Demystifying Metro Ethernet Part 2

Ethernet Virtual Private Line (EVPL): Part 2 of a 3-Part Series

In our last post, we introduced the general topic of Metro Ethernet and why it’s become the most common choice for enterprise business networking. We also looked into Ethernet Private Line (EPL), which is the simplest way to make a direct Ethernet connection between two locations. But what if you have multiple locations that need to stay connected to your main office?

A good example would be a consulting firm with a large headquarters location in Dallas, and small regional offices in Fort Worth, Austin, Houston, and San Antonio. The regional offices don’t need to have much interaction with each other, but it’s critical that they all have a fast, reliable and secure connection to the home office, where core business functions (HR, finance, etc.) and key equipment (file servers, etc.) reside.

Metro Ethernet can be a great solution for this type of business. But establishing separate EPLs from each location to the home office can be cost prohibitive. That’s when Ethernet Virtual Private Line (EVPL) might become a better solution.

All for One, One for All

EVPL is designed in a hub-and-spoke configuration, also known as point-to-multipoint. The hub, of course, would be the headquarters office at the center of the network, while the spokes would be the regional offices.

This type of network architecture puts the proverbial “fat pipe” at the hub location and enables various services to run over that single high-capacity connection to a service provider’s network. Because EVPL allows for service multiplexing, many point-to-point Ethernet Virtual Circuits can be created from one User Network Interface (UNI) to the spoke locations.

In addition to being more cost effective and flexible than traditional Frame Relay or ATM configurations, EVPL enables a business to create more structure in its network by segregating and prioritizing different types of traffic (voice, data, video, or Internet).

At the same time, however, EVPL adds a layer of complexity compared to a straight EPL connection between two points. For example, the customer’s IT staff should be comfortable with routing between multiple Virtual Local Area Networks (VLANs).

Remember the car analogy we used in the last post about EPL? If EPL is a no-frills “just get you there” kind of vehicle, you might say that EVPL is a step up in sophistication. Like a roadster with a stick shift, it puts more control in the hands of the “driver,” but could also be lost on those who neither need nor want that responsibility.

In our next post, we’ll talk about a third type of Metro Ethernet service, Ethernet Local Area Network (ELAN), and how it compares to the other two.

Richard Scott, VP of Network Engineering, Alpheus Communications