v1 Data Link
What type of physical topology can be created by connecting all Ethernet cables to a central device?
a. bus
b. ring
c. star
What is
star
When all Ethernet cables are connected to a central device, such as a switch, it creates a physical topology known as a star topology. In a star topology, all devices are connected to a central hub or switch, which acts as a distribution point for data. This type of topology is commonly used in Ethernet networks because it provides a reliable and scalable way to connect multiple devices to a network. If one cable or device fails, it does not affect the rest of the network, and additional devices can be easily added to the network by connecting them to the central switch or hub.
Which network device makes forwarding decisions based only on the destination MAC address that is contained in a frame?
a. repeater
b. hub
c. Layer 2 switch
what is
layer 2 switch
The network device that makes forwarding decisions based only on the destination MAC address that is contained in a frame is a Layer 2 switch.
Layer 2 switches operate at the data link layer (Layer 2) of the OSI model and use the destination MAC address in the Ethernet frame header to make forwarding decisions. When a switch receives a frame, it examines the destination MAC address in the frame header and looks it up in its MAC address table. If the MAC address is found in the table, the switch forwards the frame out the appropriate port to reach the destination device. If the MAC address is not found in the table, the switch floods the frame out all ports except the one it was received on, in order to learn the location of the device with that MAC address.
In contrast, a repeater and a hub operate at the physical layer (Layer 1) of the OSI model and simply regenerate and amplify signals received on one port and transmit them on all other ports. They do not examine the content of the frames they receive, so they cannot make forwarding decisions based on destination MAC addresses. A router operates at the network layer (Layer 3) of the OSI model and makes forwarding decisions based on the destination IP address, not the MAC address.
In summary, a Layer 2 switch makes forwarding decisions based on the destination MAC address that is contained in a frame.
Which information is used by routers to forward a data packet toward its destination?
a. source IP address
b. destination IP address
c. source data link address
what is
destination ip address
Routers use the destination IP address in the packet's header to forward the data packet toward its destination. Each router in a network examines the destination IP address in the packet and determines the next hop for the packet based on the information in its routing table. The routing table contains information about which network or subnetwork the router is connected to and the best path to reach other networks or subnetworks. Routers do not use the source IP address or the source or destination data link address to forward the packet
Which router component holds the routing table, ARP cache, and running configuration file?
a. RAM
b. Flash
c. NVRAM
what is
A. RAM
What is the purpose of the startup configuration file on a Cisco router?
a. It facilitates the basic operation of the hardware components of a device.
b. It contains the commands that are used to initially configure a router on startup.
c. It contains the configuration commands that the router IOS is currently using.
what is
b. It contains the commands that are used to initially configure a router on startup.
it contains the commands that are used to initially configure a router on startup. When a Cisco router is powered on or restarted, it loads the startup configuration file from non-volatile RAM (NVRAM), which contains the configuration settings that were saved previously by an administrator. These settings can include the router's hostname, IP addresses, routing protocols, security settings, and other parameters that are necessary for the router to function properly in a network. By default, the startup configuration file is named "startup-config" and can be viewed or edited using the Cisco IOS command-line interface (CLI) or other network management tools.
Which layer of the OSI model is responsible for specifying the encapsulation method used for specific types of media?
a. application
b. transport
c. data link
what is
data link
The layer of the OSI model that is responsible for specifying the encapsulation method used for specific types of media is the Data Link Layer. The Data Link Layer is the second layer of the OSI model and is responsible for the transmission of data between two devices on the same physical network. The Data Link Layer is divided into two sub-layers: the Logical Link Control (LLC) sub-layer and the Media Access Control (MAC) sub-layer.
The LLC sub-layer is responsible for identifying the protocol used for data transmission, while the MAC sub-layer is responsible for controlling how devices access the media and for specifying the encapsulation method used for specific types of media. The MAC sub-layer specifies the frame format, including the start and end delimiters, the frame check sequence, and the addressing scheme used to identify the source and destination devices.
Therefore, the Data Link Layer plays a critical role in ensuring that data is transmitted correctly and efficiently between devices on the same physical network, by specifying the encapsulation method used for specific types of media.
What does the LLC sublayer do?
a. It performs data encapsulation.
b. It communicates with upper protocol layers.
c. It is responsible for media access control.
what is
it communicates with upper protocol layers
The LLC (Logical Link Control) sublayer is responsible for communicating with upper protocol layers and providing a link between the MAC (Media Access Control) sublayer and the network layer.
