Wide area network is very important to the global to do their work easily now days every companies trying to develop their business all over the world wide area network helps them to connect their network together .the companies need to design the network according to their needs and purpose because different type of networks are available for different purpose. According to this project the company network placed in different countries each network hold different application
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Different type of architecture models is available to design network one is peer to peer model and another one is client/server model most of the network designed by using client/server model. peer to peer model is connect two or more computers connected through network this model is unsafe because it is difficult to implement security policies .different network topologies are available to design network so we have to consider these topologies when design a network. Normally every companies using star topology to design their network because this topology have more advantage when compare with other topologies various hardware components need to design a network such as switches, routers, firewalls, server, link…ect
By using Ethernet technologies and other network technologies several LAN (local area network) is created in different countries then each subnet LAN was connected together via ATM cloud to make WAN (wide area network)
In this project company network model was designed in opnet modeller to investigate the performance of a network looking at WAN technologies with varying traffic loads there are different type of link used to implement the traffic load the network was designed up to getting the final result
Computer network is more than one computers or group of computers and network devices are connected together for the purpose sharing information, file and data between each computer. Different type of devices need to design a computer network such as switches, hubs, routers, different link, firewall, server and work station Protocols are use to do sharing information, files, data’s over the network there are two transmission technology available in computer network one is broadcast and another is point to point connection.
Computer network classified according to network architecture (peer to peer model, client/server mode), network topology (star topology, ring topology, bus topology and mesh network topology).computer network it is classified as personal area network (PAN), local area network (LAN),metropolitan area network(MAN),wide area network(WAN),global area network(GAN)
Computer network is very useful to the public because it has many applications such as access to remote information by using this application any one can do their work from anywhere in the world( ticket reservation ,shopping), communication between one to another through email, videoconferencing. Business application
Different type of computer network
Local area network (LAN)
Local area network (LAN) is less number or group of computers and related devices such as printer, scanner …etc that share a common communication line.lan is considered within a small geographical area such as a home, office building here LAN is designed by using Ethernet technology such as Ethernet cables, Ethernet switches and adapters.
Local area network (LAN) performance features are depending on size of the network, network topologies and transmission technology. Advantage of LAN is cover small geographical area so transmission time is limited. Different type of topologies is support to create broadcast LAN network such as bus and ring based topologies. FIDD is used in the LAN for connect token ring. IEEE 802.11standad indicates the local area network technologies. [Andrew s]
Metropolitan area network (MAN)
Metropolitan area network (MAN) is developed version of LAN and this network also using same technologies as LAN, compare with LAN it cover large area (company offices and city).this network carrying voice signal and dates.
MAN network contain few cables it don’t have any switching elements, by using network technologies such as backbone technology, routers and switches it connect several LAN networks.
“DQDB (distributed queue dual bus) is MAN network standard” by using this standard we can expand the network up to 30km and speeds of 34 to 155 Mbit/s
Wide area network (WAN)
Wide area network (WAN) comparatively covers wide geographical (“country or continent”) area and connecting number of local area network, local area network connected to a WAN through the public net work such as internet.WAN network can use is satellite system, WAN routers contain antenna by using antenna it can make data transmission.
Switching device and transmission link are two separate mechanism of subnet in the WAN network. Different type of transmission link are available to carry the signals and data transmission from one system to another system over the WAN network such as twisted pair cable, coaxial cable and fiber optic cable. WAN is a collection of LAN, these LANs are connected via switching device router so each LAN must contain at least one router to interconnect. WAN network use backbone technology.
Global area network (GAN)
Global area network (GAN) is collection of different network such as WAN or MAN it covers the very large geographical area (unlimited area). Worldwide individual business companies use GAN network for their process.
