Wide Area Network (WAN)

WAN Types and Features

What is WAN?

Two wide-ranging network (WAN) are defined. WAN book definition is a network that spans large geographic locations, usually connecting multiple local area networks (LANs). WAN is a practical definition of a network that passes through a public network or commercial vendor using one of the WAN technologies

What are the main components?

The main components of WAN are routers, switches and modems. These components are described in the hardware section.

CPE – The devices in the subscriber's premises are referred to as the Customer's Location (CPE).

The subscriber owns CPE or leases CPE from the service provider. A copper or fiber cable connects CPE to your nearest service provider or central office. This cabling is often referred to as a local loop or "last mile".

DTE / DCE – Devices for the recovery of local loop data are data transfer devices or data communication equipment (DCE). The client devices that transmit the data to the DCE are called Data Transfer Devices (DTEs). DCE primarily provides DTE's interface to the WAN cloud communication interface.


WAN requires a variety of hardware components to work. The typical hardware elements typical for the WAN are:

Router – An electronic device that connects a local area network (LAN) to a wide area network (WAN) and handles the message sending of messages between the two networks. Operates in Layer 3 and makes decisions by using IP addresses

Switch – The switch is a network device that selects a path or circuit that transfers a data unit to the next destination. Works on Layer 2 and uses MAC addresses to send data to the correct destination

Modem – In the case of a short modulator / demodulator, the modem allows the computer to communicate with other computers over the telephone lines. It works in layer 1, where signals are converted from digital to analog and vice versa for transmission and reception.

Wan Standards

WANs work within Layer 1 and Layer 2 within the OSI model. The data link layer and the physical layer. Physical Layer Protocols describe how to provide electrical, mechanical, and functional connectivity with the services provided by the Internet service provider. The data link layer determines how the data is embedded to transfer from remote locations.


Encapsulation is a data packet in a particular protocol header. Keep in mind that WANs work in the data layer layer of the physical layer and data model, and that higher-level protocols, such as IPs, are encrypted over the WAN connection. Serial interfaces support a wide range of WAN encoding types that need to be manually entered. These types include SDLC, PPP, frame delay, and so on. Irrespective of WAN encapsulation, each must be identical on both sides of the point-to-point link.

Packet and Circuit Switching

Circuitry switching and packet switching are both high capacity networks.

Most of the switched networks today receive data over the network

by packet switch

The circuit switch is more reliable than packet switching. Switching is old and expensive, packet switching is much more modern.

General Routing Problems

What is Routing Protocol?

The routing protocol protocol that determines how routers communicate and exchange information on a network. Each router must know its immediate neighbors and know the structure of the network topology. Routers know this because the routing protocol shares this information.


The RIP (Routing Information Protocol) is one of the most commonly used protocols on internal networks. Routers use RIP dynamically for changes in network connections and provide information about which networks can access routers and the distance between them. Sometimes RIP is said to be in Pieces in Piece in view of the reputation that the RIP will unexpectedly crack and the network can not function.

Routing Algorithms

Distance Vector

The router simply informs your neighbors about the routing table. The distance vector protocol is also known as bellman-ford algorithm

Link status

This type of routing protocol requires each router to maintain a partial map of the network. The algorithm of the connection state algorithm is also known as the Dijkstra algorithm


IGRP is a type of distance vector routing protocol used by cisco to exchange routing information in the autonomous system. Distance vector protocols measure distances and compare routes. Routers using spacing vectors must send part or all of the routing table to a routing update message at regular intervals to each neighbor router.

Addressing and Routing

What is Routing?

Routing the process of moving packets from one network to another.

Routes known as a route are routed via a routing protocol using a router and then routed from the router to the router along the router's route.

IP Address

All computers connected to the Internet have assigned an IP address. An example of an IP address is IP addresses appear in decimal format to help people understand, but computers communicate in binary form. IP addresses are called four separate numbers called Octets. Each position consists of eight bits. If you add it, you get a 32-bit address. The purpose of each IP address in an IP address is to create networks that can be assigned to a network. Three major departments are dealing with classes A, B and C. The IP addresses octets are divided into two sections Network and Host. In class A, the first octet is the network part, which determines which network the computer belongs to, the last octets of the address being the network owner.