The LLC sublayer is located in the data link layer (Layer 2) of the OSI model and is responsible for providing a common interface for various LAN technologies. The LLC sublayer is responsible for flow control, error control, and multiplexing of protocols on the same physical medium. It also provides services to the network layer protocols and communicates with them to exchange information about data transfer.
In addition, the LLC sublayer adds a header and trailer to a packet to form an OSI Layer 2 PDU (Protocol Data Unit). This PDU is then passed down to the MAC sublayer, which adds its own header and trailer to form the complete frame that is transmitted over the physical medium.
In summary, the LLC sublayer is responsible for communicating with upper protocol layers and providing a link between the MAC sublayer and the network layer, and it adds a header and trailer to a packet to form an OSI Layer 2 PDU.
A computer has to send a packet to a destination host in the same LAN. How will the packet be sent?
a. The packet will be sent to the default gateway first.
b. The packet will be sent directly to the destination host.
c. The packet will first be sent to the default gateway, and then from the default
what is
B. the packet will be sent directly to the destination host
If the destination host is in the same LAN, the packet will be sent directly to the destination host. The computer will check if the destination IP address is on the same network segment or not. If the destination IP address is on the same network segment, the packet will be sent directly to the destination host using the destination host's MAC address.
Which of the following does the ARP table in a switch map together?
a. Layer 3 address to a Layer 2 address
b. Layer 3 address to a Layer 4 address
c. Layer 4 address to a Layer 2 address
what is
a. Layer 3 address to a Layer 2 address
There is no ARP table in a switch. ARP (Address Resolution Protocol) is used to map a Layer 3 address (such as an IPv4 address) to a Layer 2 address (such as a MAC address). Switches use a MAC address table (also known as CAM table) to map a MAC address to a switch port.
What will be the command prompt from the router after the command router(config)# hostname portsmouth is entered?
a. portsmouth#
b. portsmouth(config)#
c. invalid input detected
what is
b. portsmouth(config)#
What identifier is used at the data link layer to uniquely identify an Ethernet device?
a. IP address
b. MAC address
c. sequence number
what is
mac address
At the Data Link Layer, an Ethernet device is uniquely identified by its Media Access Control (MAC) address. A MAC address is a 48-bit identifier assigned to the Ethernet device at the factory. It is also sometimes referred to as a hardware address or a physical address.
The MAC address is used by the Ethernet protocol to identify the source and destination of data on a network. Every Ethernet device on a network has a unique MAC address, which is used by the Data Link Layer to ensure that data is delivered only to the intended recipient. The MAC address is embedded in the Ethernet frame header and is used by the receiving device to determine whether the frame is intended for it.
In summary, the MAC address is the identifier used at the Data Link Layer to uniquely identify an Ethernet device. It plays a crucial role in ensuring that data is delivered to the intended recipient on an Ethernet network.
What happens to a runt frame received by a Cisco Ethernet switch?
a. The frame is dropped.
b. The frame is returned to the originating network device.
c. The frame is broadcast to all other devices on the same network.
what is
the frame is dropped
When a Cisco Ethernet switch receives a runt frame (a frame that is smaller than the minimum allowed frame size), it typically drops the frame. This is because a runt frame is considered a damaged or malformed frame that may have been corrupted during transmission.
A runt frame is usually caused by collisions or other transmission errors, and it contains incomplete data that cannot be used by the receiving device. If the switch were to forward the runt frame, it could potentially cause network congestion or other issues.
Therefore, the best course of action is for the switch to simply drop the runt frame and wait for a properly formatted frame to be received.
Which IPv4 address can a host use to ping the loopback interface?
a. 126.0.0.1
b. 127.0.0.0
c. 127.0.0.1
what is
d. 127.0.0.1
When a host has an IPv4 packet sent to a host on a remote network, what address is requested in the ARP request?
a. the IPv4 address of the destination host
b. the IPv4 address of the default gateway
c. the MAC address of the default gateway, the router interface closest to the sending host
what is
c. the MAC address of the default gateway, the router interface closest to the sending host
When a host has an IPv4 packet sent to a host on a remote network, the ARP request is sent for the MAC address of the default gateway, the router interface closest to the sending host. This is because the packet is destined for a host on a different network, so it needs to be sent to the default gateway, which will then forward the packet to the remote network. The ARP request is used to obtain the MAC address of the default gateway so that the packet can be properly addressed for transmission over the local network segment.
