Triple-Play Service Deployment

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STB DSL Modem
EPG/Multicast Information to the STB
IGMP “Join” Message for Channel 2
IP Multicast for Channel 2
Membership Query Every x Seconds
Membership Query Response
IGMP “Leave” Message for Channel 2
IGMP “Join” Message for Channel 3
IP Multicast for Channel 3
Group Specific Membership Query for Channel 2
Membership Query Response
Membership Query Every x Seconds
Membership Query Response
Figure 7.3 Sample IGMP message flows
Chapter 7: Troubleshooting Video Service in the Field
MPEG-2/UDP/IP
The DSLAM, in this example, has access to the requested
programs. It performs a snooping function, looking at the
requested program material. If the requested program is directly
available at the DSLAM, the join is performed. If the requested
program is not available at the DSLAM, the IGMP messages
continue upstream to a location, such as a video hub office, where
the material is available. The join is performed at this location, and
the program is routed to the DSLAM and on to the STB. The
measurement of the variable network performance aspect of total
channel change time is the critical parameter for measuring actual
network performance.
DSLAM
Multicast
Distribution
Network