Cisco router storage and iOS upgrades

First, the Cisco router to introduce the memory

A router is similar to a computer in that it also has memory, operating system, configuration, and user interface, and the operating system in Cisco routers is called
Internet Operating System (Internetwork operating system) or iOS. The following is mainly about the storage of routers.

ROM: Read-only memory contains a copy of the iOS being used by the router;

Ram:ios the random access memory into shared and main memory. It is mainly used to store the running router configuration and the iOS data structure related to the routing protocol;

Flash (Flash): Used to store iOS software image files, flash memory is erasable, it can be covered with a new version of iOS, iOS upgrade is mainly flash memory of the iOS image file to replace.

NVRAM: Non-volatile random access memory used to store system configuration files.

The following table is the memory feature of a common type of router.
Table: Router Memory Details list

Memory type	2500, 2600, 3600	4000, 7000
Rom	Unable to upgrade basic iOS	Can upgrade iOS
Shared Ram	Storage buffers	Storage buffers
Primary RAM	Only the road has tables and iOS data structures	From flash memory into iOS, road with table and iOS data structure
Flash memory (Flash)	Contains iOS (router runs iOS from flash memory)	Includes iOS
NVRAM	Configuration file	Configuration file

Note: Because the 2500, 2600, 3600 series run iOS from flash memory, 2500, 2600, 3600 may not have enough memory to upgrade iOS during the router run. In the 4000, 7000 series, iOS runs in primary RAM, so flash can be upgraded during router operation.

Second, the installation of TFTP server software.

Download Address: http://www.skycn.com/soft/18565.html

This assumes that the computer with the software has an IP address of 10.10.10.1. Third, the router iOS upgrade and configuration file save Cisco stores its system software in flash memory, and every time you start the router, pull the system from the flash memory and execute it. After booting into the initialization configuration or using "Configer", "Setup" for configuration, the configuration to be saved for the next boot run directly, this is the configuration file. The configuration file exists in a non-volatile nvram. The configuration file is divided into start-up Configer and running Configer two kinds. Start-up Configer starts the NVRAM configuration at power-on. Since the Cisco router instruction system is in effect immediately, the configuration may be different from the configuration of the start-up, the running Configer written to the NVRAM is the start-up Configer. The system files and configuration files of a router can be copied in and copied as a host.

1, upgrade the system image and configuration files

When the system fails, the system upgrades, the configuration files are copied, we need to copy the software from the server to the router. Copy the system image from the Web server to the Flash Memory. On the network to have a computer for TFTP Server, using TFTP to copy the system files to the router's flash memeory.

We recommend that in the system upgrade, in order to prevent improper operation and other causes of the upgrade failed, please first the original router system back down, including Flash in iOS and NVRAM in the configuration file.

Copy system files to flash Memory:

Copy TFTP flash

Copy tftp File-id (Cisco 7000,7200 and 7500 series)

cisco2600# copy TFTP flash

IP address or name of remote host [255.255.255.255]?10.10.10.1 (TFTP server address)

Name of file to copy? C3640-is-mz_120-7_t.bin (this file is to be stored under the TFTP server TFTP software directory)

Copy C3640-is-mz_120-7_t.bin from 10.10.10.1 into flash memory? [Confirm]

Flash is filled to capacity.

Erasure is needed before Flash could be written.

Erase Flash before writing? [Confirm]

Eeeeeeeeeeeeeeee ...

Loading from 10.10.10.1:!!!! ...

[ok-8141044/8388608 bytes]

Verifying via checksum ...
Vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Flash verification successful. Length = 8141044, checksum = 0X12AD

Copy the configuration file from the network server to the router NVRAM.

Copy the file from the TFTP server to the router copy TFTP running-config or copy tftp startup-config.

2. Backup system image and configuration file

It is a good practice to keep system files and configuration files on a server in the Web, to help you restore the system as quickly as possible when your system or profile is missing.

Copy the system image to the Web server, first displaying the file name of the iOS file: Show flash, copy system files to tftp server:copy Flash tftp.

Copy the configuration file to the Web server, save the profile in the TFTP server copy running-config tftp or copy startup-config tftp.

Above is my experience which summarizes in the work, for everybody reference. The upgrade process also requires attention to the following points:

1. The computer that configures the router is best able to use a serial port to the router's Consol port, and the TFTP server software is installed on the computer to facilitate the reliable transfer of iOS files. The IP address of the TFTP server is on a network segment with the Ethernet port of the router.
2. When you upgrade iOS, you should be aware that if you upgrade the new version of iOS files larger than the flash memory capacity, you should increase the flash capacity.
3. Please be careful when you do the upgrade, so as not to lose operating system files, can not start the system.