The network that's never done: SS7 networks have become pervasive enough that some carriers no longer view them as an investment priority. But a new wave of applications and competitors will challenge this notion Transmission special

The quiet period is over for SS7. Investment in the standard network signaling architecture began to dwindle sometime in the last several years, after many local exchange carriers satisfied regulatory requirements for establishing two signal transfer points per LATA.

Carriers began to talk about how they were finished building their SS7 networks. It was time to move on to something else--digital subscriber line (DSL), asynchronous transfer mode or optical architectures.

But in the last few years, the story has changed. Competitive LECs have emerged, and to operate, they will need to either lease SS7 capacity from incumbent carriers or build their own SS7 architectures.

Another implication of competition, number portability, greatly increases the potential use of SS7 networks. In addition, the ongoing development of new, enhanced services applications requires quick and reliable SS7 routing capabilities. As the variety and popularity of these applications increase, SS7 dips and handoffs will occur in a much more complex network environment than they do now.

These trends will require carriers to rely on their SS7 networks as much as they have in the past, if not more. Managing SS7 traffic, access and network expansion will become key to maintaining network availability, capacity and flexibility. However, the industry will have to keep an eye on potential SS7 improvements and adjustments. Although SS7 architectures have become the trusty and much-needed signaling underpinning of the public network, they will continually have to be integrated with more advanced network technologies, such as ATM, that are capable of changing the role of SS7 and even boosting its value.

The changing SS7 market

Investment patterns for SS7 architectures may not be what they used to be, but that does not mean market opportunities are any worse off because of it.

The carrier industry still spends about $2 billion annually on SS7 network construction and related equipment.

However, there has been a dramatic shift in which carriers are spending that money as well as in their reasons for spending it. The SS7 market has shifted from traditional LECs that built out large SS7 networks exclusively for basic call signaling functions to facilities-based CLECs that are building out highly advanced networks from scratch. Many smaller interexchange carriers hoping to increase their presence also are investing.

"Originally, the whole SS7 market was [the Bell regional holding companies]. The resurgence we're seeing now is non-[RHC]," says Lee Smith, senior director of marketing for the network switching division at Tekelec.

While non-RHC could mean CLECs, international operators and even wireless providers, many vendors see most of the new investment coming from IXCs and foreign PTTs, with CLECs and wireless carriers showing great interest but no commitment yet.

For CLECs, SS7 currently may be a matter of personal choice. Many of them are choosing the less debt-laden, short-term option of leasing SS7 capacity.

For the traditional owners of SS7 networks--RHCs, GTE and a handful of regional and national SS7 network operators--the leasing trend represents a huge short-term revenue opportunity, and it pays for those operators to have reliable, expansive SS7 networks in place.

To meet the demand, these carriers must move from the traditional operational model to that of wholesale/retail operators, and they will need applications that address the billing requirements of unbundling their SS7 networks to resellers, says Andy Belcher, general manager for SS7 at Hewlett-Packard.

"They can bill out usage of SS7 services that have been unbundled. This is a huge revenue opportunity. They can also accurately measure billing through SS7 to bill other operators for incoming calls to their networks," he says.

Some traditional carriers are recognizing a need to invest in second generation SS7 equipment, upgrading their networks to handle new, more demanding applications such as local number portability, enhanced services, fraud detection and billing data carriage. "Their first generation architectures are starting to get turned out for upgrades," says Tekelec's Smith.

While incumbent LECs and CLECs are leading SS7's market resurgence, wireless carriers are not to be outdone. Although more than 90% of SS7 traffic was moved over wireline-to-wireline connections a few years ago, wireless applications and wireless network interconnection needs are now having a huge effect, Smith says.

For instance, a typical wireless call might require 14 or more SS7 messages for a network-to-network handoff. This is more than twice as many as the average wireline call.

With wireless network coverage becoming more extensive and with the growing potential for wireless local loop access finally near, timely SS7 investment will be key to ensuring wireless service reliability and performance.

"Wireless and wireline network integration via SS7 is a big driver of the market," says Patrick Donnelly, director of product management at Newnet.

The search for competitive differentiation in the wireless market also has helped create many new applications that rely on SS7 transmission.

As SS7-related investment explodes in these many corners of the industry, the beneficiaries are vendors of SS7-related infrastructure such as signal transfer points, service control points (SCPs), databases, workstation servers, routing software, and management and monitoring probes and systems. Many of them, such as Inet, Tekelec, Newnet, HP, Stratus and DGM&S, are old hands at SS7 and have spent the last few years broadening their product lines to address new needs for SS7 traffic management and applications support.

Others, such as Microsoft and Trillium, are new to the business. They are using the resurgence of opportunity in the SS7 market as a foundation for addressing a wider range of public network needs.

Microsoft, for instance, had dallied with the public network market for years as it tried to position the Windows NT server and operating software as a public network solution. What the software giant may have lacked was an approach based on satisfying fundamental public network needs. At this year's Supercomm, Microsoft changed course and targeted NT's flexibility in developing applications for the critical and fast-changing world of SS7.

The company aligned with market stalwart DGM&S to gain the SS7 proficiency it lacked, and the two companies are well on the way to porting DGM&S' Omni SignalWare software to the NT platform (Figure 1).

