There is a lot of diversity in MANs in terms of the different
types of customer applications, interfaces, and necessary bandwidth.
A Wide Area Network (WAN) refers to a network that covers a larger geographic area
than that covered by a MAN. Again, there is no standard definition, but a WAN generally
encompasses the network that extends beyond the typical distance of the MAN. In
traditional telecommunications nomenclature, a WAN references the networks that
include the metro core, regional, long haul, and ultra long-haul networks. A WAN connects
multiple LANs/MANs and is usually owned and operated by multiple Service Providers
(that may or may not, depending on local regulatory boundaries, also own and operate
one or more MANs). A WAN typically uses optical fiber as the physical medium of
transmission and usually has a much higher level of bandwidth capacity than the MAN
(since in essence it aggregates and transports traffic from several MANs simultaneously).
Figure 1.8 illustrates the MAN (including the Access) and the WAN that encompass
Service Provider networks.
Before exploring data networking in the MAN and WAN, it is instructive to note the
fundamental differences between delivering communication services in a LAN versus
doing so in the MAN and WAN.
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