occur when
Cisco ITP-Ls cannot establish data link alignment with STPs. When this misalignment occurs, the FISUs
and MSUs cease to be transmitted.
Whenever an SS7 link has good physical connectivity (MTP1), but cannot align to send and receive
either FISU or MSU traffic, LSSUs replace the FISUs and MSUs.
Figure B-3 Data Link Layer, MTP2 Communication Problem
Resolving MTP2 Communication Problems
If monitoring of the SS7 link with a protocol analyzer reveals no MSU or FISU message traffic (only
LSSU traffic), complete the following steps:
Step 1 Check to ensure that the signal link cabling is correctly connected to the Cisco ITP-L.
Step 2 Disconnect the Cisco ITP-L from both the STP and the LAN switch for offline testing. Connect two
recommended SS7 protocol analyzers.
One SS7 protocol analyzer must be equipped to send SS7 test messages to (and 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 messages from) the Cisco ITP-L over the IP interface.
27328
ITP-L1
MSUs
FISUs
SS7 signaling link
out of alignment
LSSUs
STP
MSUs
FISUs
Data Link Layer
MTP2 communications problem