100-490 Exam Dumps : Supporting Cisco Routing & Switching Network Devices (RSTECH)

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 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:

Understanding the Configuration Register (Cisco):

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