Wide-area network (WAN) is a collection of local area networks (LANs) or other networks that communicate with one another. A network of networks, with the Internet the world’s largest WAN. Today, many types of WANs are made for various use cases that reach virtually every aspect of modern life.
How did wide-area networking start?
The U.S. Air Force created the first known WAN in the late 1950s to interconnect sites in the semi-automatic ground environment (SAGE) radar defence system. The sites were linked with an extensive network of dedicated phone lines, telephones, and modems. The foundation of the IP-based Internet started with the Advanced Research Projects Agency Network, called ARPANET in short, the first wide-area packet-switching network with distributed control and the first network to implement a TCP/IP protocol suite. ARPANET initially interconnected the University of California, Los Angeles, the Stanford Research Institute, the University of California, Santa Barbara, and the University of Utah.
What is a WAN router?
A WAN router, also known as an edge router or border router, is a device that routes data packets between WAN locations and gives enterprise access to a carrier network. Several WAN protocols have been developed, including Packet over SONET/SDH (PoS), Multiprotocol Label Switching (MPLS), ATM, and Frame Relay.
What is software-defined WAN (SD-WAN)?
Software-defined WAN is an approach for making WAN architectures easier to implement, Run and manage. It is based on virtualisation, application-level policies, overlay networks, and onsite SD-WAN devices and software platforms. SD-WAN increases data-transfer efficiencies across a WAN by moving traffic to lower-cost network links to do the work of more-expensive leased or MPLS lines.
What is WAN optimisation?
Latency and bandwidth constraints often cause performance issues in enterprise WANs. WAN optimisation uses different techniques, including deduplication, compression, protocol optimisation, traffic shaping, and local caching. You can use SD-WAN technology and WAN optimisation together. Some SD-WAN vendors are adding WAN optimisation features to their products.
Types of WAN technologies
Packet switching
Packet switching is a method of data transmission in which a message is broken into different parts, referred to as packets, sent independently over whatever route is most favourable for each package and reassembled at the destination. Each pack contains a piece part called the payload and an identifying header with destination and reassembly information. The packets are sent in triplicate to check for packet integrity. Every package is verified in a process that compares and confirms that at least two copies match. When verification fails, a request is made for the packet to be re-sent.
TCP/IP protocol suite
TCP/IP is a protocol suite of foundational communication protocols used to interconnect network devices on today’s Internet and another computer/device networks. TCP/IP stands for Transmission Control Protocol/Internet Protocol.
Router
A router is a networking device typically used to interconnect LANs to form a vast area network (WAN) and is referred to as a WAN device. IP routers use IP addresses to determine where to forward packets. An IP address is a numeric label assigned to each connected network device.
Overlay network
An overlay network can be defined as a data communications technique in which software creates virtual networks on top of another network, typically a hardware and cabling infrastructure. This is often done to support applications or security capabilities unavailable on the underlying network.
Packet over SONET/SDH (PoS)
Packet over SONET can be defined as a core communication protocol used for WAN transport. It explains how point-to-point links communicate using optical fibre and SONET (Synchronous Optical Network) or SDH (Synchronous Digital Hierarchy) communication protocols.
Multiprotocol Label Switching (MPLS)
MPLS is a network routing optimisation technique. To avoid time-delaying table lookups, it directs data from one node to the next using short path labels rather than long network addresses.
ATM
ATM (Asynchronous Transfer Mode) can be defined as a switching technique common in early data networks, which IP-based technologies have mostly replaced. ATM uses asynchronous time-division multiplexing to encode data into small, fixed-sized cells. By contrast, today’s IP-based Ethernet technology uses variable packet sizes for data.
Frame Relay
Frame Relay can be defined as a technology for transmitting data between LANs or endpoints of a WAN. It specifies digital telecommunications channels’ physical and data-link layers using a packet-switching methodology. Frame Relay packages data in frames and sends it through a shared Frame Relay network. Each frame contains all vital information for routing it to its destination. Frame Relay’s original aim was to transport data across telecom carriers’ ISDN infrastructure, but it’s used today in many other networking contexts.
