ISDS 409 Exam 1 (Chapters 1 & 3)

the pathway through which the message travels

connects all of the computers in a network together via cables or cicuits

1. server
2. client
3. circuit

network that does not require a central server to communicate, all the computers function as equals

special device that connects two or more networks

most LANs are connected together to form BNs

WANS connect BNs together

the actual wire

an electronic circuit that performs logical operations on digital inputs to produce digital outputs

more efficient, more secure, and integrates voice, video and data on the same circuit is simpler

basic layout of the circuit

sometimes called dedicated circuits
used when computers generate enought data to fill the capacity of the communication circuit

many computers are connected to the same circuit which means they must share the circuit with the others

one-way transmission, such as that with radios and TVs

two-way transmission but you can transmit in only one direction at a time

the amount of time half-duplex communication takes to switch between sending and receiving

can transmit in both directions simultaneously, with no turnaround time

the process of combining multiple signals into one single medium or “pipe”

dividing the circuit “horizontally” so that many signals can travel a single communication circuit simultaneously

shares a communication circuit among two or more computers by having them take turns
- dividing the circuit vertically

allows more terminals or computers to be connected to a circuit than FDM or TDM

selection of transmission speed for the multiplexed circuit is based on a statistical analysis of the usage requirements of the circuits to be multiplexed

version of FDM used in fiber-optic cables

DSL uses a hybrid approach:
• FDM: Splits the physical line into 3 logical channels (Voice, Upstream, Downstream).
• TDM: Manages multiple data streams within the Upstream and Downstream channels by assigning them specific time slots. 
• Modulation: Uses amplitude and phase modulation to reach the desired data speeds.

most common type of guided media

- usually twisted to minimize the electromagnetic interference between one pair and another pair in the bundle

type of guided medium that is quickly disappearing

- less prone to interference and errors than basic low cost twisted pair wires

most common type of guided medium

light could reflect inside the cable at many different angles

changes the refractive properties of the glass fiber so that as the light apprached the outer edge of the fiber, it speeds up

transmits a single direct beam of light through a cable to ensure the light reflects in only one pattern

carry huge amounts of information at extremely fast data rates, works better under harsh environmental conditionw, more durable

Includes the price of the medium (cabling), installation, and maintenance

The maximum length a signal can travel before needing a repeater or amplifier

The vulnerability of the medium to wiretapping or EMI (Fiber is high security

The frequency of data corruption (Interference susceptibility

The potential bandwidth or speed supported by the medium (measured in bps)

The process of transforming 1s and 0s into physical signals (voltages or light pulses)

A coding method using only one voltage level

A coding method using both positive and negative voltages

Multiple bits are sent simultaneously over multiple wires (fast but limited distance)

Bits are sent one after another over a single wire (standard for long distance)

The number of times the signal level changes per second (measured in baud)

The time required to transmit a single symbol

A coding technique where the transition in the middle of a bit period represents the data (logic 0 or 1)

The number of wave cycles per second, measured in Hertz (Hz)

The direction or starting point of the wave at a specific time (measured in degrees)

Representing bits by varying the height/power of the carrier wave

Representing bits by varying the number of cycles per second

Representing bits by shifting the wave's starting position (e

A specific signal pattern (state) sent across a circuit

Bit Rate = Symbol Rate × Bits per Symbol

A technique where one symbol represents multiple bits

The difference between the highest and lowest frequencies a circuit can carry

The strength of the signal compared to the background interference

Defines maximum data rate on a noiseless channel: C = 2 × B × log_2(L)

Defines maximum data rate on a noisy channel: C = B × log_2(1 + SNR)

A device that performs Modulation (Digital to Analog) and Demodulation (Analog to Digital)

Reducing the number of bits sent by identifying patterns, increasing effective throughput

Digital is discrete (0s and 1s)

The standard process for converting analog voice into digital signals

The number of times per second the amplitude of an analog wave is measured

The difference between the actual analog voltage and the nearest digital "step" value

The number of discrete values available to represent a sample

A device/software that converts analog voice into digital (Coder) and back (Decoder)

Traditionally sampled 8,000 times/sec with 8-bit resolution, resulting in 64 Kbps

Stores data or software that can be accessed by clients

The input-output hardware device at the user's end of a communication circuit that typically provides users with access to the network and the data and software on the server

The pathway through which messages travel, typically a copper wire, although fiber-optic cable and wireless transmission are becoming common

A network designed to connect a set of similar computers that share their data and software with each other, where computers function as equals rather than relying on a central server

A special device that connects two or more networks and enables computers on one network to communicate with computers on the same network or on other networks

Stores data and software that can be used by computers on the network

Stores documents and graphics that can be accessed from any Web browser and can respond to requests from computers on the network or any computer on the Internet

Handles and delivers email over the network

A group of computers located in the same general area that covers a clearly defined small area such as one floor, a single building, or a group of buildings

A larger, central network connecting several LANs, other BNs, MANs, and WANs that typically spans from hundreds of feet to several miles and provides very high-speed data transmission, commonly 100-1,000 Mbps

Networks that connect BNs and MANs, typically spanning hundreds or thousands of miles and providing data transmission rates from 64 Kbps to 10 Gbps