Network architecture model
Client-server network model
Client- server model is very useful and popular network model in the network architecture client and server devices are designed for the particular function in the computer network client server model mainly used in internet as well as local area network. Personal computers are client device in the network it is installed with required network software; database and files are stored in the server devices, server devices contain more memory, bigger disk drive than client devices
The client server model client makes a request to server and server receives client request and response to their client request. Advantage of client-server model is centralised network model it means all users in the network are connected to a central server. Central server contains all user information and communication information. Configuration of data backup, security policies are easy in this model
Peer to peer network model
Peer to peer network is suitable for a small network in this model more than one computer or group of computers are connected through the network .peer nodes sharing their documents, audio, video file and data’s in digital format a and also they sharing their resource without a dedicated server all connected peers act as either client or server. One system acts as server for one transaction while simultaneously act as client for another transaction in this model every client act as server and server act as client. It is complicated to apply security policies and access policies to the network because peer to peer network is a small contain few computers. Access permission and rights of users set individuality in peer to peer network. This model do not utilize centralized network model so it don’t have any user information or communication information
Different network topologies are available in computer networking they are star topology, bus topology, ring topology, tree topology and mesh topology these topologies help to design an excellent network. when design a network designer should have to choose which topology is suitable for the particular network
Ring topology is used to connect network devices in ring shape when these devices in ring shape each device has two neighbour devices for their message transaction this message transaction between neighbour only one direction. Ring topology use token passing system to their message transmission and access control. Main drawback of this method is any device fails in network ring that cause entire network transmission become failure this kind of network can manage and implement easily and it normally uses in office, school network different technologies are available to implement ring topology such as token ring and FDDI
Most of the network use star topology because implementation and maintains of this network is easily this kind of networks use point to point connection between devices and central hub main advantage of star topology is any connection fail between device and hub that affect only particular device. This network devices use twisted pair Ethernet cable to connect with central device hub
Bus topology mainly used in LAN networks because these kinds of topology suitable for limited number of device bus topology use backbone to connect all devices together backbone function as connect different part of network and offering path to message transmission between network. Implementation of this topology is easy and inexpensive. It is possible to message transmission in both directions, to avoid message bouncing use termination at both end of the bus cable there is no need more cabling to connect devices. Main disadvantage of this topology is if backbone cable fails that affect whole network
Tree topology combines multiple several star topologies together into a bus by using point to point connection hub devices linked to the tree bus to develop network scalability bus/star topology in a hybrid approach. Implementation of this topology is very difficult, if backbone cable file whole network become failure advantage of this topology is each parts connected by point to point link and it supported by a number of hardware and software vendor.
Hardware and software components need to create a network there are different type of hardware components available in the network each of them configured for different function. Usually a network contains many components such as switch, router, server, firewall, hub, work station…est.
Router is one of the important devices in the network it is used to connect more than one network together such as two WANs or two LANs and it allow data transmission between the networks. Routers having routing tables it contain information about network devices that uses to find the destination place of the network. Routers work at transport and network layer of the OSI reference model. Routers maintain traffic control in the network.
Switch is one of the hardware devices in the network it is used to connect network device such as server, workstation and printers together with in a local area network .switches work at the data link layer of the OSI reference model. Switches have a facility to check whether that the data received or not, delivering the messages to correct destination and also identifying that the particular data was transferred from which device (source) to other device (destination).`different type of Ethernet switches are available but in this network i have used Ethernet 16 port switches to connect network devices.
In the client/server networking model a server receive requests from client in the same network or other network and response client request. There are different types of server with their related configuration. In this network i have used many servers such as database server, Email server, VoIP server, HTTP server, FTP server, file server, printer server and backup server.
Main task of the firewall is preventing unprivileged user from accessing the network. There is different type of firewalls such as packet filter firewall, application gateway and proxy server each of them doing different job in the network .firewall implemented in some hardware devices. In this project i have used firewall router in a simulation.
Open system interconnection (OSI) model
OSI reference model is clearly defined how messages transmitted from source to destination in the networking. OSI reference model contain seven layers such as application layer, presentation layer, session layer, Trans port layer, network layer, data link layer and presentation layer. This model describes structure of a network for applying protocol on seven layers. Every layers doing different function. This model spited into tow part such as upper layers and lower layers. Upper layers associated with software and lower layers associated with hardware.
Application layer is highest layer of OSI reference model. Main function of this layer is interface for users to relate with application and identifying end user, verify resource availability. By using application users can access information at application layer. Application layer providing some services such as file transfer, electronic mail and software services. Many Protocols are implemented in this layer such as file transfer protocol (FTP), hyper text transfer protocol (HTTP), simple mail transfer protocol (SMTP) and telnet.
Presentation layer is sixth layer of the OSI reference model this layer receives all messages from application and sends those messages to session layer. Main function of this layer is converting the format of receiving and sending data format and also many functions are undertaking by this layer such as data compression, encryption, decryption, protocol conversation and encodes message for email transaction. Presentation layer providing some services such as simple mail transfer protocol (SMTP), telnet and file transfer protocol (FTP). At this layer data transmission starts with syntax and semantics format.
