Chapter 4: Network Access

Refer to the exhibit. The PC is connected to the console port of the switch. All the other connections are made through FastEthernet links. Which types of UTP cables can be used to connect the devices?​

1 - rollover, 2 - straight-through, 3 - crossover

A network administrator notices that some newly installed Ethernet cabling is carrying corrupt and distorted data signals. The new cabling was installed in the ceiling close to fluorescent lights and electrical equipment. Which two factors may interfere with the copper cabling and result in signal distortion and data corruption? (Choose two.)

EMI RFI​

Which statement describes an extended star topology?

End devices connect to a central intermediate device, which in turn connects to other central intermediate devices.

straight-through cable

In Ethernet, a cable that connects the wire on pin 1 on one end of the cable to pin 1 on the other end of the cable, pin 2 on one end to pin 2 on the other end, and so on. can have either a T568A or T568B standard termination at one end and the same at the other end.

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

It is able to carry signals much farther than copper cabling.

Manchester encoding

Line code in which each bit of data is signified by at least one voltage level transition.

Match the characteristics to the correct type of fiber.

Multimode Fiber - LED as light source - several paths of light into the fiber - generally used with LANs Single-mode Fiber - only one ray of light into the fiber - generally used for campus backbone - laser as light source

Bus Topology

Network configuration wherein all computers connect to the network via a central bus cable. (one line that terminates on each end)

fiber-optic cable

Physical medium that uses glass or plastic threads to transmit data. A fiber-optic cable consists of a bundle of these threads, each of which is capable of transmitting data into light waves.

Which type of connector does a network interface card use?

RJ-45

latency

Refers to the amount of time, to include delays, for data to travel from one given point to another

Crosstalk

Source of interference that occurs when cables are bundled together for long lengths. The signal from one cable can leak out and enter adjacent cables.

Logical Link Control (LLC)

The IEEE 802.2 standard that defines the upper sublayer of the Ethernet Layer 2 specifications (and other LAN standards).

Ring Topology

Topology where the computers are connected on a loop or ring. Data flows in one direction only. Token Ring

The term ____________ indicates the capacity of a medium to carry data and it is typically measured in kilobits per second (kb/s) or megabits per second (Mb/s).​

bandwidth

Which method of data transfer allows information to be sent and received at the same time?

full duplex

physical topology

the arrangement of the nodes in a network and the physical connections between them. This is the representation of how the media is used to connect the devices.

physical media

the cabling and connectors used to interconnect the network devices.

electromagnetic interference (EMI)

Interference by magnetic signals caused by the flow of electricity. EMI can cause reduced data integrity and increased error rates on transmission channels. The physics of this process are electrictical current creates magnetic field, which in turn cause other electrical current in nearby wires. The induced electrical currents can interfere with proper operation of the other wire.

What acronym is used to reference the data link sublayer that identifies the network layer protocol encapsulated in the frame?

LLC

What is true concerning physical and logical topologies?

Logical topologies refer to how a network transfers data between devices.

A. addressing - 1. direct the frame toward its destination. error detection - 3. checks if the frame has been damaged during the transfer. type - 5. used by the LLC to identify the Layer 3 protocol. frame start - 4. beginning of a frame.

Match each type of frame field to its function. A. addressing B. error detection C. type D. frame start 1. directs the frame towards it's destination 2. identify special flow control services 3. checks if the frame has been damaged during transfer 4. beginning of frame 5. used by LLC to identify layer 3 protocol

Carrier Sense Multiple Access with Collision Detection (CSMA/CD)

Media-access mechanism wherein devices ready to transmit data first check the channel for a carrier. If no carrier is sensed for a specific period of time, a device can transmit. See also CSMA/CA and CSMA/CD

International telecommunications union (ITU)

United Nations agency responsible for issues that concern information and communication technologies

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

media-access mechanisms wherein devices ready to transmit data first check the channel for a carrier. If no carrier is sensed for a specific period of time, a device can transmit. See also CSMA/CA and CSMA/CD

What are two services performed by the data link layer of the OSI model? (Choose two.)

- It accepts Layer 3 packets and encapsulates them into frames. - It provides media access control and performs error detection.

What are two examples of hybrid topologies? (Choose two.)

- partial mesh - extended star

A network administrator is designing the layout of a new wireless network. Which three areas of concern should be accounted for when building a wireless network?

