1. By: Danielle Bowen-Dooley
Wide Area Networks
By: Danielle Bowen-Dooley

2. Wide area network (WANs) are networks that cover a broad area (i. e
Wide area network (WANs) are networks that cover a broad area (i.e., any telecommunications network that links across metropolitan, regional, national or international boundaries) using leased telecommunication lines.
What are they? (1)

3. The textbook definition of a WAN is a computer network spanning regions, countries, or even the world. However, in terms of the application of computer networking protocols and concepts, it may be best to view WANs as computer networking technologies used to transmit data over long distances, and between different LANs, MANs and other localised computer networking architectures.
What are they? (2)

4. WANs are either point-to-point, involving a direct connection between two sites, or operate across packet-switched networks, in which data is transmitted in packets over shared circuits.
Point-to-point WAN service may involve either analog dial-up lines, in which a modem is used to connect the computer to the telephone line, or dedicated leased digital telephone lines, also known as "private lines.“
Analog lines, which may be either part of a public-switched telephone network or leased lines, are suitable for batch data transmissions, such as non-urgent order entry and point-of-sale transactions.
How do they work?

5. Connection Technology Options
There are a few options available for WAN connectivity:
Leased Lines
Circuit Switching
Packet Switching (Connection Oriented and Connectionless)
Cell Relay
Connection Technology Options

6. A leased line is a service contract between a provider and a customer, whereby the provider agrees to deliver a symmetric telecommunications line connecting two or more locations in exchange for a monthly rent.
Typically, leased lines are used by businesses to connect geographically distant offices. Unlike dial-up connections, a leased line is always active.
Leased Lines

7. Circuit switching is a methodology of implementing a telecommunications network in which two network nodes establish a dedicated communications channel (circuit) through the network before the nodes may communicate.
The defining example of a circuit-switched network is the early analog telephone network. When a call is made from one telephone to another, switches within the telephone exchanges create a continuous wire circuit between the two telephones, for as long as the call lasts.
Circuit Switching

8. Packet switching is a digital networking communications method that groups all transmitted data – regardless of content, type, or structure – into suitably sized blocks.
Connection-oriented communication, in packet switching, is a network communication mode in telecommunications and computer networking, where a communication session or a semi- permanent connection is established before any useful data can be transferred, and where a stream of data is delivered in the same order as it was sent, where as connectionless communication is a data transmission method in which each data unit is individually addressed and routed based on information carried in each unit.
Packet Switching

9. cell relay refers to a method of statistically multiplexing small fixed-length packets, called "cells", to transport data between computers or kinds of network equipment.
Cell relay systems break variable-length user packets into groups of fixed-length cells, that add addressing and verification information. Frame length is fixed in networking hardware, based on time delay and user packet-length considerations. One user data message may be segmented over many cells.
Cell Relay