Global Network (WAN)

Types and characteristics of the WAN

What is a WAN?

There are two common definitions of a global network (WAN). The definition of a global WAN is a network that covers large geographic locations, usually for connecting several local area networks (LANs). The practical definition of a global network is a network that passes through a public network or a commercial carrier using one of several WAN technologies.

What are its main components?

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

CPE - Devices on subscriber promotions are called customer premises equipment (CPE).
The subscriber owns the CPE or rents the CPE from the service provider. Copper or fiber cable connects the CPE with the nearest exchange or central office of the service provider. This cable system is often called a local loop or “last mile.”

DTE / DCE — Devices that put data into the local loop are called data termination equipment or data transmission equipment (DCE). Client devices that transmit data to the DCE are called terminal equipment (DTE). The DCE primarily provides an interface to the DTE on the WAN cloud.

hardware

On the WAN, you need different types of hardware components. Typical pieces of equipment you'll need on the global network are:

A router is an electronic device that connects a local area network (LAN) to a wide area network (WAN) and handles the task of routing messages between two networks. Works at level 3 and makes decisions using IP addresses.

Switch. A switch is a network device that selects a path or pattern for sending a unit of data to the next destination. Works at Layer 2 and uses MAC addresses to send data to correct the addressee.

Modem - short for a modulator / demodulator, a modem that allows a computer to communicate with other computers via telephone lines. Works at level 1, where signals are converted from digital to analog and vice versa for transmission and reception.

Standards Wan

WANs operate in the OSI model using Layer 1 and Layer 2 layers. The data link layer and the physical layer. The physical layer protocols describe how to provide electrical, mechanical, and functional connections to the services provided by the provider. The data link layer determines how data is encapsulated for transmission to remote sites.

Encapsulation

Encapsulation is the wrapping of data in a particular protocol header. Remember that WANs operate at the physical and data link layer of the osi model and that higher layer protocols such as IP are encapsulated when sent over the WAN link. Serial interfaces support a wide range of WAN encapsulation types that must be specified manually. These types include SDLC, PPP, frame delay, and so on. Regardless of the WAN encapsulation used, it should be the same on either side of the point to point.

Switching packages and circuits

Circuit switching and packet switching are used in high-capacity networks.
Most switched networks today receive data over the network.
through packet switching.

Switch switching is more reliable than packet switching. Switch switching is old and expensive, packet switching is more modern.

Common routing problems

What is a routing protocol?

A routing protocol is a protocol that defines how routers exchange information and exchange information on a network. Each router has a preliminary knowledge of its immediate neighbors and knows the structure of the network topology. Routers know this because the routing protocol shares this information.

protocol

RIP (Routing Protocol) was one of the most commonly used protocols in internal networks. Routers use RIP to dynamically adapt changes to network connections and exchange information about which network routers can reach and the distance between them. It is sometimes said that the RIP stands for "Rest in the Plays" in terms of the reputation that the RIP has for a sudden hack and to create a network that cannot function.

Routing Algorithms

Vector distance

This type of routing protocol requires each router to simply inform its neighbors about its routing table. The distance vector protocol is also known as the bellman-ford algorithm.

Link status

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

IGRP

IGRP is a type of distance routing protocol, invented by cisco, used to exchange routing data in an autonomous system. Distance vector protocols measure distances and compare routes. Routers using a distance vector should send all or part of their routing table to a routing update message at regular intervals for each neighboring router.

Addressing and Routing

What does routing mean?

Routing is the process of deciding whether to move packets from one network to another.
The directions, also known as routes, can be learned by the router using a routing protocol, then the information is transmitted from the router to the router along the destination route.

IP address

Each computer connected to the Internet is assigned an IP address. An example of an IP address would be 192.168.0.1. IP addresses are displayed in decimal format to make it easier for people to understand, but computers interact in binary form. The four numbers that separate the IP address are called octets. Each position consists of eight bits. When added together you get a 32-bit address. The purpose of each octet in an IP address is to create classes of IP addresses that can be assigned on a network. There are three main classes that we deal with classes A, B and C. The octets of an IP address are divided into two parts: “Network and Host”. In the class A address, the first octet is a part of the network, this determines which network the computer belongs to; the last octets of the address are hosts belonging to the network.

