SS7 Assurance

With churn on the rise, many carriers are using value-added features such as SS7 IN-based services to differentiate and build customer loyalty. To implement these applications, you must add an IN node or a service control point, which increases interoperability problems, SS7 traffic and adds to the complex network.

All of this activity puts more demand on your network and increases the risk of failure.

Because service disruption plays a key role in service quality, your network must be able to support these additional demands. You need tools to support new network nodes and to battle all of these problems, including corrupt or overloaded databases and switches, and lost SS7 messages.

An efficient SS7 link-monitoring system (LMS) can arm you with the best tools to identify and troubleshoot these problems and faults as quickly as possible. LMS tools are your defense against SS7 network and interaction problems.

LMS BASICSLMS is a built-on architecture that mines SS7 traffic. It is independent and separate from the switching fabric, which allows it to provide valuable information, unaffected by other network failures.

LMS probes and computers read and process SS7 messages. These probes, deployed at signal transfer points or switching sites, provide real-time details regarding network status and execution.

LMS tools reduce the time it takes to identify and analyze problems. They provide real-time data and do not require setup simulation to reproduce and target the problem.

They also minimize the need for SS7 experts. Today's network engineers and operations teams already are shouldering additional demands, especially with SS7-skilled technicians in short supply. Without skilled support staff, network problems can affect call-completion rates, the time it takes to resolve faults and network delays.

But high-quality LMS applications are user-friendly and do not require SS7 experts to solve complex problems. With SS7 tools, all maintenance and surveillance is centralized to one location -- allowing technicians to work closely to solve problems faster and maintain a network-wide view of SS7 links.

An effective LMS features a variety of applications, including fraud identification and wholesale billing creation and verification. But surveillance applications such as call trace, protocol analysis, measurement and black-box recorders are the main drivers for implementing LMS.

Call-trace applications trace calls and procedures for a particular call. They are one of the most important surveillance features. They correlate different types of calls and procedures into one sequence. This parallel view is an essential element of call-trace applications.

Protocol-analysis tools are critical because they capture and analyze SS7 messages. They debug low-level SS7 problems. These low-level faults tend to be multiple-vendor environments that experience many interoperability problems.

The measurement package counts applications for the SS7 network. It delivers valuable information to solve network problems, and provides long-term storage for trending and predicting network growth. For example, a measurement package can help provide valuable usage metrics and quality of service about new features.

The black box records all or some SS7 messages to disk for off-line analysis. A black box SS7 recorder allows you to analyze messages before or after a major network problem, such as a connection loss to a roaming partner. In addition, if a subscriber calls the customer-service bureau to report a problem that occurred days earlier, you can use the black box recorder to analyze the SS7 messages from that time period.

SS7 SUPPORTThese LMS functions allow you to deploy advanced services confidently. You can use SS7 LMS to pro-actively manage and monitor services such as private numbering plans (PNPs). With a PNP, an IN node such as the HLR translates the number dialed. Then, the MSC continues the call as if the subscriber had dialed the IN-node number. A subscriber can dial "1234" to call a work colleague rather than dial the whole number. SS7 supports the conversation between the MSC and the IN node. If this service fails, the call isn't completed.

A LMS will monitor and measure the PNP service quality in real time. If service drops below an acceptable level, the system alerts operations so that you can troubleshoot the problem. You can use call trace to debug the problem. You can use the application while on the phone with a subscriber and monitor the SS7 in real time.

Without SS7 LMS, you may know that service quality dropped but probably won't have critical information about the source or why it happened -- usually because it requires call-processing power to store and display this information. This extra information is vital. When real-time data is available, the time to resolve problems drops dramatically compared with traditional protocol-analyzer boxes that have to be sent to a site and configure d.

Pro-active network planning can minimize the risk of service failure. Protocol analysis enables you to trace problems quickly to a faulty network element. You can troubleshoot mobile terminated calls and roaming failures as well as advanced service problems such as short-message-service failures.

MEETING NEEDSBut all LMS tools are not created equal. You need to make sure your monitoring system is up to the challenges of today's network demands.

Because you never know where a subscriber is located in the network, it is critical that the LMS provides a true network-wide view. In addition, since even a simple call in a network requires a complex series of events and ISUP and TCAP (IS-41) messages to flow across the network, it is important that LMS can correlate all of these messages and events into a single sequence.

You also should consider integrating the LMS into an overall alarm-management system, so you have the ability to take alarms and events from the LMS. The alarm-management system can integrate these additional alarms alongside alarms from the network elements.

Because the size and complexity of a network will continue to grow as subscriber numbers increase and as you add new services and features, it is important to select a LMS system that can be scaled and expanded to meet these new challenges easily.

As traditional telecom and datacom technologies become interchangeable, LMSs will have to evolve as well. This technology shift will change the paradigm from a voice focus to enhanced service and data focus. You will need information and tools that satisfy these service requirements.

The system also should be able to handle network protocol changes and updates at the lowest level in the system. The applications should not require major software changes.

INTEGRATIONA LMS is a complex system of hardware and software elements. The hardware always will have some type of data probe to non-intrusively gather signaling messages from the SS7 links. These probes are located in card cages beside first-level processing cards and communications cards. The communications cards transfer data across a LAN to the remote site processor. Each remote site communicates over a wide area network (WAN) to the central site processor. Various software components such as timing, synchronization and time-stamping are distributed throughout the system.

Because the LMS system is complex, deployment requires more than just simply installing the components and turning up the system. A small system could take between three to six months to deploy and a larger system up to a year to deploy across the entire network. You need a tight project-management team to monitor the program. In addition, close cooperation between the system vendor and network and IT groups (for LAN and WAN provisioning) is critical for successful deployment.

Once the system is installed, you will have to fit LMS tools into existing work practices and processes or, in some cases, develop completely new processes. For example, you will have to decide the best way to integrate the LMS application into your current customer-care and first-level support. You also will need to integrate the LMS system with other O&M systems to help correlate alarms and performance information. Usually, you can achieve this by using protocols such as SNMP, Q3, CMIP and CORBA.

THE PAYOFFIn the end, all of these efforts will prove worthwhile. After all, providing the best quality and innovative services is critical in today's changing industry. A SS7 LMS can provide the necessary protection as you deploy new services. An appropriate system will allow you to implement and maintain SS7-based services confidently.