Fifth layer of the OSI reference model is session layer it provides function to communicate between two nodes in the network this layer create, maintain and stop connection between the node and few protocols are implemented they are data link protocol (DLP), apple talk session protocol (ASP) and printer access control protocol (PAP) these protocols are mainly uses to multimedia messages.
Data link layer
Data link layer is second layer of the OSI reference model the use of this layer is control and arranges all sending messages from software to network link. This layer makes some network setting such as data format setting, time setting and wire setting. it gives many services such as keep all messages are correct format when they transmit, maintain flow control when messages transmit over the link ,detecting error in physical layer and encoding messages for secure transaction.
Physical layer is lowest layer of the OSI reference model. This layer receives all messages from data link layer in the format of bits and converts into signal (electrical or electromagnetic signal).messages are sending to physical media via switches and wires
TCP/IP model contain four network layers such as application layer, transport layer, internet layer and network inter face layer. TCP/IP model and OSI reference models are providing similar services.TCP/IP model contain network communication protocol used to for different type data transmission between different networks. Simple mail transfer protocol (SMTP), used to Email transaction, file transfer protocol (FTP) used to file transaction etc. This model defines how particular protocols are implemented in a computer for data transmission over the network. End to end connectivity of the TCP/IP model define how data’s received, routed and formatted at end nodes.
TCP/IP application layer
Application layer is higher level protocol of TCP/IP model this layer match to OSI reference model of session layer, application layer and presentation layer. This layer gives different services to user such as file transfer, email ect. Application layer contain many protocol such as simple mail transfer protocol (SMTP), file transfer protocol (FTP) and telnet. All data’s are coded in this layer then these data’s encapsulated into transport layer. Lower level layers of TCP/IP model treat by application layer.
Transport layer is third layer of TCP/IP model. This layer providing services these services are managed by the user datagram protocol (UDP) and transmission control protocol (TCP).
TCP is connection oriented and reliable transmission protocol. Connection oriented it means source (sender) set up connection with destination (receiver) node before the sending data. Error detection, error correction retransmission of data’s is possible in TCP.
UDP is connection less and unreliable transmission. Error detection, error correction retransmission of data’s is impossible in UDP it is suitable for audio and video transmission.
Internet layer is second layer of TCP/IP model this model used to transfer the message from source computer to destination computer. Internet protocol (IP) is main protocol of this layer. This protocol providing many services such as routing packets between source and destination. Internet protocols receive messages from network interface layer in the format of bit then make it into packets. Network interface layer is lowest layer of the TCP/IP model main function of this layer is by using protocol it create a connection to physical medium, error detection and packet framing are possible in this layer. This layer contain local area network (LAN) and wide area network (WAN) technologies such as token ring,X.25,ehhernet and frame relay. This layer responsible for physical devices such as wire, cables, network interface card and satellite links.
Asynchronous transfer mode (ATM)
Asynchronous transfer mode (ATM) contains three layers such as ATM adaption layer, ATM layer and physical layer. This model providing different type of function it used to transfer all type data’s such as audio, video and text messages. Same time we can use ATM technology in different network (LAN. MAN and WAN).
ATM model contain management, hyphenated and handshaking protocol, quality of services and flow control facilities. Hyphenated protocol is connection oriented; cell switched and point to point.ATM use different type of technologies to data transmission. Fixed -length cells model used to transfer variable frames this model use 48 bytes for data, 5bytes for overhead.
ATM adaption layer
ATM adaption layer is third layer of this model this model composed application layer, transport layer and session layer of OSI reference mode. There are two different types of layers in ATM adaption layer such as convergence sub layer and segmentation and reassembly sub layer. It is classified into five types of class for providing different type of services. According to this class of services Convergence sub layer receive messages from high level layer, identify the received message format, type finally arrange all messages for sending out.
ATM layer is second layer of this model this layer providing link between ATM adaption layer and physical layer to transmit cells between those two layers and also create virtual link, doing multiplex and de-multiplex of cells, creating cell header.
