network fundamentals ch 4

Which of the following fiber-optic cable types can travel approximately 100 km?

single mode

optical-fiber connector

terminates the end of an optical fiber. A variety of optical-fiber connectors are available.

which standards organization oversees development of wireless lan standards

IEEE

what is characteristic of UTP cabling

cancellation

wireless components of an access point

the wireless antennas several ethernet switch ports an internet port

Why are two strands of fiber used for a single fiber optic connection?

they allow for full duplex connectivity

Properly Terminated UTP Cable

Improper cable termination can impact transmission performance.

Which of the following is the most common network media?

UTP

Long-Haul Networks

Used by service providers to connect countries and cities

Fiber patch cords

are required for interconnecting infrastructure devices.

Which media uses electrical pulses to represent bits?

copper

Which of the following fiber-optic cable types is used within a campus network?

multimode

Physical Connection

to a local network must be established. A physical connection can be a wired connection using a cable or a wireless connection using radio waves.

UTP cabling conforms

to the standards established jointly by the TIA/EIA. Specifically, TIA/EIA-568 stipulates the commercial cabling standards for LAN installations and is the standard most commonly used in LAN cabling environments.

Optical fiber cable

transmits data over longer distances and at higher bandwidths than any other networking media. Unlike copper wires, fiber-optic cable can transmit signals with less attenuation and is completely immune to EMI and RFI. Optical fiber is commonly used to interconnect network devices.

What is the purpose of the OSI physical layer?

transmitting bits across the local media

Which procedure is used to reduce the effect of crosstalk in copper cables?

twisting opposing circuit wire pairs together

types of copper cabling three type of copper media used in networking

unshielded twisted pair (UTP) cable shielded twisted pair (STP) cable coaxial cable

ST connectors

were one of the first connector types used. The connector locks securely with a "Twist-on/twist-off" bayonet-style mechanism.

Which media uses patterns of microwaves to represent bits?

wireless

Which of the following wireless standards is best suited for industrial and IoT environments?

zigbee

Which of these is the name for the capacity of a medium to carry data?

bandwidth

network administrator is designing a new network infrastructure that includes both wired and wireless connectivity. Under which situation would a wireless connection be recommended?

the end user device needs mobility when connecting to the network

what is indicated by the term throughput

the measure of the bits transferred across the media over a given period of time

A wireless LAN is being deployed inside the new one room office that is occupied by the park ranger. The office is located at the highest part of the national park. After network testing is complete, the technicians report that the wireless LAN signal is occasionally affected by some type of interference. What is a possible cause of the signal distortion?

the microwave oven

some key characteristics of unshielded twisted pair cable

the outer jacket protects the copper wires from physical damage twisted pairs protect the signal from interference color coded plastic insulation electrically isolates wires from each other and identifies each pair

cable designers have discovered other ways that they can limit the negative effect of crosstalk:

Cancellation

Which type of UTP cable is used to connect a PC to a switch port

straight through

Which of the following terminates with BNC, N type and F type connectors?

coaxial

Wireless installations

Coaxial cables attach antennas to wireless devices. The coaxial cable carries radio frequency (RF) energy between the antennas and the radio equipment

WiMAX (IEEE 802:16)

Commonly known as Worldwide Interoperability for Microware Access (WiMAX), this wireless standard uses a point-to-multipoint topology to provide wireless broadband access.

Ethernet Crossover

A cable used to interconnect similar devices. For example, to connect a switch to a switch, a host to a host, or a router to a router. However, crossover cables are now considered legacy as NICs use medium-dependent interface crossover (auto-MDIX) to automatically detect the cable type and make the internal connection.

coaxial cable consists of the following:

A copper conductor is used to transmit the electronic signals. A layer of flexible plastic insulation surrounds a copper conductor. The insulating material is surrounded in a woven copper braid, or metallic foil, that acts as the second wire in the circuit and as a shield for the inner conductor. This second layer, or shield, also reduces the amount of outside electromagnetic interference. The entire cable is covered with a cable jacket to prevent minor physical damage.

