Local Computer Shop WAN Set-Up
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The need for computer networking arises out of the desire for sharing various computing resources which are geographically scattered across several standalone workstations (and their connected peripherals) within a given organization. Apart from resource sharing, both hardware (like printers, modem, memory, file servers, processors among others) and software (like operating systems and other application software), computer networking can also achieve the following: remote login, distributed databases, file transfer, email sharing, instant messaging, news, remote processing, name services and network time (Boudec et al., N.d, p. 2). In essence, a computer network is the collection of computers (commonly known as nodes), printers and other peripherals which have been connected together with the sole aim of establishing communication among them (Bakardjieva N.d, p.2). Personal Area Network (PAN), Local Area Network (LAN), Metropolitan Area Network (MAN) and Wide Area Network (WAN) with their associated topologies are the main types of computer network (Dadarlat 2008, p. 2). The network topologies, physical representations of any given network, are subdivided into two categories; vertical (consists of hierarchical and mesh topologies) topology and horizontal (ring, tree, star and bus topologies) topology (Dadarlat 2008, p. 6). According to the requirements of any given organization, it can choose from the various types of networking options and the topology to characterize it as outlines above.
Communication Services Required to Support a WAN Connection
For communication to be established within a WAN network several factors need to be taken into consideration; an understanding of the various network types and topologies, the signal transmission medium technologies, the TCP/IP model and the various hardware and software components involved in the networking.
Types of Computer Networks
A computer network is essentially an interconnection of two or more computers (interconnected with radio waves, cables, telephone lines, infrared rays and satellites), better known as nodes in a network, with an aim of sharing computing resources, exchange files and/or enable electronic communication among them (Kaur N.d, p. 2). There are four main types of computer networks: Personal Area Network (PAN), Local Area Network (LAN), Metropolitan Area Network (MAN) and Wide Area Network (WAN).
Personal Area Network (PAN)
This is a computer network with a reach of few meters that is used to interconnect devices such as tablets, smart phones, Personal Computers among other devices that re within the range of an individual’s body (Kaur N.d, p. 16).
Metropolitan Area Network (MAN)
These are computer networks covering a geographical area of a City, Municipality or town and they are generally larger than the Local Area Network (LAN) and may consist a number of Local Area Networks (LANs) resulting to a high speed of transmission like in the cable television (Singh N.d, p. 22 )
Local Area Network (LAN)
Local Area Network (LAN) is a technology that is used to connect a number of relatively close devices and in many cases within the same building (Technical tutorial 2002, p. 4). It connects personal computers, workstations, servers, printers and other peripherals within the same building or a small number of a group of buildings, office, home that are within a small geographical area (Singh N.d, p. 20).
Wide Area Network (WAN)
Wide Area Network (WAN) is a network having wide area coverage that spans countries, regions, continents and even the whole globe and it uses telephone lines, satellite communication and microwaves which are high speed communication linkage by nature (Singh N.d, p. 24). It can also be achieved through interconnecting a number of Local Area Networks (LANs) using gateways, routers, bridges to enable data sharing among them (Kaur N.d, p. 14). The internet is an example of the widely known and used type of this network (Kaur N.d, p. 14)..
Communication Network: OSI TCP/IP Model
This communication Network model was designed by the International Standards Organization and it is followed by all networks to send data (JDSU 2010, p. 2). It consists of the following layers: physical layer, data link layer, Network layer, Transport layer, Session layer, Presentation layer and Application Layer.
It is characterized by the commercialized bandwidth (signal rates and features) and physical media (copper, optic fiber or twisted pair coax) (JDSU 2010, p. 2)
Data Link Layer
It represents the basic data framing mechanisms where data begins (JDSU 2010, p. 2). It works in collaboration with the software in the device to enable sending and receiving of data through the network and offers mechanisms to detect errors in the network (Global Knowledge 2006, p. 6). It has the following physical layers: Bridges, Ethernet interface cards and switches for token rings (Global Knowledge 2006, p. 6).
