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Configuring Cisco uBR7246 Universal Broadband Router Features VC-133
Configuring Cisco uBR7246 Universal
Broadband Router Features
Cisco uBR7246 universal broadband features enable the Cisco uBR7246 universal broadband router
to communicate with a hybrid fiber coaxial (HFC) cable network via a Cisco MC11 cable modem
card. Cisco MC11 cable modem cards allow you to connect cable modems on the HFC network to
a Cisco uBR7246 in a Community Antenna Television (CATV) headend facility. The modem card
provides the interface between the Cisco uBR7246 protocol control information (PCI) bus and the
radio frequency (RF) signal on the HFC network. For a description of the commands used to
configure universal broadband features, refer to the “Cisco uBR7246 Universal Broadband Features
Commands” chapter in the Voice, Video, and Home Applications Command Reference.
The MC11 cable modem cards consist of the following components:
• One downstream cable F-connector port—The downstream port supports quadrature amplitude
modulation (QAM) speeds of 64-QAM, or 6 bits per symbol. A symbol is the basic unit of
modulation in CATV systems.
• One upstream cable F-connector port—The upstream port supports quadrature phase shift keying
(QPSK) modulation, or 2 bits per symbol.
• Cable Media Access Control (MAC) unit—The cable MAC frames and encrypts the downstream
signal for RF transmission and passes the signal to the downstream physical layer (PHY).
Reverses the signal framing and encryption on the upstream signal from the upstream PHY.
• Downstream PHY unit—The downstream PHY generates a modulated, intermediate frequency
(IF) output signal at a frequency of 44 MHz and passes the IF signal to an external IF to RF
upconverter installed in the downstream path.
• Upstream PHY unit—The upstream PHY receives the modulated, upstream signal at a frequency
of 5 MHz to 40 MHz and passes the signal to the cable MAC to remove the framing and
encryption formats.
• Spectrum manager—The spectrum manager continuously monitors the noise in unused upstream
channels. If the signal-to-noise ratio reaches an unacceptable level on a particular channel, the
spectrum manager will automatically assign a new upstream channel to the cable modem using
that channel. This feature is referred to as frequency agility.
You must install at least one Cisco MC11 cable modem card in the Cisco uBR7246 chassis to
establish communication between the Cisco uBR7246 and the HFC network.
Figure 38 shows the network topology for the modem card and illustrates network connections using
the Cisco uBR7246.