Cost: I cost’s a lot more than a standard telephone wire.
Best for Short or long cable lengths?: best used for both lengths does not have a limit
Shielded Twisted Pair (STP): used for Ethernet networks
It consists of two copper wires that are twisted together that are coated with an insulating coating that functions as a ground for wires
Might be commonly used in Ethernet networks
In summary, relative to other channels it may be described as: a very fast transfer cable.
Speed: Especially fast data rate
Cost: Expensive to buy
Best for Short or long cable lengths? Best for short lengths.
Fibre-optic cable: used for local area networks and they are replacing traditional telephone lines.
It consists of a bundle of glass threads witch transmit light waves.
Might be used in a local area network and is used by some telephone companies.
In summary, relative to other channels it may be described as:
Speed it is faster and carries a lot more data than the other cables.
Cost: it is quit expensive.
Best for Short or long cable lengths?: It doesn’t matter but it would be best for short lengths.
Radio waves: used for sending information.
It consists of radio waves and they send the information.
Might be used in local area connections.
In summary, relative to other channels it may be described as:
Speed: very quick
Cost: very expensive
Best for Short or long distances?: short distances.
Infrared: used for transferring data to another computer
It consists of radio waves pulsing to another computer.
Might be used in tv remotes.
In summary, relative to other channels it may be described as:
Speed: slow
Cost: not very much
Best for Short or long distances: any distance but probably short.
Microwave: used for transporting data to ones computer
It consists of waves that are small.
Might be used in microwaves and cables
In summary, relative to other channels it may be described as:
Speed: fast
Cost: expensive
Best for Short or long distances: short
With respect to cabling what are some of the practical considerations that might influence the choice of cabling types that a network builder might make? (Think here of factors relating to network software, the nature of the site and access issues, cost etc) It might be the cost and how good the cable is, like what speed It can go and how much data can be sent.
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Connector: is a device that allows you to connect cables to things.
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CSMA/CD access method: stands for Carrier sense Multiple Access / Collision Detection
Its rules are used to determine how network devices respond when two devices attempt to use a data channel simultaneously.
CSMA/CD is a type of protocol
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Dedicated line or leased line: is a line or a channel that is used for private use.
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Error checking:
Often on a network this is performed on the data moving across the network by what kind of software? Pcp ip protocol identifies errors via the use of crc checks. A common way to check for errors is to use parity check
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Ethernet:
Ethernet (define and give three typical speeds): An Ethernet is a local area network (LAN). And its speeds come in 10 Mbps, 100Mbps and 1000Mpbs
Ethernet uses the CSMA/CD access method to handle than one thing at a time.
Ethernet Card: This is a Network Interface Card that allows a device to participate in an Ethernet network.
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Firewall: Found in networks on a server or a PC.
It acts to prevent unauthorized access to or from a private network or PC.
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FTP: Stands for File Transfer Protocol.
It is used to exchanging files over the internet
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Gateways: A on a that serves as an entrance to another network.
For a home user of the Internet, the gateway is the ISP that allows the user onto the Internet. In industry gateways are often proxy servers, why? It is because so the gateway can determine where packets are sent.
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Hub
In general hubs are devices that connect segments of LAN.
They have multiple ports
A passive hub acts to makes the data go from one place to another.
An intelligent or manageable hub is able to monitor the traffic passing through the hub and to configure each port in the hub.
A switching hub is able to read the destination address of each packet and then makes the packet go to its correct port.
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IP: stands for Internet Protocol
It acts to specify the format of the packets and is usually found along side another protocol, TCP (Transmission Control Protocol.
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ISDN: stands for Integrated Services Digital Network. It is the international standard for sending voice, video and data over digital telephone lines or normal wires. It can support speeds up to 64 Kbps.
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Local Area Network (LAN)
A that spans a relatively small area.
There are many different types of LANs, the most common for is Ethernet.
The following characteristics differentiate one LAN from another:
Topology: The geometric arrangement of devices on the network, for example devices can be arranged in a ring or a straight line.
: The rules and encoding specifications for sending data. The protocols also determine whether the network uses peer-to-peer or client/ server architecture
: they use twisted pair wire, coaxial cables, or fibre optic cables.
LANs can transmit data at very high rates, much faster than may be achieved over a telephone line; but the distances are short, and the number of devices that can be placed on a given LAN is not great.
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Metropolitan Area Network (MAN):
Definition: A data network designed for a town or city.
MANs differ from LANs or WANs in that: LANs are for computers close together and WANs are for computers that are connected via a telephone line or radio waves.
A typical MANs could be used to provide shared access to Businesses and to the public around the town.
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Modem:
This device is used to transmit data over, telephone or cable lines.
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Modes of communication:
Simplex: refers to one way communications where one party is the transmitter and the other is the receiver.
Half-duplex: refers to two way communications where only one party can transmit at a time.
Duplex: refers to the transmission of data in two directions simultaneously.
Multiplexor: is a communications device that combines several signals for transmission over a single medium.
A demultiplexor is a communications device that completes the process by separating multiplexed signals from a transmission line.
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Network:
A network consists of two or more computer systems linked together.
Networks conform to a certain arrangement, are connected using one or more media, have a topology, and employ various protocols.
Possible benefits of networking (ie why do we use them?): You can send information to each other and you have the ability to communicate to each other.
Possible disadvantages: You can receive viruses and bad things that you don’t want.
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Network diagrams:
What do they do and why do we bother with them? (Give three reasons for using them. The diagrams tell us how many computers are on a particular network and it is easier to set a network using diagrams.
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Network Interface Cards:
These allow devices to participate in a network.
They are particular to a given type of network.
The interface software between the NIC and the network Operating System is called a driver.
