100-490 Supporting Cisco Routing & Switching Network Devices (RSTECH) Questions and Answers

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

The address that facilitates the routing of packets over an IP network is the network address. In the context of IP networking, this refers to the IP address, which is used to identify each host on a network and to determine the best path for data packets to travel from their source to their destination. Routers use IP addresses to make decisions about where to forward packets so that they reach the correct destination. The network layer of the OSI model, where IP operates, is responsible for this routing process123.

The other options listed do not facilitate routing in the same way:

Physical (A) and MAC (D) addresses are used at the data link layer to deliver packets on the same local network.

Transport (B) refers to the transport layer, which is responsible for end-to-end communication and data flow control but does not route packets over an IP network.

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

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. 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

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.

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.

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

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.

A standard UTP (Unshielded Twisted Pair) cable contains 4 pairs of copper wires, which are twisted together to help cancel out electromagnetic interference and support data transmission across various networking and telecommunications applications1. Each pair consists of two individual copper cables twisted around each othe

This configuration describes a crossover cable. A crossover cable is used to connect two similar devices directly, such as two computers or two switches, without the need for an intermediate device like a router. The wires at one end of a crossover cable are in reverse sequence to the wires at the other end, which allows the transmit and receive signals to be properly aligned between the two devices. This is different from a straight-through cable, where the wire sequence is the same at both ends1.

The show ip interface brief command provides a concise summary of the status and IP addressing configuration of interfaces on a Cisco router or switch. Here's what it displays:

Interface: The name of the interface (e.g., FastEthernet0/0, GigabitEthernet1/1).

IP Address: The Layer 3 IP address assigned to the interface (if any).

OK? Indicates the IP layer status of the interface (YES if operational, NO if not).

Method: How the IP address was configured (manual or DHCP).

Status: The Layer 1 status of the interface (up or down).

Protocol: The Layer 2 status of the interface (up or down).

Why other options are incorrect:

Layer 2 address: The show ip interface brief command does not directly display Layer 2 (MAC) addresses. You can use the show interface command for that.

Keepalive: Keepalives are used in some routing protocols but are not generally reflected in the output of the show ip interface brief command.

Encapsulation type: Encapsulation information is also not typically included in the show ip interface brief output.

References:

Cisco IOS show ip interface brief command: [invalid URL removed]

Example output of show ip interface brief: https://www.cisco.com/E-Learning/bulk/public/tac/cim/cib/using_cisco_ios_software/cmdrefs/show_ip_interface.

The show version command on Cisco devices provides a variety of system information, including:

Cisco IOS version: The version of the Cisco IOS software running on the device.

Boot image: The location of the IOS image used during startup.

Hardware information: Model, processor type, memory details.

Interfaces: A list of the device's interfaces.

Configuration register: The current value of the configuration register, typically displayed near the end of the output.

Why other options are incorrect:

show flash: Displays the contents of flash memory, but not the configuration register.

show running-config: Displays the currently active configuration, but the configuration register setting is not directly part of the running configuration.

show config-register: This is not a standard Cisco IOS command.

The ping command is specifically designed to test network connectivity and reachability. Here's how it works:

Echo Request: The ping command sends an ICMP (Internet Control Message Protocol) Echo Request packet to a specified destination IP address or hostname.

Echo Response: If the target host is reachable, it will respond with an ICMP Echo Reply packet.

Analysis: The ping command measures the round-trip time (RTT) between the source and destination. It also reports statistics like packet loss and response times.

Why other options are incorrect:

echo: In some command-line environments, the echo command is used to display text on the screen and does not relate to network testing.

access: This is a general term and does not refer to a specific command for sending echo requests.

connect: Some tools use the connect command to establish a TCP connection to a remote host, but it doesn't directly utilize ICMP echo packets like the ping command.

References:

ping (Wikipedia): https://en.wikipedia.org/wiki/Ping_(networking_utility)

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

The show inventory command in Cisco IOS is designed specifically to display detailed hardware inventory information about a Cisco device. This includes:

Component Name: The name or type of each module or card installed.

PID (Product ID): The unique product identifier for the module.

VID (Version ID): The version identifier for the module.

Serial Number: The unique serial number assigned to the module.

Why other options are incorrect:

show chassis: Some Cisco devices support a show chassis command, but the information provided usually focuses on the physical chassis rather than detailed component inventory.

show items: This is not a standard Cisco IOS command.

show router: This command doesn't provide the level of granular hardware information that show inventory does.

The show cdp neighbor command on Cisco devices displays various pieces of information about directly connected neighboring devices that support Cisco Discovery Protocol (CDP). Two key pieces of information displayed by this command are the platform of the neighboring device, which indicates the hardware type, and the device ID, which is typically the hostname of the device1. The command does not display the uptime or the Cisco IOS Software version; these details can be seen with the show cdp neighbor detail command. The IP address is also part of the detailed information and not displayed in the standard show cdp neighbor output1.