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**1. What is an important function of the physical layer of the OSI model?** - It accepts frames from the physical media. - It encapsulates upper layer data into frames. - It defines the media access method performed by the hardware interface. - **It encodes frames into electrical, o...

**1. What is an important function of the physical layer of the OSI model?** - It accepts frames from the physical media. - It encapsulates upper layer data into frames. - It defines the media access method performed by the hardware interface. - **It encodes frames into electrical, optical, or radio wave signals.** **Explanation:** The physical layer of the OSI model accepts frames from the data link layer and encodes it for transport as bits across the network media. **2. 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?** **AD** - presentation layer - network layer - **physical layer** - data link layer **Explanation:** The NIC has responsibilities in both Layer 1 and Layer 2. The NIC encodes the frame as a series of signals that are transmitted onto the local media. This is the responsibility of the physical layer of the OSI model. The signal could be in the form of electrical, optical, or radio waves. **3. 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 **Explanation:** 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. **4. Which statement correctly describes frame encoding?** - It uses the characteristic of one wave to modify another wave. - It transmits data signals along with a clock signal which occurs at evenly spaced time durations. - It generates the electrical, optical, or wireless signals that represent the binary numbers of the frame. - **It converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits.** **Explanation:** 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. **5. What is one advantage of using fiber-optic cabling rather than copper cabling?** - It is usually cheaper than copper cabling. - It is able to be installed around sharp bends. - It is easier to terminate and install than copper cabling. - **It is able to carry signals much farther than copper cabling.** **Explanation:** Copper cabling is usually cheaper and easier to install than fiber-optic cabling. However, fiber cables generally have a much greater signaling range than copper. **6. Which pairs of wires change termination order between the 568A and 568B standards?** **AD** - **green and orange** - green and brown - blue and brown - brown and orange **Explanation:** The difference between the 568A and 568B standards is the order in which the colored wire pairs are sequenced. It is the green and the orange pairs of wires that are swapped between the two standards. **7. What is the delay in the amount of time for data to travel between two points on a network?** - bandwidth - throughput - **latency** - goodput **Explanation:** Latency is a term used to indicate delay when getting a packet from one point to another. Network connections with small amounts of delay are called low-latency networks, whereas network connections with long delays are called high-latency networks. High latency creates bottlenecks in any network communications. **8. What terms represent the maximum and actual speed that can be utilized by a device to transfer data?** - **bandwidth; throughput** - throughput; bandwidth - bandwidth; goodput - throughput; goodput **Explanation:** Bandwidth measures the maximum rate at which a device can transfer data. However, in practice, the actual speed for data transfer could be reduced because of numerous factors like network congestion, overhead etc. This actual rate of transfer is known as throughput. **9. Which type of network cable contains multiple copper wires and uses extra shielding to prevent interference?** - **STP** - UTP - fiber-optic - coax **Explanation:** Shielded twisted-pair (STP) cables contain additional shielding and is commonly used when electromagnetic interference (EMI) or radio frequency interference (RFI) would negatively affect the data communication crossing a network cable. **10. What is line encoding?** - **a method to represent digital information** - a security method used to protect data being transmitted - a method to represent bits on the media - a method to change the level of an electrical signal or optical pulse on the media **Explanation:** Line encoding is a method of converting a stream of data bits into a predefined "code". In other words, encoding is the method or pattern used to represent digital information. **11. What is a factor that determines the practical bandwidth of a network?** - **physical media properties** - type of traffic - amount of traffic - latency caused by all intermediary devices **Explanation:** A combination of factors influence the practical bandwidth of a network including the properties of the physical media as well as the technologies chosen for signaling and detecting network signals. **12. What are three options for signal transmission on a network? (Choose three.)