Cable internet installations

Cable service providers provide internet connectivity to their customers by replacing portions of the coaxial cable and supporting amplification elements with fiber-optic cable. However, the wiring inside the customer's premises is still coax cable. three figures showing the construction of a coaxial cable, a cross-section of a coaxial cable, and three types of coaxial cable connectors

Some of the elements defined are as follows:

Cable types Cable lengths Connectors Cable termination Methods of testing cable

three categories of UTP cable:

Category 3 was originally used for voice communication over voice lines, but later used for data transmission. Category 5 and 5e is used for data transmission. Category 5 supports 100Mbps and Category 5e supports 1000 Mbps Category 6 has an added separator between each wire pair to support higher speeds. Category 6 supports up to 10 Gbps. Category 7 also supports 10 Gbps. Category 8 supports 40 Gbps.

some of the limitations of wireless:

Coverage area Interference Security Shared medium

Crosstalk

Crosstalk is a disturbance caused by the electric or magnetic fields of a signal on one wire to the signal in an adjacent wire. In telephone circuits, crosstalk can result in hearing part of another voice conversation from an adjacent circuit. Specifically, when an electrical current flows through a wire, it creates a small, circular magnetic field around the wire, which can be picked up by an adjacent wire.

physical layer specifications are applied to areas that include the following

Data to radio signal encoding Frequency and power of transmission Signal reception and decoding requirements Antenna design and construction

Cancellation

Designers now pair wires in a circuit. When two wires in an electrical circuit are placed close together, their magnetic fields are the exact opposite of each other. Therefore, the two magnetic fields cancel each other and also cancel out any outside EMI and RFI signals.

Electromagnetic interference (EMI) or radio frequency interference (RFI) -

EMI and RFI signals can distort and corrupt the data signals being carried by copper media. Potential sources of EMI and RFI include radio waves and electromagnetic devices, such as fluorescent lights or electric motors.

Fiber-optic cabling is now being used in four types of industry:

Enterprise Networks Fiber-to-the-Home (FTTH) Long-Haul Networks Submarine Cable Networks

main cable types that are obtained by using specific wiring conventions:

Ethernet Straight-through Ethernet Crossover

defined and governed by these standards organizations:

International Organization for Standardization (ISO) Telecommunications Industry Association/Electronic Industries Association (TIA/EIA) International Telecommunication Union (ITU) American National Standards Institute (ANSI) Institute of Electrical and Electronics Engineers (IEEE) National telecommunications regulatory authorities including the Federal Communication Commission (FCC) in the USA and the European Telecommunications Standards Institute (ETSI)

Poorly Terminated UTP Cable

It is a good connector with wires that are untwisted only to the extent necessary to attach the connector.

Terms used to measure the quality of bandwidth include:

Latency Throughput Goodput

physical layer standards address three functional areas:

Physical Components Encoding Signaling

Which of the following counters EMI and RFI by using shielding techniques and special connectors?

STP

susceptibility of copper cables to electronic noise can also be limited using these recommendations:

Selecting the cable type or category most suited to a given networking environment Designing a cable infrastructure to avoid known and potential sources of interference in the building structure Using cabling techniques that include the proper handling and termination of the cables

Fiber-optic cables are broadly classified into two types:

Single-mode fiber (SMF) Multimode fiber (MMF)

There are many factors that influence throughput:

The amount of traffic The type of traffic The latency created by the number of network devices encountered between source and destination

Ethernet Straight-through

The most common type of networking cable. It is commonly used to interconnect a host to a switch and a switch to a router.

signaling method

The physical layer must generate the electrical, optical, or wireless signals that represent the "1" and "0" on the media. The way that bits are represented is called the

practical bandwidth of a network:

The properties of the physical media The technologies chosen for signaling and detecting network signals

Wireless Access Point (AP)

These concentrate the wireless signals from users and connect to the existing copper-based network infrastructure, such as Ethernet. Home and small business wireless routers integrate the functions of a router, switch, and access point into one device, as shown in the figure.

Wireless NIC adapters

These provide wireless communication capability to network hosts.

