Specifications

DOCSIS 1.1 for Cisco uBR905 and Cisco uBR925 Cable Access Routers and Cisco CVA122 Cable Voice Adapters
How to Configure DOCSIS 1.1 Support
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Cisco IOS Release 12.2(15)CZ
Caution It is also possible to upgrade the Cisco IOS software by setting the configuration register to 0x00 and
booting the router into the ROM monitor (ROMMON). However, this method is not recommended
because it requires manually connecting a terminal to the router’s console port and downloading the
software image using the X-Modem protocol. Also, this must never be done on the Cisco CVA122 Cable
Voice Adapters because these routers do not have a console port. You will not be able to recover the
Cisco CVA122 if you boot it into the ROM monitor, and instead will have to return it to the factory for
repair or replacement.
Tip Cisco IOS software images that include “cvc” as part of the filename (ubr925cvc-k9o3sv9y5-mz) are
digitally signed. Unsigned software images do not include “cvc” as part of the filename
(ubr925-k9o3sv9y5-mz). If you are using secure software download, you must use a digitally signed
image (includes “cvc”). If you are not using secure software download, you must use an unsigned image
(does not include “cvc”). To avoid confusion, Multi-Service Operators (MSO) should choose a different
suffix to identify images that they cosign for use on their network.
Downloading the Image During Initialization Through the DOCSIS Configuration File
After you have upgraded the router to Cisco IOS Release 12.2(15)CZ, or another DOCSIS 1.1 software
image, the router must use the DOCSIS 1.1 secure software download feature to upgrade its software
image. During initialization, the cable modem compares its current software image with the one
specified in the DOCSIS configuration file and, if they do not match, the cable modem downloads the
new software image from the specified TFTP server. The router verifies the digital signature of the
downloaded file to ensure that the software image has not been corrupted or altered during transmission.
Use the following procedure to copy the Cisco IOS software image and new DOCSIS 1.1 certificates to
the TFTP server used by the cable modems.
Note If you have not already downloaded the required CVCs to the router, you must also do that now by setting
TLVs 32 or 33 in the DOCSIS configuration file. See the “Configuring for Secure Software Download”
section on page 24 for more information. If you do not load the CVCs into the cable modem before
sending the SNMP commands, the download fails with an error status.
Step 1 Copy the Cisco IOS Release 12.2(15)CZ software images to the TFTP server for the cable modems.
Typically, they should be put into the same directory that contains the other Cisco IOS software images.
For a DOCSIS secure software download, you must use a digitally signed software image, which
includes “cvc” as part of the software image filename.
Note The Cisco uBR905 and Cisco uBR925 cable access routers and Cisco CVA122 Cable Voice
Adapters will not upgrade the software image unless the Cisco IOS Release 12.2(15)CZ
software image filename is different than the filename of the software image that the router
is currently running. An easy way to ensure this is by adding “12215CZ” to the filename (for
example, cva120-k8o3v9y5-mz.12215CZ.bin or ubr925cvc-k9o3sy5-mz.12215CZ.bin).
Step 2 Create a DOCSIS 1.1 configuration file that instructs the Cisco uBR905 or Cisco uBR925 cable access
router, or the Cisco CVA122 Cable Voice Adapter to download the new Cisco IOS Release 12.2(15)CZ
software image. This information is contained in the following configuration file options: