Border Patrol

Charter Communications is using Acme Packet session border controllers to cover its nationwide Charter Telephone rollout, which, as of the third quarter of last year, included 39,600 customers and 5.9 million enabled homes and, despite a dearth of new data, probably includes a lot more right now.

Charter is Acme’s first announced cable customer in North America – although the vendor confusingly claimed to be doing business with six other top 10 MSOs. The news here is that SBCs, as those in the know call session border controllers, are being used by cable operators despite the earlier industry talk about peering between IP-enabled cable networks that would obviate the need for control at the border.

"We’re bringing SBCs into the picture because we’re now moving to an IP-type handoff using SIP trunks, so that gives us a lot more flexibility in terms of managing the traffic," said Armando Ruiz, senior director of telephone engineering at Charter. "We’re using the SBCs for control over all our IP traffic to the outside world."

SBCs – perhaps not by that name but by function – are being written into the latest PacketCable reference architecture, said Kevin Mitchell, director of solutions marketing at Acme Packet. Part of PacketCable 2.0 "There’s a role both on the interconnect side and the access side of the session border controller in the PacketCable 2.0 reference architecture," Mitchell pointed out.

Even with cable-to-cable networks?

"There’s a lot of interoperability and mediation that takes place at the border, even though we’re talking about two different IP networks," he said. "A lot of it has to do with interconnecting with other providers for either PSTN termination or connection to hosted ASP (application service provider) or directory assistance or voice mail-type providers."

The need will become more, not less, as PacketCable 2.0 evolves and "SIP-based services are rolled out. There’s a host of things we can be doing on the access side … where we might be supporting SIP-based service offerings. These are things that are more future-oriented, but always possible," he said.

For the present, Charter is using the Acme Packet gear "so all our telephony-enabled markets now have IP transport capabilities over SIP using SBCs," Ruiz said. "It allows us to do things like transcoding, and it gives us quite a few options by having the SBC controlling the sessions to any outside party."

Ruiz confirmed that "there is a lot of interest" in trying to peer IP traffic between cable operators – and said that SBCs will be playing a role there as well. CableLabs RFP "There’s a CableLabs sponsored RFP right now for peering, which we are participating in," he said. "There’s definitely a lot of interest in doing more peering. It’s a lot more efficient. If you look at the IMS architecture, which is something that is included in PacketCable 2.0, there’s some SBC function there in that overall architecture."

This, of course suggests, that despite the wails of doomsayers that SBCs will vanish like the dinosaurs and be incorporated into the next evolution of telecom equipment, there’s still a business for the old standalone devices.

"Ninety-nine percent of all deployments to date of session border controllers are standalone elements," Mitchell said. "It’s not just one thing that session border controllers do in the network; there’s a host of things."

And, apparently, a host of networks that need them. – Jim Barthold