Cisco 100-490 Supporting Cisco Routing & Switching Network Devices (RSTECH) Exam Practice Test

The Cisco Nexus 3432D-S and Cisco Nexus 3408-S are part of the Cisco Nexus 3400 Series switches that support 400-Gbps Ethernet ports. The Cisco Nexus 3432D-S is designed with 32 ports of 400G, providing high-density and high-throughput capabilities1. The Cisco Nexus 3408-S offers flexibility with 100G or 400G Line-Card Expansion Modules (LEMs), allowing for configurations with 32 ports of 400G2. These switches are engineered for data centers requiring high performance, low latency, and power efficiency, with the Cisco Nexus 3432D-S offering industry-leading performance-per-watt power efficiency at low latency1.

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

The image provided shows a networking device connected to a laptop via a console cable. Based on the visual indicators and standard port designs:

C. 3 is a USB 5-pin mini USB Type B port: The port labeled “3” on the laptop is smaller than a standard USB Type A port, which suggests it is a mini USB Type B port, commonly used for connecting to networking devices for console access.

E. 2 is a USB 5-pin mini USB Type B to USB Type A console cable: The cable labeled “2” has one end that fits into the mini USB Type B port on the laptop (as identified in point 1), and the other end, which is not clearly visible in the image, is inferred to be a USB Type A connector that would typically connect to a computer’s USB port.

SmartJacks are specialized devices used in telecommunications, particularly for T1/E1 lines. Here's why the correct answers make sense:

Signal Conversion: SmartJacks can convert between different signaling types (e.g., AMI to B8ZS). This is necessary because different telecommunication lines may use varying signaling standards.exclamation

Signal Regeneration: As signals travel over long distances, they can weaken and degrade.expand_more SmartJacks help regenerate the signal, ensuring that it maintains its strength and integrity throughout the transmission.expand_more

Why other options are incorrect:

Concentration point: SmartJacks are not primarily used as concentration points for dial-in/out connections.exclamation This function is typically handled by modems or other specialized devices.exclamation

Layer 2 operation: SmartJacks primarily operate at Layer 1 (Physical Layer) of the OSI model, focusing on the physical transmission of signals.

Channel Testing: While some SmartJacks may offer some basic channel testing capabilities, their primary functions are signal conversion and regeneration.

References:

SmartJack (Wikipedia): https://en.wikipedia.org/wiki/Smartjack

For 40 Gigabit Ethernet connectivity, the type of transceiver module used is QSFP+ (Quad Small Form-Factor Pluggable Plus). QSFP+ modules are designed to carry 40-Gigabit Ethernet signals over fiber-optic or copper networking cables. They provide high-density and low-power 40 Gigabit Ethernet connectivity options for data center, high-performance computing networks, enterprise core and distribution layers, and service provider applications. QSFP+ modules are an evolution of the SFP+ (Small Form-Factor Pluggable Plus) modules, offering four times the bandwidth capacity1.

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 tftpdnld command is specifically designed to initiate a TFTP (Trivial File Transfer Protocol) transfer of an image within ROMmon mode on a Cisco device. Here's why it's the correct answer:

ROMmon Functionality: ROMmon (Read-Only Memory Monitor) is a basic operating system mode used when the main Cisco IOS is unavailable. The tftpdnld command works from ROMmon to download a new IOS image.

TFTP Protocol: The tftpdnld command utilizes TFTP, which is a simple and reliable protocol commonly used for transferring Cisco IOS images.

Purpose: The command is used primarily for recovering corrupt images or upgrading to a different IOS version.

Why other options are incorrect:

Xmodem: XMODEM is an older and less reliable file transfer protocol that's less suitable than TFTP for Cisco IOS image transfers.

copy tftp: flash: This command format is used within the Cisco IOS itself, not in ROMmon mode.

copy flash: tftp: This command format would attempt to upload an image from flash memory to a TFTP server, instead of downloading an image.

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.

References:

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

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

Cisco routers can be readily configured to act as TFTP servers, allowing them to provide Cisco IOS images or configuration files to other devices. Here's why this is the correct answer:

Software Support: Cisco IOS includes built-in support for the TFTP protocol, making it easy to set up a TFTP server on a router.

Storage Capacity: Routers typically have flash memory where IOS images and other files can be stored, making them suitable repositories for TFTP transfers.

Network Accessibility: Routers play a central role in networks, making them an accessible location for TFTP file transfers.

Why other options are incorrect:

Cisco Content Engine: Content Engines are specialized network appliances designed for caching and accelerating web content delivery. They typically don't have functionality for acting as generic TFTP servers.

