Cisco 100-490 Dumps

The command show file system is used on Cisco devices to display a list of all the file systems available. This command provides information about each file system, including its name, size, free space, and file system type (such as flash or nvram). It’s a useful command for network administrators to manage and navigate through different storage areas on Cisco devices, ensuring they can access and maintain the device’s file structure effectively. References := File System Commands on Cisco IOS XR Software - Cisco, Working with the Cisco IOS File System, Configuration Files, and Software Images

When you initially log in to a Cisco router, the default operating mode is user EXEC mode. This mode provides a limited set of basic monitoring commands but does not allow for any configuration changes to the router’s settings. To make configuration changes, you must enter privileged EXEC mode (often accessed by the enable command), which offers a wider range of commands that allow for the viewing and modification of the configurationGlobal configuration mode is accessed from privileged EXEC mode to modify the router’s configuration, and ROM monitor mode is a low-level mode used mainly for recovery purposes1.

The command that returns the user to the main configuration prompt from the interface configuration prompt isexit. When you are in interface configuration mode on a Cisco device and you want to return to the global configuration mode, you use theexitcommand.If you want to go all the way back to privileged EXEC mode, you would use theendcommand or press Ctrl-Z1.

Theshow cellular unit networkcommand in Cisco IOS is used to view detailed information about the cellular modem and the network it's connected to. Here's the type of information this command usually displays:

• Network Status:Whether the device is registered on the cellular network.
• Carrier Information:The name of the cellular network provider.
• Technology:The cellular technology in use (e.g., 3G, 4G/LTE).
• Signal Strength:Signal strength indicators like RSSI and RSCP.
• Cell Site Information:Data about the cell tower or base station the device is connected to.
• IP Address:The IP address assigned to the cellular interface.

Why other options are less likely:

• show cellular unit radio:Provides information about the radio module itself, such as its state and power levels.
• show cellular unit hardware:Focuses on hardware-level information of the cellular unit.
• show cellular unit profile:Displays configuration details of the cellular profile used to connect to the network.

References:

• Cisco command documentation for differentshow cellularoptions:https://www.cisco.com/c/en/us/td/docs/routers/wireless-wan/Cisco-Catalyst-Cellular-Gateways/cisco-cellular-gateways-command-reference-guide/m-show_commands.pdf

The configuration register on Cisco devices is a 16-bit value, typically represented in hexadecimal notation (e.g., 0x2102). The lowest four bits (bits 0-3) of this value are designated as the boot field.

The Boot Field's Importance:

The boot field determines how the device will load its operating system (Cisco IOS) during the startup process. Here's a basic breakdown of common boot field values:

• 0x0:Stay at the ROMmon prompt.
• 0x1:Boot from ROM (often used for troubleshooting or recovery).
• 0x2 - 0xF:Load the operating system based on settings in the startup configuration (NVRAM) or from a network server if specified.

Example:

A configuration register value of0x2102indicates that the boot field is0x2(the last digit). This is a common default setting, instructing the device to load the Cisco IOS image from Flash memory.

References:

• Cisco Configuration Register Detailed Explanation:[invalid URL removed]
• Configuration Register Settings (Cisco):https://networklessons.com/cisco/ccna-routing-switching-icnd1-100-105/configuration-register-cisco-ios

The line speed of a DS0 in North America is:

C. 64 kbps

DS0, or Digital Signal 0, is a digital signaling standard in telecommunications characterized by its transmission rate of 64 Kbps. It is the basic unit of data in digital networks and is used to transmit a single voice channel or data

NVRAM (Non-Volatile Random Access Memory) is the default storage location for the startup configuration file of a Cisco router or switch.expand_more Here's why:

• Non-Volatility:NVRAM retains its contents even when the device loses power.expand_more This is essential for storing the startup configuration, which contains critical settings like interface configurations, routing protocols, and passwords.
• Read/Write Capability:Unlike ROM, NVRAM allows you to both read and write data. This makes it possible to modify the configuration and save the changes into NVRAM as the startup configuration.

Other Memory Types and Their Functions:

• RAM (Random Access Memory):RAM is volatile memory, meaning it loses its contents when the device is powered off.expand_more It's used to store the running configuration (currently active configuration), routing tables, and other temporary data required for the device's operation.
• ROM (Read-Only Memory):ROM is non-volatile and stores the bootstrap program used to initiate the boot process of the device.expand_more It's not modifiable by the user.expand_more
• Flash:Flash memory is also non-volatile.expand_more It's primarily used to store the Cisco IOS image (operating system) and can also store backup configuration files and other data.

