Probing SS7

SS7 link monitoring isn't just for techies anymore, promised Kevin Keough, INET vice president of new business development. Speaking at the Telestrategies SS7 conference in Arlington, VA, Keough suggested that SS7 is rich with business-related opportunities for carriers that take advantage of it. The industry never really has looked at SS7 as a strategic technology, but local number portability (LNP) is now driving SS7's role to a higher profile, he said.

SS7 is becoming more important to wireless carriers for a couple of reasons.

"One reason is because there are just more of them now than in the past," said Chris Brozenick, TTC product marketing manager.

When there was only one dominant carrier in a particular area, it would have SS7 links going to the local provider. That local carrier would connect its switches to the MTSO switches of the wireless company. According to Brozenick, the wireless company didn't care too much about what happened on that SS7 link.

"They really weren't concerned with the maintenance and monitoring for troubles because the provider in that area would take care of that for them," Brozenick said. "It pretty much worked or didn't work."

If it didn't work, the wireless carrier simply would call the local carrier. Now there are many more competitors vying for the same services. In a particular region, there are multiple companies that actually have to interconnect with each other. For example, if a subscriber is on a Bell Atlantic Mobile phone and wants to call somebody on a Cellular One phone, that gets routed through several different stages. So now SS7 links increasingly are interconnecting with other wireless companies as well. These interconnects are more of the domain of the wireless companies to maintain.

Local Number Portability According to carriers and vendors alike, another reason carriers are probing their SS7 links is LNP. Carriers are required to pass information back and forth that before wasn't a requirement.

"Because of the complexity involved in deploying LNP, the chance of dropping calls or creating delays is greater," said Gary Avery, Hewlett Packard (HP) acceSS7 intelligent network solution product manager. "And in turn, the potential for lower quality of service to customers also is greater."

By monitoring the links to the SS7 network, carriers will be able to identify problems created by the rigors of LNP quickly so they can implement corrective action before their customers notice.

Monitoring the Network SS7 is used to provide call-processing information between switches. The two main functions of SS7 are call setup and enhanced services and database management. However, if SS7 goes down, so does your network; thus, it is vital to monitor your SS7 network.

SS7 link monitoring and surveillance systems originally served the niche market of carriers wanting to check the health of their SS7 networks. They could use probes located at remote sites to unobtrusively gather and process real-time data from signaling links. The processed data would then be transmitted to a central site processor, where the network-wide activity could be correlated and analyzed. It gave service providers the ability to monitor every link, message and call in the SS7 network continuously.

However, there is a lot more data that can be accessed quickly. Carriers are beginning to see that with the right applications, they can use the monitoring system for business applications, not just operations.

Intermedia Communications contracted with INET to deploy a network monitoring and surveillance system at four of its major signal transfer point sites: Chicago; Dallas; and Orlando and Tampa, FL. This allows Inter-media to support a multitude of surveillance, monitoring and business applications by capturing and processing data and managing the SS7 network from a centralized operations center.

IN Apps With IN applications breaking across the horizon, monitoring is a business necessity. Carriers are looking at it as a way to gain a competitive advantage.

"As more and more service providers' revenues are delivered by SS7-based IN applications, the quality, performance and availability of their SS7 networks become even more critical," said Andy Belcher, HP Telecom Systems Division general manager.

So what business applications can SS7 monitoring help with? According to INET's Keough, network surveillance, interconnection billing, data acquisition, fraud, marketing data, statistics and custom applications are just the tip of the iceberg.

Fraud To help carriers in the fraud arena, SS7 gives them the ability to cut and issue partial call-detail records at call setup, while the call is in process and at call completion. It allows them to detect suspicious use of TCAP or features in combination with other factors.

For example, call forwarding from a cellular phone during a long international call might indicate a fraudulent call. Further, it allows carriers to tear down suspicious calls in process before additional revenue is lost. This capability is especially useful to carriers that traditionally are hesitant to disconnect a call or usage until they are certain it is fraudulent.