Which characteristic describes the default gateway of a host computer?
a. the logical address of the router interface on the same network as the host computer
b. the physical address of the switch interface connected to the host computer
c. the physical address of the router interface on the same network as the host computer
what is
the logical address of the router interface on the same network as the host computer.
A default gateway is a device that allows a host computer to send traffic outside of its own network. It acts as an intermediary between the local network and the remote network, forwarding packets between the two. In most cases, the default gateway is a router that is directly connected to the local network.
The default gateway address is configured on the host computer and represents the logical address of the router interface on the same network segment as the host. The router interface connected to the local network serves as the gateway for traffic that is destined for other networks.
Option (b) is incorrect because the physical address of the switch interface is not relevant to the default gateway function. Option (c) is incorrect because the default gateway address is a logical address, not a physical one. Option (d) is also incorrect because the logical address assigned to the switch interface is not the default gateway address.
What are the two sublayers of the OSI model data link layer? (Choose two.)
a. LLC
b. transport
c. MAC
what is
logical link control
&
Media Access Control
The two sublayers of the OSI model data link layer are LLC (Logical Link Control) and MAC (Media Access Control).
LLC is responsible for error control and flow control between two devices on the data link layer, while MAC is responsible for controlling access to the physical transmission medium.
The other options listed are not sublayers of the data link layer:
Internet is a layer in the TCP/IP model, not the OSI model.
Physical is the name of the first layer of the OSI model, but it is not a sublayer of the data link layer.
Transport is a layer in the OSI model, but it is not part of the data link layer or its sublayers.
Network access is not a sublayer of the data link layer, but rather a category that encompasses the physical and data link layers.
In summary, the two sublayers of the OSI model data link layer are LLC and MAC.
What are the minimum and maximum sizes of an Ethernet frame? (Choose two.)
a. 56 bytes
b. 64 bytes
c. 1518 byteswhat is
64 bytes
&
1518 bytes
The minimum and maximum sizes of an Ethernet frame are:
Minimum size: 64 bytes (including the preamble, header, and trailer)
Maximum size: 1518 bytes (including the preamble, header, and trailer)
Therefore, options (b) and (e) are correct. The 64-byte minimum size includes 60 bytes of data, 4 bytes of CRC (Cyclic Redundancy Check), and the 8-byte preamble and start frame delimiter. The maximum size of 1518 bytes includes the same components as the minimum size, but with a maximum of 1500 bytes of data.
A router receives a packet from the Gigabit Ethernet 0/0/0 interface and determines that the packet needs to be forwarded out the Gigabit Ethernet 0/0/1 interface. What will the router do next?
a. route the packet out the Gigabit Ethernet 0/0/1 interface
b. create a new Layer 2 Ethernet frame to be sent to the destination
c. look into the ARP cache to determine the destination IP address
what is
b. create a new Layer 2 Ethernet frame to be sent to the destination
Before the router can route the packet out the Gigabit Ethernet 0/0/1 interface, it needs to create a new Layer 2 Ethernet frame to be sent to the destination. The router will look into its ARP cache to determine the MAC address of the next-hop router or the destination host, and then it will encapsulate the IP packet in a new Layer 2 Ethernet frame with the appropriate source and destination MAC addresses before sending it out the Gigabit Ethernet 0/0/1 interface. If the destination MAC address is not in the ARP cache, the router will send an ARP request to obtain the MAC address. Once the MAC address is obtained, the router will create the new Layer 2 Ethernet frame and send the packet out the Gigabit Ethernet 0/0/1 interface.
What type of information is contained in an ARP table?
a. switch ports associated with destination MAC addresses
b. domain name-to-IPv4 address mappings
c. IPv4 address-to-MAC address mappingswhat is
c. IPv4 address-to-MAC address mappings
An ARP table contains IPv4 address-to-MAC address mappings.
