Triple-Play Service Deployment

Chapter 7: Troubleshooting Video Service in the Field
In a similar manner, the delay associated with VoD services can be
measured by establishing a latency for the Pause/Play commands.
It is suggested that once a VoD program flow has been received,
elapsed times can be measured, as outlined in the diagram below,
establishing these two latencies providing additional insight into
the transactional quality of the service.
Again, this objective measurement reveals the performance of the
network directly. Attempting to measure the delay in obtaining
the start of a VoD program would include a billing cycle or authentication
of the subscriber for pre-paid services. The latency
associated with these transactional quality items would vary more
with software operations determined by network design than a
network performance variable. Even more important, the
subscriber’s perception would vary over a wide range degrading
the value of such a metric. Further, it would be more difficult to
instrument due to the variability of specific middleware software
operation.
VoD services require that program content be stored and
accessible from servers specifically designed for such service. A
signaling protocol, typically Real Time Streaming Protocol (RTSP),
is used in conjunction with software generically called
middleware to enable the service. The middleware provides the
billing and access control necessary for on-demand services. The
following diagram illustrates this process.
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