A LAN that uses the same technologies as the Internet (e

Similar to an intranet but uses the same technologies as the Internet and is provided to invited users outside the organization who access it over the Internet, typically requiring passwords or special authentication

1. physical
2. data link layer
3. network layer
4. transport layer
5. session layer
6. presentation layer
7. application layer

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Concerned primarily with transmitting data bits (zeros or ones) over a communication circuit and defines the rules by which ones and zeros are transmitted, such as voltages of electricity, number of bits sent per second, and the physical format of cables and connectors

Manages the physical transmission circuit and transforms it into a circuit that is free of transmission errors, creates and recognizes message boundaries, performs error detection and correction, and decides when a device can transmit

Performs routing by determining the next computer to which the message should be sent so it can follow the best route through the network and finds the full address for that computer if needed

Deals with end-to-end issues such as procedures for entering and departing from the network, establishes and maintains logical connections, breaks large transmissions into smaller packets, ensures all packets are received, eliminates duplicates, and performs flow control

Responsible for managing and structuring all sessions, including session initiation, orderly termination, session accounting, and recovery from broken transport connections

Formats the data for presentation to the user and accommodates different interfaces on different computers, performing functions like data compression, translation between data formats, screen formatting, and encryption

The end user's access to the network that provides a set of utilities for application programs, where each user program determines the set of messages and actions it takes on receipt of a message

1. physical
2. data link layer
3. network layer
4. transport layer
5. application layer

The physical connection between sender and receiver that transfers a series of electrical, radio, or light signals through the circuit, including all hardware devices and physical media

Responsible for moving a message from one computer to the next computer in the network path, controls the physical layer by deciding when to transmit, formats messages by indicating where they start and end, and detects and corrects transmission errors

Performs routing by selecting the next computer to which the message should be sent and finding the address of that computer if it doesn't already know it

Responsible for linking the application layer software to the network, establishing end-to-end connections, breaking long messages into smaller messages, and detecting lost messages to request retransmission

The application software used by the network user that includes much of what the OSI model contains in the application, presentation, and session layers, serving as the user's access to the network

The physical and data link layers grouped together because they are so closely coupled, with the data link layer controlling when the physical layer can transmit

The transport and network layers grouped together because they are so closely coupled in their functions

A formal language or set of rules that defines what a layer will do and provides a clearly defined set of messages that software at the layer needs to understand

Information created by each layer (except physical) that is needed to transmit the message through the network

The protocol used for Web applications at the application layer

The transport layer protocol on the Internet responsible for breaking large files into smaller packets and opening connections to the server for transfer of large packet sets

The network layer protocol on the Internet that selects the next stop on the message's route through the network

A data link layer protocol that formats messages with start and stop markers, adds error check information, and creates Ethernet frames

The process where the PDU at a higher level is placed inside the PDU at a lower level so that the lower-level PDU encapsulates the higher-level one, similar to Russian matryoshka nested dolls

The set of software used to understand the different protocols that are used at different layers and stacked on top of one another

A set of rules, called protocols, that explain exactly how hardware and software that conform to the standard are required to operate, enabling any conforming hardware and software to communicate

A standard developed by an official industry or government body, often called a formal standard, that typically takes several years to develop

Standards that emerge in the marketplace and are supported by several vendors but have no official standing, often becoming de jure standards once widely accepted

The first stage of the de jure standardization process that consists of developing a nomenclature and identifying the problems to be addressed

The second stage of the de jure standardization process where those working on the standard identify various solutions and choose the optimum solution from among the alternatives

The most difficult third stage of the de jure standardization process that consists of defining the solution and getting recognized industry leaders to agree on a single, uniform solution

One of the most important standards-making bodies based in Geneva, Switzerland, that makes technical recommendations about data communication interfaces with membership composed of national standards organizations

The technical standards-setting organization of the United Nations International Telecommunications Union based in Geneva, composed of representatives from about 200 member countries

The coordinating organization for the U.S. national system of standards that accepts standards developed by other organizations and publishes them as American standards, coordinating development of voluntary national standards

A professional society in the United States whose Standards Association develops standards, most known for its standards for LANs

Sets the standards that govern how much of the Internet operates and is unique in that anyone can join its mailing lists, attend meetings, and comment on developing standards

A document issued by IETF that describes a proposed standard and solicits comments from the entire world during the standardization process

The status a protocol receives after IETF reviews comments on RFCs and no additional changes have been identified, usually adopted by several vendors who develop products based on it

The status achieved once at least two vendors have developed hardware or software based on a proposed standard and it has proven successful in operation, usually the final specification

The highest status that signifies mature standards not likely to change, elevated from draft standard status

A movement allowing employees to bring their own mobile devices like smartphones and tablets to work and use them to access company data such as work email

Wireless networks that employers need to add or expand to support BYOD devices

An approach to BYOD that requires an app to be developed for each application for every potential device that an employee might use

An approach to BYOD that doesn't create separate apps but requires employees to access applications through a Web browser

Technology that allows voice and data to converge into unified communications, with phones plugged into computers or directly into the LAN

The evolution of the Internet from being a Web of computers to including smart devices built into everyday things like kitchen appliances, doors, and shoes

The network where interaction between IoT devices happens seamlessly without human intervention

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