What is a WAN? [Definition, Types, and Technologies]

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What is a WAN? [Definition, Types, and Technologies]

Srijani Ghosh
Last updated on June 10, 2022

    A wide area network (WAN) is a telecommunication network that connects multiple computers and network devices within a large geographic area, such as a city, state, or country. It consists of various networks, such as local area networks (LAN) and metropolitan area networks (MAN). The best and most well-known example of a wide area network is the internet.

    The internet has become the heart of this digital world. It is a worldwide network of interconnected computer systems and network devices that leverages the TCP/IP model or the Internet Protocol suite to facilitate communication between them. In simple words, it is a vast communication network that connects computers all over the world.

    This blog post will make you familiar with a wide area network (WAN). Also, it will help you learn about different types of wide-area networks, WAN technologies, and the upsides and downsides of using a WAN.

    So, let us start our discussion!

    What is WAN?

    WAN stands for Wide Area Network. It is a type of network that connects multiple computers and network devices spread across a large geographical area. In other words, it is a geographically distributed network that connects multiple local area networks (LANs) together. In general, a LAN (Local Area Network) connects computers and network devices within a small geographic area. Therefore, we can say a WAN is a network of networks.

    Large businesses or enterprises having multiple offices at different locations often leverage a wide area network. Each of their offices has a LAN, and a WAN connects all those office networks together. As a result, employees from different offices can communicate quickly with their co-workers, share data, and access various resources.

    A wide area network primarily uses leased lines, VPNs, or IP tunnels to connect multiple LANs or other networks. Also, it is the largest and most expensive computer network available today. The internet is the best example of a wide area network.


    In the 1950s, the U.S. Air Force first created a wide area network to connect multiple sites in the Semi-Automatic Ground Environment (SAGE) radar defense system. At that time, this network linked sites in the system using phone lines, modems, and telephone lines.

    The late 1970s witnessed the development of a WAN to connect devices from two different locations across a street or city. They used leased lines, which resulted in a fast network speed, but it was an expensive solution at that time. This led to the invention of packet-switched networks. This type of network was less expensive and used network resources efficiently.

    Later, in the early 1990s, frame-relay technology was invented, which significantly lowered the overall cost of operating a wide area network. Also, it reduced the requirement for hardware components. At the same time, WANs with Asynchronous Transfer Mode (ATM) was designed to enable the transmission of various types of traffic, such as audio and video signals, without a separate overlay network.

    The invention of the Multi-Protocol Label Switching (MPLS) enabled businesses with multiple branch offices to connect devices from various offices and facilitate communication, data storage, and resource sharing. Later came the WAN optimization technology into existence. The world’s first WAN Optimization provider is Peribit.

    Furthermore, the invention of the Software-Defined wide area network (SD-WAN) in 2009 is the most recent evolution of a wide area network. The Optimized WAN and SD-WAN intend to make the management of wide-area networks easier while improving the networking capabilities.

    Types of WAN

    In general, there are two types of wide-area networks, namely switched and point-to-point.

    1. Point-to-Point Wide Area Network

    In a point-to-point wide area network, two endpoints or LANs are connected through a dedicated communication link or a secure leased line. A leased-line is a dedicated network connection from a large network provider, such as an internet service provider (ISP). The best example of a point-to-point WAN is a dial-up line that connects a home computer to the internet.

    2. Switched Wide Area Network

    A switched wide area network is a combination of a point-to-point network that provides access to several endpoints. All the endpoints or LANs are connected via a shared communication channel. The best example of a switched wide area network is an asynchronous transfer mode (ATM).

    Types of WAN Technologies

    The following are various types of WAN technologies:

    • Packet-Switching

    Packet-switching is a data transmission technique that breaks a single message into several parts called packets. It identifies the optimum route for each packet, assigns a number to each packet, and sends them independently to the destination. Moreover, all the packets at the destination are reassembled based on the numbers assigned to them.

    Each packet consists of two parts, namely the payload and an identifying header. The header consists of information about the destination and reassembly of the packet.

    Moreover, this technique involves sending data packets in triplicate to check for packet corruption. It verifies that each packet matches and confirms with its other two copies. If the verification fails, the sender has to resend that packet.

    • Overlay Network

    An overlay network is a network layered over another network. It simply means that a network is built on top of another network and is supported by the infrastructure of the underlying network.

    We can also define an overlay network as creating a virtual connection between two endpoints using software over existing hardware infrastructure. Here, endpoints can be either actual physical locations, such as a network port, or logical locations assigned by the software address in the networking cloud.

    This type of network encapsulates one packet inside another packet and decouples the network services from the underlying infrastructure. Once the encapsulated packet reaches its destination, it is de-capsulated.

