Metropolitan Area Network (MAN) Definition
Also known as a MAN, a metropolitan area network is basically a bigger version of a LAN and normally uses similar technology. It might cover a group of nearby corporate offices or a city and might be either private or public. A MAN can support both data and voice, and might even be related to the local cable television network. A MAN just has one or two cables and does not contain switching elements, which shunt packets over one of several potential output lines. Not having to switch simplifies the design.
The main reason for even distinguishing MANs as a special category is that a standard has been adopted for them, and this standard is now being implemented. It is called DQDB (Distributed Queue Dual Bus) for people who prefer numbers to letters, 802.6. DQDB consists of two unidirection buses (cables) to which all the computers are connected. Each bus has a head-end, a device that initiates transmission activity. Traffic that is destined for a computer to the "right" of the sender uses the "upper" bus. Traffic to the "left" uses the "lower" one.
- Local Area Network