On the Impact of Zero-padding in Network Coding Efficiency with Internet Traffic and Video Traces
Maroua Taghouti, Daniel E. Lucani, Morten V. Pedersen, Ammar Bouallègue · VBN Forskningsportal (Aalborg Universitet) · 2016
Random Linear Network Coding (RLNC) theoretical results typically assume that packets have equal sizes while in reality, data traffic presents a random packet size distribution. Conventional wisdom considers zero-padding of original packets as a viable alternative, but its effect can reduce the efficiency of RLNC or other erasure coding techniques. Our goal is to characterize the overhead generated by this zero-padding under real-traffic traces. These include TCP and UDP traces from traffic at core routers from CAIDA and a collection of video traces for different codecs and video resolution compiled by Arizona State University. Our numerical results show the dependence of the zero-padding overhead with the number of packets combined in a generation using RLNC. Surprisingly, medium and large TCP generations are strongly affected with more than 100% of padding overhead. Although all video traces are affected, our results show that higher resolution video has a lower overhead, due in part to the fact that most of the transmitted data packets are of the maximum size of packet in the network.