WAN Definition (Wide Area Network) | phoenixNAP IT Glossary

A Wide Area Network (WAN) is a telecommunications network that extends over a large geographic area, connecting multiple local area networks (LANs) and enabling communication and resource sharing across long distances.

What Is a Wide Area Network (WAN)?

A wide area network (WAN) is an extensive telecommunications network designed to connect multiple local area networks (LANs) over large geographic distances, which can span cities, countries, or even continents.

Unlike LANs, which are confined to a small area like a single building or campus, WANs enable devices and users in different locations to communicate and share resources as if they were on the same network. This is achieved through various transmission technologies, such as leased lines, satellite links, and public network infrastructures like the internet.

WANs are integral to modern business operations, facilitating data exchange, internet access, and centralized information systems, making them essential for organizations with dispersed offices or remote employees. They support a wide range of applications, from email and file sharing to video conferencing and enterprise resource planning (ERP) systems, by providing a robust and scalable means of connectivity. Additionally, WANs often incorporate security measures such as encryption and virtual private networks (VPNs) to protect data as it traverses potentially insecure networks.

WAN Architecture

WAN architecture refers to the design and structure of a wide area network, detailing how its components interact to ensure efficient and secure communication across vast distances. The architecture typically includes several key elements:

Core network. This is the backbone of the WAN, consisting of high-capacity routers and switches that interconnect various locations. It is designed for high-speed data transfer and reliable connectivity, often utilizing fiber optic cables, satellite links, or leased lines.
Edge network. At the periphery of the core network, the edge network connects local area networks (LANs) at different locations to the WAN. Edge routers and switches manage traffic between the LAN and the WAN, ensuring data is routed correctly.
Access network. This is the entry point where end devices such as computers, smartphones, and other network-enabled devices connect to the WAN. It often includes technologies like DSL, cable, fiber optics, or wireless connections.
Data center. Centralized repositories that store, manage, and disseminate data and applications used across the network. Data centers are equipped with powerful servers, storage systems, and network infrastructure to handle large volumes of data and ensure high availability and redundancy.
VPN (virtual private network). A technology that creates a secure, encrypted connection over a less secure network, such as the internet. VPNs are crucial for protecting data integrity and privacy when transmitting information across the WAN.
Network security. Integral to WAN architecture, encompassing firewalls, intrusion detection/prevention systems (IDS/IPS), encryption, and access control mechanisms to protect against unauthorized access, data breaches, and other security threats.
Redundancy and failover. To ensure high availability and reliability, WAN architecture often incorporates redundant links and failover mechanisms. This means that if one link or component fails, another can take over without disrupting network services.

WAN Protocols

Here are some common WAN protocols along with their explanations:

Point-to-Point Protocol (PPP). PPP is a data link layer protocol used to establish a direct connection between two networking nodes. It provides authentication, encryption, and compression and is commonly used for connecting routers on a serial cable, phone line, or other point-to-point links.
High-Level Data Link Control (HDLC). HDLC is a bit-oriented code-transparent synchronous data link layer protocol developed by ISO. It provides error detection and correction and is used in point-to-point and multipoint communications.
Frame Relay. Frame Relay is a standardized wide area network technology that specifies the physical and logical link layers of digital telecommunications channels. Originally designed for transport across ISDN infrastructure, it is used to connect local area networks (LANs) and transfer data across WANs efficiently.
Asynchronous Transfer Mode (ATM). ATM is a cell-based switching technique that uses asynchronous time-division multiplexing to encode data into small fixed-sized cells. It is designed for high-speed networks and supports various data types, including voice, video, and data.
Multiprotocol Label Switching (MPLS). MPLS is a scalable and protocol-independent transport technique that assigns labels to data packets, allowing routers to make forwarding decisions based on the labels rather than the packet's IP address. This improves speed and controls traffic flow across the network.
X.25. X.25 is an older network layer protocol for packet-switched networks. It uses a virtual circuit approach to ensure reliable and accurate data transfer, providing error correction and flow control. Although largely replaced by Frame Relay and other modern protocols, it is still used in some legacy systems.
Internet Protocol (IP). IP is the primary protocol for relaying datagrams across network boundaries. It enables internetworking and essentially establishes the internet. IP is responsible for addressing and routing packets between source and destination nodes.
Open Shortest Path First (OSPF). OSPF is a routing protocol for internet protocol networks. It uses a link-state routing algorithm and falls into the group of interior gateway protocols, operating within a single autonomous system (AS).
Border Gateway Protocol (BGP). BGP is a standardized exterior gateway protocol used to exchange routing information across the internet and between autonomous systems. It ensures that data follows the best available paths.
Dynamic Multipoint VPN (DMVPN). DMVPN is a solution for creating scalable and dynamic VPNs. It allows for the secure transfer of data between remote sites without needing to configure a permanent VPN tunnel for each site.
Link Access Procedure for Frame Relay (LAPF). LAPF is a data link layer protocol used in Frame Relay networks to provide reliable data transfer, including error detection and correction.

