Large computer networks that typically span a large city are called Metropolitan Area Networks. These are also referred to as MANs. Usually, the use fiber optic connections or wireless infrastructure in the linking of their sites. Often schools will use MANs. I recommend visiting http://www.utdallas.edu/eecs/photec/Cantrell-LEOS-2003.pdf. You will find some very valuable information about MANs
. there, including their disadvantages.
