* Defining - and possibly shifting - the almighty demarc
What constitutes a “managed network service?” This is an open-ended term that can have many meanings in the networking business.
We noted last time that even when you opt for private lines and purchase your own CPE, you do receive some management services from your carrier, in the form of service provisioning, repair, testing and monitoring. Depending on your point of view, then, even basic private-line services could qualify as managed services.
Another way of defining managed services involves determining who supplies and manages your CPE. Still another requires defining (and possibly moving) the so-called demarcation point (demarc) – sometimes called the user-to-network interface (UNI) – between the service provider and customer network.
Clearly defining the demarc/UNI is a technical necessity for dividing responsibilities with your service provider in a way that minimizes unconstructive finger-pointing. In this model, the equipment and cables residing on the enterprise side of the UNI are your responsibility, and everything on the WAN side of the UNI is the service provider’s responsibility. But it’s important to realize that throughout history, the UNI has often been defined more for political than technical reasons.
Consider the following case in point. Back in the 1980s, the demarc of 56K bit/sec and T-1 services in the U.S. was the DSU/CSU (a common piece of data circuit-terminating equipment, or DCE). But choosing the DSU/CSU as the demarc was a regulatory move to promote competition; it didn’t offer a particular benefit to enterprise customers. And since the DSU/CSU was already labeled the default demarc for private-line services, the UNI for frame relay and ATM services simply followed suit. Remember, frame relay and ATM emerged during an era of more stringent regulation than exists today.
In many cases, expanding a managed service is as simple a moving the demarc/UNI. For instance, having the service provider install and manage a DSU/CSU is typically considered a managed service. And having the service provider supply your WAN router almost always constitutes a managed service.
More recently, voice-over-IP (VoIP) carriers are venturing further onto the enterprise network. In addition to providing VoIP services across the WAN, for example, several have begun installing and managing IP PBXs and are taking on the creation and centralized management of their VoIP customers’ corporate dial plans.
Moving the physical demarc to gain more management service responsibility from your provider is not necessarily a drastic change. Instead, it simply shifts the line of responsibility to a location that is defined more by practical business and technology requirements than by outdated regulatory rationale.
