Cisco IOS Cookbook, 2nd Edition

Copying an IOS Image Through the Console

Problem

You want to load an IOS image into your router through a serial connection to the console or AUX ports.

Solution

You can use the following set of commands to copy an IOS image onto a router through either the console or the AUX port:

Router1#copy xmodem: slot1: 
                        **** WARNING ****
x/ymodem is a slow transfer protocol limited to the current speed
settings of the auxiliary/console ports. The use of the auxilary
port for this download is strongly recommended.
During the course of the download no exec input/output will be
available.
                        ---- ******* ----


Proceed? [confirm] <enter>
Destination filename []? c3620-ik9s-mz.122-12a.bin
Erase slot1: before copying? [confirm] <enter>
Use crc block checksumming? [confirm] <enter>
Max Retry Count [10]: <enter>
Perform image validation checks? [confirm] <enter>
Xmodem download using crc checksumming with image validation
Continue? [confirm]  <enter>
Ready to receive file...........CC  <start xmodem file transfer here>
4294967295 bytes copied in 1450.848 secs (1271445669961 bytes/sec)
Router1#

Tip

Cisco highly recommends using the AUX port for this procedure rather than the console port because the AUX port supports hardware flow control.

Discussion

It can be quite useful to be able to load an IOS image through a serial connection, particularly if you don’t have access to a TFTP server, or if the router doesn’t have any accessible LAN interfaces. Although this feature is rarely used, Cisco does support xmodem