• Heart of emerging RTC-enabled web applications • Strict delay on end-to-end packet delivery - 400ms (3GPP standard) • Small playout buffer - of magnitude smaller than for streaming
the error protection method • Rate control aims at optimal network path utilization – Mitigates risk of congestion losses • Rate control requires probing for capacity • Idea: 1. Use FEC to probe for available bandwidth 2. Additional stream protection è more aggressive probing
rate FEC STAY state! PROBE state! STAY state! STAY state! UP state! UP state! DOWN state! PROBE state! (A) Adding FEC (B) Swapping FEC with media (C) Partially swapping FEC with media Available Capacity
Good conditions, probe network No more bandwidth available Stable conditions Stable conditions Unstable conditions Unstable conditions Unstable conditions
FEC • Generic idea that can be incorporated to other solutions – e.g., RRTCC • Efficient new congestion control algorithm • Increased GOP size provides energy savings • Ready to deploy