Flashcards in Topic 5: Industry Standards, Practices, and Network Theory Deck (26)
When a client calls and describes a problem with a computer not being able to reach the Internet, in which of the following places of the OSI model would a technician begin troubleshooting?
A. Transport layer
B. Physical layer
C. Network layer
D. Session layer
Explanation: The bottom layer of the OSI reference model is Layer 1, the physical layer. The physical layer is the layer that defines the hardware elements of a network. These elements include: When troubleshooting a network connectivity issue, the first thing you would check is the computer’s network cabling, the network card etc. In other words, the computer’s physical connection to the network.
A network engineer is dispatched to an employee office to troubleshoot an issue with the employee's laptop. The employee is unable to connect to local and remote resources. The network engineer flips the laptop's wireless switch on to resolve the issue. At which of the following layers of the OSI model was the issue resolved?
A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4
E. Layer 7
Explanation: The bottom layer of the OSI reference model is Layer 1, the physical layer. The physical layer is the layer that defines the hardware elements of a network. These elements include: In this question, the network engineer flipped the laptop's wireless switch on to resolve the issue. The laptop was unable to connect to the wireless network because the wireless network interface card was switched off. Switching the wireless network interface card on enabled the laptop to connect to the wireless network. The wireless network interface card is a physical layer device.
When troubleshooting a network problem, browsing through the log of a switch, it is discovered that multiple frames contain errors. In which of the following layers does the problem reside? (Select TWO).
A. Layer 2
B. Layer 3
C. Layer 5
D. Transport layer
E. Data link
F. Physical layer
Explanation: Layer 2 of the OSI reference model is the data-link layer. Components of the data-link layer include frame-format, Media Access Control (MAC) addressing, protocol identification and error detection. When data is being sent, it is split into protocol data units (PDUs) as it passes through the layers of the OSI model. The PDUs have different names as they are passed through the layers of the OSI model. In layer 2, the PDU is called a ‘Frame’. The most common protocol specified in the data-link layer is Ethernet and the most common network component in the data-link layer is a network switch. In this question, problems are discovered with Ethernet frames by examining the logs in a network switch. Therefore, for this question, we are working in Layer 2, the data-link layer.
A network administrator is using a packet analyzer to determine an issue on the local LAN. Two separate computers are showing an error message on the screen and are unable to communicate with other computers in the same lab. The network administrator looks at the following output: SRC MAC SRC IP DST MAC DST IP 00:1D:1F:AB:10:7D 192.168.1.10:2000 15:BE:9F:AB:10:1D 192.168.1.14:1200 05:DD:1F:AB:10:27 192.168.1.10:1000 22:C7:2F:AB:10:A2 192.168.1.15:1300 Given that all the computers in the lab are directly connected to the same switch, and are not using any virtualization technology, at which of the following layers of the OSI model is the problem occurring?
C. Data link
Explanation: If we look at the Source Mac column, we can see two different MAC addresses. Every network interface card has a unique MAC address. These are the network cards in the two separate computers. If we look in the Source IP column, we can see that the two network cards have been assigned the same IP address (192.168.1.10). This is the problem in this question. The error message on the screens will be saying that “An IP conflict exists”. Every network card connected to the network needs to be configured with a different IP address. As the problem is with the IP address configuration of the two computers, we know that the problem is occurring at the Network layer (layer 3) of the OSI model. The network layer is responsible for Internet Protocol (IP) addressing and routing.
Which of the following will negotiate standoff timers to allow multiple devices to communicate on congested network segments?
Explanation: Carrier Sense Multiple Access/Collision Detect (CSMA/CD) is used by devices in an Ethernet network for transmitting data on the network. Any device on an Ethernet network can send data at any time. The network devices sense when the line is idle and therefore available for the transmission of data. The network device then transmits a data frame onto the network. If another device sends a frame at exactly the same time, a collision occurs and the frames are discarded. The network devices will then wait for a random period of time before attempting to send the frame again.
Which of the following devices implements CSMA/CA virtually through the RTS/CTS protocols?
C. 802.11 AP
Explanation: 802.11 AP is a Wireless Access Point used in a wireless network. If two computers on a network send data frames at the same time, a collision between the frames can occur. The frames are then discarded and the sending computers will attempt to send the data again. Carrier sense multiple access with collision avoidance (CSMA/CA) is a protocol used in wireless networks where computers connected to the wireless network attempt to avoid collisions by transmitting data only when the channel is sensed to be "idle". Carrier Sense Multiple Access/Collision Detect (CSMA/CD) is unreliable in wireless networks because computers connected to the wireless network often cannot see each other so CSMA/CA is a better option for avoiding collisions. Request to Send/Clear to Send (RTS/CTS) can also be used to mediate access to the wireless network. This goes some way to alleviating the problem of computers not being able to see each other because in a wireless network, the Wireless Access Point only issues a “Clear to Send” to one node at a time. With RTS/CTS, a Request to Send (RTS) packet is sent by the sending computer, and a Clear to Send(CTS) packet is sent by the intended receiver. This will alert all computers within range of the sender, receiver or both, to not transmit for the duration of the transmission. This is known as the IEEE 802.11 RTS/CTS exchange.
The management team wants to set up a wireless network in their office but all of their phones operate at the 2.4 GHz frequency. They need a wireless network that would be able to operate at a higher frequency than their phones. Which of following standards should be used?
Explanation: In this question, we need a wireless network that operates at a frequency higher than the 2.4GHz frequency. 802.11 is a set of IEEE standards that govern wireless networking transmission methods. The 802.11 standards commonly used today to provide wireless connectivity in home or office wireless networks are 802.11a, 802.11b, 802.11g, 802.11n and 802.11ac. The 802.11a standard supports speeds up to 54Mbps and uses the 5-GHzband.
A user with an 802.11n WLAN card is connected to a SOHO network and is only able to connect at 11 Mbps with full signal strength. Which of the following standards is implemented on the network?
Explanation: 802.11 is a set of IEEE standards that govern wireless networking transmission methods. The 802.11 standards commonly used today to provide wireless connectivity in home or office wireless networks are 802.11a, 802.11b, 802.11g, 802.11n and 802.11ac. 802.11b supports speeds up to 11Mbps and uses the 2.4GHz frequency. In this question, the user is using an 802.11n WLAN card. Although the 802.11n WLAN card can support speeds up to 300Mbps, the user is only able to connect at 11Mbps because the user is connected to a wireless network configured to use 802.11b.
A network technician has been tasked with designing a WLAN for a small office. One of the requirements of this design is that it is capable of supporting HD video streaming to multiple devices. Which of the following would be the appropriate wireless technology for this design?
D. 109 802.11a
Explanation: In this question, we need a wireless network capable of supporting HD video streaming to multiple devices. We therefore need the fastest wireless network speed available. 802.11 is a set of IEEE standards that govern wireless networking transmission methods. The 802.11 standards commonly used today to provide wireless connectivity in home or office wireless networks are 802.11a, 802.11b, 802.11g, 802.11n and 802.11ac. The 802.11ac standard is the fastest wireless network supporting speeds of over 3Gbps and uses the 5-GHz band.
A company is deploying a new wireless network and requires 800Mbps network throughput. Which of the following is the MINIMUM configuration that would meet this need?
A. 802.11ac with 2 spatial streams and an 80MHz bandwidth
B. 802.11ac with 3 spatial streams and a 20MHz bandwidth
C. 802.11ac with 3 spatial streams and a 40MHz bandwidth
D. 802.11ac with 4 spatial streams and a 160MHz bandwidth
Explanation: Spatial streaming is used in wireless communications where multiple-input-multiple-output (MIMO) is being used. With MIMO, multiple antennas are used for transmission and reception. MIMO was available in 802.11n but its capabilities have been extended in 802.11ac. 802.11ac supports a mandatory 80 MHz channel bandwidth for stations (vs. 40 MHz maximum in 802.11n), 160 MHz available optionally and more (up to 8) special streams. A single antenna and 80 MHz channel bandwidth provides a bandwidth of 433Mbps. In this question, we need a minimum bandwidth of 800Mbps. Two antennas and 80 MHz channel bandwidth provides a bandwidth of 867Mbps and therefore meets the requirement.
A network technician is attempting to connect a new host to existing manufacturing equipment on an Ethernet network. The technician is having issues trying to establish communication between the old equipment and the new host. The technician checks the cabling for breaks and finds that the CAT3 cable in use is in perfect condition. Which of the following should the technician check to ensure the new host will connect?