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Network Operating Systems: A Network Operating System controls transmission of data between multiple computers.
Examples of NOS on the market include: windows any version Linux and apple mac osx.
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Network operations:
These are the three common ways for networks to operate. They define what is called the network’s architecture
Peer-to-peer:
Definition: Peer-to-peer allows people to send information by using their shared folders
Advantages: you can get practically anything you want and a lot of people use it.
Disadvantages: allot of viruses get around and people can corrupt the system
Client/Server:
Definition: central server machine acts as a host to provide services and data to multiple clients.
Advantages: no redundant data. web server clients can access can access the web.
Disadvantages: server goes down clients don’t have access
Mainframe (centralized computing/timesharing):
Definition: single computer that users have direct access via terminals
Advantages: all you need is a monitor and keyboard basically.
Disadvantages: users could be waiting a long time to access.
The difference between network topology and network architecture is: the typology is the physical connection and the network architecture is conceptual.
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Network security:
The following aspects of a network might contribute to its security: access content, passwords, servers, fire walls, anti-virus software.
If you wished to control the physical access to a device you could use biomedical, such controls could include a fingerprint scanner
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Network Topologies:
The topology of a computer system is how it is set up.
Topologies are either logical or physical. The difference between these two types of topology is how they communicate and how they are connected to each other.
There are four principal topologies used in LANs. These, and their most significant features, and advantages/disadvantages, are (include a simple graphical representation of each LAN type):
Bus- All devices are connected to a central cable. Advantages it is inexpensive. The disadvantages are that bottlenecks may occur because all the datat must pass the central computer.
Ring- All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it. The advantages would be it is a lot easier to use. Disadvantage would that it is expensive to set up and if the ring is broken data cant get through.
Star – All devices are connected to a central hub. Nodes communicate across the network by passing data through the hub. Advantages are Star networks are relatively easy to install and manage (although requiring considerable cable).Each computer has a dedicated link to the central device: if one fails the network can still function. The disadvantage would be Bottlenecks can occur because all data must pass through the central computer : the processor needs to be as fast as possible. If the central processor fails, so does the whole network. Therefore, a backup central processor is required
Tree- A hybrid theory typology. Groups of star- configured networks are connected to a linear bus backbone. The advantages would be it is a lot easier to use. Disadvantage would be a lot of money.
A token ring is used in ring topologies and is used to send a message, a computer catches the token, attaches a message to it, and then lets it continue to travel around the network.
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Operating System: An operating system, among other things, controls file access, resource all and acts as an interface between the uses and the peripheral
It is principally found in the memory of a computer.
Examples of OS on the market include: DOS, Linux and Windows.
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OSI: stands for Open System Interconnection
OSI standard for worldwide communications that defines a networking framework for implementing protocols in seven layers.
It has 7 layers, the first four proceeds with the application.
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Ports:
A port is an interface on a computer to which you can connect a device,
Some different kinds of ports are:
USB: Universal serial bus, an external bus standard supports data transfer rates. It can connect up to 127 peripheral devices, such as mice, mobems, and keyboards. Connection devices to a computer and being very small would be its strengths. Weaknesses would be it doesn’t fit into all computers.
FireWire: the definition of fire wire is a high speed plug. Faster than USB. The strengths are it is fast. The weakness would be it is standard.
Could be used to connect a camera.
Serial: Input for various devices. One of the features dbugging port. Weaknesses is that is very old. A strength would be that it is common.
Could be used to connect to a digital connections
Parallel: the definition would be a large plug for printers. One of the phsycal features that it is big. weakness is that it is slow. Strength that it is still fairly common good for basic programming.
Could be used to connect to a printer.
IrDA and Wireless connections differ from the above as they don’t use cables. They are short range devices. Wireless long range fast don’t need line of sight.
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Protocols:
A protocol is a set of rules that controls the movement of data between devices. They are particularly concerned with the format of data, the transmitting of data, error detecion and correction, and the establishment of communication between devices
The following protocols are commonly used:
- TCP/IP - Transmission Control Protocol – it enables two hosts to establish a connection.
- SMTP – Simple Mail Transfer Protocol – sending emails
- HTTP - Hyper Text Transfer Protocol – defines how messages are formatted and transmitted.
- FTP – File transfer protocol – sending files
- What does each abbreviation stand for?
- Provide an example of when each protocol might be used.
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Repeaters: Are devices that are used to regenerate or replicate a signal.
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Routers: An intelligent that forwards data packets along networks.
A router connects to at least two networks.
Routers help in the Internet by sending packets the best way to your computer
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Servers:
A or on a that manages network resources.
Give a line on each of the following to explain what they do:
File Server: is a computer and storage device dedicated to storing files.
Print Server: Is a computer that manages one or more printers.
Network server: Is a computer that manages network traffic.
server: Is a computer system that processes database queries
Proxy server: sits between a client program and an external server to filter requests.
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Switches: A switch is a network device that you plug all the cables together into a device. It is a device capable of creating connections between two or more devices linked to the switch but to each other.
It differs from a hub in that a switch leads information directly were as a hub doesn’t
It differs from a router in that a router knows exactly what it is and it sends it straight away where as a switch wouldn’t.
It functions to enhance the flow of data in a network by reducing collisions.
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TCP: stands for Transmission Control Protocol
It is a protocol that enables two hosts to establish a connection and exchange streams of data.
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Telnet: A way to control the server and communicate with other servers on the network
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URL: Stands for Uniform Resource Locater
The first part of the address represents the protocol to use and the second part specifies the IP address or the demain where the resource is located.
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Wide Area Network (WAN):
Definition: the computers are further apart and are connected by a telephone line or radio waves.
The largest WAN in existence is the internet.
BY Andrew Cooke
