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

Microsoft Notepad is the preferred text editor for working with Cisco configuration files and other simple text documents for several reasons:

Plain Text Focus: Notepad is designed specifically for plain text editing. It does not add any formatting, hidden characters, or metadata that could interfere with the configuration file's structure.

Cisco Syntax Compatibility: Cisco configurations rely on specific syntax and spacing. Notepad preserves these elements accurately.

Universality: Notepad is a basic text editor included in all versions of Windows, ensuring accessibility and eliminating the need for additional software.

Why other options are not ideal:

Microsoft Word: Word is a word processor and includes formatting, fonts, and other features that are not compatible with Cisco configuration files. This formatting can corrupt the configuration.

Microsoft Access: Access is a database management system, not suited for text file editing.

Microsoft Excel: Excel is a spreadsheet application and adds its own structure and formatting that conflicts with configuration file formats.

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.

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 features associated with single-mode fiber-optic cable include:

Consists of a single strand of glass fiber: Single-mode fiber uses a single core (strand) of glass fiber to transmit light signals. This core is thinner than that of multimode fiber, allowing for greater transmission distances.

Carries a higher bandwidth than multimode fiber: Single-mode fiber can carry higher data rates over longer distances compared to multimode fiber. It is commonly used in long-haul communication links and high-speed networks.

References:

Single-mode vs. Multimode Fiber

Fiber Optic Cable Types

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.

References :=

Cisco Community discussions on power supply details1.

Cisco documentation on Environmental Monitoring and Power Management2.

Questions no: 12 Verified Answer: = B. switch-to-router, E. switch-to-server Comprehensive and Detailed Step by Step Explanation: = RJ-45 straight-through cables are used to connect different types of devices in a network. The standard practice is to use straight-through cables for connections that are unlike to each other, such as:

Switch-to-Router: A switch connects devices within a network by using MAC addresses to forward data to the correct destination. A router, on the other hand, connects multiple networks and uses IP addresses to determine the best path for the data packets. Connecting a switch to a router requires a straight-through cable because they are different types of devices12.

Switch-to-Server: Servers are the powerful computers that provide resources, data, services, or programs to the client machines in the network. When connecting a switch to a server, a straight-through cable is used because the switch and the server are different types of devices with different functions within the network12.

References := Guru99, TheTechMentor

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.

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.

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.

 The decompressed form of Cisco IOS Software and the running configuration are stored in DRAM (Dynamic Random-Access Memory) on Cisco devices. DRAM is used as the main memory for the device, where the operating system runs and the running configuration is stored. When a Cisco device boots up, the IOS image is decompressed and loaded into DRAM, and the running configuration is also held in this memory type. It’s important to note that DRAM is volatile memory, which means its contents are lost when the device is powered off or restarted12. References := Maintaining System Memory Configuration Guide, Cisco IOS Release 15M&T - Cisco, Types of memory on a Cisco device - Study-CCNA

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 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.

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

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

A DTE (Data Terminal Equipment) device is an end instrument that converts user information into signals or reconverts received signals. In the context of networking, a router can be considered a DTE device because it is typically at the user end of a user-network interface and serves as a data source or destination. It communicates with the data circuit-terminating equipment (DCE), such as a modem, to send and receive data across the network345.

References := Wikipedia, Techopedia, Network Encyclopedia

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

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.