Cisco 100-490 Practice Test - Questions Answers, Page 4

Thedata link layerof the OSI model, which is Layer 2, defines how data is formatted for transmission and controls access to the physical media. This layer is responsible for the node-to-node delivery of data and handles error detection and correction from the physical layer. It also manages the way data packets are sent over the network, including the framing, addressing, and flow control.The data link layer ensures that messages are delivered to the proper device on a LAN using hardware addresses (MAC addresses) and translates messages from the network layer into bits for the physical layer to transmit

Topic 2, Cisco Equipment and Related Hardware

The show environment command in Cisco devices is used to display the status of the system's environment, including power supplies and sensor temperatures. This command provides a comprehensive overview of the environmental conditions affecting the device, such as temperature readings and power supply status.

Option A, show hardware, is not specific to power supplies and sensor temperatures. Option B, show module, displays information about the network modules installed in the device but not the environmental conditions. Option D, show diag, is used for diagnostic purposes and does not specifically provide the status of power supplies and sensor temperatures.

Therefore, the correct answer is C, show environment, which is the command that specifically shows the status of power supplies and sensor temperatures in Cisco devices12.

Cisco Community discussions on power supply details1.

Cisco documentation on Environmental Monitoring and Power Management2.

Two standard fiber-optic connectors are Lucent Connectors (LC) and Subscriber Connectors (SC). The Lucent Connector, commonly referred to as LC, was developed by Lucent Technologies and is characterized by its small form factor with a 1.25mm ferrule. It is widely used in high-density applications due to its compact size and square shape1. The Subscriber Connector, or SC, is known for its push-pull latching mechanism and uses a 2.5mm ferrule. It is a square-shaped, duplex connector that has been a dominant fiber optic connector for decades due to its performance and reliability12.

The configuration register on Cisco devices controls how the device boots up. By changing the configuration register to 0x2142, you instruct the router to bypass the startup configuration file stored in NVRAM. This is crucial in the password recovery process because the passwords are stored in this configuration file.

Procedure for Password Recovery:

1. Break the boot sequence: Power cycle the router (turn off/on). During the boot process, send a 'Break' signal to get into ROMmon mode.

2. Change the configuration register: In ROMmon mode, type confreg 0x2142 and reload the router.

3. Boot without startup-config: The router will boot up, ignoring the saved startup configuration, allowing you to enter privileged EXEC mode without a password.

4. Change the password: Access configuration mode (configure terminal), and change the passwords as needed (enable password, enable secret, etc.).

5. Reset the configuration register: Set the configuration register back to its original value (usually 0x2102).

6. Save changes: Save the new configuration with copy running-config startup-config.

* A. SSH...secure remote access: This is correct. SSH (Secure Shell) is designed specifically for secure remote access. It utilizes strong encryption to protect data transmissions, including login credentials and commands.

* B. Telnet...secure remote access: This is incorrect. Telnet is inherently insecure as it transmits all data, including sensitive passwords, in cleartext.

* C. SSH uses...TCP port 23: This is incorrect. SSH uses TCP port 22 by default, while Telnet uses TCP port 23.

* D. Telnet preferred...security reasons: This is incorrect. SSH is vastly preferred over Telnet due to its strong security features.

* E. Telnet connection...router reboots: This is correct. Telnet connections are not persistent, so a router reboot disrupts them. This re-enforces their lack of suitability for critical management tasks.

Key Points:

* Security: SSH is the recommended protocol for remote access to network devices due to its strong encryption and authentication mechanisms.

* Persistence: Telnet connections are temporary and get disrupted on events like router reboots.

The cmd program, also known as the Command Prompt, is the primary command-line interface in Windows. It allows you to execute various commands, including the ping command, to perform network testing and troubleshooting.

Here's how to use ping in the Command Prompt:

Open the Command Prompt: Search for 'cmd' in the Windows Start Menu or use the Run dialog (Windows key + R) and type 'cmd'.

Type the ping command: Enter ping followed by a space and then either the IP address or hostname you want to test. For instance: ping 8.8.8.8 or ping www.google.com.

Press Enter: The Command Prompt will send ping requests and display the results.

Why other options are incorrect:

Find: The Find utility in Windows is used to search for files and folders based on their content or attributes.

Start: The Start Menu in Windows provides access to programs, settings, and power options.

ipconfig: The ipconfig command is used to display network configuration information but doesn't directly execute the ping command.

Windows Command Prompt (cmd): https://en.wikipedia.org/wiki/Cmd.exe

Ping command: https://en.wikipedia.org/wiki/Ping_(networking_utility)

RJ-45 is the standard connector used for Ethernet networks. Here's why it's the correct answer:

Compatibility: Ethernet ports on both laptops and Cisco switches use RJ-45 connectors. This makes RJ-45 cables ideal for direct connections between these devices.

Appearance: RJ-45 ports are rectangular and slightly larger than typical phone jacks (RJ-11). They have eight metal pins inside.

Why other options are incorrect:

DVI: DVI ports are used for video connections between computers and displays.

RJ-11: RJ-11 ports are primarily associated with analog phone lines and are smaller than RJ-45.

DB-9: DB-9 connectors were traditionally used for serial connections on older computers and peripherals.

Rollover cables are specifically designed for connecting to the console ports on Cisco routers and switches. Here's why they are the right choice:

Pinout: Rollover cables have a reversed pinout compared to standard Ethernet cables. This matches the console port's wiring, allowing for configuration access.

Appearance: Rollover cables are often light blue in color to help distinguish them from standard Ethernet cables.

USB Adapter: Many modern laptops may not have a direct serial port. In this case, a rollover cable with a USB-to-serial adapter is used.

Why other options are incorrect:

Straight-through: Used for connecting unlike devices (e.g., switch to computer). They won't have the correct wiring for console connections.

Fiber: Used for high-speed, long-distance networks. Console ports use a serial-based connection, not fiber optics.

Crossover: Used to connect similar devices (e.g., switch to switch). The pinout is not the same as what a console port requires.

USB thumb drives (also called flash drives) serve several practical purposes in networking:

File Transfer: They are excellent for transferring Cisco router or switch configuration files between the device and a PC. This allows you to back up configurations, easily restore configurations, or work with them offline.

IOS Image Storage: USB thumb drives are convenient for storing and transferring Cisco IOS images, especially when you need to upgrade or recover network devices.

Why other options are incorrect:

to save the system log: While you might temporarily store log files on a USB drive, routers and switches generally utilize internal memory or a remote syslog server for logging purposes.

to save router hardware information: Hardware inventory information obtained from commands like show inventory is often copied and pasted to text files, which can then be stored on a USB drive. However, the drive itself doesn't directly save or store this hardware information.

to increase system memory: USB drives are not designed to act as additional system memory (RAM) for a router or switch.