Modem: Modems primarily modulate/demodulate signals to facilitate communication over traditional telephone lines. They lack the software capabilities to run a TFTP server.

CSU/DSU: Channel Service Unit/Data Service Units are devices used to interface with digital leased lines. They don't possess the necessary software to run a TFTP server.

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.

An RJ-45 56K loopback plug is used to test the functionality of network ports, particularly for T1/56K lines. The correct loopback wiring for such a plug involves looping pins 1 and 4, as well as pins 2 and 5. This configuration allows the device to send and receive signals on the same wire pairs, effectively testing the transmit and receive paths of the port1.

References := Loopback Tests for T1/56K Lines - Cisco

In the context of IPv4 addresses, a host address is an identifier for a specific device on a network. The addresses 10.1.1.20 and 192.168.10.15 are both within ranges typically reserved for private networks, making them suitable for assignment to host computers within a local network. Address 292.10.3.4 is not a valid IPv4 address because the first octet is beyond the maximum value of 255. Address 255.255.255.255 is reserved for broadcast messages to all hosts on the local network, and 0.0.0.0 is used to denote an unspecified address, often indicating the absence of an IP address123. References := IP address, Network address, and Host address Explained, IP address - Wikipedia, Understanding IP Addresses: How IP Addressing Works | ENP

Cisco NX-OS has added support for Python scripting to help manage user networks. Python is a powerful and versatile scripting language that is widely used for automation tasks, including network management. Cisco NX-OS leverages Python to enable network administrators to write custom scripts and programs that can interact with the network operating system, automate repetitive tasks, and integrate with other systems and APIs. This support for Python scripting is part of Cisco’s commitment to network programmability and automation, allowing for more efficient and flexible network operations12.

When deploying Cisco Catalyst 3850 Series switches, there are two modes of operation to choose from: Install mode and Bundle mode. Install mode is the default mode for the switch and uses a package-provisioning file named packages.conf to boot the switch. It allows for a more complete set of features and requires fewer resources upon boot1. Bundle mode, on the other hand, is similar to using traditional monolithic Cisco IOS images to boot the switch. It consumes more memory than Install mode because the packages are extracted from the bundle and copied to the RAM2. Cisco recommends using Install mode for operation due to its efficiency and feature set2.

The type of memory used to store Cisco IOS Software permanently is flash memory. Flash memory is non-volatile, meaning it retains its content even after the device is powered down or restarted. It is commonly used in Cisco devices to store one or more Cisco IOS software images, as well as other files such as backup configuration files. This allows the device to reload the operating system after a reboot without the need to retransfer the IOS image

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

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 of 0x2102 indicates that the boot field is 0x2 (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 configuration register on Cisco routers and switches controls specific bootup behaviors. Here's how to modify it:

1. In ROMmon Mode:

rommon>confreg 0x2102 : This command is used when the device is in ROMmon mode (a basic operating system loaded when the full Cisco IOS cannot be found). ROMmon offers limited functionality and is often used for troubleshooting or password recovery.

2. In Global Configuration Mode:

router(config)#config-register 0x2102 : This command is used from within the Cisco IOS itself when you have normal access to the router. You would enter privileged EXEC mode and then global configuration mode to use it.

Importance of Configuration Register Settings:

The most common reasons to modify the configuration register are:

Password Recovery: Setting the configuration register to 0x2142 tells the router to ignore the startup configuration (stored in NVRAM), allowing you to bypass password protection.

Changing Boot Behavior: Settings can control the boot sequence, such as specifying where the Cisco IOS image should be loaded from.

References:

Cisco Configuration Register: https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/50421-config-register-use.html

Understanding the Configuration Register (Cisco): https://networklessons.com/cisco/ccna-routing-switching-icnd1-100-105/configuration-register-cisco-ios

TFTP, or Trivial File Transfer Protocol, is a simple protocol used for transferring files. Unlike other file transfer protocols, TFTP operates on top of the User Datagram Protocol (UDP), which is a connectionless protocol. This means that TFTP does not establish a persistent connection between the client and server, and it does not guarantee reliable delivery of packets, error checking, or correction. TFTP is typically used in scenarios where simplicity and minimal memory footprint are more critical than the need for reliable delivery, such as when booting a device over a network123. References := Wikipedia, GeeksforGeeks, PyNet Labs

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

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 Telnet 2: phoenixNAP - Telnet vs. SSH: How Is SSH Different From Telnet? 3: Guru99 - Telnet vs SSH – Difference Between Them 4: Difference Between - Difference Between Telnet and SSH