Title: Module Ten Quiz
Course: CNT 2001 Computer Networks & Communications > Section: Module 10 Wireless Technologies

Q: In what type of technology is the whole message routed to its destination one hop at a time?
- circuit switching
- packet switching
- message switching
- cellular switching
A: message switching
If right: In message switching, whole messages are routed to their destination one hop at a time. Over time, the message switching idea evolved into what we call packet switching today. With message switching, the entire message is sent out at once.

Q: What technology has data broken into smaller packets so that each packet can go through different routes?
- circuit switching
- packet switching
- message switching
- cellular switching
A: packet switching
If right: In packet switching, each packet is given enough information to find its own path to its intended destination.

Q: What technology takes a voice communication, breaks the data into small packets, and sends the packets from one network segment to another?
- circuit switching
- packet switching
- message switching
- cellular switching
A: packet switching
If right: Packet switching opens up connections only long enough for a small data packet to move from one network segment to another. Data—regardless of type, content, or structure—is broken into small blocks called packets and sent to its destination.

Q: What traditional technology has been used for phone calls, but is not done with automatic phone switches?
- circuit switching
- packet switching
- message switching
- cellular switching
A: circuit switching
If right: Probably the oldest and most well-known example of a basic circuit-switched network is the telephone service, which has been around since the late 1800s. When a phone call is made, different physical network segments are linked to create a single unbroken telephone circuit for each phone call.

Q: What communications term describes the establishment of a dedicated communications channel for the duration of a given transmission?
- circuit switching
- packet switching
- message switching
- cellular switching
A: circuit switching
If right: In its most basic definition, circuit switching is a type of communications that establishes a dedicated communications channel for the duration of a given transmission. Initially, circuit switching was done manually, where operators would perform physical connections to establish a circuit or connection. Later, this type of switching was done electronically.

Q: What can you use to overcome the limitations of microwave towers and the curve of the earth?
- terrestrial moving vehicles
- moon bouncing
- ocean scaling
- satellites
A: satellites
If right: Satellite communications is a variation on microwave communications as both the ground stations and the satellites themselves use microwave signals to communicate with each other. With satellite communications, instead of two microwave towers communicating to each other, a ground station communicates to one or more satellites in orbit.

Q: What type of wireless communications is seen in WAN environments?
- fiber
- microwave
- Bluetooth
- infrared
A: microwave
If right: Microwaves are a form or wireless communications seen in WAN environments. Microwaves use the electromagnetic spectrum between the frequencies of 300 MHz and 300 GHz.

Q: What type of cabling is light to carry data?
- fiber
- water
- copper
- wireless
A: fiber
If right: Fiber-optic cables in their most basic form are tiny hollow/transpaarent glass tubes with a reflective coating that allows them to reflect light pulses down the tubes as a means of transmitting network communications.

Q: Which type of cabling is the preferred media for WANs?
- fiber
- water
- copper
- wireless
A: fiber
If right: Phone lines still use copper in the last part of the network connections. However, today fiber optic cabling is usually used up to distribution boxes on the street and often comes directly into businesses. Fiber optic cables are now the preferred media for WAN networks.

Q: Which type of cables uses electrical pulses to transmit network communications?
- fiber
- water
- copper
- wireless
A: copper
If right: Copper cables are the oldest network transmission media used. They are transmission media that sends electrical pulses across a copper wire to transmit network communications.

Q: What type of technology does a VPN use?
- physical circuit switching
- virtual circuit switching
- black-box switching
- VoIP switching
A: virtual circuit switching
If right: Virtual Private Network (VPN) is an example of a technology that makes extensive use of virtual circuit switching through the Internet.

Q: What communication link is established between two points in a larger network, such as the Internet?
- physical circuit switching
- virtual circuit switching
- black-box switching
- VoIP switching
A: virtual circuit switching
If right: In virtual circuit-switched technology, a communications link is established between two points in a larger network such as the Internet. Also, the data is broken into discrete packets just like with packet switching. After the link is established and the data is broken into packets, the packets are then sent to the destination computer using the pre-established communications path.

Q: What technology does email use to send messages?
- circuit switching
- packet switching
- message switching
- cellular switching
A: message switching
If right: The biggest technology currently using message switching is email. In an email server, messages are stored and then sent out as a group to the next stop down the line. The biggest advantage of this store-and-forward process is that messages can be stored during high traffic times and then sent out later when network traffic has slowed down.

Q: In the United States, how many data channels are available for ISDN-PRI?
- 2
- 14
- 23
- 24
A: 23
If right: The PRI portion of ISDN-PRI stands for Primary Rate Interface. This version of ISDN is very similar to ISDN-BRI except that instead of just two B channels bonded together, it has more than two B channels bonded together. Also, the D channel for ISDN-PRI has a throughput of 64 kbps instead of 16 kbps.