"Carriers have recognized that their SS7 networks are a huge asset that [needs] to be fully developed to [its] potential. The maturity of our platform is there now to support the fundamental elements of the public network infrastructure," says Bill Anderson, director oftelecom industry sales and marketing at Microsoft.

Services and SS7 The old and new vendors of the SS7 market are rushing to support a new generation of applications, the most notable of which is local number portability. "Local number portability is probably the single biggest driver of SS7 investment right now," says Newnet's Donnelly (Figure 2).

Local number portability trials were in the news even before deregulation took hold last year. The industry has long debated how to implement local number portability, and trials of various portability methods have occupied carriers and vendors for the better part of the last two years.

One thing is certain. Local number portability applications will increase SS7 traffic by the hundreds. Some solutions for local number portability will require a query of SS7 databases for every call made. Even if queries are limited to calls to ported exchanges, most carriers' SS7 architectures still require capacity-enhancing SS7 infrastructure expansions.

"Carriers try to grow into their services, and some of them might have modest expectations, but they will have to invest in more SS7 capacity," says Paul Osborn, business development manager for OSS and decision support systems at Stratus Computer.

Much of this work is being done now, as carriers hustle to reach the March 31, 1998, regulatory deadline for having local number portability capability in the largest metropolitan area of each Bell company region and the Dec. 31, 1998, deadline for the top 100 metropolitan areas nationwide. "There is a lot of [local number portability] activity right now, with deployment, testing and integration," says Tekelec's Smith. "Everyone is waiting to see what kind of impact it will have."

It remains to be seen how pervasively SS7 re-engineering by the carriers will take hold. Some vendors predict that the industry probably will not meet deadlines, but most carriers have begun to support local number portability requirements within the last six months.

Translation of database queries in the traditional SS7 architecture has always been done through SCPs, which never have experienced congestion problems. However, as local number portability introduces unforeseen levels of traffic to SS7 link sets, an architecture in which signal transfer points switch queries in and out is becoming quite popular. These signal transfer points can act as switches to move along SS7 messages without creating switch congestion.

Among other hot applications for SS7, carriers are beginning to use data collected from SS7 links to detect and track fraud development. SS7 can identify fraud in real time by surveying call detail records, calling patterns and even calling card queries going through SS7 links, says HP's Belcher.

Insider fraud can be detected through analysis of billing records over SS7. Also, SS7 links near network handoff points can act as authentication centers for digitally encrypted wireless signals.

Meanwhile, although custom local area signaling services, such as calling name delivery, require SS7 to work, the even more imaginative set of emerging enhanced services also requires the advanced routing capabilities that well-planned, extensively built SS7 networks can provide.

Single number services and integrated voice mail/messaging services are two examples. Both might require multiple SS7 handoffs between different kinds of network elements and devices.

Other applications specifically designed to take advantage of SS7 probably will appear in the months ahead. In fact, the combination of NT and SignalWare already is stimulating development of new services from Amdahl, Tandem/Compaq and Data General, says Seamus Gilchrist, channel manager at DGM&S.

ATM and SS7

The generation of so many new applications will have such a dramatic effect on SS7 traffic that some are left to wonder what the long-term effect on SS7 architectures will be. Will standardized signaling always be the answer for supporting such applications?

The answer to this question is, generally, yes. SS7 networks have been strategically developed using architectures that can be expanded easily by adding new links through the deployment of signal transfer points and SCPs. However, the SS7 network of tomorrow likely will differ greatly from today's SS7 network. The ongoing deployment of ATM switching has seen to that.

Although the spread of ATM architectures at first may seem a threat to SS7's role in the public network, ATM's high-speed nature may help SS7 mature. ATM switching can be integrated with SS7 call signaling to ensure high-speed transmission of SS7 messages and high-speed access to SS7-collected data, says Denny Terry, vice president of engineering at Heurikon Computer Group, a maker of board level component cards that are capable of integrating the two technologies.

Migrating SS7 applications onto ATM bandwidth definitely would calm any concerns about the congestion-inducing possibilities of applications such as local number portability. "Local number portability has overwhelmed networks and any ideas about mediated access. This integration of SS7 and ATM will happen at some point," says Osman Duman, vice president of marketing at Newnet.

"Pulling SS7 into the broadband world is very critical," says Stratus' Osborn. "It's something that's on our drawing board."

Exactly when it will happen is the source of some debate. Some carriers are already dabbling with SS7/ATM integration schemes, but several vendors say any widely seen integration is at least two years away--when the industry will begin to experience the SS7 traffic boom.

Meanwhile, other vendors talk of the potential of SS7 riding on global Internet protocol backbones, although SS7 over the Internet probably would raise many quality-of-service issues that would make such an endeavor too risky for service providers.

In any case, integrating SS7 with new high-speed infrastructures will raise the value of the public network's reliable old signaling architecture, allowing it to handle a new generation of carrier and user demands. SS7's legacy of reliability and flexibility always has been its strongest advantage, and combined with new, valuable applications interpreted from the wealth of information available through SS7 networks, the transmission protocol will continue to have a sharp edge for years to come (Table 1).

"The industry now recognizes that SS7 holds the key to some very valuable network information that can have a big impact on carriers' future operational costs and competitiveness," says HP's Belcher.