Wide-Area Network
A wide area network is a data communications network that
operates beyond the geographic scope of a LAN. There are three major
characteristics of LANs. They connect devices that are separated by wide
geographical areas. They also use the service of carriers such as cell phone
companies or cable companies, satellite systems, and network providers.
Typically, the customer equipment will use various types of serial connections
to connect to the wide area network.
The Internet could be seen as the WAN of whims, it covers all
requirements and major characteristics, however, the term WAN is often referred
to and used in private networking scenarios. In other words, for connectivity
between offices and branches of the same organization. To the service provider,
it is the backbone of sources of revenue not only for connectivity to customers
but also for additional services like internet access, office-to-office
connectivity, and voice transmissions among others.
Need for WANs
So WANs were born to meet the wide area communications needs of
organizations of all kinds. Through the years though, the concept has been
expanded to not only connect branch offices to remote offices, but also allow
organizations to communicate with business partners, suppliers and customers. Also,
with the transient mobility and universal access, telecommuters and mobile
workers have been included as beneficiaries of WAN services, due to the
pneumatic nature of those connections. More ubiquitous networks like the
Internet have been used to expand the WAN and allow connectivity to this mobile
users.
WANs vs. LANs
The differences between WANs and LANs are intuitive. One is for
wide area connectivity; the other one is for local connectivity within a small
geographic area, buildings, campuses, etc. Also, the WAN typically uses an
outside service provider, whereas the LAN is owned by the organization. The
important point in today’s reality though is the fact that the boundaries are
blurring and if we think of technologies like MPLS and virtual private
networks, then a wide area connection is virtually part of the LAN and a
logical extension of the LAN and is treated other than distance and perhaps
performance as another LAN connection.
There is also the concept of the metropolitan area network
(MAN), which is perhaps a smaller WAN with some LAN capabilities, if you think
of metro Ethernet services at a high speed. In terms of this criteria though,
area and ownership, there is a clear distinction between WANs and LANs.
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