Session border control: making dreams reality - Sponsored Educational Supplement - Industry Overview

Telecommunications Americas, June, 2003

New products overcome the roadblocks to delivering profitable voice, video and other real-time interactive communication services across IP network borders.

IP NETWORKS HAVE TRADITIONALLY been viewed as poor revenue generators. And unfortunately, they have been plagued with security and end-to-end performance problems blocking the delivery of high-quality, real-time interactive voice and video that could significantly brighten the bleak picture.

After all, some 70 percent to 80 percent of all communication services revenues still come from voice. As service providers increasingly seek to converge networks to reduce CAPEX and OPEX, the ills only worsen. But a new breed of products, called session border controllers (SBcs), offer a way to address those problems head-on while enabling new revenue-generating interactive communication services--voice, video, multimedia--across IP network borders.

As service providers look to creatively reach out to more customers, offer new services and converge IP networks, an entirely new set of problems arises. Merely connecting two IP networks--whether between service provider and customer or between two service providers--creates an entirely new set of security, service assurance and law enforcement requirements at the network edge. Those new requirements have isolated today's voice over IP (VoIP) networks like islands and have severely limited service provider revenue opportunities.

Session border controllers: the new intelligent edge devices

Service providers are not helpless, however, thanks to new technology. Unlike many new products that are developed first and then adapted to handle network problems later, a new category of products called session border controllers has been designed specifically to tackle the sticky issues associated with delivering interactive communications across IP network borders. A Massachusetts, U.S.-based equipment vendor, Acme Packet, has developed a family of SBCs now being deployed by providers worldwide in a variety of applications.

"There is a strong need for a secure bridge between IP islands," said Sam Shiffman, vice president of engineering at Texas, U.S.-based service provider PointOne. PointOne concentrates on selling VoIP services to service providers and is using Acme Packet's Net-Net SBC to connect the islands of VoIP networks, according to Shiffman.

This is where the SBCs come into play. SBCs reside at the service provider's network borders complementing existing edge routers. They closely integrate signaling and media control and serve as both the source and destination for all signaling messages and media streams entering or exiting the provider's network. In more technical terms, they act as SIP (Session Initiation Protocol) B2BUAs (back-to-back user agents), MGCP (Media Gateway Control Protocol) proxy/NAT (Network Address Translation), and/or H.323 back-to-back gateways or gatekeepers.

SBC applications: any service, any protocol, any border

Generically speaking there are three different applications, or scenarios, for the SBC deployment.

The first is peering service provider networks. Today many providers employ managed P networks with softswitches and gateways to reduce the operational and capital costs of trunking PSTN traffic between central offices. The next step in this network evolution entails connecting these softswitch-gateway "islands" to expand network reach and minimize PSTN termination costs. SBCs enable these VoIP providers to peer networks for PSTN origination and termination, IP transit and, ultimately, IP termination and origination.

Facilities-based providers offering hosted IP-based interactive communication (IC) services--voice, video, unified messaging, conferencing, presence and instant calling, multimedia collaboration, gaming and IP PBX transport--will also benefit from the use of SBCs at the borders to their business and residential customers in addition to other providers.

The third application is at the doorway to the data centers of voice applications service providers. These providers deliver calling card, directory, messaging, and other services to other retail providers or directly to users.

Across all of these applications, there are critical security, service assurance and law enforcement requirements that must be satisfied.

Security: security, security

For both service providers and enterprises, ensuring network security is one of their biggest concerns. "As you join networks together, you have to be concerned about who can get to you, said Shiffman.

"No one trusts anyone else anymore," said Jim Hourihan, vice president of marketing and product management for Acme Packet. And when it comes to IP networks, that lack of trust is only magnified, according to Hourihan.

"There is a great need for border elements because [VoIP networks] are inherently insecure," said Michael Aglietti, Senior NexGen Network Design Engineer at a major U.S.-based service provider. "We have to protect the VoIP network from attack, fraud or misuse while maintaining voice quality."