Components Of a Network

Different Types Of Network

Ring Network

A ring topology is like a circle of computers connected together. Each computer has a network card and the cable from computer 1 connects to computer 2 and so on until you connect back to computer 1. This creates the ring. Less expensive network because you don’t need a switch or router. However not very flexible because you can only get to nodes on the ring. Unless one of the nodes was a router which would then connect you to another ring or topology. A ring topology is mostly used in a token ring environment. IBM developed token ring. Token Ring’s popularity has dwindled to a very low percentage of topologies used in today’s market.

Advantages:


  • Data is quickly transferred without a ‘bottle neck’. (very fast, all data traffic is in the same direction)
  • The transmission of data is relatively simple as packets travel in one direction only.
  • Adding additional nodes has very little impact on bandwidth
  • It prevents network collisions because of the media access method or architecture required.



Disadvantages:


  • Data packets must pass through every computer between the sender and recipient therefore this makes it slower.
  • If any of the nodes fail then the ring is broken and data cannot be transmitted successfully.
  • It is difficult to troubleshoot the ring.
  • Because all stations are wired together, to add a station you must shut down the network temporarily.
  • In order for all computers to communicate with each other, all computers must be turned on.
  • Total dependence upon the one cable


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Star Network

A star topology is like a hub and spoke layout. The star topology is the most widely used and recognized topology in today’s market place. A Star Topology is more expensive because a router, switch, or hub is required to route the network across to all nodes on the hub and spoke technology. The switch or hub is used to connect clients (computers), printers, server’s etc. The router is used to connect more than one hub and spoke network together. In addition, the router can do things like DHCP giving out dynamic IP addresses and routing the clients to the Internet if connected to an Internet Service Provider (ISP).

Advantages:


  • Good performance
  • Easy to set up and expand. Any non-centralized failure will have very little effect on the network.

Disadvantages:



  • Expensive to install
  • Extra hardware required


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Bus Network

A bus topology is a network of computers connected in a straight line or cable with a termination connector at both ends. These computers all share the same communications path called a bus. Again not as pricy because you don’t need a router or switch to build a bus topology network. You can have 10 or so PC’s connected in one long line of cable with a printer or a server somewhere in the bus. You would need a router or layer 3 switch to get outside of the bus topology.
Advantages:
  • Easy to implement and extend
  • Requires less cable length than a star topology
  • Well suited for temporary or small networks not requiring high speeds(quick setup)
  • Cheaper than other topologies
Disadvantages:
  • Limited cable length and number of stations.
  • If there is a problem with the cable, the entire network goes down. Maintenance costs may be higher in the long run.
  • Performance degrades as additional computers are added or on heavy traffic. Proper termination is required (loop must be in closed path).
  • Significant Capacitive Load (each bus transaction must be able to stretch to most distant link).
  • It works best with limited number of nodes.
  • It is slower than the other topologies.
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LAN and WAN

LAN

A LAN (Local Area Network) is a localized network, typically within a single building. Each LAN is separate from each other, and cannot reach each other except through a wider connection (like a WAN). LANs typically have a faster transfer rate and don't require any equipment that can't be purchased off a shelf. They typically have one or more routers hooked to several computers, workstations and/or servers. They can be used for anything from internet sharing in a home setting to internal company communications and resource sharing.

Advantages:

• Workstations can share peripheral devices like printers. This is cheaper than buying a printer for every workstations.

• Workstations do not necessarily need their own hard disk or CD-ROM drives which make them cheaper to buy than stand-alone PCs.

• User can save their work centrally on the network’s file server. This means that they can retrieve their work from any workstation on the network.

• They don’t need to go back to the same workstation all the time.

• Users can communicate with each other and transfer data between workstations very easily.

• One copy of each application package such as a word processor, spreadsheet etc. can be loaded onto the file and shared by all users.

• When a new version comes out, it only has to be loaded onto the server instead of onto every workstation.

Disadvantages:

• Special security measures are needed to stop users from using programs and data that they should not have access to;
• Networks are difficult to set up and need to be maintained by skilled technicians.
• If the file server develops a serious fault, all the users are affected, rather than just one user in the case of a stand-alone machine.

Examples of use:

  • 2 or more computers connected together
  • A small office

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WAN

A WAN is more expensive than a LAN. It is easier to expand a LAN than a WAN. The equipment needed for a LAN is a network interface card (NIC), a switch and a hub. On the other hand, the equipment needed to connect a WAN to the Internet is a modem and a router. The modem may be a cable modem or a DSL modem that is connected to a wall jack, while the router should be configured so that it can handle the packets traveling between the WAN and the Internet.

Advantages:


  • Messages can be sent very quickly to anyone else on the network. These messages can have pictures, sounds, or data included with them (called attachments).
  • Expensive things (such as printers or phone lines to the internet) can be shared by all the computers on the network without having to buy a different peripheral for each computer.
  • Everyone on the network can use the same data. This avoids problems where some users may have older information than others.
  • Share information/files over a larger area


Disadvantages:


  • Setting up a network can be an expensive and complicated experience. The bigger the network the more expensive it is.
  • Security is a real issue when many different people have the ability to use information from other computers. Protection against hackers and viruses adds more complexity and expense.
  • Once set up, maintaining a network is a full-time job which requires network supervisors and technicians to be employed.
  • Information may not meet local needs or interests
  • Volunerable to hackers or other outside threats

Examples of use:

  • Internet

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Addressing Packets And Protocols

Protocols

A protocol is the language used by computers while talking with each other. In its simplest form, a protocol is the rules used in talking and communication between computers.

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MAC Address

The MAC address (Media Access Control) is a hexadecimal number that is


unique to a particular computer.

Example: B0-D0-86-BB-F7

There can be 281,474,976,710,656 possible MAC addresses!


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Network Packet

In computer networks, a packet is a container or box that carries data over a network. A packet is the most fundamental logical arbitration of data that is passed over a network.

Packet headers contain destination MAC address.

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