What is a WAN in Networking? What Are the Features of WAN?

What is a WAN

A WAN, in the networking, is the Wide Area Network, also named Long Haul Network. WAN can cover up to thousands of kilometers, connecting several cities or countries. Furthermore, it can connect several continents and provides long distance telecommunication, in order to build an international network. Its covering areas are bigger than LAN and MAN.

The communication subnet of WAN mainly uses the packet-switched network. It can use the public packet-switched network, satellite communication network and wireless packet-switched network, to connect those different regions of the LAN or computer systems, in order to achieve the purpose of resource sharing. For example, our Internet is the largest Wide Area Network in the world.

The WAN is composed of many switches. These switches are connected by point-to-point line. Almost all point-to-point communication can be used to establish wide area networks, including leased lines, optical fiber, microwave, satellite channels, etc. The WAN switch is actually a computer with a processor and input / output devices to send and receive data packets.

Features of WAN

The WAN data transmission rate is usually higher than the LAN, but the signal propagation delay is much larger than the LAN. Typical rates of WAN are ranged from 56kbps to 155Mbps, with 622Mbps and 2.4Gbps or higher wide area networks available. However, the propagation delays can range from a few milliseconds to hundreds of milliseconds (when using satellite channels).

The WAN connects devices that are far apart. These devices include:

1. Routers - provide services, such as LAN interconnects, WAN interfaces, etc.
2. Switches - connect to the WAN for voice, data and video communications.
3. Modems - provide voice-grade services. The Channel service units are interfaces for T1 / E2 services. The Terminal adapters are interfaces for the Integrated Services Digital Network.
4. Communication server - A collection of incoming and outgoing connections by users.

The WAN is different from the LAN because its broader is bigger. The WAN has different feature:

1. Coverage Wide range of communication distance is up to thousands of kilometers.
2. Unlike some fixed structures on the LAN, WANs have no fixed topology and usually use high-speed fiber as the transmission medium.
3. It mainly provides communication-oriented services to support users of the computer for long-distance exchange of information.
4. The LAN is usually connected to the WAN as an end user of the WAN.
5. The WAN management and maintenance are more difficult than the LAN.
6. The WANs are generally formed, managed and maintained by telecommunications departments or companies and provide paid communications, traffic accounting and billing issues to the whole society.

Instance

There are several common WAN, such as PSTN, X.25, DDN, FR, and SMDS.

1. PSTN

The public switched telephone network (PSTN) is the aggregate of the world's circuit-switched telephone networks that are operated by national, regional, or local telephony operators, providing infrastructure and services for public telecommunication.

2. X.25

X.25 is an ITU-T standard protocol suite for packet switched wide area network (WAN) communication. An X.25 WAN consists of packet-switching exchange (PSE) nodes as the networking hardware, and leased lines, plain old telephone service connections, or ISDN connections as physical links. X.25 is a family of protocols that was popular during the 1980s with telecommunications companies and in financial transaction systems such as automated teller machines. X.25 was originally defined by the International Telegraph and Telephone Consultative Committee (CCITT, now ITU-T) in a series of drafts and finalized in a publication known as The Orange Book in 1976.

3. DDN

Digital Data Network (DDN) is a transmission network that uses digital channels to provide data communication. It mainly provides point-to-point and point-to-multipoint digital leased lines or private networks.

4. FR

Frame Relay is a standardized wide area network technology that specifies the physical and data link layers of digital telecommunications channels using a packet switching methodology. Originally designed for transport across Integrated Services Digital Network (ISDN) infrastructure, it may be used today in the context of many other network interfaces.

5. SMDS

Switched Multi-Megabit Data Service (SMDS) was a connectionless service used to connect LANs, MANs and WANs to exchange data, in early 1990s. In Europe, the service was known as Connectionless Broadband Data Service (CBDS).

SMDS was specified by Bellcore, and was based on the IEEE 802.6 metropolitan area network (MAN) standard, as implemented by Bellcore, and used cell relay transport, Distributed Queue Dual Bus layer-2 switching arbitrator, and standard SONET or G.703 as access interfaces.

It is a switching service that provides data transmission in the range between 1.544 Mbit/s (T1 or DS1) to 45 Mbit/s (T3 or DS3). SMDS was developed by Bellcore as an interim service until Asynchronous Transfer Mode matured. SMDS was notable for its initial introduction of the 53-byte cell and cell switching approaches, as well as the method of inserting 53-byte cells onto G.703 and SONET. In the mid-1990s, SMDS was replaced, largely by Frame Relay.