All Together Now
Integrating an ensemble of PacketCable components so that they make beautiful music together is among VoIP’s most pertinent challenges
By Jeff Baumgartner, Assistant Editor
May 2003
cedmagazine.com
In one way of looking at it, operating a distributed PacketCable network is a bit like conducting a 20-piece orchestra. When everyone’s playing their instruments properly and timing themselves just right, it can be a beautiful thing to behold. But if a tuba starts blaring over a flute solo, it can sound pretty ugly, pretty fast.
In a more integrated approach, it can start to look like a one-man band. But, if the timing is off, it can sound more like gobbledygook than well-synchronized music.
The distributed PacketCable architecture, as written by CableLabs, is comprised of several individual elements–among them the call management server, the media server, signaling gateway, media gateway, media gateway controller, multimedia terminal adapters (MTAs), cable modem termination systems (CMTSs), provisioning and record keeping servers and key distribution centers.
Each piece has a specific job to do, but making sure they’re all doing their job well and, at the same time, playing nice with all the other pieces presents quite an integration challenge for vendors and MSOs alike.
“It’s a 10-box problem,” says Joe Van Loan, senior vice president of technology for Mediacom Communications. “The security, call set-up, billing and a series of modules have to be completed in order for it to work as a whole.”
That challenge has spawned a raft of VoIP integration efforts. In many cases, vendors have teamed up to create their own integration clubs, while others have built pre-integrated devices that fuse together several elements that make up the PacketCable architecture. And while this is going on, system integrators seem to be garnering more and more attention.
Although CableLabs specifications offer some important interoperability guidelines, they don’t give operators necessarily everything they need to make VoIP plug-and-play.
“PacketCable, by and large, doesn’t really sweat interoperability,” says Sam Chernak, vice president, VoIP for Comcast Cable Communications, which is overseeing a large-scale VoIP trial in Coatesville, Pa.
Integration pacts form
That puts plenty of the responsibility on the operators and vendors, which are tasked with making the innards of PacketCable work with the synchronicity of a Swiss watch. In fact, many manufacturers are already moving ahead on their own integration pacts.
Among recent examples, Arris and Net2Phone struck an agreement to pre-integrate and conduct scalability tests for Arris’ CMTSs and MTAs. Net2Phone, meanwhile, is providing the local and long distance interconnects. Additionally, those companies have taken it upon themselves to select, integrate and test other components on the PacketCable network.
Arris has also invested $35 million in a lab that features a loaded HFC plant running roughly 20,000 cable modems and embedded MTAs.
“I can emulate virtually any MSO’s network and drive the PacketCable architecture to scale,” says Jim Lakin, president of Arris’ broadband business unit.
At the 2002 Western Show, four companies–system integrator Imagine Broadband, gateway maker Nuera Communications, media server vendor IP Unity and call management server firm Syndeo Corp.–partnered to create the “Voice Now” consortium.
Among their benefits, pre-integration projects such as these can help operators that don’t have the money and manpower to do that on their own, says Joe Matibag, director of product marketing with Nuera Communications.
Different schools of thought
Although most of the separate interoperability work is based on the distributed PacketCable network, another architecture that’s gaining steam calls for a much more pre-integrated, one-device system.
Cedar Point Communications has become the poster child for this approach. Its SAFARI C3 platform combines components such as the call management server, signaling gateway, media gateway and record keeping server.
David Spear, Cedar Point’s executive vice president, strategy and market development, disagrees with the notion that the one-box technique could “lock-in” an MSO with one vendor. He points out that that the SAFARI C3 provides the open interfaces necessary to integrate equipment from other vendors.
Spear also argues that integrated solutions–whether they’re DVR-capable set-tops or stereo systems–tend to win out over the long-term because they are easier to implement and typically cost less. When CMTS vendors started to add a routing component, “no one asked them to separate that out,” he observes. “Inevitably, you always integrate.”
Doing otherwise, “requires more hardware and more protocols, creating an enormous operational nightmare for the operator,” Spear adds.
Probably to the surprise of no one, there are many in the industry, especially those with competing approaches, who disagree.
In addition to the potential lock-in problem, putting everything into one system could force an operator to put more horsepower in one area than it might need, says Achmad Chadran, manager of product marketing for Siemens Carrier Networks.
Others who offer equipment with an eye toward the distributed PacketCable infrastructure also point out that their method gives the operator more flexibility in selecting vendors and that the distributed model provides a better fit with cable’s current network topologies.
Still, it’s too early to say which topology will win the heart and mind of the cable industry, or if more than one will share in the VoIP spoils.
“Cable operators are kicking tires on all the different architectures,” says Matibag at Nuera.