ATM physical layer
ATM physical layer is first layer of this model the main function of this layer is encapsulate all incoming cells in a proper format before transmit bit to the physical medium. Physical layer divided into two sub layers such as transmission convergence sub layer and physical medium dependent sub layer these sub layers are doing different function such as transmission convergence sub layer doing error correction, framing and de-framing of cells and physical medium dependent sub layer assign bit time and coding for the physical medium.
Protocol is a set of rules it is used to transfer the message between one ends to another end. OSI reference model is clearly defined how messages transmitted from source to destination in the networking. This reference model contain seven layers each layers must contain one or more protocol for their message transmission.
Internet protocol (IP)
Main function of internet protocol (IP) is transmits message between one end to another end. When sends the messages via this protocol message divided into many parts each part contain IP address if end system and this small segment send different ways receiver receive this segment in different order. This protocol implemented in network layer of OSI reference model and internet layer of TCP/IP model so internet protocol (IP) support data transmission to upper level layers in OSI and TCP/IP reference model. This protocol is connection less protocol and we can’t make sure about delivery of message. Now days two different version of internet protocols (IP) are available in the networking such as internet protocol version4 (IPV4) and internet protocol version6 (IPV6).
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Transmission control protocol (TCP)
Transmission control protocol (TCP) applied in transport layer of OSI reference model and host to host transport layer of TCP/IP model for message transmission. This protocol is a connection oriented and reliable transmission protocol. Connection oriented it means source (sender) set up connection with destination (receiver) node before the sending data. Error detection, error correction retransmission of data’s is possible in TCP. Message transmission via this protocol is very slow because of overhead (20bytes) for error correction/detection and acknowledgement. There are two types of buffers such as sending and receiving buffers these buffers are used to storage, flow control, error detection and correction. Same time messages can be transfer both direction in TCP it provides full duplex transaction and also multiplexing and de-multiplexing are possible in TCP. [Behrouz A.]
User datagram protocol (UDP)
User datagram protocol (UDP) installed in transport layer of OSI reference model and host to host transport layer of TCP/IP model for message transmission between the layers. This protocol is a connection less and unreliable transmission protocol. Message transmission via UDP is very fast because there is small header (8bytes).this protocol containing many drawbacks such as no error control and no flow control. Receiver can’t identify whether this message is original or duplicate when message transfer via UDP. Encapulation and decapitation of messages are possible in UDP when messages transfer from source to destination. [Behrouz A.]
Hyper text transfer protocol (HTTP)
Main function of hyper text transfer protocol (HTTP) is access data from internet (www).this protocol is applied in application layer of OSI and TCP/IP reference model. It is describe the message transmission over the network from client to server and data format. This protocol use TCP for data transmission between client and server in this model the client first send request to server then server send response message to client. There is no secure message transmission because “HTTP does not provide security” HTTP provide security when it “run over the secure socket layer” This protocol messages can only understand by HTTP client and server. [Behrouz A.]
File transfer protocol (FTP)
File transfer protocol (FTP) is applied in application layer in TCP/IP model. Main function of this protocol is transferring data’s from source to destination (client to server or server to client) in easy way.FTP protocol create two link between source and destination one is for message transmission other link for replay.FTP use three commands such as RETR command function of this command is copying files, STOR command function of this command is store the files and LIST command this is for list the files.FTP use different transmission mode to transfer the files such as “compressed mode, stream mode and block mode” .through the FTP protocol we can send text files, images and ASCII files.FTP use two different TCP port, port 20 is used transfer data’s or files between client and server and port 21 is used to control transmission between them. [Behrouz A.]
Simple mail transfer protocol (SMTP)
Simple mail transfer protocol (SMTP) is installed in application layer in TCP/IP reference model. Function of this protocol is transferring the email messages between client and server and also it contains some commands these commands are used to transfer the data’s between client and server. Some other protocols are support to email transmission with SMTP such as post office protocol (POP3) and internet mail access protocol (IMAP4) [Behrouz A.]
Simple network management protocol (SNMP)
Simple network management protocol (SNMP) is applied in application layer of TCP/IP reference model this type of protocol is used to manage the network for providing better network performance by regular testing system, protect the network from unwanted user by monitoring system. SNMP protocol defines the transaction between the manager and agent. SNMP manager verify the agent details by sending requesting message to agent. “SNMP identify the packets exchange between manager and agent” [Behrouz A.]
