Infrastructure challenges for triple play networks

With wireless and VoIP eroding wireline voice revenue and cable modems outselling DSL, local exchange carriers are starting to modernize their networks to deliver the triple play. Voice, video and Internet service bundled for residential users is essential for survival.

Unlike DSL, which has been aimed at heavy Internet users, the triple play is envisioned as the POTS of the 21st century: universal and priced affordably. Cost to consumers must be pretty much in line with what they pay today for POTS and cable TV.

A premium triple play package (basic, several premium video channels, advanced video features, unlimited telephone service, and broadband--4 Mbps downstream) as offered by cable MSOs is about $200 per month. Verizon's CEO believes the price needs to approach $100 per month for widespread acceptance--I agree.

Truly converged voice, data and video infrastructure is needed to deliver services to tens of millions of consumers and achieve profitable operations at the $100 per month price point. Meeting this objective will require eliminating telephone circuit switching because circuit switching cannot achieve the efficiency of softswitches.

Highly reliable networking infrastructure is essential. For example, if customers feel they must retain POTS for E911 calls, the service bundle falls apart, causing revenue per user to fall below the breakeven point and obviating the need for triple play infrastructure.

Similarly, if customers perceive video services to be less reliable than cable TV and renting DVDs, they will not switch to triple play. And unlike telephone service and the Internet, television is viewed by half the population for more than two hours per day. Outages will be duly noted.

The reliability challenge is more than just perceptual. Legacy services really are highly reliable. POTS and cable TV are designed to deliver high-availability services. The design standard for telephone circuit switches is two hours downtime every 40 years, and analysis of cable TV designs shows 41 minutes downtime per year for the hybrid fiber-coax plant.

Measurements of Internet performance reveal much poorer execution. Researchers at the University of California, Berkeley, measured the success rate of Web queries. They found the success rate--full response to a Web site request--to be 0.9888. The network component had a 0.99 success rate: 1 percent of all requests failed due to network problems.

Of course the reliability of an individual Internet router will be higher than 0.99 because multiple routers sit between the Web server and the user. However, even if five routers are employed, the reliability of an individual router will be 0.998, much less than the circuit switch availability number.

Routers custom-built for triple play are needed to meet its reliability and cost requirements simultaneously. The key is to use modular routing software distributed across the architecture, so that hard resets and network-wide route table updates are eliminated, and to build in flow-control capabilities suitable for broadcasting hundreds of video channels to thousands of consumers. A number of such product announcements likely will be featured this month at SUPERCOMM.

Alternatives to using a custom-built router include using standard routers in redundant pairs and deploying Ethernet switches that are low on the price/performance curve due to their popularity in enterprise networks.

These alternatives, while useful in the short run, will not position triple play as the new POTS. The Ethernet switches were designed to meet much less demanding enterprise standards and cannot deliver the required reliability. The dual router designs working as a pair come nearer to meeting the availability of a router with modular software but still fall short, handicapped by their use of routing protocols with long convergence times to resolve outages. Furthermore, using two routers to do the job of one is an obvious total-cost-of-ownership handicap.

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Triple play very likely will become the POTS of the 21st century but it will not be achieved by making incremental improvements to either existing telephone switches or Internet routers. The new products needed to reach both the cost and reliability objectives are now emerging.

Michael Kennedy is co-founder and managing partner of Network Strategy Partners, LLC, management consultants to the networking industry. ([email protected])

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