CCT Routing and Switching 100-490 Syllabus Exam Questions Answers

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.

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.

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.

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