Comcast, for example, is taking a look at a variety of flavors. It’s piloting the distributed system to support its Philadelphia-area trial, but it’s also checking out the Cedar Point chassis at its Moorestown, N.J. laboratory.
But Comcast isn’t ready to make any long-term decisions on which way to go. “We’re in a show-me mode, and we’ll go through each process and give every architecture a chance to show what its attributes are, and to show where it’s good and where it’s not so good,” Chernak says.
“Anytime you see an integrated solution, it makes you feel a little bit better because you’re working with one vendor, versus four,” he adds. “Theoretically, it should be easier because it’s handling that intrinsically within one box.”
But, Chernak is quick to note, the vision for PacketCable’s fully distributed topology stems well beyond IP telephony and into more advanced multimedia services and applications. “The name of the game right now is to make them all successful, because there’s probably a good space for each of them in the future,” he says.
Back office challenges
Hardware integration aside, the industry is also turning plenty of attention to the back office. That challenge, “is our longest pole in the tent. The back office is by far the most complicated,” Chernak says.
Plus, PacketCable doesn’t address the OSS side of the house until version 1.3, says Apollo Guy, director of marketing and business development for OSS firm Lemur Networks.
CableLabs has tested equipment based on the 1.0 version of the spec. “PacketCable only touches the surface in 1.0 for what is required to make this thing work,” Guy adds. Lemur and other OSS vendors “have taken a very proactive stance in making sure that those interoperability issues are addressed,” he says.
Those issues include complexities such as data relationships and data mining. Among them, an MTA’s MAC address must be mapped to an IP address and all of the server touch points on the PacketCable network. “All of that has to be mapped in real-time for telephone calls to occur,” Guy says. “You have to automate all of that.”
Integrating the billing elements from traditional constant bit rate to IP telephony services represents a “major shift; it’s a pretty wide chasm to cross,” says George Ewman, executive director of voice services for OSS and customer care firm CSG Systems.
Inside that chasm are things like flow-through order provisioning, service activation, event records and billing for recurring and non-recurring usage. IP telephony “is still a hobby until you can bill for it,” Ewman says.
Enter the system integrator
For system integrators like Imagine Broadband, the goal is to get a firm handle on the massive amount of engineering, system integration and operational work required by complicated VoIP deployments.
Once that integration is completed, the project is then “operationalized,” allowing someone like Imagine Broadband “to hand over the keys to [the operator] and enable them to scale up their activities immediately,” says company CEO Dr. Arjang Zadeh.
The real trick in approaching a complex service like VoIP, he says, is not to see it only through engineering eyes.
“One of the major issues that operators face is that they don’t address the capturing of the business and marketing requirements in a vigorous way,” Zadeh says. “Engineers are good at designing aspects, but not all of them have operational experience, which can lead to platforms for new services that take a lot of time to mature.”
Imagine Broad-band, a spin-off from consulting specialist Accenture, suggests a phased approach, which typically takes no less than seven to eight months to get to an initial commercial service launch of IP telephony services, Zadeh says.
A system integrator can also serve as an “honest broker” for MSOs as they make their vendor selections. “Vendors will promise anything,” Zadeh says. “We make sure that the right time scale is given and that it makes engineering sense. And when things go wrong–and they always do–we will find a workaround to enable the service launch and work on the final solution in the background, in a transparent way to the customer.”
Net2Phone offers a host-based VoIP system to cable operators that pre-integrates components such as the record keeping server, call management server and gateway, but leaves the choice of the MTA and CMTS up to the operator. Net2Phone also manages and tests the interfaces to the billing and provisioning systems.
Though it doesn’t sell itself as a system integrator, “it’s a necessary evil in terms of deploying a multi-element, distributed architecture,” says Mike Paster, vice president of Net2Phone’s cable technology division.
“What we are trying to avoid is a unique implementation with different vendors in every market we deploy.” Without that, “it would be difficult to maintain a level of assurance, he adds. “We’d like to do what we’re doing in Puerto Rico (with Liberty Cablevision), and do that elsewhere.”
But Net2Phone’s VoIP system set-up is not necessarily set in stone. “If an operator wants or has a [vendor] preference, we would consider that,” Paster says.
Of course, not all operators require a high level of outside integration expertise. Comcast does not use an outside system integrator for its current VoIP project, but has drafted about 50 of its own people to help put everything together.
But Comcast isn’t like a lot of operators. It has deep pockets and can draw upon a large base of internal telephony knowledge, including the knowledge of those who joined the company after it merged with AT&T Broadband. “My view has been that no one really knows this better than we do,” Chernak says. |