** - **radio waves** - vibration pulses - sound waves - **electrical pulses** - **light pulses** **Explanation:** There are three common methods of signal transmission used in networks: - Electrical signals -- Transmission is achieved by representing data as electrical pulses on copper wire. - Optical signals -- Transmission is achieved by converting the electrical signals into light pulses. - Wireless signals -- Transmission is achieved by using infrared, microwave, or radio waves through the air. **1. What method can be used by two computers to ensure that packets are not dropped because too much data is being sent too quickly?** - encapsulation - **flow control** - access method - response timeout **Explain:**\ In order for two computers to be able to communicate effectively, there must be a mechanism that allows both the source and destination to set the timing of the transmission and receipt of data. Flow control allows for this by ensuring that data is not sent too fast for it to be received properly. **2. What type of communication will send a message to all devices on a local area network?** - **broadcast** - multicast - unicast - allcast **Explain:**Broadcast communication is a one-to-all communication. A unicast communication is a one-to-one communication. Multicast is a one-to-many communication where the message is delivered to a specific group of hosts. Allcast is not a standard term to describe message delivery. **3. What process is used to place one message inside another message for transfer from the source to the destination?** - access control - decoding - **encapsulation** - flow control **Explain:**Encapsulation is the process of placing one message format into another message format. An example is how a packet is placed in its entirety into the data field as it is encapsulated into a frame. **4. A web client is sending a request for a webpage to a web server. From the perspective of the client, what is the correct order of the protocol stack that is used to prepare the request for transmission?** **AD** - HTTP, IP, TCP, Ethernet - **HTTP, TCP, IP, Ethernet** - Ethernet, TCP, IP, HTTP - Ethernet, IP, TCP, HTTP **Explain:**\ 1. HTTP governs the way that a web server and client interact.\ 2. TCP manages individual conversations between web servers and clients.\ 3. IP is responsible for delivery across the best path to the destination.\ 4. Ethernet takes the packet from IP and formats it for transmission. **5. Which statement is correct about network protocols?** - Network protocols define the type of hardware that is used and how it is mounted in racks. - **They define how messages are exchanged between the source and the destination.** - They all function in the network access layer of TCP/IP. - They are only required for exchange of messages between devices on remote networks. **Explain:**\ Network protocols are implemented in hardware, or software, or both. They interact with each other within different layers of a protocol stack. Protocols have nothing to do with the installation of the network equipment. Network protocols are required to exchange information between source and destination devices in both local and remote networks. **6. Which statement is true about the TCP/IP and OSI models?** - **The TCP/IP transport layer and OSI Layer 4 provide similar services and functions.** - The TCP/IP network access layer has similar functions to the OSI network layer. - The OSI Layer 7 and the TCP/IP application layer provide identical functions. - The first three OSI layers describe general services that are also provided by the TCP/IP internet layer. **Explain:**\ The TCP/IP internet layer provides the same function as the OSI network layer. The transport layer of both the TCP/IP and OSI models provides the same function. The TCP/IP application layer includes the same functions as OSI Layers 5, 6, and 7. **7. What is an advantage of using standards to develop and implement protocols?** - A particular protocol can only be implemented by one manufacturer. - **Products from different manufacturers can interoperate successfully.** - Different manufacturers are free to apply different requirements when implementing a protocol. - Standards provide flexibility for manufacturers to create devices that comply with unique requirements. **Explain:**\ Standards-based protocols enable products from different manufacturers to interoperate successfully. Standards-based protocols enable many manufacturers to implement that protocol. If different manufacturers implement different requirements within the same protocol, then their products will not be interoperable. **8. What three application layer protocols are part of the TCP/IP protocol suite? (Choose three.)** **AD** - ARP - **DHCP** - **DNS** - **FTP** - NAT - PPP **Explain:**\ DNS, DHCP, and FTP are all application layer protocols in the TCP/IP protocol suite. ARP and PPP are network access layer protocols, and NAT is an internet layer protocol in the TCP/IP protocol suite. **9. What are proprietary protocols?** - protocols developed by private organizations to operate on any vendor hardware - protocols that can be freely used by any organization or vendor - **protocols developed by organizations who have control over their definition and operation** - a collection of protocols known as the TCP/IP protocol suite **Explain:**\ Proprietary protocols have their definition and operation controlled by one company or vendor. Some of them can be used by different organizations with permission from the owner. The TCP/IP protocol suite is an open standard, not a proprietary protocol. **10. What is an advantage of network devices using open standard protocols?