Movable mesh

Sub netting allows you to create multiple networks within class A, B, or C addresses. A subnet address is the address used by your local network. In the class C network address you will have a subnet mask of 255.255.255.0. The subnet mask determines which part is the network and which is the host. For example, 192.168.6.15, the first octets of octets are the network address, and the last octet is the host (workstation). The network subnet is important because gateways need to forward packets to other LANS. By providing each gateway card with an IP address and subnet mask, it allows gateways to route packets from the local network to the local network. Once the packet arrives at the destination, the gateway then uses the bits of the subnet portion of the IP address to decide which LAN to send the packets to.

Circuit switched lines

A circuit-switched network is one that establishes a dedicated circuit (or channel) between nodes and terminals before users can exchange data. Here are some circuit-switched network terms.

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

Basic speed interference is a service used by a small business to connect to the Internet. ISDN BRI provides two 64 Kbps digital channels for a user.
Primary Speed ​​Interface (PRI) is a telecommunications standard for transferring voice and data between two points.
All data and voice channels are ISDN and operate at 64 Kbps

Packet switching

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

Packet switching refers to protocols in which messages are broken up into small packets before they are sent. Each packet is then transmitted over the Internet. At the destination, the packets are reassembled into the original message. The main difference from circuit switching is that the communication lines are not designed to transmit messages from the source to the destination. With packet switching, different messages can use the same network resources for the same period of time.

http://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode

Asynchronous transfer mode (ATM) is a cell relay, a packet switching network and a protocol that encodes data into small, fixed-size cells.

ISDN is used to transmit voice, data, video and images over the telephone network. ISDN is an integrated Digital Network service. Isdn also provides users with a 128 kbps bandwidth. This is done through the frame relay. Frame relay complements and provides a service between ISDN, which provides bandwidth at 128 Kbps and asynchronous transfer mode, which works slightly differently than frame relay, but at a speed of 155.520 Mbps or up to 622.080 Mbps. The Frame relay is based on the old X.25 packet switching technology and is used to transmit analog signals, such as telephone conversations.

PSDN stands for a packet-switched data network and is a data network. Packet switched networks do not establish a physical communication signal, as a regular telephone (circuit switched network) does. Packages are sent on a fixed basis and are assigned by source and destination address. Then the packets explicitly on the routers read the address and route the packets through the network.

Mobile and broadband services

Digital Subscriber Line (DSL) is mainly used to connect high-speed connections to homes and small businesses over a telephone line with a copper wire. This can only be achieved if you stay within the range of the telephone exchange. DSL offers download speeds of up to 6 Mbps, which provides continuous transmission of video, audio and 3D effects. DSL is configured to replace ISDN and competes with a cable modem in providing multimedia at home. DSL works by connecting your telephone line to a telephone set through copper wires that are twisted together.

Asymmetric digital subscriber line is most often used for home users. It provides high download speeds, but lower download speeds. Using ADSL, up to 6.1 megabits per second data can be sent downstream and up to 640 Kbps upstream.

http://en.wikipedia.org/wiki/Symmetric_Digital_Subscriber_Line

A symmetric digital subscriber line is a subscriber's digital line that runs through one pair of copper wires. The main difference between ADSL and SDSL is the difference in download and download speeds. SDSL provides the same downstream data rate and downstream data rate because the upstream ADSL stream can be very slow.

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HDSL A high-speed digital subscriber line, one of the earliest forms of DSL, is used for broadband digital transmissions on a corporate site and between a telephone company and a customer. The main characteristic of HDSL is that it provides equal bandwidth in both directions.

IDSL is a system in which data is transmitted at a speed of 128 Kbps on an ordinary copper telephone line from a user to a destination using a digital transmission.

The local cycle allows operators to directly connect to the consumer through local copper loops, and then add their own equipment to provide broadband and other services. This process involves operators accessing local exchange buildings to connect to the network of copper lines that connect them to homes and businesses. BT is an example of a local exchange. The local loop connecting the telephone exchange to the majority of subscribers is capable of transferring frequencies far exceeding the upper limit of 3.4 kHz.

Benefits of using DSL

DSL can provide virtual, instantaneous voice, data and video transmission over ordinary copper telephone lines. A DSL connection can eliminate delays while waiting for downloading information and graphics from the Internet. It provides users with a cost-effective high-speed Internet connection. Another advantage is that a DSL connection is always online (for example, connecting to a local network), without waiting for dialing or connecting.

There are currently more than 10 million broadband connections in the UK. By December 2005, there were 9.792 million broadband connections in the UK, and the average broadband speed for the three months to December was more than 70,000 per week.