Network transmission media
A transmission media is necessary to transfer a signal form source to destination in the networking system. Signals are transfer via Guided and unguided transmission media now a day’s different type of guided transmission media support to carry the signal such as twisted pair cable, coaxial cable and fiber optic cable. Unguided transmission media it is radio wave, micro wave and infrared
Twisted pair cable
Twisted pair cable is one of the guided transmission media to carry the signal over the network. Analogy and digital signal can be carried by this cable. This cable contains two shield copper wire then these wires are sick together. This type of cables used in telecommunication system. Twisted pair cable not suitable for long expanse, repeaters is needed to use long distance, for small area it will work without amplification. Compare to other cables this type of cable is inexpensive. Two types of twisted pair cables are available one is unshielded twisted pair cable (UTP) another one is shield twisted pair cable (STP). [Andrew s]
Compare to twisted pair cable it is better shield cable it is suitable for carry the signal to long distance. This kind of cables used to carry the high frequency signals and broad band signals as well as this cable carries analogy and digital signal but using different cable. Coaxial cables providing functions in several ways one is baseband it use total bandwidth to carry the signals, another one is broad band it divide the bandwidth with signals. Centre core it is made by hard copper wire, this core is bounded by inner dielectric insulator, copper screen and plastic sheath. [Andrew s], [Michael]
Fiber optics cable
Fiber optic cables transfer the signal in the form of light beam. This type of cable is used to connect different cities and countries such as telephone connection because these cables are suitable for long distance. Two different types of fibre optic cables are available such as single mode fibber optic cable and multimode fiber optic cable and this cables contain two part such as “inner class cylindrical core and outer class cladding” Compare with other cables it has many advantage such as it can be used to long distance, signal transmission is very fast and loss of signal is very low. Disadvantage of this cable it is very expensive. [Michael]
Quality of services
Quality of services (QOS) contains many network technologies to develop a network. Quality of services gives expected result to the network and quality of services develop and determine data transfer, delay, and error rate and loss of cell in the network. It is very use full apply the quality of services to VOIP and video but implementation of quality if services to network is very difficult.
Quality of service measure
Type of Delay
Different type of delay are occur in the network during the data transmission from one system to another system they are processing delay, queuing delay, transmission delay and propagation delay.
A data(1 bit) transmission time between the end systems (source to destination) it is called processing delay this delay may occur for the following reaction such as error data’s transmitting from one system to router, network architecture, switching mode and also it include in configuration of network devices
A data (1 bit) of transmission between the source and destination it is called propagation delay. This delay depends on distance between routers and propagation speed; it depends on the transmission media “propagation delay calculated by dividing the distance by propagation speed”
Propagation delay= [Behrouz A]
Data’s or packets waiting in queue at intermediate device (router) for their transaction, when the network is busy router can’t rout all the packet at same time it process these packet one by one so packets need to wait this waiting time is called queuing delay.
Transmission delay is amount of time is needed to transfer one bit of data via transmission media. Transmission delay depends on bandwidth and size of the data.
Transmission time= [Behrouz A]
Voice over internet protocol (VOIP)
Voice over internet protocol (VoIP) is used to communication purpose it means one person can transfer his information to another person through telephone call, voice and fax over the IP based network. To reduce the bandwidth waste VOIP use packet- switching method to telephone calls. Normally more bandwidth is needed to voice transmission but voice data is compressed to small for the transaction so it require small bandwidth. Main advantage of VOIP is reducing the cost of long distance calls, when compare with ordinary phone call for this reason every organization applying VOIP in their networks.
IP telephone is used in the VOIP network because IP telephone designed with coder/decoder for convert the voice signal from analogy to digital signal and digital to analogy signal. Software’s and hardware components are helps to connect the phone with network. Different protocols are implemented in the VOIP network for support voice transaction such as RTP(real time transport protocol) it support the delay of audio, H.323 protocol used to multimedia transmission, H.235 protocol used to data encryption. ) [Michael]
List of books
MICHAEL A, WILLIAM M Networking explained, second edition
2) [Behrouz A.]
Behrouz A. Frozen, TCP/IP protocol Suite Fourth Edition
3) [Andrew s]
Andrew S.Tanenbaum, computer networks fourth edition
4) [James F]
James F.Kurose, Keith W.ROSE Computer networking, fourth edition, a top down approach
5) [Behrouz A]
Behrouz A.Forouzan, data communication and networking, fourth edition
List of Internet and
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