** - Network communications is confined to data transfers between devices from the same vendor. - **A client host and a server running different operating systems can successfully exchange data.** - Internet access can be controlled by a single ISP in each market. - Competition and innovation are limited to specific types of products. **Explain:**\ An advantage of network devices implementing open standard protocols, such as from the TCP/IP suite, is that clients and servers running different operating systems can communicate with each other. Open standard protocols facilitate innovation and competition between vendors and across markets, and can reduce the occurrence of monopolies in networking markets. ** A computer in a given network is communicating with a specific group of computers. What type of communication is this?** - broadcast - **multicast** - unicast - ARP - HTTP **25. Which protocol is responsible for controlling the size and rate of the HTTP messages exchanged between server and client?** **AD** - HTTP - ARP - **TCP** - DHCP **26. A user is viewing an HTML document located on a web server. What protocol segments the messages and manages the segments in the individual conversation between the web server and the web client?** - DHCP - **TCP** - HTTP - ARP **27. Which IEEE standard enables a wireless NIC to connect to a wireless AP that is made by a different manufacturer?** - 802.1 - **802.11** - 802.3 - 802.2 **28. What is a function of Layer 4 of the OSI model?** - to specify the packet type to be used by the communications - to apply framing information to the packet, based on the attached media - to represent data to the user, including encoding and dialog control - **to describe the ordered and reliable delivery of data between source and destination** **29. What is a benefit of using a layered model for network communications?** **AD** - **fostering competition among device and software vendors by enforcing the compatibility of their products** - enhancing network transmission performance by defining targets for each layer - avoiding possible incompatibility issues by using a common set of developing tools - simplifying protocol development by limiting every layer to one function **30. What is the general term that is used to describe a piece of data at any layer of a networking model?** - frame - packet - **protocol data unit** - segment **31. Which statement accurately describes a TCP/IP encapsulation process when a PC is sending data to the network?** - Data is sent from the internet layer to the network access layer. - Packets are sent from the network access layer to the transport layer. - **Segments are sent from the transport layer to the internet layer.** - Frames are sent from the network access layer to the internet layer. **32. What statement describes the function of the Address Resolution Protocol?** - ARP is used to discover the IP address of any host on a different network. - ARP is used to discover the IP address of any host on the local network. - ARP is used to discover the MAC address of any host on a different network. - **ARP is used to discover the MAC address of any host on the local network.** **Explanation:** When a PC wants to send data on the network, it always knows the IP address of the destination. However, it also needs to discover the MAC address of the destination. ARP is the protocol that is used to discover the MAC address of a host that belongs to the same network. **33. Which address provides a unique host address for data communications at the internet layer?** **AD** - data-link address - **logical address** - Layer 2 address - physical address **34. Which protocol is used by a computer to find the MAC address of the default gateway on an Ethernet network?** - **ARP** - TCP - UDP - DHCP **Explanation:** TCP provides reliable delivery of data. UDP provides unreliable delivery of data. DHCP is used for the automatic assignment of IP addresses. ARP is used to discover the MAC address of a device on the Ethernet network. **35. If the default gateway is configured incorrectly on the host, what is the impact on communications?** - The host is unable to communicate on the local network. - **The host can communicate with other hosts on the local network, but is unable to communicate with hosts on remote networks.** - The host can communicate with other hosts on remote networks, but is unable to communicate with hosts on the local network. - There is no impact on communications. **36. Open the PT Activity. Perform the tasks in the activity instructions and then answer the question. Based on the configured network, what IP address would PC1 and PC2 use as their default gateway?** - 192.168.1.2 - 10.1.1.1 - 172.16.1.1 - **192.168.1.1** - 192.168.1.10 **37. A user sends an HTTP request to a web server on a remote network. During encapsulation for this request, what information is added to the address field of a frame to indicate the destination?** **AD** - **the MAC address of the default gateway** - the IP address of the destination host - the MAC address of the destination host - the IP address of the default gateway