The network layer aids in routing data from one end to the other through the network layer protocols (Hekmat 2005. P. 16). It hides the details of the interfaces between the network and the hosts, and among hosts from the higher layer levels (Hekmat 2005. P. 17).
This layer offers host-to-host communication in the network which can either be reliable, best-effort, connectionless and connection-oriented communications (Global Knowledge 2006, p. 6).
This layer provides virtual connection between nodes in the network, creates dialogue units, partitions tasks into functional groups, retransmission of undelivered data, enables synchronization of data flow, establishes acknowledgement for delivered data in any given session and it negotiates for connection parameters (Global Knowledge 2006, p. 6).
This layer has the following functionalities in computer networks: it enables graphics formatting, message encryption and decryption to enable security, message compression and expansion to enable its efficient travel/transmission, content translation and translation for system-specific functionalities (Global Knowledge 2006, p. 8)
This layer has the following functionalities: file transfers support, network printing capability, supports electronic mail, browsing the internet through the World Wide Web and supports electronic messaging (Global Knowledge 2006, p. 10)
Types of Network Topologies
A network topology is the physical representation of how a given network type will look when implemented. The following are some of the factors to consider when choosing a given topology to represent a certain network type: the size of the network determined by the number of computers (nodes) expected to be included in the network and their Geographical distribution, the expected system performance, the total budget (estimated cost) of setting up the network, the system reliability and the nature of the communication links to be used (Singh N.d, p. 9). The following are some of the network topology types; vertical (consists of hierarchical and mesh topologies) topology and horizontal (ring, tree, star and bus topologies) topology
In this topology, there is a central node that performs a logical routing function that controls the communication of all the other nodes which must communicate only through the host node (Singh N.d, p. 9).
In this topology, there is no host node and all the interconnected nodes have equal privileges. Each node has exactly two subordinate nodes, with which it communicates with, and once a node identifies that a message it has received was intended for it, it takes it; otherwise it passes it on to the next adjacent node (Singh N.d, p. 12).
The nodes in the network are connected with a single interconnection link (transmission medium) (Singh N.d, p. 16). Once a certain node wants to communicate with another node within the network, it attaches a destination address of the receiving node and after confirming the interconnection line to be free it broadcasts the message in the line to be checked by all the nodes that it encounters in the way before delivering it to the intended addressee node which then sends an acknowledgement note to the sending node to free the communication link (Singh N.d, p. 16).
Completely connected Network Topology
Each node in the network has a direct physical link (point-to-point) to all the other nodes in the network, whereby each node sets its own communication priorities. (Singh N.d, p. 14).
It is a type of topology that has incorporated all the properties of the above mentioned topologies; ring, star, bus and completely connected topologies
WAN-LAN Interconnection Equipment
The Wide Area Network (WAN) in most cases is achieved through interconnection of individual Local Area Networks. This is achieved through the following network components: Repeaters and Multiplexors, Bridges, Routers and Gateways.
They extend the physical features of the network by regenerating the network signals to cover optical distances with the same signal strength as from the start, and they operate at the physical level (International Technical Support Organization 1994, p. 50). In certain circumstances it enables conversion of media from fiber optic to copper and vice versa (International Technical Support Organization 1994, p. 50).
They interleave data onto one physical link after taking its data bits from a number of nodes, and it operates at the physical layer (International Technical Support Organization 1994, p. 50). They are also bandwidth managers since they can administer available bandwidth on the serial link (International Technical Support Organization 1994, p. 52).
Bridges are used to interconnect two Local area Networks (LANs) together, better achieved through forwarding one LAN frames forwarded from one LAN segment to another within the established network (International Technical Support Organization 1994, p. 52). Bridges are subdivided into two; local and remote bridges. A local bridge is the one that exists between adjacent LANs, and the remote one is that which exists between LANs which are not adjacent to each other as they have been separated by a WAN (International Technical Support Organization 1994, p. 52)
Routers make it possible for different sub network types to carry out their routing function by enabling their interconnection (International Technical Support Organization 1994, p. 52). Routers also make it possible to determine the optimal traversal path of a given data packet (International Technical Support Organization 1994, p. 52).