- security - interference - coverage area

fiber-optic cable

A cable that transmits data at close to the speed of light along glass or plastic fibers. A fiber-optic cable is not terminated using RJ-45 connectors.

Partial Mesh Topology

A hybrid of a hub-and-spoke topology and a full-mesh topology. Can be designed to provide an optimal route between selected sites, while avoiding the expense of interconnecting every site to every other site. some but not all end devices are interconnected.

virtual circuit

A logical connection created within a network between two network devices

The end-user device needs mobility when connecting to the network.

A network administrator is designing a new network infrastructure that includes both wired and wireless connectivity. Under which situation would a wireless connection be recommended? A. The end-user device only has an Ethernet NIC. B. The end-user device requires a dedicated connection because of performance requirements. C. The end-user device needs mobility when connecting to the network. D. The end-user device area has a high concentration of RFI.

wireless access point (WAP)

A network device that provides connectivity of wireless clients to connect to a data network.

extended start An extended star topology is an example of a hybrid topology as additional switches are interconnected with other star topologies.

A network team is comparing topologies for connecting on a shared media. Which physical topology is an example of a hybrid topology for a LAN? bus extended star ring partial mesh

crossover cable

A twisted pair patch cable in which the termination locations of the transmit and receive wires on one end of the cable are reversed. has a T568A standard termination at one end and a T568B standard at the other end.

Rollover Cable

A type of cable in which the terminations on one end are exactly the reverse of the terminations on the other end. A Cisco proprietary used for serial connections to a computer system to a router or switch console port. can have either a T568A or T568B standard termination at one end, and at the other end have the same standard, but with the wires connected in reverse order.

shielded twisted - pair (STP)

A type of network cabling that includes twisted-pair wires, with shielding around each pair of wires, as well as another shield around all wires in the cable

Extended Star Topology

An extension of the physical star topology, in which a central switch or hub is the central connecting point for other switches or hubs .that have computers and other network devices attached, forming a star of stars. See also physical star topology.

International organizations for standardization ISO

An international standards body that defies may networking standards. Also, the standards body that created the OSI model.

Institute of Electrical and Electronics Engineers (IEEE)

An international, nonprofit organization for the advancement of technology related to electricity. IEEE maintains the standards defining many LAN protocols.

telecommunication industry association/electronic industries association (TIA/EIA)

An organization that develops standards that relate to telecommunication technologies, Together the TIA and the electronic industries alliance (EIA) have formalized standards, such as EIA/TIA-232, for the electrical characteristics of data transmission.

full-duplex

Both devices can transmit and receive on the media at the same time.

half-duplex

Both devices can transmit and receive on the media but cannot do so simultaneously.

coaxial cable/coax

Cable consisting of a hollow outer cylindrical conductor that surrounds a single inner wire conductor. Two types of coaxial cable are currently used in LANs: 50-ohm cable, which is used for digital signaling, and 75-ohm cable, which is used for analog signaling.

Network Interface Card (NIC)

Computer hardware, typically used for LANs, that allows the computer to connect to some networking cable. The NIC can then send and receive data over the cable at the direction of the computer.

Refer to the exhibit. Which statement describes the media access control methods that are used by the networks in the exhibit?

Network 1 uses CSMA/CD and Network 3 uses CSMA/CA.*

C. straight-through

One end of the cable is terminated as displayed, and the other end is terminated in accordance with the T568A standard. What type of cable would be created in this manner? A. crossover B. rollover C. straight-through D. fiber-optic

Radio frequency interference (RFI)

Radio frequencies that create noise that interferes with information being transmitted across unshielded copper cabling.

Request for Comments (RFC)

Series of documents and memoranda encompassing new research, innovations, and methodologies applicable to Internet technologies. RFCs are a reference for how technologies should work.

Media Access Control (MAC)

The lower of the two sublayers of the IEEE standard for Ethernet. It is also the name of that sublayer (as defined by the IEEE 802.3 subcommittee)

As data travels on the media in a stream of 1s and 0s how does a receiving node identify the beginning and end of a frame?​

The transmitting node inserts start and stop bits into the frame.

Refer to the exhibit. What is wrong with the displayed termination?

The untwisted length of each wire is too long.

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

They allow for full-duplex connectivity.