Q: What technology allows you to connect over the Internet using PSTN while talking on the phone?
- cable
- DSL
- ATM
- VoIP
A: DSL
If right: Digital subscriber lines (DSLs) come in several variations, but all of them have some common attributes. The main common attribute is that they can use the PSTN because they use a higher frequency than voice communications to carry data. This means that line filters can be used to filter out the DSL signal for voice communications so they are not interfered with by the DSL data signal.

Q: How many data channels does an E1 carry?
- 14
- 23
- 24
- 30
A: 30
If right: In other parts of the world, ISDN-PRI is carried on E1 lines, which contain 30 B channels of 64 kbps and one D channel of 64 kbps.

Q: Approximately how much data can an ISDN PRI carry?
- 1.0 mbps
- 1.5 mbps
- 2.0 mbps
- 4.0 mbps
A: 1.5 mbps
If right: In the United States, ISDN-PRI is commonly carried over a T1 line of 1.544 mbps. This gives ISDN-PRI in the United States 23 B channels of 64 kbps and one D channel of 64 kbps for a total of 1.544 mbps.

Q: What technology uses Packet Assembly/Disassembly (PAD) facilities?
- X.25
- Frame Relay
- cable modem
- ATM
A: X.25
If right: X.25 had devices called packet-switching exchange (PSE) nodes that were used to connect different systems to the X.25 network as well as connect the various PSEs in the X.25 network. These nodes were connected in turn to Data Carrier Equipment (DCE) devices that were then used to connect to different types of Data Terminal Equipment (DTE) devices. Some of the DTE devices that connected to X.25 networks via the DCEs were computers, mainframes, communications switches, and local Packet Assembly/Disassembly facilities (PAD). PADs were used to connect to dumb terminals to the X.25 network.

Q: What early packet-switched network technology originally designed for analog technology?
- X.25
- Frame Relay
- cable modem
- ATM
A: X.25
If right: The X.25 technology was developed in the 1970s as a means to use packet-switched communications in a WAN environment. This technology is not as widely used today because it has been replaced by newer alternatives. X.25 was originally designed as an analog technology. It also does error checking on the packets it passes through.

Q: What WAN technology is based on cells 58 bytes in size?
- T-1
- Frame Relay
- ATM
- DSL
A: ATM
If right: The name Asynchronous Transfer Mode (ATM) derives from ATM using asynchronous time division multiplexing to break up communications into small frame-like segments called cells. ATM cells are a fixed size; unlike frames, which they resemble, they cannot have variable sizes. The set size of ATM cells is 5 bytes for header and an additional 48 bytes for data. Therefore, the total size of an ATM cell is 53 bytes.

Q: What is the speed of a T-3 line?
- 1.544 mbps
- 4.5 mbps
- 10.0 mbps
- 44.7 mbps
A: 44.7 mbps
If right: T-Lines, also called T-Carriers and sometimes T-CXR, refer to a group of technologies that used various means of digital multiplexing used in telecommunications. T-3 line can carry 672 channels and 44.736 mbps data.

Q: What is the speed of an OC-3?
- 1.544 mbps
- 44.7 mbps
- 155.5 mbps
- 622 mbps
A: 155.5 mbps
If right: SONET has several different levels carriers can choose from. These levels are called SONET optical carrier levels and are abbreviated OC-X, where X is the actual multiple of the base level called OC-1. The basic OC-1 level data rate is 51.84 mbps. Each optical carrier level in turn has its own unique frame format. Therefore, OC-3 is 3 times OC-1, which is 155.52 mbps.

Q: Which of the following is based on fiber-optic cables?
- SONET
- Frame Relay
- ATM
- DSL
A: SONET
If right: SONET and the related technology Synchronous Digital Hierarchy (SDH) are multiplexing protocols used to transfer multiple digital bit streams, also called channels, over fiber-optic cables using either lasers or LEDs (light-emitting diodes). Both multiplexing protocols can also be used to send multiple digital bit streams over copper wires at data rates slower than those possible with fiber optic.

Q: Which of the following is used create a secure connection to a corporate network from home using the Internet as the network medium?
- VPN
- ATM
- Frame Relay
- ISDN-BRI
A: VPN
If right: The Virtual Private Network (VPN) technology is commonly used by corporations to allow their users to gain remote access to their corporate servers. VPN is so commonly used for this purpose because it can use the Internet to establish these connections.

Q: What is the ideal position for satellites that allow depending network connectivity?
- locked position in space
- geosynchronous orbit
- lunar locked
- celestial navigated
A: geosynchronous orbit
If right: The higher a satellites orbit, the fewer satellites are needed to be able to see every point on the earth. The ideal position to do this is something called geosynchronous orbit (GEO), also known as geostationary orbit (GSO). Satellites in this orbit will maintain their position over a set geographic position at all times.

