Networking I NETACAD Chapter 4 Quiz Cards
The end-user device needs mobility when connecting to the network. Refer to curriculum topic: 4.1.1 When the end-user devices need mobility to connect to the network, wireless is recommended. If an end-user device only has an Ethernet NIC, the user will only be able to use Ethernet cabling. If RFI is an issue, wireless is not recommended. An end-user device that requires a dedicated connection for performance would perform better with a dedicated Ethernet cable.
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?
extended star Refer to curriculum topic: 4.4.3 An extended star topology is an example of a hybrid topology as additional switches are interconnected with other star topologies. A partial mesh topology is a common hybrid WAN topology. The bus and ring are not hybrid topology types.
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?
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.
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.
Types of UTP Cable
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. Both ends T568A or both ends T568B 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. One end T568A and one end T568B Rollover: A Cisco proprietary cable used to connect a workstation to a router or switch console port. Cisco proprietary The console cable used for Cisco routers and switches is a rollover cable. This cable uses the older serial standard RS-232 and is not an IP connection.
light Refer to curriculum topic: 4.1.2 In fiber optic media, the physical layer produces the representation and groupings of bits as patterns of light.
In fiber optic media, the signals are represented as patterns of _________.
Data Link layer
Layer 2 in the OSI model. Layer 2 wraps IP packets in a layer of encapsulation called frames, and is responsible for moving the data across each link in the path from the source to the destination. Each different type of media has requirements specific to that type, and so there are many different types of frames. Layer 2 (L2) uses framing to encapsulate its payload of layer 3 packets. The fields in the frame header are usually much more simple than an IP or a TCP header (wireless framing is an exception to this) Layer 2 is media dependent (unlike Layer 3) - we will use different framing on an ethernet network than on a wireless network or a serial point-to-point network
addressing - This field helps to direct the frame toward its destination. error detection - This field checks if the frame has been damaged during the transfer. frame start - This field identifies the beginning of a frame. type - This field is used by the LLC to identify the Layer 3 protocol. Refer to curriculum topic: 4.4.4
Match each type of frame field to its function.
STP - This type of copper media is used in industrial or similar environments where there is a lot of interference. wireless - This type of media provides the most mobility options. optical fiber - This type of media is used for high transmission speed and can also transfer data over long distances coaxial - Traditionally used for television but can now be used in a network to connect the customer location to the wiring of the customer premises. Refer to curriculum topic: 4.2.1 UTP cables are used in wired office environments. Coaxial cables are used to connect cable modems and televisions. Fiber optics are used for high transmission speeds and to transfer data over long distances. STP cables are used in environments where there is a lot of interference.
Match the description with the media.
Characteristics of Copper Cabling
Networks use copper media because it is inexpensive, easy to install, and has low resistance to electrical current. However, copper media is limited by distance and signal interference. The longer the signal travels, the more it deteriorates. This is referred to as signal attenuation. The timing and voltage values of the electrical pulses are also susceptible to interference from two sources: Electromagnetic interference (EMI) or radio frequency interference (RFI) Crosstalk
Standard cable terminations
RJ 45 for UTP; BNC N-type and F-type for coaxial cable; ST and SC for fiber
straight-through Refer to curriculum topic: 4.2.2 A straight-through cable can have either a T568A or T568B standard termination at one end and the same at the other end. A crossover cable has a T568A standard termination at one end and a T568B standard at the other end. A rollover cable 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. A fiber-optic cable is not terminated using RJ-45 connectors.
Refer to the exhibit. 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?
128 kb/s Refer to curriculum topic: 4.1.3 The maximum throughput between any two nodes on a network is determined by the slowest link between those nodes.
Refer to the exhibit. What is the maximum possible throughput between the PC and the server? (PC)10Mbs-100Mbs-128kbs-100Mbs-1000Mbs(Server)
contention-based access networks
WLANs, Ethernet LANs with hubs, and legacy Ethernet bus networks are all examples of contention-based access networks. All of these networks operate in half-duplex mode. This requires a process to govern when a device can send and what happens when multiple devices send at the same time. The Carrier Sense Multiple Access/Collision Detection (CSMA/CD) process is used in half-duplex Ethernet LANs.
The branch sites are connected to a central site through point-to-point links Refer to curriculum topic: 4.4.2 A hub-and-spoke topology is a WAN version of the star topology in which a central site interconnects branch sites using point-to-point links. A mesh topology requires that every end system be interconnected to every other system using point-to-point links. A partial mesh is a variation of this topology, where some but not all end devices are interconnected. There is no topology where all the sites have to have hub devices that are connected to a router.
What is a characteristic of a WAN hub-and-spoke topology?
transmitting bits across the local media Refer to curriculum topic: 4.1.2 The physical layer is responsible for transmitting the actual signals across the physical media as bits. Exchanging frames, controlling media access, and performing error detection are all functions of the data link layer.
What is the purpose of the OSI physical layer?
greater distances per cable run limited susceptibility to EMI/RFI greater bandwidth potential Refer to curriculum topic: 4.2.3
What makes fiber preferable to copper cabling for interconnecting buildings? (Choose three.)
CSMA/CA Refer to curriculum topic: 4.2.4 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?
rollover Refer to curriculum topic: 4.2.2 UTP cable wire pairs can be terminated in different configurations for use in different applications. 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?
to identify which network layer protocol is being used Refer to curriculum topic: 4.3.1 Defining the media access processes that are performed by the hardware and providing data link layer addressing are functions of the MAC sublayer. 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?
full duplex Refer to curriculum topic: 4.4.3
Which method of data transfer allows information to be sent and received at the same time?
It converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits. Refer to curriculum topic: 4.1.3 Frame encoding converts a stream of data bits into a predefined code that is recognized by both the sender and receiver. These codes are used for a variety of purposes, such as distinguishing data bits from control bits, and identifying the beginning and end of a frame.
Which statement correctly describes frame encoding?
They vary depending on protocols. Refer to curriculum topic: 4.4.4 All data link layer protocols encapsulate the Layer 3 PDU within the data field of the frame. However, the structure of the frame and the fields that are contained in the header vary according to the protocol. Different data link layer protocols may use different fields, like priority/quality of service, logical connection control, physical link control, flow control, and congestion control.
Which statement describes a characteristic of the frame header fields of the data link layer?
how the connection between nodes appears to the data link layer how nodes share the media Refer to curriculum topic: 4.4.1 The media access control 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. 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 for media access control.
Which two factors influence the method that is used for media access control? (Choose two.)
Coaxial cable
coaxial cable consists of: A copper conductor used to transmit the electronic signals. A layer of flexible plastic insulation surrounding 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. Mainly used in wireless and Cable Internet installations
Unshielded Twisted Pair (UTP) cabling (cat 5, cat 5E, cat 6)
there are four pairs of color-coded wire covered with a plastic jacket, and it is by far the common cable type used in wired Local Area Networks 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 intermediate networking devices, such as switches and routers. In LANs, UTP cable consists of four pairs of color-coded wires that have been twisted together and then encased in a flexible plastic sheath that protects from minor physical damage. The twisting of wires helps protect against signal interference from other wires. The color codes identify the individual pairs and wires and aid in cable termination.
Wireless networks
there are several different kinds of wireless networks, from Bluetooth to satellite communications - but most of our focus in this program are on the wireless LAN standards defined by the 802.11 specifications. Know that the medium used with wireless networks is an electromagnetic carrier wave, and is used in a way very similar to the way radio and television signals are sent