Subnetting allows you to create multiple networks within a class A, B or C. The subnet address is the address used by the LAN. Class C network address has subnet masks. The subnet mask identifies which part of the network and which host it is. For example, the first octet three octets is the network address and the last octet is the host (workstation). It is important to create an important network subnetwork, because gateways have to forward packets to other LANs. If the IP addresses and the subnet mask are enabled by the NICs on the gateways, it allows gateways to route the packets from LAN to LAN. After the packet arrives at the destination, the gateway uses the bits of the subnet part of the IP address to determine which LAN to send the packets.

Circuit Switched Leased Lines

A circuit-switched network is one that creates a (or channel) between nodes and terminals before users can communicate. Below are some terminology related to circuit-switched networks:

Frame Relay is a telecommunications service designed for cost-effective data transmission between local area networks (LANs)

Basic interference is the Internet connection used by small businesses. ISDN BRI provides 64kbit / s digital channels to the user.

The Primary Radio Interface (PRI) is a telecommunications standard for voice and data transfer in two places

All data and audio channels are ISDN and 64 kbit / s

Packet switching

http://www.raduniversity.com/networks/2004/PacketSwitching/main.htm _Toc80455261

Packet switching refers to protocols where messages are sent to small packets before they are sent. Each package is then transmitted over the Internet. At the destination, packages are put together in the original message. The main difference in packet switching from circuit switching is that communication lines do not devise the transmission of the source to the destination. In packet switching, different messages may use the same network resources during the same period.


Asynchronous Transmission Mode (ATM) is a cellular relay, a packet switched network, and a protocol that stores data in small, fixed size encodes cells.

ISDN carries audio, data, video, and images over a telephone network. ISDN means integrated services for Digital Network. Isdn also provides 128 kbps bandwidth to users. This is done with a frame relay. The frame relay supplements and provides services between ISDN, which offers a 128 kb / s bandwidth and asynchronous transmission, which works a bit like the frame relay but at 155.520 Mbps or 622.080 Mbps. The frame relay is based on the older X.25 packet-switched technology and can be used to transmit analog signals, such as telephone conversations

PSDN is a packet data transmission network and a data communication network. Packeted networks do not create a physical communication signal such as a public telephone (circuit-switched network). The packets are sent for a specified period of time and are assigned to a source and a destination address. Packages then rely on routers to read their addresses and route packets over the network.

Mobile and Broadband Services

Digital Subscriber Line (DSL) primarily serves to establish high-bandwidth connections in homes and small businesses using a copper wired telephone line. This can only be achieved if it is within the scope of the telephone exchange. DSL offers a maximum download speed of 6 megapixels, enabling streaming video, audio and 3D effects. DSL is set up for ISDN exchange and is competing with cable modem to provide multimedia services. DSL works by linking the telephone line to the telephone office with copper wires that are wired together.

Asymmetric Digital Subscribers Line is the most widespread for home users. It provides a high download speed but a lower upload speed. With ADSL, up to 6.1 megabits per second can be transmitted and up to 640 Kb / s up.


Symmetric Digital Subscriber Line is a digital subscriber line that runs through a pair of copper wires. The main difference between ADSL and SDSL is the difference between upload and download speeds. SDSL allows the same uplink data rate and downstream data rate as ADSL upstream, can be very slow.

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HDSL's high-speed digital subscriber line is one of the earliest forms of DSL for broadband digital transfer between a company site and a telephone company and a customer. The main feature of HDSL is to provide bandwidth equal to both directions

IDSL is a system that transmits 128 kbit / s data on a regular copper telephone line from the user to the destination via digital transmission

A local A loop enables service providers to connect directly to the consumer through copper local loops, then add their own equipment to provide broadband and other services. This process involves operators connected to local exchange buildings to join the copper wiring network, linking them with homes and businesses. The BT example is a local exchange. The local loop that connects the phone to most subscribers can far exceed the frequencies at the 3.4 kHz ceiling.

Advantages of Using DSL

DSL provides virtually instant voice, data, and video on standard copper lines. Your DSL connection can avoid delays when you expect information and graphics downloadable from the Internet. Provides cost-effective, high-speed Internet connectivity for users. Another advantage is that a DSL connection is always on-line (such as a LAN connection), no waiting time for dialing or interconnection

There are currently over 10 million broadband connections in the UK. By December 2005, there were 9,792 million broadband connections in the United Kingdom, with average broadband up to 70,000 per week during the three months to December


Source by Chris Michael Jones

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