100-490 Exam Dumps - Cisco CCT Routing and Switching Questions and Answers

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 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 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. =========================

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 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.

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

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.

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.

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

While the initial answers focused on the most common causes, here's why the other options could also contribute to an interface being stuck in the "up/down" state:

A. Speed or Duplex Mismatch: Devices on either end of an Ethernet connection need to use compatible speed (e.g., 100 Mbps, 1 Gbps) and duplex (full-duplex or half-duplex) settings. Mismatches can prevent the line protocol from coming up even if the physical link is established.

B. Layer 2 Mismatch in Encapsulation Type: Some protocols used on Ethernet networks, like ISL and 802.1Q, have specific encapsulation requirements. If devices on each end aren't using the same encapsulation type, the line protocol will likely remain down.

C. The Ethernet Interface Has Been Manually Disabled: Correct! Administrators can put an interface in a shutdown state using commands like shutdown. This brings down the line protocol even if the physical connection is good.

D. Keepalives Are Not Being Received by the Local Device: While less likely to be the sole cause, issues with keepalive mechanisms used in some routing protocols could potentially lead to the line protocol going down. If the local device expects keepalives and doesn't receive them, it might assume a connectivity problem and affect the interface status.

E. The Ethernet Cable Might Not Be Attached Properly: While a disconnected or faulty cable would usually make the interface down/down, it's possible in some scenarios for a partially connected or damaged cable to result in a link being detected (Layer 1 up) but with errors preventing the line protocol (Layer 2) from initializing.

Troubleshooting network issues often involves considering multiple factors and testing different possibilities. The "up/down" status gives important clues but might have several potential root causes.