What is a WAN? Pros, Cons and Examples

July 24, 2023

This article on wide-area networks (WAN) includes helpful definitions, examples, answers to frequently asked questions, and more. Read on to learn what a WAN is, in addition to the advantages and disadvantages of WANs.

What is a WAN?

A wide-area network (WAN) is a technology that spans several locations in a geographic area, connecting homes, offices, cloud applications and the like.

WANs are made up of multiple networks, including local area networks (LAN), that communicate with one another. Put simply, a WAN is a network of networks, the largest of which is the Internet, which constitutes multiple international networks 

What’s the purpose of a WAN connection?

WANs are essential in an increasingly digital world and serve an array of functions necessary for individuals and corporations. For example, we use WANs to:

• Communicate with voice and video
• Share resources and media
• Remotely back up data and access data storage
• Use applications running in the cloud
• Run internal applications

WAN technology is particularly helpful to businesses and organisations, enabling them to access information quickly and securely. 

WAN: A History

Below, we’ve included a brief overview of how wide-area networking began:

• Wide area networks were first created by the US Air Force in the late 1950s to connect sites in the Semi-Automatic Ground Environment (SAGE) radar defence system. The WAN comprised an array of phone lines, telephones, modems, and more to connect the various sites. 
• The IP-based Internet’s origins can be traced back to the Advanced Research Projects Agency Network (ARPANET), which served as the foundation for the development of this global network. ARPANET was the first-ever wide-area packet-switching network that featured distributed control. It was also the pioneering network to implement Transmission Control Protocol/Internet Protocol (TCP/IP) – a suite of communication protocols used to interconnect network devices on the Internet.
• Initially, ARPANET was interconnected with institutions like the University of California, Los Angeles (UCLA), the Stanford Research Institute (now SRI International), the University of California, Santa Barbara (UCSB), and the University of Utah.

What are the different types of WAN technologies?

There are a variety of WAN technologies, including:

Packet switching

Packet switching is a means of data transmission whereby messages are compartmentalised into several parts (known as spackets). Each packet is sent in the most optimal way – whether this be independently, in triplicate, or any other route – before they’re reassembled at the destination. Each packet features a piece part (known as the payload), as well as an identifying header which states the destination and reassembly information. Sending packets in triplicate is a reliable way to check for packet corruption, while each packet is checked to see that at least two copies match. If this isn’t the case, a request is made for the packet to be re-sent.

TCP/IP protocol suite

TCP/IP is a suite of communication protocols that allow interconnection between network devices on the Internet and other networks.

Router

Routers are devices used to interconnect local area networks (LANs) to form a WAN. A router’s IP address determines where to forward packets.

Overlay network

Overlay networks refer to virtual computer networks layered on top of another network. Overlay networks often function to support applications or features that an underlying network can’t facilitate.

Packet over SONET/SDH

Packet over SONET/SDH (POS) is a communications protocol used to transmit packets over SDH (Synchronous Digital Hierarchy) or SONET (Synchronous Optical Networking).

Multiprotocol Label Switching (MPLS)

Multiprotocol Label Switching (MPLS) is a technology that routes traffic using the shortest path based on labels, as opposed to network addresses. It functions to handle forwarding over private WANs and has a positive impact on traffic speeds.

ATM

Asynchronous Transfer Mode (ATM) is a telecommunications standard for digital transmission of various types of traffic. While it’s been surpassed by IP-based technologies in the modern day, ATM was a common switching technique in early data networks. The method utilises synchronous time-division multiplexing to codify data into small cells; this is opposed to modern, IP-based technology, which utilises variable packet sizes.

Frame relay

Frame relay uses packet-switching technology to transmit data between LANs or the endpoints of a WAN. The method involves breaking data into smaller packets which are then transmitted through a shared frame relay network. Once the packets arrive at the destination, they’re reassembled.