Which command is used to encrypt all passwords in a router configuration file?
a. Router_A(config)# enable secret <password>
b. Router_A(config)# service password-encryption
c. Router_A(config)# enable password <password>
what is
b. Router_A(config)# service password-encryption
What method is used to manage contention-based access on a wireless network?
a. CSMA/CD
b. priority ordering
c. CSMA/CA
what is
CSMA/CA
The method used to manage contention-based access on a wireless network is CSMA/CA, which stands for Carrier Sense Multiple Access with Collision Avoidance.
In wireless networks, devices cannot detect collisions directly, as they can in wired networks, because the signal is broadcast over the air. Instead, devices use a protocol called CSMA/CA, which allows them to sense whether the channel is busy before transmitting data. If the channel is busy, the device waits for a random amount of time before attempting to transmit again.
CSMA/CA also includes a mechanism for avoiding collisions, called the Request to Send (RTS) and Clear to Send (CTS) mechanism. Before transmitting data, a device sends an RTS frame to request permission to transmit. If the receiving device is available, it responds with a CTS frame to grant permission to transmit. This mechanism helps to avoid collisions by reserving the channel for the duration of the transmission.
In summary, CSMA/CA is the method used to manage contention-based access on a wireless network, allowing devices to sense whether the channel is busy before transmitting data and using a mechanism for avoiding collisions called the RTS/CTS mechanism.
What addressing information does a switch record in order to build its MAC address table?
a. the destination Layer 3 addresses of incoming packets
b. the destination Layer 2 addresses
c. the source Layer 2 addresses of incoming frames
what is
the source layer 2 address of incoming frames
A switch records the source Layer 2 addresses of incoming frames in order to build its MAC address table. This allows the switch to associate a specific MAC address with the port on which it was learned. When a switch receives a frame, it examines the source MAC address in the header of the frame and adds the MAC address and the port on which it was received to its MAC address table. In this way, the switch can quickly forward frames out of the correct port based on the destination MAC address in the frame.
When a connectionless protocol is in use at a lower layer of the OSI model, how is missing data detected and retransmitted if necessary?
a. Connectionless acknowledgments are used to request retransmission.
b. An upper-layer connection-oriented protocol keeps track of the data received and can request retransmission from the upper-level protocol on the sending host.
c. Network layer IP protocols manage the communication sessions
what is
b. An upper-layer connection-oriented protocol keeps track of the data received and can request retransmission from the upper-level protocol on the sending host.
When a connectionless protocol is in use at a lower layer of the OSI model, missing data is detected and retransmitted through the use of upper-layer protocols. In connectionless communication, each packet is treated independently and there is no error correction process. If data is lost or damaged during transmission, the upper layer protocols will be responsible for requesting the retransmission of the missing data. For example, in the case of UDP (User Datagram Protocol), which is a connectionless transport layer protocol, applications can implement their own mechanisms for detecting and retransmitting missing data.
A cybersecurity analyst believes an attacker is spoofing the MAC address of the
default gateway to perform a man-in-the-middle attack. Which command should
the analyst use to view the MAC address a host is using to reach the default gateway?
a. ipconfig /all
b. route print
c. arp -awhat is
c arp -a
The command that should be used to view the MAC address a host is using to reach the default gateway is the "arp -a" command. This command will display the ARP table of the host, which includes the IP and MAC addresses of devices that the host has communicated with recently. By looking at the entry for the default gateway, the analyst can determine if the MAC address matches the actual MAC address of the gateway or if it has been spoofed.
What is stored in the NVRAM of a Cisco router?
a. Cisco IOS
b. the running configuration
c. the startup configurationwhat is
d. the startup configuration
The NVRAM (Non-Volatile Random Access Memory) of a Cisco router typically stores the startup configuration, which is the configuration that the router loads when it is powered on or restarted. Therefore, the correct answer is option (d): the startup configuration.
The startup configuration is a text file that contains the configuration commands necessary for the router to function correctly, including interface configurations, routing protocols, security settings, and other parameters. This configuration is typically saved manually by an administrator, using the "copy running-config startup-config" command or a similar command.
The running configuration, on the other hand, is the configuration that the router is currently using and is stored in RAM (Random Access Memory). This configuration is lost when the router is powered off or restarted, and is therefore not stored in NVRAM.
The bootup instructions, which are responsible for loading the router's IOS (Internetwork Operating System), are stored in ROM (Read-Only Memory) and are not typically stored in NVRAM. The IOS itself is stored in flash memory, which is a type of non-volatile memory, but not in NVRAM specifically.