Ethernet is the standard protocol of the LAN. Most network interfaces run at 10 Mbps, 100 Mbps, 1000 Mbps or 10 Gbps. Many standard network devices support multiple speeds, typically 10/100/1000 Mbps. It is only logical to want to extend the LAN through the WAN and to another LAN somewhere else. The way to avoid speed bumps that cause network congestion while avoiding over-provisioning and overpaying for WAN bandwidth is to match your LAN to your WAN. That means standard LAN speeds and protocol. Fortunately, this has all been figured out by the Metro Ethernet Forum (MEF), an industry group that sets standards for interoperability among vendors. They have created the standards necessary to take LAN Ethernet and transport it through WAN connections. In the WAN, this is called Carrier Ethernet.
It all starts and ends with a User Network Interface or UNI. This is a “port” provided by the carrier or service provider and installed at the user location or locations. The UNI is designed to run at standard LAN operating speeds of 10 Mbps, 100 Mbps, 1 Gbps or 10 Gbps. That doesn’t mean that you are limited to one of those service speeds. The installed UNI defines the upper limit to the bandwidth it will support. The carrier rate limits the actual speed of the service to match the bandwidth you are paying for. That could be 20 Mbps, 75 Mbps, 450 Mbps or some other value. There are typically many increments to choose from so you only have to pay for the bandwidth you really need.
There is a big advantage to this arrangement. Not only are you not stuck with a service that is too big or too small for your needs, but all the hardware is set up to support the port speed of the UNI. The rate limiting is a software function that can be changed quickly by the service provider with a few keystrokes into their system. That means that you can call up and request a bandwidth increase at any time and have it available in days, maybe hours of your request. The carrier will enter the change and adjust your billing to match. Compare that to traditional telecom service that require truck rolls to install new equipment and perhaps pull new wiring. If your UNI supports 1 Gbps, you won’t need any hardware changes until you want to go above that speed.
The actual transportation takes place on an Ethernet Virtual Connection or EVC. The EVC provides point to point connectivity between designated UNIs and prevents data transfer between sites that aren’t part of the same EVC. The popular Ethernet point to point service is known as EPL or Ethernet Private Line. It is a direct replacement for TDM private lines.
Another interesting feature of Ethernet UNIs is that they can handle multiple EVCs. That may seem a little strange compared to typical telecom UNIs that connect physical wires and transport a single Point to Point (PTP) line service. Each EVC can be considered a separate private line. Multiple EVCs delivered over a single UNI is called EVPL or Ethernet Virtual Private Line service. One popular topology is a hub and spoke arrangement where a headquarters location is connected to multiple branch offices using EVPL. Only a single physical UNI is needed at HQ to support all the private line spoke connections.
Is your operation ready for higher bandwidth WAN service? Find out how little it now costs to support 1 Gbps Point to Point Ethernet Connections using EPL and EVPL.
