Small and Medium-Sized Enterprise Network Management: vro startup and Management (1)

Today, we continue with the second article on Network Management for small and medium-sized enterprises, the router startup process and various management methods. The content involves two aspects: one is the start of the router, of course, including the START process of the router, the router components, and IOS-related operations, the second is to introduce several methods for managing Cisco devices.

Let's take a look at the vro startup process. In fact, the vro and the computer also have a power-on startup process. If you want to know the vro startup process, you must first understand the internal components of the route, let's take a look.

Internal router Components

Generally, a vro consists of the following components:

 

Flash is like the BIOS (Basic Input and Output System) on a PC, which stores the IOS of the Cisco router. The maintenance of Flash is mainly to back up and restore IOS files. Run the "dir" command in the enable state of the vro to view the IOS file name and size stored in Flash. Flash is a programmable memory. Therefore, you can program Flash and upgrade IOS. You can also use erase flash to delete IOS in Flash. Therefore, you must be cautious when using this command. We can back up an IOS image file on the computer to fix IOS as needed. The computer used for backup should act as the TFTP Server, that is, it must run the software of the TFTP Server.

Nvram I personally think it is more appropriate to translate into non-volatile RAM. Like CMOS on a PC, which stores the configuration file of the router. For NVRAM content, you can use "erase memory" or "write erase" to delete the configuration parameters to the factory settings. Therefore, the consequence of deleting NOVRAM is not serious when the IOS vro is lost, recovery is easier. After the vro starts normally, it copies the NVRAM content to the memory. Our vro setting is actually to modify the parameters in the memory. Therefore, the content in the memory and NVRAM can be different until you use "write memory" and "copy running-config startup-config" to save the memory settings to NVRAM, you can also use "reload", "copy startup-config running-config", or restart a vro to re-import NVRAM content to the memory to synchronize NVRAM with the memory. Run the "show configuration" command to view the settings in NVRAM. Run the "show running-config" and "write terminal" commands to view the currently running settings (in memory ).

ROM is similar to ROM in a computer in a Cisco router and is mainly used for system initialization and other functions.

 

The main functions of ROM include:

POST registration

Fine-tune the guiding sequence (password recovery and other functions can be implemented)

Startup of Mini IOS

ROM mode startup

After IOS is started, you can run the show version command to view the ROM information.

Bootstarp is a program located in the ROM microcode and used to execute the program. It is responsible for finding the location of each IOS and then loading the file. By default, all Cisco routers load IOS software from flash.

POST is also a program stored in the ROM microcode, used to check whether the basic hardware configuration is normal, and then decide which interfaces are available.

ROM Momitor: it is stored in the ROM microcode and used for testing and troubleshooting.

Mini IOS: A simplified IOS

RAM, which we call memory, is a readable and writable memory, but the content it stores will be cleared after the system is restarted or shut down. Like RAM in a computer, RAM in a Cisco router is also a storage for temporarily storing operating systems and data during operation, allowing the router to quickly access this information. RAM has a higher access speed than the preceding three types of memory .)

Of course, there should be another necessary component here: CPU. As for its role, it is clear that white people do not need to elaborate!

Another important thing is IOS.

Cisco IOS Software Features

IOS is short for the operating System of routers and switches. Its full name is Internetwork Operation System. That is to say, IOS is equivalent to a PC operating System.

Only vswitches have default settings, but vrouters do not have default settings. Therefore, no matter what type of vswitches you buy, you can directly use them without configuration. However, no matter what type of vswitches you buy, you are afraid of vrouters, even the Broadband Router used by the family must be configured before it can work.

This IOS is divided into two types: major release version (MR) and preliminary development release version (EDR ).

Major version (MR) is the IOS version managed and released by the IOS Technical Department. These versions inherit from earlier R & D versions and have more reliable features, platform support, functions, and technologies. Therefore, ios mr has better reliability and performance. In the same county, MR does not accept support for new features and platforms. Changes to the version for each upgrade and maintenance are only corrections to known software errors.

The development version (ED) is an IOS version developed by Cisco to meet the needs of new technologies and new platform technologies. That is to say, in addition to correcting known software errors, the release of each updated ED version will continuously bring more new features to customers. In addition, one to two years after each version of ED is released, it will be promoted to become the next major version of IOS.

Cisco IOS naming rules

The name of the Cisco IOS binary file consists of three parts: The first part indicates the platform, which is the appropriate model, the second part is the feature, and the third part is the runtime memory and compression format.

 

Like C7200-ajs40-mz

C7200 indicates the Cisco 7200 system Router

Ajs a represents advanced, and j Represents enterprise features. s represents additional features.

Mz m indicates the memory in which IOS is running. z indicates zip compression.