WAN advantages

WAN advantages include:

• Area coverage: WAN covers vast geographical areas, meaning businesses and organisations in different locations can connect and communicate through the same network. 
• Centralisation: Organisations using a WAN can share the data connected to all associated devices. For instance, a head office server will be able to share data among all subsidiary branches. 
• Updated files: WANs allow users to access updated files and data from the servers, while companies can update files so that all connected devices get them quickly.
• Communication: The progression of the IoT and LAN has led to an increase in the visibility of WAN-based devices. This makes communication via message much quicker.
• Larger bandwidth: Corporate LANs often use leased lines, providing a larger bandwidth than many standard broadband connections. 

WAN disadvantages

WAN disadvantages include:

• Security: WAN faces more security issues than LAN as a result of utilising more technologies.
• Necessity of security solutions: As a result of these potential security issues, those using WANs will need to find appropriate security solutions, such as antivirus software.
• Cost to install: Installing WANs costs money while setting up a WAN requires routers, switches, and security solutions.
• Connection problems: In more remote areas, users may face connection problems; to remedy this, they may have to buy a dedicated line from the ISP.
• Troubleshooting: Troubleshooting issues on a WAN can be tricky and time-consuming. It’s not always easy to identify the cause of an issue due to its broad coverage.
• Maintenance: Maintenance can be similarly tricky, and is a full-time task

WAN examples

Below, we’ve included a few examples of WANs to help illustrate what they are and how they work:

Enterprise or organisation

In enterprises, WANs may be used to ensure all branch offices are interconnected or to connect remote employees to the organisation’s main office. Universities may utilise WANs so students can access research resources or library databases.

Banks

Baks may utilise a WAN for its branches and ATM machines. WANs can connect branches in multiple secure locations, benefitting both employees and users.

The Internet

The internet is often described as the world’s largest WAN, for it’s a network of networks that connects devices and computers all over the world.

What’s the difference between a WAN and a LAN?

WANs and LANs (local area networks) serve different purposes and cover different areas. LANs cover relatively small areas, such as a home or office building, connecting devices in fairly close proximity to one another. WANs, on the other hand, cover large geographical areas and connect multiple LANs. 

Ultimately, WANs facilitate communication and connection over longer distances, whereas LANs are designed for sharing within a specific location.

More helpful articles:

• What Is the PSTN and How Does it Work?
• What Is the ISDN and How Does it Work?
• Broadband Technology and Terminology

Frequently asked questions

What is a WAN router?

Also referred to as edge routers or border routers, WAN routers route data packets between WAN locations, providing organisations access to a carrier network. There are a variety of WAN protocols, including:

• Packet over SONET/SDH (PoS)
• Multiprotocol Label Switching (MPLS)
• ATM
• Frame Relay

What is an SD-WAN?

A software-defined Wide Area Network (SD-WAN) is a virtual WAN architecture that connects and extends networks over vast geographical distances. SD-WANs enable businesses to utilise an array of transport services – such as MPLS, LTE, and broadband internet services – to reliably connect users to applications.

What’s the difference between WAN and SD-WAN?

The main difference between a traditional WAN and an SD-WAN is that the former offers a conventional way to manage a wider area network, whereas the latter utilises a software-defined approach. This has a number of implications, such as:

• Traditional WANs don’t allow for load balancing and disaster recovery through carrier diversity. Contrastingly, SD-WANs are a lot more flexible, and can make changes in real-time should environmental situations change. 
• Traditional WANs take time to configure and scale up; SD-WANs, on the other hand, are much quicker.
• Traditional configurations require human intervention, whereas SD-WAN configuration is automatic.

Ultimately, SD-WAN presents greater flexibility, scalability, and cost-effectiveness than traditional WANs.

What is WAN optimisation?

WAN optimisation, also known as WAN acceleration, refers to a range of techniques for improving data transfer across WANs.

It involves implementing bandwidth preservation techniques like compression, caching, data deduplication, image optimisation, and more as a remedy for network congestion and latency.

WAN optimisation is important because it streamlines network traffic and gives people access to the information they need quicker.