The branch sites are connected to a central site through point-to-point links.​

What is a characteristic of a WAN hub-and-spoke topology? It requires that some of the branch sites be interconnected through point-to-point links. It requires that every site be interconnected to each other through point-to-point links. All sites require a hub device that connects to a router. The branch sites are connected to a central site through point-to-point links.​

128 kb/s

What is the maximum possible throughput between the PC and the server? 128 kb/s 10 Mb/s 100 Mb/s 1000 Mb/s

transmitting bits across the local media

What is the purpose of the OSI physical layer? controlling access to media transmitting bits across the local media performing error detection on received frames exchanging frames between nodes over physical network media

greater distances per cable run limited susceptibility to EMI/RFI

What makes fiber preferable to copper cabling for interconnecting buildings? (Choose three.) greater distances per cable run lower installation cost limited susceptibility to EMI/RFI durable connections greater bandwidth potential easily terminated

greater distances per cable run limited susceptibility to EMI/RFI greater bandwidth potential

What makes fiber preferable to copper cabling for interconnecting buildings? (Choose three.) greater distances per cable run lower installation cost limited susceptibility to EMI/RFI durable connections greater bandwidth potential easily terminated

CSMA/CA Carrier sense multiple access with collision avoidance (CSMA/CA) is used with wireless networking technology to mediate media contention. Carrier sense multiple access with collision detection (CSMA/CD) is used with wired Ethernet technology to mediate media contention. Priority ordering and token passing are not used (or not a method) for media access control.

What method is used to manage contention-based access on a wireless network? CSMA/CD priority ordering CSMA/CA token passing

rollover To use a UTP cable for consoling into a Cisco router from a PC serial port, it must be terminated as a rollover or console cable.

What type of cable is used to connect a workstation serial port to a Cisco router console port? crossover rollover straight-through coaxial

Hub-and-Spoke Topology

When interconnecting multiple sites (for example, multiple corporate locations) via WAN links, from each remote site (a spoke site) to the main site (the hub site). WAN version of the star topology in which a central site interconnects branch sites using point-to-point links

B. to identify which network layer protocol is being used Defining the media access processes that are performed by the hardware and providing data link layer addressing are functions of the MAC sub-layer. The data link layer accepts Layer 3 packets and packages them into data units that are called frames.

Which is a function of the Logical Link Control (LLC) sublayer? A. to define the media access processes that are performed by the hardware B. to provide data link layer addressing to identify which network layer protocol is being used C. to accept segments and package them into data units that are called packets

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

Which statement correctly describes frame encoding? A. It uses the characteristic of one wave to modify another wave. B. It transmits data signals along with a clock signal which occurs at evenly spaced time duration. C. It generates the electrical, optical, or wireless signals that represent the binary numbers of the frame. D. It converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits.

how the connection between nodes appears to the data link layer how nodes share the media

Which two factors influence the method that is used for media access control? (Choose two.) how data is generated by end devices applications how signals are encoded by the NICs on end devices​ how the connection between nodes appears to the data link layer how nodes share the media how the IP protocol forwards the packet to the destination

unshielded twisted pair (UTP) cable

a general type of cable, with the cable holding twisted pairs of copper wires and the cable itself having little shielding

logical topology diagram

a map of the devices on a network representing how the devices communicate with each other. Identifies devices, ports, and addressing scheme.

Which layer of the OSI model is responsible for specifying the encapsulation method used for specific types of media?

data link

What is contained in the trailer of a data-link frame?

error detection

Mesh Topology

every computer connects to every other computer; no central connecting device is needed requires that every end system be interconnected to every other system using point-to-point links.

throughput

the actual data transfer rate between two computers at some point in time. Throughout is impacted by the slowest-speed link used to send data between the two computer as well as myriad variables that might change during the course of a day

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 crosstalk?

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

What is indicated by the term throughput?

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

bandwidth

the rated throughput capacity of a given network medium or protocol. Bandwidth is listed as available or consumed data communication resource expressed in bits/second.

The media access control (MAC) method used depends on:

the topology (how the connection between the nodes appears to the data link layer), and how the nodes share the media. Have no influence The type of data generated by end devices applications, the way signals are encoded by the NICs on end devices, and even the way the IP protocol forwards the packet through the network have no influence on the choice of the method used.

What are two reasons for physical layer protocols to use frame encoding techniques? (Choose two.)

to distinguish data bits from control information to identify where the frame starts and ends

What is a role of the Logical Link Control sublayer?

to mark frames to identify the network layer protocol being carried

What is the function of the CRC value that is found in the FCS field of a frame?

to verify the integrity of the received frame

What technique is used with UTP cable to help protect against signal interference from crosstalk?

twisting the wires together into pairs