VoIP may not be rolling at breakneck speed, but that doesn’t mean you can’t learn from real-world trials and deployments that have occurred. Here are some tips from the VoIP-initiated for prepping for your own IP telephony future.

"Wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles," Albert Einstein said. "And [wireless] operates exactly the same way. You send signals here. They receive them there. The only difference is that there is no cat."

Funny how Einstein’s simple explanation still describes most modern telephony—both wired and wireless. Unfortunately, we don’t have him around today to let us know how voice over Internet protocol (VoIP) might fit into his feline networking analogy. Perhaps it’s a very muscular packet-switched cat that consumes less raw meat (bandwidth) than its circuit-switched cousin. Or, maybe it’s just an elusive beast with sharp claws ready to rip the heck out of an unwary engineer’s operating budget. VoIP is moving slowly, but that doesn’t mean technical trials and real deployments aren’t happening in cable. Early in the game or not, you still can benefit from other’s lessons-learned as they’ve blazed the VoIP engineering trail. Lesson 1: Keep time on your side "VoIP works, but be realistic in your timeframes," Chuck Carroll, chief technical officer at ish, stresses when he shares his IP telephony rollout experiences in Germany. "And don’t underestimate your resource needs." He also advises that you need to keep complexity to a minimum because "the solution is complex enough already." While proper attention to integration at the headend is key, it can’t catch everything. Field testing is key, Carroll says. Lesson 2: Start backoffice talk early While backoffice operations are not a task for engineers per se, they will consume your VoIP service if you don’t pay attention to them from the start. That means that even in the trial stages of VoIP, engineers must converse with the business, marketing and training people to ensure that network ops don’t clash with backoffice realities, Carroll adds. Lesson 3: Develop a solid TDM-to-IP plan Cox, long a forerunner in cable telephony technology, has identified several possible approaches to deploying VoIP and has started testing them in a lab environment and in the field. Take for example the company’s technical trial in its Oklahoma City, Okla., system early this year. The trial was set up to test a VoIP alternate-line architecture overlaid on existing circuit-switched architecture. In this hybrid design, which links circuit-switched time division multiplexing (TDM) and IP technology, a gateway was installed to bridge the two architectures. Cox’s engineering staff laid out specific goals for the trial as follows: 1) Test the concept of an alternate-line service. 2) Evaluate the integration of the architecture with Cox’s ICOMS customer management system. 3) Learn how to provision service on a multimedia terminal adapter (MTA). 4) Test the performance of several types of MTAs. 5) Evaluate the performance of the CMTS, routers and other last-mile equipment that typically carry data traffic in delivering phone service. 6) Identify and quantify the economies of scale from using the existing network investment. "We wanted to break down every process to its most basic elements to understand all of the implications of IP vs. circuit-switched technology, as well as the integration of data and IP telephony services," Albert Young, vice president of telephony engineering, says. "Basically, we wanted to determine how different VoIP services are from existing telephony operations—down to specifics like identifying and issuing IP addresses and phone numbers." MSOs can choose to "cap-and-grow" or fully migrate their circuit-switched telephony systems to VoIP. "By upgrading to a hybrid solution—with software and limited hardware—they can run TDM and VoIP lines from the same switch avoiding the costly replacement of the access equipment," Sue Spradley, president of wireline networks at Nortel Networks, says. "As that older access equipment needs to be replaced, or perhaps following a scheduled upgrade strategy, the MSO can migrate TDM lines to VoIP lines." Lesson 4: Remember that ROI is king One of the most attractive possibilities of VoIP is the opportunity to integrate Cox’s data/telephony platforms, and gain cost savings in the process, Jay Rolls, the MSO’s vice president of data engineering stresses. "For instance, the cable modem termination system (CMTS), which is in essence the traffic cop directing data traffic on our IP network, also has the capability to deliver voice packets." The newest versions of CMTSs are voice-compliant, and Cox started buying these upgraded versions last year. "ROI is what matters right now—not for piece parts, but it is the overall ROI, or total cost of ownership that has become table stakes for MSOs," Rajoo Nagar, director of product management at Ceon Corp., says. Cable ops still face an uphill battle putting together the business case for competing with the likes of the ILECs. "For this reason, they must go into it with primary line capabilities (E-911, CALEA, LNP, etc.). Anything less will not be acceptable," Nagar adds. Lesson 5: Get packet-smart before it’s too late "Cable operators have a skill issue—most are coming to it from a data or content perspective and don’t understand a mission-critical application like voice," Nagar believes. Sue Spradley, president of wireline networks at Nortel Networks gives the following advice to RF engineers: "Work with SCTE and leading vendors to gain the technical knowledge in the areas of IP fundamentals and PacketCable standards, specifically DOCSIS 1.1, in the next [several] months." Lesson 6: Get behind PacketCable "We have three live cable VoIP networks in service: Charter, ish and TeleCable," reports Nortel’s Spradley. "MSOs are continuing down the VoIP path, getting their networks ready, doing equipment trials, taking all the natural steps prior to major deployment announcements," she says. "There is a strong commitment to the PacketCable process, and we’re aware that MSOs would like to see more results out of CableLabs before they make large-scale commitments." Editor’s note: At deadline, CableLabs gave the first PacketCable qualification nod to two call management servers (CMSs), which are considered the cornerstone of the PacketCable net. The CMSs are from Cisco and Syndeo. Lesson 7: Think beyond telephony "All the excellent engineering that takes place on the last mile to maximize bandwidth needs to be complemented with edge and core networks that ensure quality of service is sustained throughout the whole network," Spradley recommends. "A well-engineered IP backbone with Multiprotocol Label Switching (MPLS) or an equivalent is essential as more packet-based services are introduced." VoIP Lessons Learned Broadband engineers may not be rolling out VoIP at a breakneck speed, but that doesn’t mean you can’t learn from some real-world trials and deployments that have already occurred. Some of those lessons include: Keep time on your side Start backoffice talk early Develop a solid TDM-to-IP plan Remember that ROI is king Get packet-smart before it’s too late Get behind PacketCable Think beyond telephony

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