    • Multiprotocol Label Switching (MPLS)

    Multiprotocol Label Switching (MPLS) is a routing optimization technique that uses the shortest path to route network traffic based on the ‘labels’, rather than looking at the complex routing tables of routers. MPLS assigns labels to each data packet and controls the path they follow.

    Moreover, MLPS is a protocol-independent and scalable solution. It significantly increases the delivery rate of IP packets so that users do not experience downtime when connected to the network.

    In addition, MPLS works somewhat similarly to VPN . It separates the traffic of one customer from other customers. Though it does not encrypts data like a VPN but ensures that a packet from one customer cannot be received by other customers.

    • ATM (Asynchronous Transfer Mode)

    Asynchronous Transfer Mode (ATM) is a telecommunication standard for the transmission of various types of traffic, such as voice, data, audio, etc., in one network, without the requirement for a separate overlay network.

    Also, it is a switching technique that encodes data into small fixed-size cells by using asynchronous time-division multiplexing.

    ATM is completely in contrast to Ethernet or the internet, which use variable packet sizes for data transmission. Moreover, the synchronous optical network (SONET) uses ATM as its core protocol.

    • Frame Relay

    Frame Relay is a networking technology that enables data transmission between LANs or endpoints of a wide area network. It is a standardized wide area network technology that uses a packet switching methodology to specify the physical and data link layers of digital telecommunications channels.

    This protocol works at the data link layer of the network. It is the best alternative to a point-to-point network that connects multiple nodes, which eliminates the need for establishing a dedicated link between every two nodes. In addition, frame relay allows dynamic bandwidth allocation and the transmission of different sizes of packets.

    • Packet over SONET/SDH (PoS)

    Packet over SONET/SDH (PoS) is a communication protocol for transmitting data packets in the form of the point-to-point protocol (PPP) over SDH or SONET. SONET and SDH are standardized protocols for transmitting digital bitstreams using lasers or LEDs over optical fiber.

    The primary application of PoS is to transmit IP packets across a wide area network. Also, a large amount of internet traffic is carried out over PoS links.

    Advantages and Disadvantages of a WAN

    Let us now throw light on the major upsides and downsides of using a wide area network.


    • Area Coverage: A wide area network covers a large geographical area of up to 1000 kilometers. As a result, if you have a business with multiple office branches, you can use a wide area network to connect all the office branches and enable communication between them.
    • Centralized Data: A wide area network enables you to share data with all other connected devices within a network. For instance, you can set up a head office server for your business and share data among all office branches without any hassle. The head office server provides support and backup of data to all other connected devices.
    • Updated Data: The server stores all files and documents in a wide area network. If the data stored on the server is modified or updated, all other connected computers and network devices within a network receive the updated information.
    • High Bandwidth: Since a wide area network spans a large geographic area of up to 1000 km, it has higher bandwidth than LANs and MANs.
    • Sharing of Resources and Software: Like LANs, wide area networks also facilitate sharing of various resources and software among all the computers connected to a network.
    • Guaranteed Uptime: Wide area networks provide a guaranteed uptime.


    • Installation Costs: Because of the large geographical area coverage, the installation of WANs is pretty expensive and more complex than LANs and MANs. To set up a wide area network, you need to buy various hardware components, such as routers, switches, and security solutions.
    • Security: Wide area networks are more vulnerable to malicious attacks than LANs and MANs. As they combine multiple networks and use various types of technologies, they face a lot of security issues.
    • Security Solutions: Since a wide area network is prone to malicious attacks and viruses, you need security solutions, such as firewall and antivirus software, to prevent security threats.
    • Troubleshooting Issues: Fixing a problem if anything goes wrong in a wide area network is pretty challenging. This is because it covers a large area, and identifying the exact cause may be difficult and time-consuming.
    • Maintenance Issues: Maintaining a wide area network is again a challenging task. Since it comprises various hardware and software components, the network administrators and technicians have to maintain them regularly and repair them in case of issues.


    This concludes our discussion on wide area networks. Since it has a large geographic coverage, a WAN is very useful for large-scale businesses having multiple office branches. It assists them in connecting the networks of all the office branches and carrying out their operations smoothly.

    In this article, we have explained different types of WAN, types of WAN technologies, and the advantages and disadvantages of using a wide area network.

    We hope you find this article interesting and enlightening. Feel free to share your queries regarding this topic in the comments section below.

    Frequently Asked Questions

    1. What is the common use of a WAN?

    Large organizations and enterprises commonly use a wide area network to connect the networks of their multiple office branches, where each office branch has a local area network.

    2. What is a WWAN?

    WWAN stands for Wireless Wide Area Network. It is a type of a wide area network that involves wireless network connections.

    3. What is SD-WAN?

    SD-WAN stands for Software-Defined Wide Area Network. It is a virtual wide area network architecture that enables businesses to use any combination of transport services, including LTE, MPLS, and internet services, to securely connect the users to their applications.

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