Active Discarding Packet Mechanisms for Video Transmission

This paper presents a survey of active discarding packet mechanisms for video transmissions. Conventional queue management algorithms based their packet dropping decision on fairness, latency, etc. However, they don´t take into account packet content and its importance in relation to the transmitted media type. Active mechanisms are a solution to overcome this limitation. Three key factors are identified: (i) the packet discarding algorithm; (ii) active solution approach; and (iii) the packetisation scheme. Our review is focused on these elements. For (i) this includes the packet discarding policy considering frame type, dependency and size, and loss pattern. In (ii) it involves when, where and how the active network solution is implemented. For (Hi) we consider packet content, size and transmission time. We present some of the main active solutions along with a discussion of what we consider opened research questions in this area.