TG 4.1: The Telecommunications Systems
1. Compare and contrast the three main wired communications channels?
Twisted-pair wire
· Inexpensive
· Widely Available
· Easy to work with
· Unobtrusive
Disadvantages
· Slow (low bandwidth)
· Subject to Interference
· Easily Tapped (low security)
Coaxial Cable
Advantages
· Higher bandwidth than twisted-pair
· Less susceptible to electromagnetic interference
Disadvantages
· Relatively expensive and inflexible
· Easily tapped (low-to-medium security)
· Somewhat difficult to work with
Fiber-optic Cable
Advantages
· Very high bandwidth
· Relatively inexpensive
· Difficult to tap (good security)
Disadvantages
· Difficult to work with (difficult to splice)
2. Describe the various telecommunications technologies that enable users to send high-volume data over any type of network.
Integrated Services Digital Network (ISDN): is and older international telephone standard of network access that uses existing telephone lines and allows users to transfer voice, video, image, and dada simultaneously.
Digital Subscriber Line (DSLs): provide high0-peed, digital data transmission from homes and businesses over existing telephone lines. Because the existing lines are analog and the transmission is digital, you need DSL modems.
Asynchronous Transfer Mode (ATM): ATM networks permit almost unlimited bandwidth on demand. ATM offers several advantages: it makes possible large increases in bandwidth; and it provides support for data, video and voice transmissions on a single communications line. ATM currently requires fiber-optic cable, but it can transmit up to 2.5 gigabits per second. On the downside, ATN is more expensive than ISDN and DSL.
T-Carrier System: is a digital transmission system that defines circuits that operate at different rates, all of which are multiples of the basic 64Kbps used to transport a single voice call. These circuits include T1 (1.544Mpbs, equivalent to 24 channels); T2 (6.312 Mbps, equivalent to 96 channels); T3 (44.736 Mbps, equivalent to 672 channels); ad T4 (274.176 Mbps, equivalent to 4032 channels),
TG 4.2 – Types of Networks
1. What are the main business reasons for using networks?
· A company network connects computers via communications media so that data can be transmitted along them.
· Firstly, Network computer systems enable organisations to be more flexible so tah ttheycan adapt to rapidly changing business comditions
· Secondly, Networks enable companies to share hardware, computer applications, and data across across the organisation and among organisations.
· Thirdly, networks make it possible for geographically dispersed employees and workgroups to share documents, idfeas, and creative insights. This sharing encourages teanwork, innovation, and more efficient and effective interactions.
· A company network connects computers via communications media so that data can be transmitted along them.
· Firstly, Network computer systems enable organisations to be more flexible so tah ttheycan adapt to rapidly changing business comditions
· Secondly, Networks enable companies to share hardware, computer applications, and data across across the organisation and among organisations.
· Thirdly, networks make it possible for geographically dispersed employees and workgroups to share documents, idfeas, and creative insights. This sharing encourages teanwork, innovation, and more efficient and effective interactions.
2. What is the difference between LANs and WANs?
Local Area Network (LANs): connects two or more devices in a limited geographical region, usually within the same building, so that every device on the network can communicate with every other device.
Wide Area Networks (WANs): are networks that cover large geographic areas and typically connect multiple LANs. WANs generally are provided by common carriers such as telephone companies a d the international networks of global communications services providers. WANs have large capacity, and they typically combine multiple channels (e.g. Fiber-optic cables, microwave, and satellite). The internet is a n example of a WAN.
TG 4.3 – Network Fundamentals
1. What is a network protocol?
Network Protocol: computing devices that are connected to the network access and share the network to transmit ad receive data. These components are often referred to as “nodes” of the network. They work together by adhering to a common set of rules that enable them to communicate with one another. This set of rules and procedures that govern transmission across a network is a protocol.
2. Describe the Ethernet and TCP/IP protocols.
Ethernet: A common LAN protocol. Most large corporations use gigabit Ethernet in which the network provides data transmission speeds of 1 billion bits per second. However, 10-gigabit Ethernet is becoming the standard (10 billion bits per second).
Transmission Control Protocol/Internet Protocol (TCP/IP): is the protocol of the internet. A file transfer protocol that can send large files of information across sometimes unreliable networks with the assurance that the data will arrive uncorrupted.
Transmission Control Protocol/Internet Protocol (TCP/IP): is the protocol of the internet. A file transfer protocol that can send large files of information across sometimes unreliable networks with the assurance that the data will arrive uncorrupted.
The TCP perfomr s3 basic functions:
1. It manages the movement of packets between computers by establishing a connection between the computers.
2. It sequences the transfer of packets
3. It acknowledges the packet that have been transmitted .
The Internbet Protool is responsibnle for disassembling, delivering, and reassembling the data during transmission.
Rainer, R. & Turban, E. (2009). Introduction to Information Systems: Supporting and Transforming Business. 2 Ed. John Wiley & Sons
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