Troubleshooting guide

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Cisco PGW 2200 Softswitch Release 9.8 Operations, Maintenance, and Troubleshooting Guide
OL-0800-14
Chapter 6 Troubleshooting the Cisco PGW 2200 Softswitch Platform
Resolving SS7 Network Related Problems
• Uninhibit (UNH)—Signaling channel is requested to be removed from an INH state and to provide
service for call processing. This state is for SS7 signaling channels only and fails on other types of
signaling channels.
Use this option (UNH), rather than the IS option, to return an inhibited signaling channel to service.
Note Changing the state of a signaling channel generates an alarm. For more information on retrieving and
clearing alarms, see the “Troubleshooting Using Cisco PGW 2200 Softswitch Alarms” section on
page 6-3.
Signaling Destination Problems
Signaling destinations refer to the endpoints of a network. Typically, if signaling links are in service, the
signaling destinations should also be in service.
For ISDN signaling, the signaling channel is in service if the Cisco PGW 2200 Softswitch can
communicate with the media gateway and ISDN backhaul is configured. The destination is in service if
the signaling channel is in service and the remote ISDN device is in service.
Apparent mismatches can occur because of:
• SS7 traffic restart processing (TRW/TRA)
• SS7 STP problems
• Configuration problems
• Software problems
The Cisco PGW 2200 Softswitch regards an SS7 STP as an adjacent point code (APC). SS7 MTP uses
a message exchange called Signaling Link Test Message (SLTM)/Signaling Link Test Acknowledgment
(SLTA) to confirm that the far-end point code is the one configured. The SLTM consists of the
originating point code (OPC) of the Cisco PGW 2200 Softswitch, an APC number, and an SS7 network
indicator. If the values for these parameters match with the values used at the far-end switch, an SLTA
is returned. If the value for any of these parameters does not match, the far-end switch does not send an
SLTA. The Cisco PGW 2200 Softswitch drops the link and tries to realign it. This process continues until
the SLTM parameters match on both sides. The symptom of this problem is SS7 links dropping and
recovering in roughly 30-second cycles (this symptom is referred to as bouncing).
The following sections describe signaling destination problems:
• Bouncing SS7 Links, page 6-101
• Configuration Errors, page 6-101
• Traffic Restart, page 6-102
• SS7 Destination is Out of Service, page 6-102
• SS7 Route is Out of Service, page 6-102
• SS7 Destination is Unavailable, page 6-103