Routing Operations; Upgrading The Software Image - Cisco CVA122 Hardware Installation Manual

Chapter 1 Product Overview
parameter. So if the headend allowed only one PC per cable voice adapter, subscribers could connect
only one PC to the cable voice adapter, even if the MAX CPE parameter were set to the maximum
possible value of 254.
For better network performance, Cisco recommends a maximum limit of 16 CPE devices;
Note
this recommended maximum might be less depending on the services the subscriber has
purchased.
See Figure 1-1 for a typical configuration.
Figure 1-1
All Cisco IOS releases that support the Cisco CVA122/CVA122E Cable Voice Adapter
Note
support basic DOCSIS connectivity that provides both high-speed Internet data access and
VoIP connectivity.
The cable voice adapter ships from the factory with a Cisco IOS software image stored in nonvolatile
Flash memory that supports DOCSIS-compliant bridging data operations. Based on the feature licenses
your company purchased, other Cisco IOS images can be downloaded from Cisco Connection Online
(CCO). These images might provide additional functionality, depending on the software release.

Routing Operations

When configured as a router, the Cisco CVA122/CVA122E Cable Voice Adapter can directly connect
one PC to each of its Ethernet and USB ports at the rear of the router. The Ethernet port can also be
connected to a standard 10BaseT Ethernet hub, which then connects additional computers or Ethernet
devices at the site to a local area network (LAN).
In routing mode, the Cisco CVA122/CVA122E Cable Voice Adapter is typically configured to use the
IP address of the headend router as its default IP gateway. Routing mode does not have a maximum
limitation on the number of CPE devices, as is the case in bridging mode; however, the CMTS can still
limit the number of CPE devices by limiting the number of IP addresses that any particular cable modem
can provide services for. If this is the case, the cable voice adapter can use NAT/PAT translations to use
one IP address for multiple CPE devices.

Upgrading the Software Image

When Cisco IOS images are updated to new releases, the service provider can download them as needed
to Cisco CVA122/CVA122E Cable Voice Adapters installed in the field (based on the software licenses
purchased). See the release notes for the cable voice adapter for a complete list of features and
Cisco IOS images that are currently supported.
OL-0799-02 (05/2001)
Cisco CVA122/CVA122E in a Bridging Configuration
CATV
coaxial cable
HFC
network
Cisco CVA120 Series
cable voice adapter
Cisco CVA122/CVA122E Cable Voice Adapter Description
PC
USB
PC
Ethernet
Cisco CVA122/CVA122E Hardware Installation Guide
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