VOIP Borders Stir Debate

Networking executives disagree on whether a new category of VOIP networking gear, session border controllers, will stay around or be subsumed into routers and firewalls.

SANTA CLARA, Calif.—A new breed of networking gear has been developed to shepherd and control the connection of multiple VOIP networks, but whether the functionality of these session border controllers will eventually move directly into other networking equipment stirred debate during the Spring 2004 VON Conference & Expo here Monday.

Networking executives disagreed on the future of session border controllers, though most agreed that there is a market need for overcoming the disruption of VOIP (voice-over-IP) traffic caused at the border between IP networks and by firewalls in carrier and enterprise networks.

Session border controllers, or SBCs, sit at the edge of service provider or enterprise networks and provide control functions across network borders. For example, they help VOIP traffic transverse NAT-enabled firewalls. Market researchers predict rapid growth for the networking gear, with Infonetics Research projecting that worldwide revenue for SBCs will grow from $29 million in 2003 to $453 million in 2007.

"One reason session border controllers have emerged is they are a very inexpensive way to go from one IP network to another IP network without going back to circuit technology," said Bruce Hill, president and CEO of Netrake Corp. "Growth in this market is on track."

/zimages/4/28571.gifClick here to read more about how VOIP is reaching the "tipping point."

To Dan Freedman, CEO of Jasomi Networks, SBCs serve a critical function in todays still growing VOIP networks that other gear, such as firewalls, routers and softswitches, currently do not provide. But he expects the large networking vendors such as Cisco Systems Inc., Nortel Networks Corp. and Check Point Software Technologies Inc. to increasingly consider adding the work of session border controllers directly into routers and firewalls.

"There will be pressure from customers of those companies to put more session border control functionality on those devices," Freedman said. "We should not be asking if it will happen but when."

Though unlikely to occur in the next year or so, Freedman said, the addition of SBC functions into other networking elements could be common in about five years.

Others arent so certain of the migration of SBCs into broader networking gear. Opher Kahane, co-founder and CEO of Kagoor Networks Inc., said the firewall market itself serves as a good example. While the major router makers have added firewall functions into their equipment over the past decade, the independent firewall market continued to grow because of the need for the security focus.

"Twelve years later, the stand-alone firewall market is still standing," Kahane said. "The distance between the session border controllers and routers is dramatically, dramatically larger than the difference between the firewalls and routers."

Whatever the predictions for the evolution of SBCs, their growth could spell the eventual demise for another part of the network—the softswitches that bridge public-switched telephone networks and IP networks, said Raj Sharma, president of NexTone Communications Inc. Even if router makers begin to more aggressively add SBC functionality, the SBCs have years of lead time in development, he said.

More likely to Sharma is the emergence of SBCs as a more central element of VOIP networks for service providers and enterprises.

"The session controller functions will evolve to the core of the network and become the softswitches of tomorrows networks," he said.

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