System Overview - Cisco GoQAM Installation And Operation Manual

Chapter 1 Introducing the GoQAM

System Overview

Diagram of Cisco's Overlay Solution
The GoQAM is an integral component of the Overlay solution. The Overlay solution
uses Digital Broadband Delivery System (DBDS) technology to create a network in
which different conditional access (CA) systems can coexist in a coherent manner.
Overlay technology assumes that a PowerKEY DBDS network will be "laid over" an
existing but different cable network.
Important! The GoQAM is supported in SR 2.5/SR 3.5 (or later).
Depending on the system architecture, the GoQAM can be used in either headends
or hubs. The following illustrations are examples of typical Overlay environment
setups.
Overlay Environment Without a Multiplexer With an IRT
In an Overlay environment without a multiplexer (MUX), the Integrated Receiver
Transcoder (IRT) does the encryption for the non-Cisco set-tops.
The following graphic illustrates how Overlay technology interfaces to a non-Cisco
headend that uses a simple IRT. The IRT performs a number of functions including
Mediacipher encryption. With an IRT, clear and encrypted signals are available
through DHEI connectors on the IRT back panel.
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