Insert the plug (the end of the hole) of the power cord of the router into the power outlet behind the machine, and then insert the public plug of the other end into the corresponding power outlet. In addition to the 1000 series, all other series I0S Cisco routers provide power switches. If this start is found, dial it to the "open" position (1 ). Then, the heat dissipation fan in the vro will be turned on immediately, and you can hear a slight buzz. Next, let's officially enter the standard START process of the new router.
Run pilot software
The first software running on a vro is called the boot software ". Each computer has its own boot software, and the router is no exception. It is also a special computer. In English, the word Boot comes from Bootstrap ). You can imagine that, without the help of any external force, the computer will "stand" by "pulling your own shoelaces" after it starts up. The boot software runs a POST: Power-oo-Self-Test process, and then finds a boot device that contains valid I0S copies (that is, the operating system. Boot devices are usually the system's "Flash ".
After a vro is opened for several seconds, a boot message is sent to the console. 4. This message is displayed on Dallas, A 2520 router.
In the figure, based on the report of this message, it has found and started the boot software. Boot software may be located in two locations on the vro: read-only memory (ROM) or boot flash memory. For vrouters of the 2500 series, the boot software is stored in the ROM.
In the figure, the message shows us the version number of the boot software (1st rows) and the main memory capacity of the router (3rd rows ). According to the 2520 boot message, we know that the boot software version is (10 TB) and 6 MB of main memory is installed. The primary memory must be a random access memory (RAM), where all I0S operations are completed. It is also called system memory or system RAM. During boot, the system RAM is allocated to all the RAM capacity.
The boot software is responsible for finding a 10 s copy (copy) for loading and running, so that the router can work properly. Therefore, the software checks for special boot commands in non-volatile memory (NVRAM. NVRAM usually contains important configuration information. When the vro starts I0S, You need to load the configuration information. However, because this example uses a brand new router, its NVRAM is empty (5th rows in the middle ). Under normal circumstances, the boot software will try to find an I0S image in the system flash memory.
Run IOS
In our example, the boot software will find a copy of ios in the system flash memory. Displays messages recorded on the 2520 console during 10 s of searching and starting.
In the long string of messages recorded, we first see that the IOS software version is 11.3 (5). For details, see row 1st. On line 3, we know that this is a 7th vro with a total of 8 mb ram installed. "6144 K/2048 K byte s of memory" refers to allocating 6 MB to the system RAM and 2 MB to the shared RAM. 2520 includes an Ethernet interface (14th rows), two serial (fast serial) interfaces (15th rows), two low-speed serial interfaces (16th rows), and one ISDN basic rate interface (BRI) (17th rows ). The 2520 machine is installed with 32 Gbit/s NVRAM (18th rows) and 16 Mbit/s system flash memory (19th rows ).
At the end of the message, a dedicated line is used to tell us that NVRAM is vacant (Row 3 ). During 10 s of startup, the system checks NVRAM and loads the configuration from it. Vro configurations include multiple aspects, such as the vro name, password, running protocol, used interface, and interface address.
Because the router is newly opened, there is no 10 S Configuration available for loading. Now, we need to tell how to configure 10 s. First, use I0S Setup Facility (IOS Installation tool ).