ROM:只读存储器包含路由器正在使用的IOS的一份副本；
RAM:IOS将随机访问存储器分成共享和主存。主要用来存储运行中的路由器配置和与路由协议有关的IOS数据结构；
FLASH (闪存)：用来存储IOS软件映像文件，闪存是可以擦除内存，它能够用IOS的新版本覆写，IOS升级主要是闪存中的IOS映像文件进行更换。
NVRAM：非易失性随机访问存储器，用来存储系统的配置文件。
IOS升级方法一
在对能够正常启动的CISCO路由器的IOS进行升级时，比较简单。具体步骤如下：
1、寻找一种TFTP服务器软件（有CISCO公司的TFTPServer或3COM公司的3Cserver等，在升级较大IOS映象文件时，建议用3Cserver），安装在一台计算机上，将要升级的IOS映象文件拷贝到相关的目录中（例：D:\），并运行TFTP服务器软件，通过菜单设置Root目录为拷贝IOS映象文件所在目录（如D:\）。假设该计算机的IP地址为10.32.10.1；
2、连接路由器的console口与PC机的COM1，使用PC的超级终端软件访问路由器，将路由器的地址设为10.32.10.32（与计算机的IP地址同网段即可）。建议在进行IOS升级前将原有IOS文件备份下来，防止待升级的IOS文件存在问题不可用；
QUOTE:
Router# dir flash: (查看目前IOS映象文件名，也可用Router#Show version)
Directory of flash:/
1 -rw- 5998292 C2600-I-MZ.122-11.BIN
8388608 bytes total (2390252 bytes free)
Router#copy flash tftp （备份IOS文件）
Source filename []?c2600-i-mz.122-11.bin
Address or name of remote host []? 10.32.10.1 (TFTP服务器地址)
Destination filename [c2600-i-mz.122-11.bin]?
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
…
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5998292 bytes copied in 324.071 secs (18509 bytes/sec)
Router#
3、对路由器进行IOS升级；Directory of flash:/
1 -rw- 5998292 C2600-I-MZ.122-11.BIN
8388608 bytes total (2390252 bytes free)
Router#copy flash tftp （备份IOS文件）
Source filename []?c2600-i-mz.122-11.bin
Address or name of remote host []? 10.32.10.1 (TFTP服务器地址)
Destination filename [c2600-i-mz.122-11.bin]?
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
…
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
5998292 bytes copied in 324.071 secs (18509 bytes/sec)
Router#
QUOTE:
Router#copy tftp flash
Address or name of remote host []? 10.32.10.1 (TFTP服务器地址)
Source filename []? c2600-i-mz.122-11.bin （需升级的新IOS映象文件名）
Destination filename [c2600-i-mz.122-11.bin]?
Do you want to over write? [confirm]
Accessing tftp://10.32.10.1/c2600-i-mz.122-11.bin...
Erase flash: before copying? [confirm]
Erasing the flash filesystem will remove all files! Continue? [confirm]
Erasing device... eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ...erasedee
Erase of flash: complete
Loading c2600-i-mz.122-11.bin from 10.32.10.1 (via Ethernet0/0): !!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
…
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 5998292 bytes]
Verifying checksum... OK (0xA0C0)
5998292 bytes copied in 318.282 secs (18846 bytes/sec)
Router#
Address or name of remote host []? 10.32.10.1 (TFTP服务器地址)
Source filename []? c2600-i-mz.122-11.bin （需升级的新IOS映象文件名）
Destination filename [c2600-i-mz.122-11.bin]?
Do you want to over write? [confirm]
Accessing tftp://10.32.10.1/c2600-i-mz.122-11.bin...
Erase flash: before copying? [confirm]
Erasing the flash filesystem will remove all files! Continue? [confirm]
Erasing device... eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ...erasedee
Erase of flash: complete
Loading c2600-i-mz.122-11.bin from 10.32.10.1 (via Ethernet0/0): !!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
…
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 5998292 bytes]
Verifying checksum... OK (0xA0C0)
5998292 bytes copied in 318.282 secs (18846 bytes/sec)
Router#
转载地址：http://www.netsp.com.cn/Article/config/cisco/router/200609/20060905160153.html
