Metropolitan Area Network (MAN) is the network of devices that spans within the range of 5 – 100 km. i.e. a large city, or the collection of few towns, or in buildings in that sort of range. Its domain falls somewhere between the local area network (LAN) and Wide Area Network (WAN) – definitely bigger than LAN but smaller in size than WAN. Contrary to the name it is given, MAN can exist anywhere not just in the metropolitans. Its name has more to do with the size within which it exists rather than its location.
Now, how exactly is MAN different from WAN? Well, the answer to this lies in its efficiency. MAN interconnects with multiple LANs, similar to WANs but because its size is much smaller than the latter, its performance gets better as it doesn’t require data to be carried over long distances. Stretch over shorter distances also makes it more feasible to be connected using the fiber optic cables preferably on a leased line from the third party Internet Service Providers (ISPs) or Governmental network. It greatly enhances its speed and efficiency, which automatically makes MAN an ideal choice to transfer greater chunks of data – although this also increases congestion, which apparently makes it more prone to inflicting errors and faults on the network. And yes, MANs setup and maintenance cost is also quite high.
In MAN, data is transmitted through a piece of hardware such as modems and/or via cables. Your town’s cable TV connection or a high speed DSL connection via the phone line is a prime example of the Metropolitan Area Network.
A small sized MAN topology could connect a number of LANs together using a backbone line bridge. It offers a very high speed data transfer capability that shares locally available resources as well as network connections, both wired and wireless. Wireless MANs (WMANs) are an ideal choice for connecting multiple sites within a small range. It offers a cheaper networking alternative compared to costly fiber optic or a leased line connection.
IEEE 802.6 has defined Distributed Queue Dual Base (DQDB) as an accepted standard for MAN. It is also supported by Dense Wavelength Division Multiplexing (DWDM) for increased bandwidth capacity, and Optical Packet Switching (OPS) that offers a very flexible, high bandwidth and reconfigurable optic layer data transmission.
The advantages of MAN are having a centralized security for firewall and its management, mitigated malware/security threat using a centralized gate-keeping point for internet, internet exchange point infrastructure, better administration and data entry systems. However, ISPs are often quite reluctant to offer MAN connections due to the overhead it entails including its charges and profitability concerns. For this reason, Metropolitan Area Network (MAN) is specifically implemented for organizations regarding which there are clear requirements to administer this functionality.