RJ-45 UTP Sockets

This bad connector has wires that are exposed, untwisted, and not entirely covered by the sheath.

Bluetooth (IEEE 802.15)

This is a wireless personal area network (WPAN) standard, commonly known as "Bluetooth." It uses a device pairing process to communicate over distances from 1 to 100 meters.

Varying the number of twists per wire pair

To further enhance the cancellation effect of paired circuit wires, designers vary the number of twists of each wire pair in a cable. UTP cable must follow precise specifications governing how many twists or braids are permitted per meter (3.28 feet) of cable. Notice in the figure that the orange/orange white pair is twisted less than the blue/blue white pair. Each colored pair is twisted a different number of times.

Enterprise Networks

Used for backbone cabling applications and interconnecting infrastructure devices

Fiber-to-the-Home (FTTH)

Used to provide always-on broadband services to homes and small businesses

Submarine Cable Networks

Used to provide reliable high-speed, high-capacity solutions capable of surviving in harsh undersea environments at up to transoceanic distances. Search the internet for "submarine cables telegeography map" to view various maps online.

Shared medium

WLANs operate in half-duplex, which means only one device can send or receive at a time. The wireless medium is shared amongst all wireless users. Many users accessing the WLAN simultaneously results in reduced bandwidth for each user

wireless standards:

Wi-Fi (IEEE 802.11) Bluetooth (IEEE 802.15) WiMAX (IEEE 802:16) Zigbee (IEEE 802.15.4)

WLAN requires the following network devices:

Wireless Access Point (AP) Wireless NIC adapters

Wi-Fi (IEEE 802.11)

Wireless LAN (WLAN) technology, commonly referred to as Wi-Fi. WLAN uses a contention-based protocol known as carrier sense multiple access/collision avoidance (CSMA/CA). The wireless NIC must first listen before transmitting to determine if the radio channel is clear. If another wireless device is transmitting, then the NIC must wait until the channel is clear. Wi-Fi is a trademark of the Wi-Fi Alliance. Wi-Fi is used with certified WLAN devices based on the IEEE 802.11 standards.

Security

Wireless communication coverage requires no access to a physical strand of media. Therefore, devices and users, not authorized for access to the network, can gain access to the transmission. Network security is a major component of wireless network administration.

Coverage area

Wireless data communication technologies work well in open environments. However, certain construction materials used in buildings and structures, and the local terrain, will limit the effective coverage.

coaxial cable design is used in the following situations:

Wireless installations Cable internet installations

Interference

Wireless is susceptible to interference and can be disrupted by such common devices as household cordless phones, some types of fluorescent lights, microwave ovens, and other wireless communications.

Zigbee (IEEE 802.15.4)

Zigbee is a specification used for low-data rate, low-power communications. It is intended for applications that require short-range, low data-rates and long battery life. Zigbee is typically used for industrial and Internet of Things (IoT) environments such as wireless light switches and medical device data collection.

LC simplex connectors

are a smaller version of the SC connector. These are sometimes called little or local connectors and are quickly growing in popularity due to their smaller size.

electrical characteristics of copper cabling

are defined by the Institute of Electrical and Electronics Engineers (IEEE).

SC connectors

are sometimes referred to as square connector or standard connectorThey are a widely-adopted LAN and WAN connector that uses a push-pull mechanism to ensure positive insertion. This connector type is used with multimode and single-mode fiber.

physical components

are the electronic hardware devices, media, and other connectors that transmit the signals that represent the bits. Hardware components such as NICs, interfaces and connectors, cable materials, and cable designs are all specified in standards associated with the physical layer.

Which of the following wireless standards is used for Personal Area Networks (PANs) and allows devices to communicate over distances of 1 to 100 meters?

bluetooth

Unshielded twisted-pair (UTP)

cabling is the most common networking media. UTP cabling, terminated with RJ-45 connectors, is used for interconnecting network hosts with intermediary networking devices, such as switches and routers.

