Jack Burton is director of systems engineering at Cablevision, where he is involved in R&D projects for voice, business services and network transport.
At first it seemed that operators would use SIP for peering, but then SIP-enabled business apps gathered steam. What’s up with SIP?
SIP trunking for peering purposes is alive and well. A large quantity of our long distance and directory assistance calls today connect to their carriers via SIP trunks through "paid" interconnections rather than "free" peering from MSO to MSO. However, technically they are the same.
In a way, inter-MSO peering has not yet developed partly because of our success – costs for termination of off-net calls have dropped because of volume, so the anticipated cost savings of MSO peering are not that significant. The main driver for MSO peering probably will not be the cost reduction originally envisioned, but rather the ability to interconnect advanced services such as wideband voice and video telephony.
Business applications for SIP trunks, (which we are trying to rename "IP Multimedia Trunks" to avoid the confusion) will develop as the customer premises devices that accept SIP services become available.
Is SIP trunking a good option for premises-based telephony systems?
Today, very few devices are ready to accept a SIP trunk from a service provider, but this is changing. Vendors are starting to adopt the "SIP Connect" standards, and this is a good start. I hope we will have more standards activity soon and that in the future it will be as easy to connect a SIP trunk as it is to connect a PRI. Until that time, we will continue to make specific customizations for each type of SIP-based equipment we support.
Could you comment on the mutually beneficial relationship between Cablevision’s business and residential telephony offerings?
The Optimum Voice and Optimum for business service use the same infrastructure. This allows for a level of efficiency. We have standardized toward indoor devices, which controls deployment costs and also makes it possible to have a "business class" product priced at a level of affordability similar to our residential service. We have every reason to believe the same thing will happen when we offer SIP endpoint services.
Does Ethernet have enough hooks and levers to enable SLAs and guarantee QoS? (We note that Optimum Lightpath is delivering voice over Ethernet.)
If you have enough raw bandwidth, you do not need QoS guarantees. That would work fine if customers were using 10 Mbps circuits on a 10 GigE backbone. Metro Ethernet service customers, however, are purchasing up to GigE contracted rates, and we are serving them on a mix of GigE and 10 GigE access facilities, so there is a need to classify service types in order to ensure we meet the contracted bandwidth. That said, voice for a typical office represents a very small bandwidth requirement and can be served over Metro Ethernet without special handling.
Combining a system’s fiber and coax assets seems like winning combination for MSOs in the business services arena. Are there others?
The cable industry has many competitive advantages, and the ability to serve a portion of a large company’s sites via fiber and others via coax is just one of them. To name a few:
We have a field force, ready to install at customer locations, and we have our own access network, unlike other Internet telephony service providers.
We have low cost access systems – DOCSIS over HFC for smaller customers and Metro Ethernet for larger ones. Contrast this with the obsolete narrowband platforms and high-cost broadband networks of our telephone company competitors.
We have an entrepreneurial spirit and work together as an industry. The telephone companies function independently, as do the ITSPs and CLECs for the most part. We have NCTA, CTAM, and Cablelabs, and we share and cooperate with other MSOs.