Contents

• Putty Xmodem File Transfer App
• Putty Xmodem File Transfer Mac

File transfer via XMODEM / YMODEM (and RS-232. (or YMODEM) file transfer uses a special. Expect to receive an acknowledge character over the serial port. I'd like to send the text content of a file over the serial port, over PuTTY. Managing HP ProCurve switches is a breeze when you've got an HP ProBook 6570b handy with its (really under-rated) RS232 connector. Some of the switches don't have a USB port (which itself is a hassle to get working) so I've found the easiest way to pull config files over the wire in Windows is with ExtraPuTTY - this little fork of PuTTY integrates file transfer protocols like XMODEM which have. ExtraPuTTY is a fork of PuTTY that adds XMODEM and a few other file transfer protocols. Then in your terminal emulation program start the transfer. In teraterm it is under the file menu, while secure CRT has a whole menu structure dedicated to various methods to transfer files. Simple chose the xmodem protocol (I found selecting the 1K option was more reliable), and browse to the configuration file, and away it goes.

Introduction

This document explains how to use the xmodem command at the console to download Cisco IOS® software using the ROM monitor (ROMmon).

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

• Cisco 827, 1600, 1700, 2600, 3600, and 3700 Series Routers

• Cisco AS5200, AS5300, AS5350, and AS5400 Universal Access Servers

Note: Xmodem can also be used on certain Catalyst switches.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

Refer to Cisco Technical Tips Conventions for more information on document conventions.

Overview

Xmodem can be used on a group of routers (see Components Used) and is used in disaster recovery situations where the router has no valid Cisco IOS software or bootflash image to boot from and hence, only boots up in ROMmon. This procedure can also be used where there are no Trivial File Transfer Protocol (TFTP) servers or network connections, and a direct PC connection (or through a modem connection) to the router's console is the only viable option. Because this procedure relies on the console speed of the router and the serial port of the PC, it can take a long time to download an image. For example, downloading Cisco IOS Software Release 12.1(16) IP Plus image to a Cisco 1600 Series Router using a speed of 38400 bps takes approximately 25 minutes.

Usage

Here is the command syntax for xmodem as per the Command Reference Manual for Cisco IOS version 12.2.

This table describes the command syntax for the xmodem command.

Note: xmodem options e, f, and s are only supported on the Cisco 1600 Series Routers. In order to find out the syntax and available options to use with the xmodem command, enter xmodem -? at the ROMmon prompt.

Here is an example of the xmodem command issued on a Cisco 1603 Router:

Here is an example of the xmodem command issued on a Cisco 2620 Router:

Examples

Notes:

• The xmodem transfer only works on the console port. You can only download files to the router. You cannot use xmodem to get files from the router.

• It is also important to note that the -sdata-rate option is only available on the Cisco 1600 Series Routers and was implemented to overcome the console baud rate limitation of 9600 bps. If you specify -sdata-rate of 115200 bps for example, you can increase the download rate and hence, reduce download time. Other Cisco routers support console speeds up to 115200 bps. Therefore, the -sdata-rate option is not required.

• Ensure that the PC serial port is using a 16550 universal asynchronous transmitter/receiver (UART) if you are downloading a Cisco IOS software image through the router's console speed at 115200. If the PC serial port is not using a 16550 UART, it is recommended that you use a speed of 38,400 or lower.

Xmodem Procedure for Downloading a Cisco IOS Software Image onto a Cisco 1603 Router

Use this xmodem procedure in order to download a Cisco IOS software image onto a Cisco 1603 Router.

1. Launch a terminal emulator program.

   In this example, configure Windows HyperTerminal for 8-N-1 at 9600 bps and connect your PC's serial port to the console port of the router. Once connected, you need to get into the ROMmon prompt (rommon 1>). Typically, if the router's Cisco IOS software image and bootflash image are both corrupt, the router only comes up in ROMmon mode. If the former is not true and you need to get into the ROMmon prompt, you need to change the configuration register (typically 0x2102 as given by show version) to 0x0:

2. From the ROMmon prompt, issue the xmodem command. However, before you issue the xmodem command, ensure that you have the new Cisco IOS software image on your PC.