A. Confirm the new host is using 10GBaseSR due to the manufacturing environment
B. Confirm the new host is compatible with 10BaseT Ethernet
C. Confirm the existing 10Base2 equipment is using the proper frame type
D. Confirm that CSMA/CD is disabled on the Ethernet network
Explanation: The question states that the equipment is old and that CAT3 cabling is being used. 10BaseT Ethernet networks are old and slow by today’s standards. 10BaseT Ethernet networks use CAT3 UTP cabling and offer a maximum bandwidth of just 10Mpbs. A new host computer nowadays will have a network card that supports 1000Mpbs to be used with CAT5, CAT5e or CAT6 network cables in a 1000BaseT network. In this question, we need to check that the network card on the new host computer is backward-compatible with the old 10BaseT network.
Before logging into the company network, users are required to sign a document that is to be stored in their personnel file. This standards and policies document is usually called which of the following?
Explanation: AUP stands for Acceptable Use Policy. An Acceptable Use Policy defines what a user can or cannot do with his or her computer during business hours. For example, using the company’s Internet connection to look at the sports scores on a sports website may be deemed inappropriate or unacceptable during business hours. Other examples include the use of social media websites such as Facebook or using Instant Messaging clients to chat to your friends.
The service provider could be in violation of the:
Explanation: SLA stands for Service Level Agreement. This is a common document in business used to define a minimum standard of service that a customer can expect from a supplier. SLA’s are particularly common in the I.T. sector where a service provider is offering a service to a customer. As a customer, you want your hosted services and Internet or WAN connections to be available all the time. SLAs often guarantee 99.9% uptime for a service. In this question, the service provider is providing WAN links to remote sites with a guaranteed bandwidth on the WAN links. A failure to maintain the connectivity to the remote sites would be a violation of the Service Level Agreement (SLA).
A customer has engaged a company to improve the availability of all of the customer's services and applications, enabling the customer to minimize downtime to a few hours per quarter. Which of the following will document the scope of the activities the company will provide to the customer, including the intended outcomes?
Explanation: SOW stands for Statement of Work. When a company has been hired for a project that involves many tasks, a statement of work is often issued at the start of the project. The SOW will outline the tasks or activities in a project, their costs and the timelines for deliverables within the project. In an IT project, the SOW would define what tasks will be performed (hardware and software upgrades etc.), why the work is being done and how long each stage of the project will take.
A technician has prolonged contact with a thermal compound. Which of the following resources should be consulted?
Explanation: MSDS stands for Material Safety Data Sheet. An MSDS is a health and safety document that contains information on the potential hazards of working with a chemical product and how to work safely with the chemical product. In this question, the thermal compound is a chemical product so the MSDS will provide information about the effects of prolonged contact with the thermal compound.
An organization is moving to a new datacenter. During the move, several technicians raise concerns about a system that could potentially remove oxygen from the server room and result in suffocation. Which of the following systems are they MOST likely discussing?
A. Fire suppression
B. Mantraps at the entry
D. UPS and battery backups
Explanation: Fire suppression systems are often deployed in server rooms to prevent a fire destroying all the I.T. equipment. Different fire suppression systems work in different ways. Obviously a fire suppression system that sprays water onto the fire is no good for a server room as the water would do as much damage as the fire. A common fire suppression system used in server rooms is one that suppresses the fire by starving it of oxygen. One way the oxygen can be removed from the server room is to fill the server room with an inert gas such as carbon dioxide.
Which of the following describes an area containing a rack that is used to connect customer equipment to a service provider?
A. 110 block
Explanation: MDF stands for Main Distribution Frame. A Main Distribution Frame is a commonly a long steel rack accessible from both sides. On one side of the rack is cabling that connects the service provider’s network. The other side of the rack is for the connections to the customer’s equipment.
In an engineering office, all plotters are configured via static IP. Which of the following best practices will alleviate many issues if equipment moves are required? (Select TWO).
A. Rack monitoring
B. Device placement
C. Wall plate labeling
D. Room numbering
E. Patch panel labeling
Explanation: By labeling each wall plate (where the plotters’ network cables plug in to) and the patch panel ports (where the cables connecting to each wall plate terminate), we’ll be able to see which device is connected to which port. If equipment moves are required, we will be able to easily see which patch cables need to be moved in the patch panel.
A network technician is attempting to locate a switch connected to the fourth floor west side of the building. Which of the following will allow quick identification of the switch, when looking at a logical diagram?
A. Building layout
B. Patch panel labeling
C. Packet sniffing
D. Naming conventions
Explanation: The building in this question has several floors and the floors are large enough to be identified by area such as ‘west side’ etc. It is likely that a logical diagram of the network in such a building would be quite complicated and the network is likely to have several switches. A naming convention is a standard for naming items, in this case, networking components. When it comes to naming switches, using names like Switch1, Switch2 etc. for example won’t help when you need to know where the switches are located. In a building with multiple floors with each floor large enough to be defined by area names, you could a naming convention like SW1-FL4-WS where SW1 identifies the item as a Switch with the number 1, FL4 identifies the location as Floor 4 and WS further identifies the location as West Side. Using this convention, switch number 2 on the third floor east side would be named SW2- FL3-ES.
