BJC Unit 4 Review

What is the purpose of protocol?

Standards that ensure that all of the different kinds of devices using the internet can interact with each other smoothly.

Application Layer Protocols have the highest level of abstraction. What do they do?

Application Layer Protocols define the language the message a computer is sending.

Transport Layer Protocols manage what?

They manage the breakdown of a message into packets to be transmitted by lower-level protocols and the reconstruction of the message from the packets upon arrival.

What do Internet Layer Protocols manage?

They manage the pathways that the data packets travel across network. They treat the internet like one large network.

Network Interface Hardware or “Link Layer” does what?

This protocol manages the physical interface connection to the local network for any given device.

HTTP

1. Hyper Text Transfer Protocol

2. It interprets HTML code instructions for page formatting.

DNS

1. Domain Name System

2. It converts user-friendly web addresses into IP addresses

TCP

1. Transmission Control Protocol

2. It simulates a reliable, long-term connection between two computers by only displaying data once all packets have arrived.

IP

1. Internet Protocol

2. The addressing protocol that manages routing of data between computers.

SMTP

1. Simple Mail Transfer Protocol

2. An email protocol that sends mail.

SSL/TLS

1. Secure Sockets Layer / Transport Layer Security

2. Protocol that allows for data to be encrypted to make it private and secure.

Give two examples of Link Layer Protocols

1. WiFI radio antenna

2. Ethernet Cable

What is an “open protocol”?

Open protocols are available for anyone to see, use and code with.

What is a “closed protocol”?

Closed protocols are industry secrets.

Who is the IETF?

The Internet Engineering Task Force. They develop and approve protocols.

What country dominates the decisions about internet protocols?

USA

Which technology is especially vulnerable to software bugs that make it possible for cyber criminals to hack them?

Smart Phones

What do Certificate Authorities issue?

The issues public keys use for encryption/decryption.

How do open standards help security?

They allow the good guys - mathematicians - to study cryptography so the bad guys can’t exploit secret ideas.

What is the difference between a kilobit, a petabit, a gigabit and a megabit? Order them from biggest to smallest.

Peta 1,000,000,000,000,000

Giga 1,000,000,000

Mega 1,000,000

Kilo 1,000

What is the best way to measure latency?

ms (milliseconds)

What is the best way to measure bandwidth?

Bits per second (kilo, giga, mega)

Internet

A computer network that uses open protocols to standardize communication.

Computer Network

An interconnected computing system that is capable of sending or receiving data

Computer System

A group of computing devices and programs working together for a common purpose

Computing Device

A physical object that can run a program

World Wide Web

A system of linked pages, programs, and files that uses the Internet

Router

A computer that passes information from one network to another

ISPs (Internet Service Providers)

The companies who sell Internet access to homes and institutions

Bandwidth

The maximum amount of data that can be sent in a fixed amount of time

Storing data on the cloud

Storing data somewhere on the Internet

Path

A sequence of directly connected computing devices that connect a sender to a receiver

Routing

The process of finding a path from sender to receiver

Scalability

The ability of the Internet to keep working as it grows

Redundancy

The inclusion of back-up elements in case one part fails

Fault Tolerance

The ability of a system to work around problems

A Protocol

A set of rules that specify the behavior of a system

IP Address

A unique number assigned to each device on a computer network

A Packet

A small chunk of any kind of data and metadata that is passed through the Internet as a data stream

Packet Switching

The Internet sends short bursts of information, not long continuous strings

IP (Internet Protocol)

Lets your computer pretend it has a direct connection to another computer

TCP (Transmission Control Protocol)

Lets your computer pretend it has a reliable connection to the other computer

Encryption

The process of encoding data to prevent unauthorized access

Decryption

the process of decoding the data

Symmetric Encryption

using the same key for both encryption and decryption

Public Key Encryption

using a pair of keys: a public key for encryption and a private key for decryption

SSL/TLS (secure sockets layer/transport layer security)

the standard used for cryptographically secured information transfer on the Internet

Certificate Authorities

organizations that issue digital certificates to verify who owns the encryption keys used for secured communications

Malware

Software that was designed to harm or take partial control over your computer

Keylogging Software

A kind of malware that records every key pressed by a user

Computer Virus

A type of malware that spreads and infects other computers

Antivirus/Anti-malware Software

Software designed to scan your files and Internet transmissions looking for malware

Firewall

A security system that controls the kinds of connections that can be made between a computer or network and the outside world

Phising

A common security attack in which the victim is tricked into giving up personal information or downloading malware

DDoS (Distributed Denial of Service) attack

Using a virus to flood a server with many requests from many computers at once so that users of that server are denied service.

Rogue Access Point

A wireless access point that gives access to a secure network without the authorization of the network administrator.

Digital Divide

Unequal access to computers and the Internet based on poverty, racism, sexism, isolation in the countryside, age, and other factors

Citizen Science

Scientific research conducted in whole or part by distributed individuals, many of whom may not be scientists, who contribute relevant data to research using their own computing devices

Crowdsourcing

The general term for using the Internet to get a lot of people to help solve a problem

Computing Innovation

A physical, non-physical, or conceptual software innovation that includes a program as an integral part of its function

Bit

A single unit of data that can only have one of two values

Byte

Eight Bits

Word

A sequence of however many bits the CPU processes at a time

Binary Sequence

A string of ones and zeros

Analog

Data that has values that change smoothly, unlike digital data which change in discrete intervals

Sampling

Measuring samples of an analog signal at regular intervals

Sampling Rate

The number of samples measured per second

Floating Point

Scientific notation using powers of two to represent very large or very small values

Width

The number of bits that a CPU processes at a time

Lossless Data Compression

Algorithms that are reversible

Lossy Data Compression

Algorithms that are not fully reversible