Troubleshooting guide

B-15
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 Cisco PGW 2200 Softswitch Communications
Cisco ITP-Ls package received SS7 message data into RUDP datagrams that are transmitted through the
LAN switches onto the Cisco PGW 2200 Softswitch. This process is reversed (Cisco ITP-L strips RUDP
datagrams) as the Cisco ITP-Ls add standard SS7 message framing when the Cisco PGW 2200
Softswitches send SS7 messages to the Cisco ITP-Ls.
If a tested SS7 link has connectivity (MTP1) and alignment (MTP2), but network management tools
report SS7 error messages, there is probably an MTP3 or higher layer SS7 communication problem. This
problem requires testing to verify Cisco ITP-L operation.
Figure B-4 MTP3 and Higher-Layer SS7 Protocol Processing
Resolving MTP3 and Higher Layer SS7 Communication Problems
Coordinate a signaling link test of the SS7 transceive path within the system, excluding connectivity to
distant end SS7 nodes. Use a recommended SS7 protocol analyzer to send SS7 messages to the suspected
Cisco ITP-L while monitoring the output of the Cisco ITP-L with a recommended protocol analyzer. If
the test does not discover an MTP1 (connectivity), MTP2 (link alignment), or MTP3 or higher layer
problem, the problem probably is not the Cisco ITP-L.
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 your protocol analyzer generates, which could cause error
conditions between the Cisco PGW 2200 Softswitch and the media gateway.
Identifying Ethernet Connectivity Problems
SS7 message components are Ethernet framed and transceived through one of the two Cisco ITP-L
Ethernet 10BASE-T ports. A physical break or a virtual break prevents a percentage of messages from
traveling along the Cisco PGW 2200 Softswitch path (Cisco ITP-L-to-switch-to-Cisco PGW 2200
Softswitch). Use the ping utility to perform echo response tests. The ping utility should identify Ethernet
connectivity problems within these components.
44251
MTP3
ISUP
MTP1
MTP2
MTP3
ISUP
MTP1
MTP2
STP to ITP-L to Cisco PGW 2200
MTP3 and higher layer SS7 protocol data processing
Cisco PGW
2200
ITP-L1
SS7 network