Gateways can exist between networks, applications and Other LANs, resulting to derivation of their various names; application gateways, network gateways and LAN gateways (International Technical Support Organization 1994, p. 55). Network gateways can be network devices appended to communication network or existing between and within network (International Technical Support Organization 1994, p. 55). Application gateways can change all the application layers as needed but is itself specific to a given application (International Technical Support Organization 1994, p. 55)
It is the security service provided by the protocol layer that ascertains sufficient security for the communicating nodes and the data they are exchanging via the WAN network (Stallings 2011, p. 19). It is achieved through; system authentication, access control, data confidentiality, data integrity and non-repudiation.
It is the mechanism of ascertaining that the entity wanting to access the network resource is what it claims to be (Stallings 2011, p. 20). There are two types of authentication methods; Peer Entity Authentication ( used to provide confidence in the process of entity identification) and Data-Origin Authentication (provides assurance in a connectionless transfer that the source of received data is as claimed) (Stallings 2011, p. 20)
System Access Control
Prevention of use of a given resource by unauthorized entities; resource access control is established and only authorized individual can access it, and it determines the conditions under which access can occur, and what those allowed are privileged to a to carry out (Stallings 2011, p. 20).
This is the process of protecting data from disclosure by unauthorized entities and it is achieved through the following ways; connection confidentiality (all user data protection on the network), connectionless confidentiality (all user data protection in a single data block), selective-field confidentiality, Traffic-Flow Confidentiality (Protection of Information likely to be have been derived from traffic flows observation) (Stallings 2011, p. 20).
It is the certainty of establishing that data received through the network is exactly as sent by the authorized sender and has not been modified by means of insertion, modification, replay or deletion) achieved by; connection integrity with recovery, connection integrity without recovery, selective-field connection integrity, connectionless integrity and selective-field connectionless integrity (Stallings 2011, p. 20).
It is the process of providing proof that a given entity had sent or received a given message in the network and in the process counteracts denial of doing so by the entity and it is achieved through Non-Repudiation of origin ( proof that a certain entity sent a given message) and Non-Repudiation of destination (proof that a given entity in the network received a certain message) (Stallings 2011, p. 20).
Security mechanisms are those measures that have been put in place to ensure security and privacy of data is achieved in the network. It is divided into two; specific security mechanisms and pervasive security mechanisms.
Specific Security Mechanisms
These are those security measures appended into the protocol layers to provide security to specific OSI layer in the network and are achieved through; decipherment, digital signature, access control, data integrity, authentication exchange, traffic padding, routing control and notarization (Stallings 2011, p. 20).
Pervasive Security Mechanisms
These are network security and privacy measures achieved through; trusted functionality (perceived to be correct by evaluating security policies in operation), security label, event detection, security audit trail and security recovery (Stallings 2011, p. 20).
Firstly, it is recommended that two separate LAN networks be designed and constructed in the two buildings where the offices are located. After that, the two LANs can be connected to form a WAN. This will save the costs of employing expensive telephone lines, satellite communication and microwaves communication linkages. The most suitable topology to be emulated for this network is the bus topology. This topology can easily enable the interconnection of the two LANs by the repeaters, multiplexors, bridges, routers and gateways through their transmission medium.
The various network types (Personal Area Network (PAN), Local Area Network (LAN), Metropolitan Area Network (MAN) and Wide Area Network (WAN)) are distinctively different from the types of network topologies (ring, bus, star, and hybrid). To minimize the costs of establishing a WAN network, it is recommendable to establish two separate LAN networks and then you interconnect the two LANs to form a WAN.
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