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Flashcards in Computer Networks and the Internet Deck (59)
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What are the two ways we can discuss the Internet (when defining what IS the Internet)?

The "nuts and bolts":
-the hardware and software that make up the Internet

As a "networking infrastructure":
-a service provided to distributed applications


What is the Nuts and Bolts definition of the Internet?

The Internet is a computer network that interconnects hundreds of millions of devices. The network is made up of hosts and end systems that transmit data back and forth.


What is a host?

A network host is a computer or other device connected to a computer network. A network host may offer information resources, services, and applications to users or other nodes on the network.


What is an end system?

An end system is a node or user device.


What is a communication link?

A communication link is a channel that connects communicating devices.


What is a packet switch?

Takes a packet from an incoming communication link and forwards the packet on one of its outgoing communication links. Examples of these are routers and link layer switches.


What is transmission rate?

The rate at which data can be transmitted across a communication link. Transmission rate is measured in bits/second.


What is a packet?

A unit of data that is sent over a network.


What is a router?

Routers are typically found in the network core and are used to forward packets to their ultimate destinations.


What is a link layer switch?

Link layer switches are typically found in access networks and are used to forward packets to their ultimate destinations.


What is a "route" or "path"?

The collection of communication links and packet switches that a packet traverses to reach its destination.


How is a packet switched network analogous to a transportation network?

At a factory, cargo is divided between trucks. Each truck travels independently through a series of highways to reach their destination and deliver the cargo.


What is an ISP? Give some examples.

ISP stands for Internet Service Provider. An ISP is a small network of communication links and packet switches that provides users with access to the Internet. Examples are cable and phone companies.


What is TCP?

TCP stands for Transmission Control Protocol. TCP enables two hosts to establish a connection and exchange streams of data. TCP guarantees delivery of data and also guarantees that packets will be delivered in the same order in which they were sent.


What is IP?

IP stands for Internet Protocol. IP specifies the format of the packets that are sent and received among routers and end systems.


What is an RFC?

RFC stands for Request for Comments and is an Internet standards document.


Why are Internet Applications said to be Distributed Applications?

Internet applications are said to be distributed applications because they involve multiple end systems that exchange data with each other.


What is a Protocol?

A protocol defines the format and the order of messages exchanged between two or more communicating entities, as well as the actions taken on the transmission and/or receipt of a message or other event.


What is a client?

an end system that an obtain information from a server.


What is a server?

a computer or computer program that manages access to data or a network.


What are the two most prevalent types of broadband residential access? And what is the main difference between them?

DSL - digital subscriber line, and cable.

DSL makes use of the existing telephone infrastructure, while cable makes use of the existing cable television infrastructure.


What does WiFi stand for?

Wireless LAN access based on IEEE 802.11 technology


What are some examples of physical mediums?

Copper wire, coaxial able, fiber-optic cable, + radio and satellite spectrum.


What is the difference between guided and unguided media?

With guided media the waves propagate along a physical medium, while unguided media waves propagate through the atmosphere.


What is a guided shared medium?

Coaxial cable is an example of a guided shared medium. A guided shared medium is a cable with a number of end systems connected directly to it, and receiving whatever is sent by others.


What has hindered the deployment of fiber optics in short-haul transport?

The high cost of of optical devices such as transmitters, receivers, and switches.


What are three groups of terrestrial radio channels?

short distance like wireless headphones, local area like wireless LAN, or wide area like cell service.


What is the formula for transmission time of a packet of size L?

Transmission rate is Rbits/second, and L is the size of the packet being transmitted in bits, so the transmission time will be L/R.


What is store-and-forward transmission?

Store-and-forward transmission means that the packet switch must receive the entire packet before it can begin to transfer the first bit of the packet on an outbound link.


What is an output buffer?

An output buffer (or output queue) is used by a packet switch to store packets it is about to transmit.