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Cisco uBR7225VXR Universal Broadband Router Hardware Installation Guide
OL-17309-02
Chapter 1 Cisco uBR7225VXR Overview
Supported System Configurations Overview
Supported System Configurations Overview
The Cisco uBR7200 series universal broadband routers is installed at a cable television headend or a
distribution hub. Related networking and RF equipment, servers, and other host computers are installed,
along with the Cisco uBR7225VXR router, to support digital data transmission.
To deliver data and VoIP services over the cable television system, TV channels are allocated to carry
digital data. Data is modulated downstream on:
• 6-MHz channels in the 88 to 860 MHz range, using North American channel plans through
Cisco cable interface line cards installed in the chassis. For bidirectional cable plants, a portion of
the 5 to 42 MHz range is used for upstream data transmission. For one-way cable plants or cable
segments yet to be upgraded, DOCSIS-based cable interfaces configured for telco return are also
supported.
• 8-MHz channels in the 108 to 862 MHz range using PAL/SECAM channel plans through
Cisco cable interface line cards installed in the chassis. For bidirectional cable plants, a portion of
the spectrum in the 5 to 65 MHz range is used for upstream data transmission.
• 6-MHz channels in the 70 to 860 MHz range, using J-DOCSIS channel operation (extensions for
Japan and select regions) through Cisco cable interface line cards installed in the chassis. For
bidirectional cable plants, a portion of the 5 to 55 MHz range is used for upstream data transmission.
The following sections illustrate the supported configurations including:
• Basic Internet access services
• Virtual private network (VPN) services
• IP telephony services
• Telco return
Basic Internet Access Services
A Cisco uBR7225VXR universal broadband router is installed at the headend or distribution hub. The
Cisco uBR7225VXR downstream cable interface line cards, with onboard upconvertor, translate the
downstream signals to RF for broadcast. The Cisco uBR7225VXR router enables you to transmit
downstream data in both the 6-MHz North American or Japanese and the 8-MHz European channel
environments using the appropriate model of the cable interface line card.
Receivers, scramblers, and descramblers process the television signals to encode or decode signals as
needed for broadcast. Modulators format the analog television and digital signals while upconverters
change the carrier frequency of a modulated signal to a specified frequency. The analog TV channels and
digitally modulated carriers then pass through the RF combiner.
The signals are broadcast from the headend through optical transmitters typically to fiber nodes in the
network. Amplifiers, coaxial cable, and taps carry the signals to the subscriber premises. Signals are
processed as follows:
• Set-top boxes (STBs), televisions, or VCRs receive analog and digital data signals.
• DOCSIS-based cable interfaces and STBs connected to customer premises equipment (CPE) receive
digital data signals:
–
Two-way cable interfaces transmit RF signals back through amplifiers to optical fiber receivers
at the headend. These receivers pass the upstream signal to the upstream ports on the
Cisco uBR7225VXR router for processing.