Synchronization Interval Unit (SIU)

Smallest unit for maintaining synchronization
SIU for a video object can be 1/30th of a second.
SIU for an image or text can be the entire object.

Deadline-Based Scheduling for Synchronization

SIU should be pre-scheduled because of network delay : control time
Control time depends on size,delay and channel capacity requirement of a representative data object.
If the QOP parameters can not meet, the connection can be denied or use partial dropping.

Feedback Techniques for Synchronization

Multimedia server must keep some data in the buffer.
Client send light-weighted message called feedback unit periodically to server.
Server use feedback unit to estimate a better actual playback rate.
Re-synchronization policies are

conservative	Server reacts only when play-out of different streams is guaranteed to be asynchronous.
aggressive	Server reacts as soon as there is even a slight chance that playback is asynchronous.
probabilistic	Server reacts on the average