Q: What type of orbit covers the northern part of the earth?
- Molniya orbit
- locked-step orbit
- rotating orbit
- lunar orbit
A: Molniya orbit
If right: The Molniya orbitnamed after a group of Soviet-era satellites that used this orbitis designed to cover locations in far northern regions. Russia makes great use of this orbit dynamic. Three satellites in Molniya orbits can achieve 24-hour coverage of far northern regions.

Q: What is the most common form of radio frequency WAN media?
- Bluetooth
- microwave
- satellite
- cellular
A: cellular
If right: The term cellular comes from the way a cellular network functions. Each tower in a cellular network can broadcast up to a set range based on the technology used. In the case of WANs, cellular networks are the most common form of radio frequency WAN media.

Q: What topology uses transceiver tower to broadcast in a circular range?
- mesh
- bus
- ring
- cellular
A: cellular
If right: A cellular network is made up of transceiver towers. Generally, based on the technology, each cellular transceiver tower can broadcast in a radius between 1 and 30 kilometers wide. Each broadcast circle is called a cell—thus, any network that uses this technology is called a cellular network.

Q: Why do today’s cell towers use three directional antennas?
- To increase range
- To prevent jamming
- To prevent eavesdropping
- To broadcast on different frequencies
A: To increase range
If right: Whereas early cell networks used antennae that broadcasted in an omni-directional manner, modern cell networks do not. Directional antennae can get a longer range for the same amount of power. Nowadays, when a cell tower is being set up, it is usually equipped with three directional antennas pointed 120 degrees away from each other, allowing full coverage in a circle around the tower while pushing the towers range out further.

Q: What technology does a common dial-up service use that’s based on the standard telephone service?
- DSL
- cable
- ATM
- POTS
A: POTS
If right: Dial-up is one of the oldest WAN network communication technologies available and is still used in some area of both the US and abroad. Dial-up works by using a modem to connect a computer to a plain old telephone service, also called POTS. POTS is just what it sounds likethe standard telephone service that pretty much every household in America has access to.

Q: How much data can an E1 line carry?
~ In other parts of the world, ISDN-PRI is carried on E1 lines, which contain 30 B channels of 64 kbps and one D channel of 64 kbps. This means that an E1 line can carry a total throughput of 2.048 mbps.

Q: How much data can a T-1 line carry?
~ T-lines, also called T-carriers and sometimes T-CXR, refer to a group of technologies that used various means of digital multiplexing used in telecommunications. A T-1 line can support up to 1.544 mbps, which is 23B+D channels.

Q: How large are the data channels used in ISDN?

Q: What DSL line allows for faster speeds for downloads and slower speeds for uploads?
~ Asymmetric Digital Subscriber Line (ADSL) is one of the most common forms of DSL found today. ADSL is called asymmetric because it provides a different data throughput for upstream communications than it does for downstream communications.

Q: You have setting up a Frame Relay WAN. However, you do not want to lease a full T-1. What would you call a T-1 that is only using half of the bandwidth?
~ Frame Relay offers full T-1 service to end users as well as something called fractional T-1 services without charging the full cost for such connection. In a fractional T-1 setup, a T-1 connection is divided up into 24 channels of 64 kbps each. Each fractional T-1 channel is then leased to end users at less than full T-1 cost.

Q: Another name for message switching is also known as _________.
A: store-and-forward
If right: With message switching, the entire message is sent out at one time. The biggest technology currently using this technology is email. In an email server, messages are stored and then sent out as a group to the next stop down the line. The biggest advantage of store-and-forward is that message can be stored during high traffic times and then sent out later when network traffic has slowed down.

Q: The part of the network that goes from the demarc to the central office is called the _________.
A: local loop
If right: The central office is generally a building somewhere within a few miles of your home or business in towns and cities, though it may be a few tens of miles in more rural areas. The central office is where all remote switching facility boxes terminate. The whole thing from a customers demarc to the central office is called the local loop.

Q: When you configure microwave technology, the transceivers need to be ________.
A: line of sight
If right: The main drawback of microwave technology is that Microsoft technology is a point-to-point configuration that requires line of sight. This means that the transceivers need to be placed in high locations because if they are below the curve of the Earth from each other, the signals cannot be received.

Q: What is the biggest disadvantage of using dial-up to access the Internet?
~ The single biggest drawback of dial-up Internet access is speed. Dial-up Internet is limited to about 50 kbps transfer rates. Although speed is the biggest limiting factor for using dial-up to access the Internet, some interesting modern technologies are attempting to minimize that problem.

Q: What is used to designate an unknown network such as the Internet?
~ A large cloud indicates a large unknown network such as the Internet. It can sometimes be through of as a black box because you typically don’t worry about how packets get from one end of the cloud to the other.