Which of the following does a network technician need to implement if a change is unsuccessful within the approved maintenance window?
A. Configuration procedures
B. Stakeholder notification
C. Impact analysis
D. Rollback procedure
Explanation: A rollback procedure is something that should be documented in a change management document. In this question, the network technician has made a change during a maintenance window. The change has not worked so the technician needs to ‘undo’ the change he made to revert the system back to its previous state. The network technician can then investigate why the change has not worked as expected. The rollback procedure is the list of steps required to undo the changes made to the system.
Which of the following is true about the main difference between a web session that uses port 80 and one that uses port 443?
A. Port 80 web sessions often use application-level encryption, while port 443 sessions often use transport-level encryption.
B. Port 80 web session cannot use encryption, while port 443 sessions are encrypted using web certificates.
C. Port 80 web sessions can use web application proxies, while port 443 sessions cannot traverse web application proxies.
D. Port 80 web sessions are prone to man-in-the-middle attacks, while port 443 sessions are immune from man-in-the-middle attacks.
Explanation: HTTPS stands for HTTP over SSL or HTTP Secure. It is used for secure access to websites. Port 80 web sessions are HTTP (HyperText Transfer Protocol) sessions which offers no security. Port 443 web sessions use HTTPS. HTTPS uses SSL or TLS to encrypt the HTTP traffic. HTTPS provides authentication of the website and associated web server that you are communicating with, which protects against man-in-the-middle attacks. Additionally, it provides bidirectional encryption of communications between a client and server, which protects against eavesdropping and tampering with and/or forging the contents of the communication.
Which of the following is the main difference between TCP and UDP?
A. TCP data flows in two directions, while UDP data flows from server to client.
B. The TCP header implements flags, while the UDP header does not.
C. The TCP header implements checksum, while the UDP header does not.
D. TCP connections can be secured by stateful firewalls, while UDP connections cannot
Explanation: Transmission Control Protocol (TCP) is a connection-oriented transport protocol. Connection oriented transport protocols provide reliable transport. When a computer wants to send data to another computer, TCP will first establish a connection between the two computers. When a sending computer sends data segments, the receiving computer acknowledges receipt of the segments. If the receiving computer does not receive an expected segment, the sending computer will send it again. User Datagram Protocol (UDP) is a connectionless transport protocol. Connectionless transport protocols provide unreliable transport. With UDP, there is no connection establishment between the sending and receiving computers. If a data segment is lost in transit, the sending computer will not know about it so it will not resend the segment. TCP uses control messages to manage the process of contact and communication. TCP uses a set of control flags in the TCP header to indicate whether a segment is being used for control purposes or just to carry data.
Which of the following PDUs is used by a connectionless protocol?
Explanation: UDP is a connectionless transport protocol that operates in the transport layer of the OSI model. UDP stands for User Datagram Protocol. PDUs (Protocol Data Units) used by UDP are known as Datagrams.
A network technician is utilizing a network protocol analyzer to troubleshoot issues that a user has been experiencing when uploading work to the internal FTP server. Which of the following default port numbers should the technician set the analyzer to highlight when creating a report? (Select TWO).
Explanation: FTP (File Transfer Protocol) is used for transferring files between an FTP client and an FTP server. FTP uses TCP Ports 20 and 21.
A network technician has just installed a TFTP server on the administrative segment of the network to store router and switch configurations. After a transfer attempt to the server is made, the process errors out. Which of the following is a cause of the error?
A. Only FTP can be used to copy configurations from switches
B. Anonymous users were not used to log into the TFTP server
C. An incorrect password was used and the account is now locked
D. Port 69 is blocked on a router between the network segments
Explanation: The question states that the TFTP server is installed on the “administrative segment of the network”. This implies that the network has multiple segments (subnets) and TFTP server is on a different network segment to other computers. For a computer on one subnet to connect to a computer on a different subnet, a router is required to route traffic between the two subnets. Routers often include firewalls so they can be configured to allow specific traffic to be routed between the subnets and block unwanted traffic. TFTP uses UDP port 69. The most likely cause of the connection timeout error in the question is that the firewall has not been configured to allow traffic using UDP port 69.