Types of WAN

Wide Area Networks (WANs) come in various types, each designed to meet specific connectivity and performance needs. Here are the main types of WANs:

Leased line WAN. This type uses a dedicated, private circuit to connect different locations. Leased lines provide high reliability and consistent performance because they are not shared with other users. They are often used for mission-critical applications requiring guaranteed bandwidth and low latency.
Circuit-switched WAN. This WAN type establishes a dedicated communication path between two points for the duration of the connection. Traditional telephone networks, where a call establishes a direct circuit between the caller and receiver, exemplify circuit-switched networks. While reliable, they are less efficient for data transmission compared to other types.
Packet-switched WAN. In packet-switched networks, data is broken into packets and transmitted over a shared network. Each packet can take different paths to reach its destination, where they are reassembled. Examples include Frame Relay, X.25, and modern IP-based networks. These networks are efficient and cost-effective, as they make optimal use of available bandwidth.
Public switched telephone network (PSTN). Originally designed for voice communication, PSTN can also be used for data transmission through dial-up modems. While outdated for high-speed data, it is still used in remote areas lacking modern infrastructure.
Integrated services digital network (ISDN). ISDN transmits voice, video, and data over traditional telephone lines, providing better speed and quality compared to dial-up connections. It is used for applications requiring reliable and synchronous data transmission, like video conferencing.
ATM (asynchronous transfer mode). ATM is a high-speed networking standard designed for transmitting data, voice, and video over a single network. It uses fixed-size cells to ensure predictable performance and is suitable for real-time applications. However, its complexity and cost have limited its widespread adoption.
MPLS (multiprotocol label switching). MPLS directs data from one network node to the next based on short path labels rather than long network addresses, improving speed and efficiency. MPLS is popular for its ability to handle multiple types of traffic and its flexibility in creating virtual private networks (VPNs).
SD-WAN (software-defined wide area network). SD-WAN uses software-based technologies to dynamically manage and optimize WAN connections. It allows for the combination of various connection types (e.g., broadband, LTE, MPLS) to improve performance, reduce costs, and enhance flexibility and control.

WAN Best Practices

Implementing a wide area network (WAN) involves a range of best practices to ensure optimal performance, security, and reliability. These practices help organizations maintain efficient communication and data exchange across dispersed locations:

Thorough network planning. Careful planning is essential. This includes understanding business requirements, traffic patterns, and future growth. A well-thought-out design reduces the risk of performance bottlenecks and ensures scalability.
Quality of service (QoS). Implement QoS policies to prioritize critical applications and services. This ensures that essential traffic, such as VoIP and video conferencing, receives the necessary bandwidth and low latency, improving overall user experience.
Redundancy and failover. Incorporate redundant connections and failover mechanisms to enhance network reliability. Redundancy ensures that if one link fails, another can take over, minimizing downtime and maintaining continuous service.
Secure connectivity. Use robust security measures, including encryption, firewalls, and VPNs. Secure connectivity protects data in transit from unauthorized access and cyber threats, ensuring data integrity and privacy.
Regular monitoring and maintenance. Continuously monitor network performance and health using advanced monitoring tools. Regular maintenance, including software updates and hardware checks, helps identify and resolve issues before they impact the network.
Optimized bandwidth management. Efficient bandwidth management prevents congestion and ensures smooth data flow. Techniques like traffic shaping and load balancing help distribute network load evenly, optimizing performance.
Centralized management. Utilize centralized management systems to streamline network operations. This allows for easier configuration, monitoring, and troubleshooting, enhancing operational efficiency.
Implement SD-WAN. Adopting SD-WAN can provide dynamic path selection, improved performance, and cost savings. SD-WAN enables better utilization of available bandwidth and more flexible network management.
User training and awareness. Ensure that users are aware of best practices and potential security threats. Training employees on proper network usage and security protocols helps maintain a secure and efficient WAN environment.
Scalability planning. Design the WAN with scalability in mind. Anticipate future growth and emerging technologies to ensure the network can adapt to evolving business needs without significant overhauls.