Troubleshooting guide

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Cisco PGW 2200 Softswitch Release 9.8 Operations, Maintenance, and Troubleshooting Guide
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Chapter 1 Cisco PGW 2200 Softswitch Platform Overview
Cisco PGW 2200 Softswitch Software Architecture
• Connection manager—Interfaces with the nodes and protocols external to the Cisco PGW 2200
Softswitch that are necessary to establish an IP (TCP, UDP, or RUDP) or PSTN connection that is
managed by the Cisco PGW 2200 Softswitch. The types of nodes supported are:
– VoIP/VoATM trunking gateways using MGCP.
– Time Domain Multiplex (TDM) trunking gateways using MGCP.
• Call manager—Contains and selects the appropriate protocol adapters. These are protocol-specific
entities that perform the following functions:
– Communicates with the corresponding protocol-specific IOCC.
– Converts incoming protocol data units (PDUs) received from the IOCC to an internal, protocol
independent format.
– Converts internal, protocol-independent PDUs to protocol-specific format.
– Communicates current circuit states to the IOCM using the IOCCs.
– Creates a call instance when an incoming call message is received.
– Destroys that instance and frees any associated memory when the call is terminated.
– Supports multiple call instances. It processes incoming messages from the event dispatcher
queue and routes them to the call instance for which they are destined.
– Generates call detail blocks (CDBs), which are used to create CDRs.
– Operates as a standby entity, which is created when the call engine is created at system startup,
and waits to create a new call, destroy an existing call, or process an event for an existing call.
– Checkpoints call information, such as call signaling state and data, to the standby Cisco PGW
2200 Softswitch to guarantee that the signaling link is not lost during a manual or automatic
switchover.
Call Instance Component
A call instance is the dynamic component of the Cisco PGW 2200 Softswitch that is created at run time
and is the place where call processing takes place. The call instance is commonly referred to as the
Message Definition Language (MDL) component, which is the language used to implement it.
The system creates a call instance when it receives an incoming call message. There is always a
one-to-one relationship between a call instance and a call switched by the Cisco PGW 2200 Softswitch.
There are several significant subcomponents involved in a call instance:
• Originating call control (OCC)—Instance of the originating protocol’s state machine. In defining a
protocol, two MDL modules are created:
– General declarations module, which contains protocol-specific types and definitions.
– Protocol definition module, which contains the state logic for two state machines—one for call
origination and one for call termination. This module produces an object file named
protocolName.mdo.
• Universal call model (UCM)—Protocol-independent state machine that is used to:
– Provide protocol interworking between the originating and the terminating sides of the call.
– UCM MDL module is used to define the UCM behavior and logic. The UCM module is
compiled into an object file, but can only be loaded by the Call Engine and cannot be used by
any of the protocols.
– Provide event-driven logic, which controls the following call-processing functions: