Backup and Recovery
IT388-01 Routing & Switching I
November 17, 2008
Backup and Recovery
1. Describe the four-step process to locate and load the IOS. The four step process to locate and load the Internetwork Operating System, or IOS, is known as the boot sequence. These are the steps that a router must follow in order to bring the device into an operational status. The first step is known as POST. POST is a ROM based program that runs whenever the device is booted up. This is where the hardware will get checked to ensure they are “operational and present” (Lammle, pg 253). This will include each interface as well as any other hardware based device necessary to run the device. After the device passes POST, the IOS are loaded by another ROM based program called the bootstrap. The bootstrap will be responsible for finding and running the necessary files. All Cisco routers are set by default to load the IOS from flash memory (Lammle, pg 254). After the IOS is loaded, it will take over for the bootstrap in loading the next file or files. The IOS software will look for valid configuration files known as startup-config from NVRAM. The startup-config will only be stored in NVRAM if the administrator copies the running-config to that location (which he had better if he is smart). Finally, the startup-config, if present in NVRAM, will be loaded into RAM so it can be used to operate the router. This file is now called the running-config. If it is not present in NVRAM, a broadcast signal will be sent out any device interface that detects carrier detect for a TFTP host looking for configuration files (Lammle, pg 254). This detection would be used in VLANs.
2. What does a configuration register of 0x2101 specify? Provide an example of when you would see this configuration register value and the command to set the configuration register to 0x2101. The configuration register of 0x2101 is a command that changes the configuration register and tells the router to boot a small IOS from ROM. The configuration register is one way to alter how the router is booted. The command to change the configuration register looks like the following:
One of the top reasons you would change the configuration register would be to force the system into ROM monitor mode, or ROMMON. This mode is used for recovering lost or forgotten passwords. Another reason you would use this configuration would be to enable booting from a TFTP. 3. What does a configuration register of 0x2142 specify? Provide an example of when you would see this configuration register value and the command to set the configuration register to 0x2142. The configuration register of 0x2142 is used to bypass startup-config and load the setup mode of the router. Certain situations warrant breaking into your router, like a forgotten password. The 0x2142 configuration will turn bit 6 on and allow you to change your password, after a series of commands of course (Lammle, pg 258). In order to change the configuration register, the commands would look like the following: Boot router
Cntrl+break during boot up
4. Configure routers to use Telnet using the CCNA Virtual Labs simulator. Click on Net Visualizer Screen button. Here you will configure both routers so RouterB will Telnet into RouterA. a) Configure RouterA (double-click 2600 Router A to open the router) i) Change the router name to RouterA
ii) Configure interface S0/0 so the IP address is 10.10.1.1/24 iii) Set the clock rate to 64000
iv) Configure the enable password to Hello
v) Configure the Telnet password to Router1
b) Configure RouterB (double-click 2600 Router B to open the router)...
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