Wide Area Network
Introduction
A Wide Area Network (WAN) is a telecommunications network that extends over a large geographical area for the primary purpose of computer networking. WANs are often established with leased telecommunication circuits.
History
The history of WANs dates back to the late 1960s and early 1970s, when the Advanced Research Projects Agency Network (ARPANET) was established by the United States Department of Defense for research purposes. It was the first network to implement the protocol suite TCP/IP, which became the technical foundation of the modern Internet.
Design and Function
The design and function of a WAN are determined by its purpose and the specific needs of the organization it serves. A WAN can be privately owned or leased, but the term usually connotes the inclusion of public (shared user) networks. An important function of a WAN is to allow different local area networks (LANs) to communicate with each other. The WAN provides a method for businesses and government agencies to exchange information more effectively.
Technologies
Various technologies are used in WANs, including packet switching, circuit switching, and leased lines. Packet switching allows for data to be broken into small packets and transmitted over various routes on a network until reaching its destination. Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel through the network before the nodes may communicate. Leased lines are dedicated lines that provide direct connectivity between offices.
WAN Protocols
WANs operate using a variety of protocols. The most common WAN protocols include IP, MPLS, ATM, Frame Relay, and X.25. IP is the most common protocol used and is the standard for transmitting data over the Internet. MPLS is a protocol for speeding up and shaping network traffic flows. ATM and Frame Relay are protocols that provide services such as data link layer and network layer. X.25 is a suite of protocols that was popular during the 1980s but has since been replaced by less complex protocols such as IP.
Advantages and Disadvantages
Like any technology, WANs have their advantages and disadvantages. The primary advantage of a WAN is its size. By using a WAN, different types of organizations (e.g., businesses, governments) can communicate across long distances. This allows for increased collaboration and sharing of resources. However, WANs also have their disadvantages. They are complex to set up and manage, and they require significant resources and expertise to maintain. Additionally, as the distance between network sites increases, performance can decrease due to latency.
Future of WANs
The future of WANs is likely to be shaped by the increasing demand for high-speed, high-capacity networks. Technologies such as software-defined networking (SDN) and network function virtualization (NFV) are likely to play a significant role in the future development of WANs. These technologies allow for more flexible and efficient use of network resources, which can help to meet the increasing demand for network capacity.