Cisco SS7 Interconnect for Access Servers Operations

This chapter provides a brief overview of unattended operations and manual control options available on your Cisco SS7 Interconnect for Access Servers Solution.

Unattended Operation

Understanding System Redundancy

The Cisco SS7 Dial Access Solution uses two SC hosts with software-based checkpointing and heartbeat to facilitate redundancy. The call-processing application is active only on one SC host platform at a time and switches to the standby platform under failure conditions. See the "Understanding Automatic Switchover" section.

The Session Manager software on the Cisco SLT manages the communication sessions with the SC hosts. When Cisco SLTs are used with a redundant pair of SC hosts, the Session Manager maintains separate communication sessions with each SC host in the pair. The session between the Cisco SLT and the active SC host transports the SS7 traffic, while the session between the Cisco SLT and the standby SC host provides backup. Upon SC host switchover, the Session Manager on the Cisco SLT must be instructed by the now active (formerly standby) SC host to switch traffic to the now active SC host. Upon switchover, all calls answered in progress are preserved.

Note

Full system redundancy is available only on continuous service configurations.

Understanding Automatic Switchover

The Cisco SS7 Dial Access Solution offers the continuous service configuration to protect your system against failures and downtime. A feature enhancement to Redundant Link Manager (RLM) (Version 2) provides redundancy at the link and signaling controller level for added switchover. When each RLM group has multiple signaling controllers associated with a NAS, a signaling controller priority and link priority are examined by the RLM client (RLM software on the NAS) during switchover, ensuring improved control handling.

The switchover system consists of two signaling controllers (either dual Sun E450s or Sun Netras) connected through IP, as shown in Figure 3-1. One SC functions as the active host, while the other SC functions as the standby host. The switchover system provides a seamless transition to the standby host in case of system failures.

The active host maintains communications between the active and standby hosts. The standby host constantly checks the active host for new and changed configurations and updates itself on a regular basis. When the standby host becomes the active host, its configuration mirrors that of the former active host without losing the link with the NAS, thus preserving calls.

System Messages

The Cisco Signaling Controller software generates system messages that provide you with call processing, management, configuration, and alarm status.

After you enter an MML command, one of the following messages is generated: MML status, MML error code, auto-generated or autonomous, and alarm.

The Portable Execution Environment (PXE) logging system outputs messages to log files determined during the client initialization period.

The PXE log server software takes messages initiated by various applications (other software processes) within the Cisco signal controller software, formats the messages, and outputs them to the appropriate files. The PXE log server also adds a time stamp, an application identifier (also known as a service ID or service name), a process identifier (that is, the UNIX process), and a log level.

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Cisco Signaling Controller console messages generated by the UNIX operating system

For detailed information about system messages, see the Cisco Media Gateway Controller Software Release 7 Reference Guide at the following location:

Call Detail Records

CDRs comprise call data elements (CDEs). The CDE is the data element (field) that includes a basic information field within a billing record. Examples of CDEs are the calling number, called number, and so on. The call data block (CDB) consists of several CDEs, related to a certain point in call (PIC).

New data elements are added to the CDBs as a result of Cisco signaling controller system enhancements. For detailed information about CDEs and CDBs and an overview of the Cisco Signaling Controller billing system, see these Cisco SS7 Interconnect for Access Servers Solution documents:

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Cisco Media Gateway Controller Software Release 7 Operations, Maintenance, and Troubleshooting Guide at the following location:

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Cisco Media Gateway Controller Software Release 7 Installation and Configuration Guide at the following location:

Disk Mirroring

Disk mirroring is a feature that duplicates the information contained in a file system by using two disk partitions located on separate physical disks. In the event of a physical disk failure, the file system continues to operate using the unaffected disk.

Disk mirroring is used on fault-tolerant configurations with the Sun Netra t 1400 server platform. This feature increases the availability of the Cisco SC2200 by keeping the system operating when a physical disk fails—a mirrored disk can be removed and replaced while the system remains active. With redundant SC hosts using disk mirroring, a single disk failure does not cause switchover, as described in the "Understanding System Redundancy" section.

The Sun Volume Manager software running on your Cisco SC2200 provides this feature in a transparent manner so that the application software does not know that there are multiple disk partitions making up the file system.

For detailed information about how to install disk mirroring through Volume Manager, see the Cisco Media Gateway Controller Software Release 7 Installation and Configuration Guide at the following location:

Note

Disk mirroring is optional on the Sun Netra t 112x and Sun Ultra E450 server platforms.

Manual Control Options

The Cisco Signaling Controller includes two tools that you can use to provision the software: the Cisco MGG Manager (CMM) graphical user interface (GUI) application and the Man-Machine Language (MML) Command Line Interface (CLI) application.

CMM makes provisioning easier for less-experienced administrators by listing all the components that need to be configured and by providing windows that display all configuration parameters for each component. Instructions for provisioning with CMM can be found in the Cisco Media Gateway Controller Software Release 7 Provisioning Guide at the following location:

http://www.cisco.com/univercd/cc/td/doc/product/access/sc/rel7/soln/das/provgde/index.htm

Although MML provisioning requires more keystrokes, quick provisioning updates can sometimes be made faster with MML commands, because you don't have to go through the process of launching CMM. When you enter MML commands into a batch file, you can copy and paste configuration commands to speed command entry, and you can copy and modify MML scripts to configure additional Cisco MGC switches. For information on provisioning with MML, see the Cisco Media Gateway Controller Software Release 7 Provisioning Guide.

You can use both CMM and MML to provision the Cisco Signaling Controller. However, you can use only one of these tools at a time for actual configuring. Table 3-1 lists some of the features of CMM and MML and provides guidelines for selecting between the two tools

Table 3-1 TCM and MML Features
Specifications/Features	CMM	MML
System Basics	X-windows GUI front end, SNMP back end	CLI that interacts directly with the Cisco Signaling Controller.
System Hardware/Software Requirements	SC host server running Sun Solaris 2.6 OS Running the CMM on the same server as the Cisco Signaling Controller can adversely impact performance. Cisco recommends using a separate server.	Runs on the SC host server.
Batch File Support	No	Yes
Level of Network/Telephony Experience Required	Little experience required; very easy to use.	Requires a high level of experience with MML and the Cisco Signaling Controller software.
Best Used For	•Setting up a single configuration or few configurations on individual SC host servers. •Modifying an existing configuration.	•Creating batch files to configure many SC host servers or retrieve measurements. •Modifying configurations (experienced users). •Scaling large configurations.

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