CNA 101 | Ch. 4, Physical Layer

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 are two possible causes of the signal distortion? (Choose two.) A. The microwave oven B. The large number of trees that surround the office C. The cellular phones that are used by the employees D. The elevated location where the wireless LAN was installed E. The number of wireless devices used in the WLAN

A. The microwave oven C. The cellular phones that are used by the employees

Match the unit of bandwidth to its corresponding equivalence in bits per second. Bits per second Gigabits per second Terabits per second Kilobits per second Megabits per second 1 1,000 1,000,000 1,000,000,000 1,000,000,000,000

Bits = 1 Kilobit = 1,000 Megabit = 1,000,000 Gigabit = 1,000,000,000 Terabit = 1,000,000,000,000

A wireless personal area network (WPAN) standard, that uses a device pairing process to communicate over distances from 1 to 100 meters.

Bluetooth (IEEE 802.15)

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

C. Coaxial

What is the definition of bandwidth? A. The measure of the transfer of bits across the media over a given period of time. B. The speed at which bits travel on the network. C. The amount of data that can flow from one place to another in a given amount of time. D. The measure of usable data transferred over a given period of time.

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

What is it called when two wires in an electrical circuit are placed close together, so that their magnetic fields are the exact opposite of each other?

Cancellation

Match the category of UTP cable to the correct definition. Cat3 Cat5 and 5e Cat6 Cat7 Cat8 Supports 40 Gbps Has an added separator between each wire to support hire speeds. Originally used for voice communication, but later used for data. Supports 10 Gbps Used for Data Tranamission, supports 100 and 1000 Mbps respectively

Cat3 = Originally used for voice Cat5 & 5e = 100/1000 Mbps Cat6 = Added separator Cat7 = 10 Gbps Cat8 = 40 Gbps

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

Digital bandwidth

__________ refers to the spreading out of a light pulse over time.

Dispersion

This type of fiber connector is similar to a LC simplex connector, but it uses a duplex connector.

Duplex Multimode Lucemt Connector (LC)

___ and ___ signals can distorty and corrupt the data signals being carried by copper media.

Electromagnetic Interference (EMI) Radio Frequency Interference (RFI)

A method of converting a stream of data bits into a predefined "code"

Encoding (or line encoding)

Fiber-optic network used for backbone cabling applications and interconnecting infrastructure devices.

Enterprise Networks

Match the portion of the frame to the most accurate term. Ethernet IP TCP Data Segment Frame Packet Data

Ethernet = Frame IP = Packet TCP = Segment Data = Data

A cable used to interconnect similar devices.

Ethernet Crossover

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

Ethernet Straight-through

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.

The capacity at which a medium can carry data.

Bandwidth

Which media uses electrical pulses to represent bits?

Copper

Which medium is inexpensive, easy to install, and has a low resistance to electrical current?

Copper

A disturbance caused by the electric or magnetic fields of a signal on one wire to the signal in an adjacent wire.

Crosstalk

Why are two strands of fiber used for a single fiber optic connection? A. The two strands allow the data to travel for longer distances without degrading. B. They prevent crosstalk from causing interference on the connection. C. They increase the speed at which the data can travel. D. They allow for full-duplex connectivity.

D. They allow for full-duplex connectivity.

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

Data link (layer 2)

True or False? SMF has a greater dispersion than MMF, which is why SMF can only travel up to 500 meters before signal loss.

False. MMF has the higher dispersion rate, meaning it can only travel up to 500 meters before signal loss.

True or False? An end-user device can have either a wireless local area network (WLAN) network interface card (NIC), or an Ethernet NIC, but not both.

False. Some devices have only one, but devices can have both types of NIC card.

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

False. WLANs operate in half-duplex

True or False? Wireless is not well suited for enterprise networks?

False. Wireless provides great mobility of all media and is gaining popularity in enterprise networks.

Which media uses patterns of lights to represent bits?

Fiber-optic

Fiber-optic network used to provide always-on broadband services to home and small businesses.

Fiber-to-the-home (FTTH)

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

Frame

The measure of usable data transferred over a given period of time.

Goodput

The electrical characteristics of copper cabling are defined by the ____.

Institute of Electrical and Electronics Engineers (IEEE)

The services and protocols in the TCP/IP suite are defined by the ____.

Internet Engineering Task Force (IETF)

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

Latency

Fiber-optic network used by service providers to connect countries and cities.

Long-Haul Networks

A smaller version of the SC fiber connector.

Lucent Connector (LC)

Which fiber-optic cable can help data travel approximately 1.24 miles or 2km?

Multimode

Which fiber-optic cable can type uses light emitting diodes (LEDs) as a data light source transmitter?

Multimode

A type of fiber-optic cabling that consists of a larger core and it uses LED emitters to send light pulses.

Multimode Fiber

The ________ layer of the OSI model sits at the bottom of the stack. It is part of the Network Access layer of the TCP/IP model.

Physical

Name two of the three functional areas addressed by physical layer standards.

Physical Components Encoding Signaling

A Cisco proprietary cable used to connect a workstation to a router or switch console port.

Rollover cable

Which cabling counters EMI and RFI by using shielding techniques and special connectors?

Shielded twisted-pair (STP)

The way that bits are represented is called what?

Signaling method

A type of fiber-optic cabling that consists of a small core and uses expensive laser technology to send a single ray of light.

Single-Mode Fiber

Which fiber-optic cable can travel approximately 62.5 miles or 100km?

Single-mode

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

Single-mode

Which fiber-optic cable uses lasers in a single stream as a data light source transmitter?

Single-mode

One of the first fiber connectors used. It locks securely with a "Twist-on/twist-off" bayonet-style mechanism.

Straight-Tip (ST)

Fiber-optic network used to provide reliable high-speed, high-capacity solutions capable of surviving in harsh undersea environments up to transoceanic distances.

Submarine Cable Networks

Sometimes referred to as square or standard connector, these are a widely-adopted LAN and WAN connector that uses a push-pull mechanism to ensure positive insertion.

Subscriber Connector (SC)

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

Throughput

True or False? In telephone circuits, crosstalk can result in hearing part of another voice conversation from an adjacent circuit.

True

True or False? Using a crossover or straight-through cable incorrectly between devices may not damage the devices, but connectivity and communication between the devices will not take place.

True

What cabling is the most common network media?

Unshielded twisted-pair (UTP)

This wireless standard uses a contention-based protocol known as carrier sense multiple access/collision avoidance (CSMA/CA).

Wi-Fi (IEEE 802.11)

This wireless standard uses a point-to-multipoint topology to provide wireless broadband access.

WiMAX (IEEE 802:16)

Which media uses patterns of microwaves to represent bits?

Wireless

This wireless specification is 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 (IEEE 802.15.4)

What wireless standard is best suited for industrial and IoT environments?

Zigbee (IEEE 802.15.4)

Devices on a wireless network must be connected to a wireless __ or wireless ________.

access point (AP) router