Upgrade the Firmware / IOS on the Cisco 837 Broadband Router

Introduction

The Cisco 837 ADSL / Broadband router like most Cisco routers can have it's software( firmware ) upgraded. Generally this isn't a difficult process but it is a bit fiddly if you haven't done it before. This guide will walk you through this process.

Requirements

Cisco 837 router and Cisco console cable

Fairly obvious really, this is the router you wish to upgrade and the cisco serial cable used to configure the router.

Cisco 837 Firmware image

This is the software "image" that you will upgrade your router with. This is the most difficult requirement to fulfil since cisco doesn't give access to it's IOS software via anonymous download. You actually have to have a CCO login which has access to download IOS images. Hopefully you have one of these or know someone who does.

A PC or laptop with a Serial RS232 port

Use this along with a terminal client such as PUTTY or HyperHerminal to configure the router. This will be required as you will need to issue commands to the router.

TFTP Server

Since the Cisco 837 doesn't have a CDROM / floppy or USB port you can only transfer images across the network. A server providing the tftp service for transferring firmware images across the network is required. There are plenty of free ones such as TFTP32

Preparation

Step 1. Prepare the PC and Router Serial
Plug the Console cable from the cisco into the PCs serial port.
On the PC you have just connected the console cable to open Hyperterminal or PUTTY. I am going to use PUTTY in this example.
Connect to the routers console and fire open PUTTY choose serial and leave the baud as 9600

Hit the return key on your pc and you should see the routers command prompt

Now enter enable (the mode required to configure the router) mode by typing

and entering the routers enable level password
Once in "Enable" mode you will see a hash next your command prompt. This indicates "Enable" mode. You can now configure the router

Step 2. Prepare the PC and Router for TFTP transfer

-Make sure you have a TFTP server application on your PC. I am using TFTPd32 for this example.

-Patch the PC with the TFTP software into the router using an Ethernet cat 5 cable.

-Check the ip address of the Ethernet interface of router an ensure that you have network connectivity between the router and the PC. Ping is a good tool for this.

I am going to set my routers ethernet IP to 192.168.1.20 with a subnet mask of 255.255.255.0 by running the following commands

Now I test ping my PCs ip which has address of 192.168.1.229

I got a 100% response so we have connection between the PC and router of the network.

Finally we need to download the IOS and place it in the TFTP servers directory so the router can upgrade itself with this new IOS image.

Login to the cisco site and get the image. You will need a CCO login for this. Go to the download page and to the cisco 837 area. At time of writing the url for this is

Download ths software to the TFTP directory. On my pc that is c:\program files\Tftp32.

Start the TFTPD32 Software so the tftp service is running.

Begin the upgrade

If you have not done so already ensure the TFTP server is running.
Open a serial connection to the Cisco.

From the command prompt type

You will be prompted for the ip of the tftp server. Enter this, in my case it is 192.168.1.229

You will now be prompted for the filename you wish to copy to the flash. This is one we downloaded from Cisco. In my case it is c837-k9o3sy6-mz.124-25b.bin. Enter the name of the file you have and press return / enter.

You will be prompted for the Destination filename. For this simply press return as we are happy for it to be called that on the cisco box itself.

You will now be asked if you wish to Erase flsh before copying. This really depends on whether you have enough space on your flash device. In my case I don't so I am going to type "y" for yes.
y

I will then be asked to confirm this decision. Which i will do.

Now your router will erase its flash.

And begin copying the file from the TFTP server.

Once this is finished the router will do a checksum on the images you copied.

Now ensure the router will attempt to boot a IOS image from flash

That's pretty much it - the router can be rebooted. Double check your router config is backed up just in case things go wrong.

Watch the Video version

I have recorded it and put it on youtube if you are very bored.