Troubleshooting guide

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Cisco PGW 2200 Softswitch Release 9.8 Operations, Maintenance, and Troubleshooting Guide
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Chapter 6 Troubleshooting the Cisco PGW 2200 Softswitch Platform
Resolving SS7 Network Related Problems
Ensure that the MTP2 timers and thresholds match the network defaults. Confirm that the far-end switch
or STP has the same values as your system.
When you use a Cisco ITP-L to terminate MTP2, confirm that the RUDP parameters match on both sides
and are consistent with the documentation.
Supporting Entity Failures
An SS7 signaling link has a hierarchy of network element entities that must be functioning before the
link can function. The entities include the physical interface (discussed previously) and the control
software for the link. If any of these entities fail, the link also fails.
Incomplete Signaling
The following problems can cause a link to fail between the Cisco ITP-L and the Cisco PGW 2200
Softswitch.
• Ethernet card failure on the Cisco ITP-L
• Ethernet card failure on the Cisco switch
• Cisco switch failure
• Fast Ethernet interface card failure on the Cisco PGW 2200 Softswitch
In each of the preceding cases, it is impossible to transfer MTP3 signaling messages from the Cisco
ITP-L to the Cisco PGW 2200 Softswitch. Cisco ITP-L platform failure (which is equivalent to MTP2
failure) prevents signaling messages from going to MTP3. The MTP2 layer on the Cisco ITP-L is
supposed to send SIPO messages to the STP mated pair to start the changeover procedure. The mated
STP pair, which detects timer expiration and link unavailability, detects Cisco ITP-L platform failure on
the SS7 network.
Changing Service States
Signal channels comply with the Generic Service State model that is defined in the “Physical Layer
Failures” section on page 6-98. You can change the service state of a signaling channel by using the
following transition requests. Note that there is a difference between a desired service state and an actual
service state, and the Cisco PGW 2200 Softswitch might not be able to honor the request. For example,
a signal channel that is out-of-service because of an equipment failure cannot transition to an in-service
state upon request. The Cisco PGW 2200 Softswitch attempts to bring the channel in-service, but it fails.
You must resolve the failure before the transition can succeed.
• In-service (IS)—Signaling channel is requested to start providing service.
• Out-of-service (OOS)—Signaling channel is requested to stop providing service.
For some protocols, the system accepts this request, but does not grant the request until after all calls
have been released. During the interim period, the channel service state appears as OOS, PEND.
• Forced out-of-service (FOOS)—Signaling channel is requested to stop providing service
immediately, regardless of related call states, and to drop currently active calls.
• Inhibit (INH)—Signaling channel is requested to transition to an inhibit state. This state is for SS7
signaling channels only and fails on other types of signaling channels.
In this state, the channel is active but does not provide service for call processing. If the signaling
channel is the last one in the signal path, the system denies the inhibit request and returns an error.