SS7 network information is so valuable for fraud detection that last year INET teamed with Coral Systems, known for its Fraud-Buster system. The technical alliance allows a carrier to pick up information from the SS7 network using INET's Geoprobe and feed it to FraudBuster, which puts it through its profiling algorithms. Through the development of personalized customer profiles based on the subscriber's typical calling patterns and data collected from the signaling system, FraudBuster immediately can detect suspicious usage. Service providers can target the most pervasive types of fraud, including cloning and subscription fraud.

QoS To assure service quality, carriers can track quality all the way to the customer. Beyond the network-level view, they can collect statistics on specific elements ranging from call completion and setup to conversation time. Carriers also can generate alarms to alert them when performance falls below preset standards.

Last year, Vodafone Ltd., a wireless operator in the United Kingdom, wanted to monitor its quality and reliability.

"Quality of Service (QoS) is a competitive differentiator for mobile operators," said Simon Durrant, HP marketing manager.

Likewise, Finnish wireless carrier Radiolinja Oy also has implemented monitoring.

"Providing a high level of service is uppermost in the minds of executives and engineers at Radiolinja," said Kari Partanen, vice president of technology.

Partanen said the carrier now "pinpoints" the source of problems before they affect customer service. Radiolinja also is using the monitoring and surveillance system to check the deployment of intelligent network services to make sure they are operating properly. Recently, the company experienced an area-code change in Finland. Using the monitoring function, engineers were able to spot and resolve potential problems associated with the changeover.

Customer Information Carriers traditionally are hungry for marketing data but usually lack all that they want. By monitoring SS7 links, carriers can collect more statistics and generate vital reports. (See Figure 1.) Possibilities include call-completion rates, transaction-success rates, call-disposition analysis, complex transaction analysis, 800-call completion and customer-specific performance analysis.

For instance, a wireless carrier could look at a particular switch and at its SS7 link and could tell how many people are making long-distance calls vs. local calls from a particular location. In other words, on an average day, a wireless carrier could see that 30% of users are calling within the local area, 30% are calling long distance, and the rest are calling other cellular phones on the same system. This information would be helpful for marketing purposes as well for engineering, which would let them know when they need to add additional links to the outside world as their volume increases.

According to TTC's Brozenick, a wireless carrier also could see how many times someone is accessing another competitor.

"If somebody from, say, Sprint is calling somebody from Cellular One, Sprint can look at the SS7 link and see how many times a call goes through to Cellular One," Brozenick said. "That might be helpful competitive information."

SS7 monitoring also helps carriers with interconnection billing by reconciling revenue between service providers in recognition of the resources used by each.

In the old model, before the Telecommunications Act of 1996, bill and keep and flat rates typified the interconnection arrangement. Today, carriers use reciprocal compensation and fees based on usage. Because of this new approach, new billing architectures are needed.

Carriers can conduct call-detail- record billing with SS7. It is used to generate bills for trunk termination and SS7 services used by interconnecting service providers. It allows service providers to track usage of voice trunks and delivery of SS7-based services. The call-detail record contains information on trunk activity, origination point code, destination point code, call duration and the services executed.

Probing the Future What is the future of SS7 link monitoring? According to INET's Keough, you can expect other protocols and transports such as ISDN, IP and ATM to be incorporated. With that, carriers will begin to blend the operations functions with maintenance functions. Finally, there will be a correlation of trunk and signaling monitoring.

TTC's Brozenick agrees. For the immediate future though, he sees the benefit mainly for competitive and fingerpointing reasons.

"There are so many different companies now that they are going to be required to do more themselves to figure out exactly what is going on and why the call is not being connected," Brozenick said. "If they want to get a customer back up and running quickly, having their own monitoring capability for SS7 is going to improve that performance."

Everyone agrees that features such as LNP and WIN services will push SS7 monitoring even harder. "One of the disadvantages of improved technology is as the technology gets better, we tend to put more information on less links," Brozenick said. "The way we do that is multiplexing that together. If you can't look at where things are coming from and where they are going, it makes it very hard to troubleshoot."