Cisco Headend Digital Broadband Delivery System 安装指南
Chapter 1 Introducing GQAM Software Version 4.2.1
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Why Choose This Release?
Overview
GQAM software version 4.2.1 is designed to be installed on a GQAM. After the
software is installed and the modulator is active, it provides additional support for
sites that deploy video-on-demand (VOD), anything-On-Demand (xOD), and other
interactive or broadcast services.
Note: For a complete description of the GQAM modulator, refer to the Gigabit QAM
Note: For a complete description of the GQAM modulator, refer to the Gigabit QAM
Modulator Model D9479 Hardware Installation and Operation Guide (part number
745431) or the Dual SFP Gigabit QAM Modulator Installation and Operation Guide (part
number 4014102).
This section provides descriptions of the major new features supported in GQAM
This section provides descriptions of the major new features supported in GQAM
software version 4.2.1.
New Features
Transport Stream Route Support
The FCC requires Program and System Information Protocol (PSIP) support for
The FCC requires Program and System Information Protocol (PSIP) support for
off-air content. A transport stream route (TSR) is required to support PSIP on a
GQAM. This feature provides the following enhancements:
Enables a passthrough mode on a GQAM for PSIP support
Allows GQAMs to be used for tru2way™ (formerly OCAP™) common
download
Allows system operators to select and encrypt a single multi-program transport
stream (MPTS)
Allows GQAMs to be used with a Netcrypt™ Overlay Bulk Encryptor (NOBE) at
Overlay sites
Allows for re-purpose and re-use of GoQAMs
Important: System Release (SR) 4.3 is required to configure this feature on the
GQAM.
Real Time Protocol Tolerance
Real time protocol (RTP) was originally developed for voice applications and is now
Real time protocol (RTP) was originally developed for voice applications and is now
used in both VoIP and video applications. As a part of the new MPEG encapsulation
scheme, the MPEG UDP packets are encapsulated in an RTP header. This feature
enables GQAMs to accommodate this new MPEG scheme by stripping off the header
and then transmitting the MPEG stream. A significant benefit of this new feature is
that RTP reduces jitter and packet loss through upstream network components.