Wireless media

carry electromagnetic signals that represent the binary digits of data communications using radio or microwave frequencies

Which of the following attaches antennas to wireless devices? It can also be bundled with fiber-optic cabling for two-way data transmission.

coaxial

network interface cards

connect a device to the network. are used for a wired connection

Multimode Fiber

consists of a larger core and uses LED emitters to send light pulses. Specifically, light from an LED enters the multimode fiber at different angles,

Single-Mode Fiber

consists of a very small core and uses expensive laser technology to send a single ray of light,is popular in long-distance situations spanning hundreds of kilometers, such as those required in long haul telephony and cable TV applications.

Physical Layer Standards

consists of electronic circuitry, media, and connectors developed by engineers. Therefore, it is appropriate that the standards governing this hardware are defined by the relevant electrical and communications engineering organizations.

The physical layer of the receiving device passes bits up to which higher level layer?

data link

True or false. Wireless LANs operate in full-duplex allowing all devices to send or receive data at the same time so the number of users does not impact performance.

false

True or false. Wireless is not well suited for enterprise networks.

false

True or false? The physical layer is only concerned with wired network connections.

false

True or false? When a frame is encoded by the physical layer, all bits are sent over the media at the same time.

false

Which media uses patterns of light to represent bits?

fiberoptic

What PDU is received by the physical layer for encoding and transmission?

frame

Encoding or line encoding

is a method of converting a stream of data bits into a predefined "code". Codes are groupings of bits used to provide a predictable pattern that can be recognized by both the sender and the receiver.

yellow jacket

is for single-mode fiber cables and orange (or aqua) for multimode fiber cables

duplex multimode LC connector

is similar to a LC simplex connector, but uses a duplex connector

Bandwidth

is the capacity at which a medium can carry data

RJ-45 UTP Plugs

is the female component of a network device, wall, cubicle partition outlet, or patch panel. When terminated improperly, each cable is a potential source of physical layer performance degradation.

throughtput

is the measure of the transfer of bits across the media over a given period of time.

Goodput

is the measure of usable data transferred over a given period of time. Goodput is throughput minus traffic overhead for establishing sessions, acknowledgments, encapsulation, and retransmitted bits. Goodput is always lower than throughput, which is generally lower than the bandwidth.

Copper cabling

is the most common type of cabling used in networks today. In fact, copper cabling is not just one type of cable. There are three different types of copper cabling that are each used in specific situations.

Which statement correctly describes frame encoding?

it converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits

What is one advantage of using fiber optic cabling rather than copper cabling?

it is able to carry signals much farther than copper cabling

Digital bandwidth

measures the amount of data that can flow from one place to another in a given amount of time.

Which of the following fiber-optic cable types can help data travel approximately 500 meters?

multimode

Which of the following fiber-optic cable types use light emitting diodes (LEDs) as a data light source transmitter?

multimode

coaxial cable

or coax for short, gets its name from the fact that there are two conductors that share the same axis

some key features of coaxial cable

outer jacket braided copper shielding plastic insulation copper conductor

some key feature of shield twisted pair cable

outer jacket braided or foil shield foil shield twisted pairs

A network administrator is troubleshooting connectivity issues on a server. Using a tester, the administrator notices that the signals generated by the server NIC are distorted and not usable. In which layer of the OSI model is the error categorized?

physical layer

shield twisted pair (STP)

provides better noise protection than UTP cabling. However, compared to UTP cable, STP cable is significantly more expensive and difficult to install. Like UTP cable, STP uses an RJ-45 connector.

OSI Physical Layer

provides the means to transport the bits that make up a data link layer frame across the network media

Latency

refers to the amount of time, including delays, for data to travel from one given point to another.

What type of cable is used to connect a workstation serial port to a Cisco router console port?

rollover

Which of the following fiber-optic cable types is used to connect long-distance telephony and cable TV applications?

single mode

Which of the following fiber-optic cable types use lasers in a single stream as a data light source transmitter?

single mode

What is the definition of bandwidth?

the amount of data that can flow from one place to another in a given amount of time

which characteristic describes cross talk

the distortion of the transmitted messages from signals carried in adjacent wires

Which of these is a measure of the transfer of bits across the media?

throughtput