Theshow environmentcommand 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.

References:=

• Cisco Community discussions on power supply details1.
• Cisco documentation on Environmental Monitoring and Power Management2.

Loopback plugs are used to test the physical connections and configurations of network equipment. In a 56K modem loopback plug, the following pins are looped to create a test signal:

• Pins 1 and 7 (Transmit):Looping the transmit pins back to each other allows the device to test its own signal transmission.
• Pins 2 and 8 (Receive):Looping the receive pins back to each other allows the device to test its ability to receive its own signal.

Understanding RJ-45 Wiring:

RJ-45 connectors are standardized and have a specific pinout for various applications like Ethernet networking and analog telephony connections. You can find resources online that show the standard RJ-45 color coding and pin assignments.

The Cisco CPAK-100G-SR4 module is designed to support Multimode Fiber (MMF) cable. It is specifically engineered for high-bandwidth 100G optical links and supports link lengths of up to 70 meters over OM3 and 100 meters over OM4 Multimode Fiber with MPO connectors. This module is well-suited for short-range, high-speed data communications and data center applications where Multimode Fiber is typically used due to its ability to handle the large amount of data traffic over relatively short distances. References := Cisco CPAK 100GBASE Modules Data Sheet

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

Here's how to usepingin 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 thepingcommand:Enterpingfollowed by a space and then either the IP address or hostname you want to test. For instance:ping 8.8.8.8orping 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:Theipconfigcommand is used to display network configuration information but doesn't directly execute thepingcommand.

References:

• Windows Command Prompt (cmd):https://en.wikipedia.org/wiki/Cmd.exe
• Ping command:https://en.wikipedia.org/wiki/Ping_(networking_utility)

Thetftpdnldcommand in Cisco IOS is specifically designed for recovering or upgrading a system image. Here's how it's the most effective method:

• Purpose:Thetftpdnldcommand directly initiates a TFTP download of a new system image and stores it in memory. This is ideal for replacing a corrupt image or upgrading to a newer version of Cisco IOS.
• ROMmon:Thetftpdnldcommand can often be used from ROMmon mode, which is essential when the existing image is unusable.
• Efficiency:It streamlines the image transfer process specifically using TFTP, which is commonly used for Cisco IOS images.

Why other options are less ideal:

• USB storage:While some newer Cisco devices may allow direct loading of an IOS image from USB, this isn't universally supported and often requires specific boot commands.
• FTP:FTP (File Transfer Protocol) can be used for file transfers, but it's not as commonly used as TFTP in the context of Cisco IOS image recovery. Thetftpdnldcommand offers a more tailored solution for this purpose.
• the xmodem command:XMODEM is a legacy file transfer protocol that is slower and less reliable than TFTP, especially for larger files like Cisco IOS images.

The-coption in Xmodem file transfers is used to enable CRC (Cyclic Redundancy Check) for enhanced error checking. Here's why it's the correct answer:

• Error Detection:CRC is a more robust error detection mechanism compared to the standard checksum method used in Xmodem. It provides greater reliability in identifying file corruption during the transfer.
• Flash Memory:Since flash memory on a Cisco router or switch stores critical data like configuration files or the IOS image, ensuring the integrity of transferred files is crucial.

Why other options are incorrect:

• -e, -r, -x:These are not standard Xmodem options for error checking purposes. While some implementations may have custom flags, they are not universally applicable.

Important Note:Xmodem is a legacy protocol that is often replaced by more reliable options like TFTP in modern Cisco devices. However, understanding Xmodem options is still relevant for certain cases or older equipment.

References:

• Xmodem overview:https://en.wikipedia.org/wiki/XMODEM
• Cyclic Redundancy Check (CRC):https://en.wikipedia.org/wiki/Cyclic_redundancy_check

The commands to copy a saved configuration to RAM on Cisco devices are:

• copy startup-config running-config: This command is used to copy the startup configuration (saved configuration) into the running configuration (current configuration in RAM). It is typically used when you want to restore the device to a previously saved configuration after changes have been made1.
• copy tftp running-config: This command allows you to copy a configuration file from a TFTP server directly into the running configuration of the device. It’s useful for applying a new configuration or for restoring a configuration from a backup located on a TFTP server1.

