Tinst 310 - Chapter 7

Front 1

Why were WANs first studied?

Back 1

For reasons of reliability and fault tolerance

(The U.S. military was interested in communication systems that could survive and function even if some of their components were destroyed)

Front 2

Definea protocol in the context of networking.

Back 2

a mutually agreed-upon set ofrules, conventions, and agreements for the efficient and orderly exchange ofinformation.

Front 3

What is groupware?

Back 3

Groupware is software that facilitates thecreative efforts of individuals connected by a network and working on asingle, shared projectking.

(One of the most successful examples of a wikiis Wikipedia, an online encyclopedia written, reviewed, and maintainedby about 76,000 active volunteers working independently. Google Docs)

Front 4

What are the twocritical responsibilities of the Network layer?

Back 4

1) create a universal addressingscheme for all network nodes

2) deliver messages between any two nodes in the network.

Front 5

What is IPv6?

Back 5

From the current IPv4, with its 32-bit address, toIPv6, with a 128-bit address field, will certainly solve the “lack ofaddresses” problem.

(The designers were determined never to run out ofaddresses again!)

Front 6

Explainwhat the function of a WWAN network is in the context of the transmissionlimitations of Wi-Fi.

Back 6

Its transmission limitations means it cannot providemobile Internet access from a car or outdoor site far from any base station.

To handle this typeof wireless communications, we need a different type of network called a wireless wide area network(WWAN). In this type of network, the computer (often a tablet or smartphone)transmits messages to a remote base station provided by a telecommunicationscompany, which may be located many miles away. The base station is usually alarge cellular antenna placed on top of a tower or building, providing bothlong-distance voice and data communication services to any system within sightof the tower.

Front 7

What is a WAN and how does it differ from a LAN in terms of its unit of transmission?

Back 7

A wide area network (WAN) connects devices that arenot in close proximity but rather are across town, across the country, oracross the ocean

WAN messages “hop” from one node to another to make its way directly from source to destination. Unlike LAN, in which a message is broadcast on a sharedchannel and is received by all nodes.

The unit of transmission in a WAN is a packet—aninformation block with a fixed maximum size that is transmitted through thenetwork as a single unit. For example, if you send a long message, the source node may “chop”it into N separate packets (such as the first 1,000 characters, the next1,000 characters, and so on) and send each packet independently through thenetwork. When the destination node has received all N packets, itreassembles them into a single message. (Text messages).

Front 8

Whatdo the Physical layer protocols govern? What do they specify?

What is the goalof the Physical layer?

Back 8

The Physical layer protocols govern the exchange of binary digits (bits) across a physicalcommunication channel, such as a fiber-optic cable, copper wire, or wirelessradio channel.

These protocols specify such things as:

• How to tell when a bitis present on the line

• How long will the bit will remain on the line

• Bit form: digital vs analog signal

• Physical quantities used to represent a binary 0 and a binary 1

• The shape of the connector between the computer and the transmission line

The goal of the Physical layer is to create a “bit pipe” betweentwo computers, such that bits put into the pipe at one end can be read andunderstood by the computer located at the other end.

Front 9

Provide three reasonswhy email rapidly became the most popular application of networks.

Back 9

Email is convenient. You can send a message whenever you want.

Email is fast. A message from the United States typically arrives anywhere in the world inless than a minute.

Email supports multimedia. Supports a wide range of attachments, including photographs,text, graphics, and sound.

Email is a broadcast medium. Can send a letter to a thousandrecipients as easily.

Front 10

What does the termnet neutrality mean?

Back 10

The term netneutrality means that apublic information network such as an Internet service provider (ISP)should treat all users, all platforms, and all content equally—essentiallyit should be operated like thewater, electric, and gas companies, as publicly regulated utilities.