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
Troubleshooting Overview
The following sections present solutions to various equipment failure scenarios:
• Cisco ITP-L Failure
• Cisco PGW 2200 Softswitch Failure
• Operating System Failure
Cisco ITP-L Failure
Each Cisco IP Transfer Point LinkExtender (ITP-L) has a Reliable User Datagram Protocol
(RUDP)/User Datagram Protocol (UDP)/IP connection to each Cisco PGW 2200 Softswitch for the
transfer of Message Transfer Part (MTP) Level 3 (MTP3), ISDN User Part (ISUP), and Transaction
Capabilities Application Part (TCAP) information. A Cisco ITP-L platform failure causes the surviving
Cisco ITP-L platforms to take over the distribution of messages to the active Cisco PGW 2200
Softswitch. You should provision Cisco ITP-L platforms so that half of the platforms can support the
entire signaling load. A single Cisco ITP-L platform failure should not have a significant effect on call
processing.
There are several Cisco ITP-L failure scenarios to consider:
• IP link failure between the Cisco ITP-L and the Cisco PGW 2200 Softswitch, which indicates that
it is impossible to transfer MTP3 messages. In this case, MTP Level 2 (MTP2) transmits Status
Indication Processor Outage (SIPO) messages to the signaling transfer point (STP) to begin
switchover to another Cisco ITP-L.
• If MTP2 failed (equivalent to a Cisco ITP-L failure), no SIPO messages are sent because MTP2 is
inoperable. Instead, the mated STP pair detects the failure because of timer expiration or link
unavailability and starts the switchover to another SS7 link.
• If a Cisco ITP-L timer detects a Cisco PGW 2200 Softswitch fault, a coordination mechanism causes
SS7 messaging to flow to the newly active (formerly standby) Cisco PGW 2200 Softswitch. The
standby Cisco PGW 2200 Softswitch assumes control for all calls in progress and all new calls.
Cisco PGW 2200 Softswitch Failure
Cisco PGW 2200 Softswitches run in active-standby mode. The call-processing application is active on
only one Cisco PGW 2200 Softswitch at a time, and the application switches to the standby platform
when a critical alarm occurs. Consequently, a Cisco PGW 2200 Softswitch failure and switchover events
are invisible to the SS7 signaling network.
Cisco PGW 2200 Softswitch alarms can be minor, major, or critical. Critical alarms are generated
whenever any significant failure occurs. Any critical alarm causes a switchover to occur. For example,
if the call engine or I/O channel controller (IOCC)-MTP in the active Cisco PGW 2200 Softswitch fails,
there is a disconnection from the process manager and a switchover to the standby Cisco PGW 2200
Softswitch.
Operating System Failure
An operating system or hardware failure in the active Cisco PGW 2200 Softswitch can also cause a
switchover to the standby Cisco PGW 2200 Softswitch. The failover daemon in the standby Cisco PGW
2200 Softswitch detects the failure of the active Cisco PGW 2200 Softswitch and instructs the process
manager to start a switchover. The standby Cisco PGW 2200 Softswitch then takes over all
call-processing functions. The switchover is transparent to all Cisco ITP-Ls.