CCNA Study Notes 4 --- vro Startup Process and register value

CCNA Study Notes 4 --- vro Startup Process and register value
◆ Role of the vro register value (after understanding, used to adjust the optimization of the vro switch work) power-on self-check (post) load and run boot guide microcode to search for IOS image) file loading IOS image file search configuration file loading configuration file normal operation hex 2102 two Bytes 8 bits, sixth adjustable process: ◎ after the boot self-check is successful, read the register value, first, check whether the minimum four-digit group is 0 (2102 by default). If it is 0, it enters rom monitor mode (restart to enter the mode after the IOS upgrade fails ). Monitor mode must be enabled when you need to change the underlying configuration. For example, when you change the console rate, the default value is 9600. You can enter monitor mode to change the console rate. ◎ If it is not 0, check whether the last bit is 1. If it is 1, enter mini IOS (only the 2500 series router has this IOS ). If the last digit is not 1, check startup-config. (The Real-time input command is stored in running-config, which is lost after power failure. Save it to nvram for permanent saving, save it to startup-config) to check whether there is a boot command (not available by default). If not, it is started from the first effective IOS in the flash card. Start IOS with boot. If the flash card does not have a valid IOS, it is broadcast to the network for search. If it is found, it is started. If not, check whether the 13th bits are 115 14 13 12 | 11 10 9 8 | 7 6 5 4 | 3 2 1 0 ^ 13th bits are 1 by default, (because the default value is 2102,2, and the 13th-bit value is 1.) At this time, the attempt fails to be searched five times. If the value is 0, an infinite loop is broadcast in the network. If it fails five times, it enters the miniIOS mode. If there is no MINIios, it enters the monitor mode. Therefore, the first 2 in 2102 is used to prevent being stuck in the startup process. ◎ After IOS is loaded successfully, check whether the 6th-bit value is 1 (the default value is 0 ). If it is 1, it is 2X42; otherwise, it is 2X02. If the value is not 1, a valid configuration is loaded. If no valid configuration is available, the setup mode is enabled. If the value is 1, the setup mode is enabled. ◆ Role of the vro register value (after understanding, used to adjust the optimization of the vro switch work) power-on self-check (post) load and run boot guide microcode to search for IOS image) file loading IOS image file look for configuration file loading configuration file normal run configuration register value option part Value Meaning 0x2102 read startup-config0x2142 in nvram ignore existing configuration and enter setup mode SWAp process: ◎ after the self-check is successful, read the register value. First, check whether the minimum four-digit group is 0 (2102 by default). If it is 0, it enters the rom monitor mode (after the IOS upgrade fails, restart to enter the mode ). Monitor mode must be enabled when you need to change the underlying configuration. For example, when you change the console rate, the default value is 9600. You can enter monitor mode to change the console rate. ◎ If it is not 0, check whether the last bit is 1. If it is 1, enter mini IOS (only the 2500 series router has this IOS ). If the last digit is not 1, check startup-config. (The Real-time input command is stored in running-config, which is lost after power failure. Save it to nvram for permanent saving, save it to startup-config) to check whether there is a boot command (not available by default). If not, it is started from the first effective IOS in the flash card. Start IOS with boot. If the flash card does not have a valid IOS, it is broadcast to the network for search. If it is found, it is started. If not, check whether the 13th bits are 115 14 13 12 | 11 10 9 8 | 7 6 5 4 | 3 2 1 0 ^ 13th bits are 1 by default, (because the default value is 2102,2, and the 13th-bit value is 1.) At this time, the attempt fails to be searched five times. If the value is 0, an infinite loop is broadcast in the network. If it fails five times, it enters the miniIOS mode. If there is no MINIios, it enters the monitor mode. Therefore, the first 2 in 2102 is used to prevent being stuck in the startup process. ◎ After IOS is loaded successfully, check whether the 6th-bit value is 1 (the default value is 0 ). If it is 1, it is 2X42; otherwise, it is 2X02. If the value is not 1, a valid configuration is loaded. If no valid configuration is available, the setup mode is enabled. If the value is 1, the setup mode is enabled.