The idea behind a metro network is that many offices, medical centers, manufacturers, governmental bodies and retailers have multiple locations within the same geographical area. Within a particular building or campus, you are free to install as much wiring as you want. But what happens when you need to get that connection across town?
The legacy answer is to lease point to point dedicated circuits from a telco provider. These can be T1 lines, DS3 for higher bandwidth or very expensive OC3 and above optical connections. Essentially, you create your own metropolitan networks from leased lines and routers that you install and manage.
It turns out that many, many businesses and organizations need this same service. This opens the opportunity for a metro network operator to install the necessary fiber optic cabling, add-drop multiplexers and other equipment to create a publicly available resource that meets the needs of most businesses in the area. By connecting to the MAN instead of building your own network, you can save considerable cost. You’ll also likely have additional resources at your disposal just in case your bandwidth needs suddenly increase.
Metro networks have more inherent security than the Internet in that there is no general public access. The residential users downloading movies and browsing the Internet or looking for mischief have no real need for the MAN and aren’t willing to pony up the price of a connection. Certainly, you have the ability to encrypt any packets you send through the MAN to improve security even further.
Many Metropolitan Area Networks are built from SONET rings, which are fiber optic networks organized as rings with many access points. Usually there are at least two fiber rings sending traffic in opposite directions. The idea is that if one strand fails, the other redundant strand will maintain the network. A ring arrangement is a good fit with most metro needs. The ring circles the business district and includes important industrial parks, hospital campuses, office complexes and the like.
The newest development is MEN as a specific type of MAN. MEN stands for Metropolitan Ethernet Network. This network is based on the Ethernet protocol, although it may be running on a SONET core network or a native IP network. As a user, you are able to get Ethernet service in the metro area.
What makes Ethernet so desirable? Metro Ethernet is based on standards established by the Metro Ethernet Forum (MEF) so that you know what to expect when you order a particular Ethernet service. There are two services of particular interest to most business users. The first is E-Line which is a private dedicated point to point connection between two locations. You use E-line the same way you’d use a T1 line, except that you have many more bandwidth options and the price per Mbps is often much lower than traditional telecom services.
The other service of note is E-LAN, a private LAN service. But you already have a LAN, right? Not like this one. E-LAN is a metro network version of the LAN. It connects the individual LANs at each of your metro locations to make one large bridged LAN connecting all of them in a layer 2 meshed network. It’s as if all those different buildings were really just different departments in the same building.
How do you connect to the MAN? Typical methods include T1 lines, DS3 and OC3 or OC12 fiber last mile connections. However, if you want to take advantage of Ethernet services like E-LAN, you’ll need EFM or Ethernet in the First Mile. You can use Ethernet over Copper for bandwidths from 1 to 100 Mbps. Higher speeds require Gigabit Ethernet or 10 GigE fiber optic service.
In some downtown areas, there is such as thing as a fixed wireless MAN. This is different from 3G and 4G cellular wireless intended for smartphones. Fixed wireless operates on private licensed frequencies with directional transmission from the service provider to all-weather terminal equipment mounted to the roof of each customer. High speeds, excellent security and fast installation characterize fixed wireless MAN.
What type of metro networking will work best for your business or organization? The best way to evaluate your choices is to get a list of available services and pricing for Metropolitan Area Networks serving your location.