This document addresses common questions and issues that new owners of
uBR900 series cable modems may encounter in configuring the modem and upgrading
Cisco IOS® Software. For information about other
aspects of configuring and using uBR900 series cable modems, refer to the
When should I consider upgrading the Cisco IOS Software that is running
on my uBR900 cable modem?
A. If your uBR900 cable modem is working satisfactorily and you are not
lacking any required functionality, then there is no reason to upgrade the
Cisco IOS Software on your router.
You should only upgrade the Cisco IOS Software on your uBR900 cable
There is a known bug that is present in your current version of
firmware that is negatively impacting your Internet connectivity through the
uBR900 cable modem.
You require access to a new feature not supported in your current
You have been advised to upgrade by the Cisco Technical Assistance
Center (TAC) or your cable service provider.
How do I obtain a copy of a new Cisco IOS Software
A. Cisco IOS Software for the uBR900 cable modem can be downloaded from
the Cisco Software
registered customers only)
. If the Cisco TAC or your cable service provider asks you to
upgrade, they will typically provide the image for you.
Note: The Cisco Technical Assistance Center (TAC) will only provide new
Cisco IOS Software images in order to fix bugs that are affecting your uBR900
cable modem. The TAC will not generally provide Cisco IOS Software images in
order to provide extra features and functionality. For example, if your current
version of Cisco IOS Software does not support IPSec functionality, the TAC is
not authorized to give you a Cisco IOS Software image that does support IPSec.
You must purchase this image with extra functionality from Cisco, or from
another authorized party.
How do I upgrade the Cisco IOS Software that is running on my uBR900
A. If your service provider is recommending that the version of Cisco IOS
Software on your uBR900 cable modem should be upgraded, then the cable service
provider can generally do this themselves, assuming that the cable modem is
If you find that you need to upgrade your uBR900 cable modem yourself
through the the local Ethernet segment, you will first need to manually assign
an IP address to the cable modem's Ethernet port and manually assign an IP
address to one of your local PCs. In addition, you need to download and install
a TFTP server application. There are many TFTP servers available, and they can
be easily found by searching for "tftp server" on your favorite Internet search
engine. Cisco does not specifically recommend any particular TFTP
Note: UNIX-based operating systems typically have a built-in TFTP Daemon
such as tftpd or in.tftpd. Consult your operating system documentation for more
Once you have downloaded the Cisco IOS Software image to your PC
through FTP, use the following procedure to load it onto the uBR900 cable
Connect your PC to the cable modem with an Ethernet cross-over cable.
Assign appropriate IP addresses on the two Ethernet interfaces in the
Note: The procedure for manually assigning an IP address to your local PC
or workstation varies depending on what platform and operating system you use.
If you are using a Microsoft Windows-based system, then the IP address of your
PC can normally be set using the control panel application.
Note: For this example, assume that the PC's IP address will be manually
changed to 192.168.1.10 with a network mask of 255.255.255.0. No other
IP-related parameters need to be set on the PC at this stage.
Make sure that you record the initial IP address settings on your PC
so that you can put them back after the Cisco IOS Software upgrade procedure is
complete. When you change the IP address on your PC or workstation, you may
have to reboot it in order for the changes to take affect.
Once you have manually configured your PC's IP address, launch the
TFTP server application. Your TFTP server should be ready to run.
Note: If you are running the Cisco TFTP server application, you need to
change some settings in order to avoid a potential problem with the server
which may surface when using some versions of Windows. To make the necessary
changes, complete these steps:
In the TFTP server application, select View >
In the Options dialog, deselect Show
file transfer progress and Enable
Note: At this stage, the TFTP server should be ready to run.
Locate the Cisco IOS Software image that you intend to place on the
uBR900 cable modem, and copy it to the appropriate directory on your computer.
Typically, users name such a directory TFTPboot, but you
can name it whatever you want. By default, the Cisco TFTP server uses the
following location for the TFTP root directory:
C:\Program Files\Cisco Systems\Cisco TFTP Server
This means that you must copy the new Cisco IOS Software image to
this directory. If you would like to change the TFTP root directory using the
Cisco TFTP server, specify it by selecting View > Options
and indicate the desired TFTP root in the Options dialog.
