Good and evil in Atlanta

VON attendees debate SIP vs. softswitches One of the few controversies at this fall's Voice on the Net show in Atlanta has been a philosophical argument over the relative merits of networks built around Session Initiation Protocol and those constructed using softswitches. The dispute comes down to a question of where intelligence should reside in the IP voice network - at its outmost edges or in a switched component located at the interface with the public network?

For Henry Sinnreich, chief technologist of WorldCom, it's all about which system gives providers the greatest ability to add services and features. He advocated complete dispersal of the service creation function via SIP out to a voice-over-IP network's edge servers and edge devices. Without that distribution, he said, "You don't have an Internet model." Worse, locating call controls in a switch - whether software-based or hard wired - at a central office raises regulatory problems.

"You're re-inventing unequal access at the control level," he said. "That invites the regulators to come in, and it also invites expensive litigation. If you have a softswitch phone, you cannot choose your service provider and you cannot choose your communications applications, which are two essential freedoms of the Internet."

Matt Holdrege, director of standarization and interoperability at ipVerse, countered that software could be used to enhance growth as easily as it could restrict it. Softswitch makers today are sensitive to carriers' need for multiple vendors, and the logical separations within softswitches allow manufacturers to incorporate multiple protocols, including SIP.

Softswitches are architected in layers to provide optimal control of intrinsic features required, including service creation, allowing the software primitives to talk to call agents and routing elements, and driving actions to the media gateways, Holdrege said. The layered approach allows each one to be optimized for serving different markets - trunking gateways, Internet access devices and third generation wireless, for example.

"We're not stuck in the old world, where we had 25 million lines of code on a single platform controlling a phone switch," he said.

ipVerse used VON to debut its softswitch that integrates advanced SIP functionality into a multiprotocol architecture. Using a softswitch makes for a more robust and more scalable IP voice network, said R. Paul Singh, ipVerse's co-founder and vice president of business development.

LMAP engines LongBoard is a communications software company embodying the layered approach to softswitch architecture. The company announced at VON that the LongBoard Multi-engine Application Platform (LMAP) will enter beta testing with competitive carrier Birch Telecom, running over Salix switches from Tellabs. The LMAP design includes separate engines for management, features, policies, connectivity, directory services and media (see figure).

Among its other properties, the LMAP architecture allows the network elements and functions to be dispersed geographically around the network. At VON, LongBoard demonstrated LMAP using switches located in four cities around the country.

Telia's carrier demands completely open standards in its networking components, something most softswitch vendors cannot supply, said Hans Eriksson, chief technology officer of voice-over-IP services for Telia.

"Publishing proprietary APIs on your Web site does not count - even if you're Ericsson, Lucent or whomever," he said.

As for softswitches, they are "being used for doing old proprietary stuff," Eriksson said."H.323 is the last dinosaur of the telcos, and it's going to go away."

Telia is expanding its intra-company trial of SIP communications from the Swedish carrier's 27,000 employees to its 660,000 ISP customers. Working with Ubiquity Software, Telia will offer a specially targeted SIP offering for teens.

Ike Elliott, vice president of softswitch services for Level 3 Communications, described the SIP-softswitch debate as a "moral question of what is good and evil in the world of protocols."

"It's a debate between choice vs. control," he said. "Choice is good, especially for those of us steeped in Internet culture, and control is bad."

In the public network, service providers and their supporting vendors have control. But although softswitches can be used to replicate that level of centralized control, they also can be used to put that control in the hands of end users, providing seamless any-to-any communication.

Finally, real-world conditions mandate that networks integrate the best elements of SIP and softswitches, said Gary Rogers, vice president for worldwide sales and marketing with Sonus Networks.

"You're going to have plenty of people who will be willing to replace their old black phones with intelligent SIP devices," he said. "But for a long time to come, there will be a legacy of old black phones and a number of people who won't want to learn how to use something fancy and new but who will be able to get a few nice new services - call forwarding, call waiting - over their old equipment. That's where softswitches can help."