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Table Of Contents
Understanding System Redundancy
Understanding Automatic Switchover
Solution Operations
This chapter provides a brief overview of unattended operations and manual control options available on your Cisco SS7 Interconnect for Voice Gateways Solution. It includes the following sections:
Unattended Operation
The following operations are described in this section:
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Understanding System Redundancy
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Understanding System Redundancy
The Cisco SS7 Interconnect for Voice Gateways Solution uses two SC hosts with software-based checkpointing and heartbeat to facilitate redundancy. The call-processing application is active on only 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 to switch traffic to the now active SC host. On switchover, all calls answered in progress are preserved.
Note
Understanding Automatic Switchover
The Cisco SS7 Interconnect for Voice Gateways Solution offers the continuous service configuration to protect your system against failures and downtime. A feature enhancement to 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 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.
Figure 3-1 Switchover Processes on the Signaling Controller Hosts
System Messages
The Cisco Signaling Controller software generates system messages that provide you with call processing, management, configuration and alarm status.
Status messages include these types:
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After you enter an MML command, one of the following messages is generated: MML status, MML error code, auto-generated or autonomous, and alarm.
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The Portable Execution Environment (PXE) logging system sends 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 Signaling Controller software, formats the messages, and sends 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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For detailed information about system messages, see these Cisco SS7 Interconnect for Voice Gateways Solution documents:
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Call Detail Recording (CDR)
CDRs are comprised of 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 results from Cisco system enhancement or from special customer-oriented CDB design. For example, a new TLV (Time, Length, and Value) element is added to comply to NTT (Nippon Telephone and Telegraph) CDR requirement.
For detailed information about CDEs and CDBs and an overview of the Cisco Signaling Controller billing system, see these Cisco SS7 Interconnect for Voice Gateways Solution documents:
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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 140x 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 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.
Note
Manual Control Options
The Cisco Signaling Controller includes two tools that you can use to provision the software: the Cisco MGC 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 TCM Provisioning Guide.
Although MML provisioning requires more keystrokes, quick provisioning updates can sometimes be made faster with MML commands, because you do not have to go through the process of launching CMM. MML commands entered into a text file can be batched from the UNIX command line to speed up provisioning, and you can copy and modify MML scripts to configure additional MGC switches. For information on provisioning with MML, refer to the Cisco Media Gateway Controller Software Release 7 MML 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.
Posted: Thu Oct 14 10:10:27 PDT 2004
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