Now that the TFTP server is running and the new Cisco IOS Software
image is in the TFTP root directory, make sure that the TFTP server application
is pointing to that directory and its path. In this case the directory name is
TFTPboot. Usually this parameter is set in the
Options dialog of the TFTP server application, and it looks
Manually assign an IP address to the Ethernet port of the cable
modem. Accomplish this by performing the following steps:
Shut down the cable interface of the modem.
Disable bridging and enable routing, as shown below. In the example
below, the Ethernet port is being assigned an IP address of 192.168.1.1 with a
network mask of 255.255.255.0.
Note: If you have already enabled routing on your uBR900 cable modem,
then you will not need to perform these steps.
!--- This saves the cable modem's current configuration.
Router(config)#no bridge 59
Router(config)#interface cable-modem 0
Router(config-if)#no cable-modem compliant bridge
Router(config)#interface ethernet 0
Router(config-if)#ip address 192.168.1.1 255.255.255.0
At this point, make sure that the router and the PC are able to
communicate with each other over the Ethernet segment. You can verify
connectivity between the two devices by issuing the
ping command. For example, if your PC's IP address
was set to 192.168.1.10 then you could execute the following router command:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.10, timeout is 2 seconds:
Success rate is 80 percent (4/5), round-trip min/avg/max = 1/35/100 ms
An exclamation point means that a ping was successful. If you get
more than three out of five successful pings then this is good enough. If you
get less than three out of five successful pings, then check the physical
cabling between your uBR900 cable modem and PC. Also check to make sure that
the PC and cable modem have IP addresses that are not the same as each other,
and that the IP addresses have the same network number and subnet mask.
Copy the Cisco IOS Software image to the router, as shown in the
example below. The address or name of the remote host should be set to the TFTP
server PC's IP address, and the source filename should be set to the exact
Cisco IOS Software image name as in your TFTP root directory. In this example
the upgrade image name is ubr920-k8o3v6y5-mz.122-3.
Router#copy tftp flash
Address or name of remote host ? 192.168.1.10
Source filename ? ubr920-k8o3v6y5-mz.122-3
Destination filename [ubr920-k8o3v6y5-mz.122-3]?
<hit enter here>
Erase flash: before copying? [confirm]
<hit enter here>
Erasing the flash filesystem will remove all files! Continue? [confirm]
<hit enter here>
Erasing device... eeeeeeeeeeeeeeeeeeeeeeeeeeeeeee ...erased
Erase of flash: complete
Loading ubr920-k8o3v6y5-mz.122-3 from 192.168.1.10 (via cable-modem0):
. . . . .
. . . . .
[OK - 4147112/8093696 bytes]
Verifying checksum... OK (0xE6BB)
4147112 bytes copied in 123.135 secs (32903 bytes/sec)
Look for a message like the following:
%Error opening tftp://192.168.1.10/ubr920-k8o3v6y5-mz.122-3
(No such file or directory)
If you see such a message at any stage, double-check to make sure
that you have the image name correct and that the Cisco IOS Software image is
in the correct directory on your workstation. In addition, you can try adding
.bin to the end of the filename when you type it in on the
uBR900 cable modem.
Also, look for the following message:
%Error opening tftp://192.168.1.10/ubr920-k8o3v6y5-mz.122-3 (Timed out)
If you see this or a similar message at any stage, then make sure
that the TFTP server is up and running and that you can ping the IP address of
the TFTP server machine from the uBR900 cable modem.
Reload the uBR900 cable modem.
If the TFTP transfer was successful, you have the new Cisco IOS
Software image on your uBR900 cable modem and you need to reload the device in
order to run the new software. You can do this by either power cycling the
router or by issuing the reload command. If you
issue the reload command, do not tell the router to
save the configuration. Remember that you have made some temporary
configuration changes that you probably do not wish to keep, and you have
already saved the original configuration.
System configuration has been modified. Save? [yes/no]: no
Proceed with reload? [confirm]
Your router should now reload with the new version of Cisco IOS
Software. When the router has successfully rebooted, issue the
show version command to confirm that the router has
successfully loaded the new Cisco IOS Software image.
At this stage you should set your PC's IP address properties back to
what they were originally. You may need to reboot your PC in order for the
changes to take affect.