The other options listed are not valid for copying a saved configuration to RAM:

• copy running-config startup-config copies the current running configuration to the startup configuration, which is the opposite of what’s asked.
• copy running-config tftp is used to save the running configuration to a TFTP server, not to copy to RAM.
• copy tftp startup-config would copy a file from a TFTP server to the startup configuration, not to the running configuration in RAM.

References := Solved: Copy config to new router - Cisco Community

Electrostatic Discharge (ESD) poses a significant risk to delicate electronic components. Here's why the correct answers are essential tools for ESD protection:

• Antistatic Mat:Provides a grounded surface to work on, dissipating static buildup from your body and the components you're handling.
• ESD Wrist Strap:When connected to a grounding point (often on the antistatic mat), this strap creates an electrical path to safely discharge static electricity from your body.
• Antistatic Bag:These special bags are designed to shield sensitive components from static charge, crucial for storing and transporting electronic parts.

Why other options are incorrect:

• Negative static bag, negative static mat:These terms don't exist in standard ESD protection practices. The focus is on creating a grounded environment to neutralize static charges.
• Latex gloves:While they offer insulation, they can actually generate static electricity, increasing the risk of ESD damage.

IPv4 addresses consist of four octets, each ranging from 0 to 255. The addresses are used to uniquely identify devices on a network.

• A. 255.255.255.255is reserved for broadcast messages to all hosts on the local network, so it cannot be assigned to a single host.
• B. 10.1.1.20falls within the range of private IP addresses (10.0.0.0 to 10.255.255.255) and can be assigned to a host within a private network.
• C. 0.0.0.0is used to denote an unknown or non-applicable target address, often used as a default route, and cannot be assigned to a host.
• D. 192.168.10.15is also within the range of private IP addresses (192.168.0.0 to 192.168.255.255) and can be assigned to a host within a private network.
• E. 292.10.3.4is not a valid IPv4 address because the first octet exceeds the maximum value of 255.

References:=

• IPv4 Addressing
• Valid IP Address
• IP Address Validation

A. Correct. SSH, or Secure Shell, is indeed a protocol that provides a secure remote access connection to network devices.It encrypts the data to ensure secure transmission over insecure networks like the internet1.

C. Correct. Telnet connections are not secure and are terminated when a router reboots.This is because Telnet does not have any mechanism to maintain the connection in case of network interruptions or device reboots1.

B, D, and E are incorrect because: B.SSH uses TCP port 22 by default, not port 23, which is used by Telnet1. D.Telnet does not provide a secure connection; it transmits data in plain text, which can be intercepted easily1. E.SSH is preferred over Telnet for security reasons because it provides encrypted connections and authentication mechanisms, which Telnet does not1.

References:=1:GeeksforGeeks - Difference between SSH and Telnet2:phoenixNAP - Telnet vs. SSH: How Is SSH Different From Telnet?3:Guru99 - Telnet vs SSH – Difference Between Them4:Difference Between - Difference Between Telnet and SSH

The data link layer of 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

The correct IPv6 address notation follows the format of eight groups of four hexadecimal digits, separated by colons. The address must have exactly eight groups unless it uses the double colon (::) to represent consecutive groups of zero value. The double colon can only appear once in an address to avoid ambiguity.

Option A is incorrect because it includes a subnet mask (/128) which is not part of the actual address notation. Option B is incomplete as it does not contain enough groups and ends with a single colon. Option C has too many groups (nine instead of eight) and is therefore not a valid IPv6 address. Option D is the correct notation with eight groups of four hexadecimal digits, where necessary leading zeros are included.

References:=

• IPv6 Address Types, Notation, and Structure Explained1.
• IPv6 address formats - IBM2. =========================

A Wide Area Network (WAN) connection typically involves several components that work together to enable data communication over large distances. Two key components of a WAN connection are:

• CSU/DSU (Channel Service Unit/Data Service Unit): This device acts as a gateway between the local area network (LAN) and the WAN. It converts the digital signals used in the LAN to the signals used in the WAN, which are often analog12.
• Router: A router is used to connect multiple networks together and direct data traffic. In the context of a WAN, routers are responsible for determining the best path for data to travel across the network12.

References := Spiceworks, Cisco