   In this example, all Flash memory is erased before downloading using the f option (only on the Cisco 1600 Series ). Perform a CRC-16 checksum using the c option and using a download speed of 115200 bps (only on the Cisco 1600 Series ) by specifying -s115200:

   Note: If the console port is attached to a modem, both the console port and the modem must be operating at the same baud rate.

   Warning:

3. Configure the terminal emulator program for a data rate of 115200 bps to match the xmodem speed specified above. This is done by closing the previous terminal session of 9600 bps and opening a new one at 115200 with 8-N-1. The trick here is that the Cisco 1603 only supports a maximum baud rate of 9600 bps. Therefore, when connecting at 115200 bps, you cannot see the router prompt. This is an important point to remember. Once connected to the router at 115200 bps, select Transfer and Send File from the HyperTerminal menu bar.

4. Specify the image file name and location and enter xmodem as the protocol.

5. Click on Send to start the transfer.

   This message is received when the transfer is complete:

6. Per the message above, you need to exit your 115200 bps HyperTerminal session and restart a new one at 9600 bps. Once connected, the router's ROMmon prompt appears. Verify that the download was successful by issuing a dir flash:.

7. Change the config register back to 0x2102 and reset or power cycle the router so that the new Cisco IOS software image gets loaded.

Xmodem Procedure for Downloading a Cisco IOS Software Image onto a Cisco 2620 Router

Putty Xmodem File Transfer App

Use this xmodem procedure in order to download a Cisco IOS software image onto a Cisco 2620 Router.

1. Launch a terminal emulator program.

   This example Windows HyperTerminal is configured for 8-N-1 at 9600 bps. Connect your PC's serial port to the console port of the router. Once connected, get into the ROMmon prompt (rommon 1>). Typically, if the router's Cisco IOS software image and bootflash image are both corrupt, the router only comes up in ROMmon mode. If the former is not true and you need to get into the ROMmon prompt, then you will need to change the configuration register (typically 0x2102 as given by show version) to 0x0 as follows:

2. Once in ROMmon, change the console baud rate from 9600 bps to 115200 bps to speed up the download time. Use the confreg command and complete the instructions presented on the screen.

3. Once the router boots up in ROMmon, the HyperTerminal sessions start to display illegible characters. You need to exit the current terminal session and start a new one at a data rate of 115200 bps to match the console rate as in step 2.

4. You are now ready to issue the xmodem command. However, before issuing the xmodem command, ensure that you have the new Cisco IOS software image on your PC.

   Warning:

5. From the HyperTerminal menu bar, select Transfer > Send and specify the image name/location and xmodem protocol as in steps 3 and 4 and start the transfer.

6. Once the transfer is complete, these messages appear:

   Notice how the Flash gets erased towards the end automatically compared to Cisco C1600. Therefore, the reason why the f option is not required here. Finally, ensure that you reset the console speed back to 9600 and change the boot sequence back to default by changing the configuration register back to 0x2102:

Putty Xmodem File Transfer Mac

Xmodem Procedure for Downloading a Cisco IOS Software Image onto a Cisco 3600 Router

Use this xmodem procedure in order to download a Cisco IOS software image onto a Cisco 3600 Series Router.

The standard procedure uses the default console speed of 9600 bits per second. Xmodem is a slow transfer protocol, and the transfer of a file as large as a Cisco IOS software image could take an unacceptably long time. An increase to the console speed on the 3600 router helps decrease the time it takes to do the xmodem file transfer.

When in ROMMON mode, complete this procedure using the ROMMON confreg utility.

1. Open a new hyperterminal with these settings:

2. After setting the hyperterminal, you receive a rommon prompt. Enter the xmodem command. Before you enter an xmodem command, there should be a software image residing in your terminal or your local hard drive.

3. After this message appears, you have to download the file using xmodem and this procedure:

   1. Go to Hyperterminal and click the Transfer menu.

   2. Select Send File.

   3. In the dialog box which appears, click on browse and look for the file name on your local hard drive.

   4. Under the filename field is the Protocol drop-down box. Choose Xmodem.

   5. Click Send to initiate the file transfer.

4. After the transfer completes, the router will reload itself. When the reload completes, press the return key to be taken to a prompt and to reset the configuration register and the console line speed.

5. Upon changing the console speed, you will lose connectivity. Go to your terminal program, change the baud rate to 9600, and reconnect to the router console.

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