SSSim

This is SSSim, the Simple & Scalable Simulator for P2P scheduling algorithms. SSSim is not a real event-based simulator, but a tool for comparing the schedules generated by different chunk/peer selection algorithms (called "chunk scheduling algorithms" and "peer scheduling algorithms" in SSSim). To simplify such comparisons and to make the schedules easier to predict/analyse, SSSim is based on some simplifying assumptions (which explain why the simulator is "simple & stupid"): 1) All peers are synchronised 2) All the peers have the same output bandwidth, which is equal to the stream bitrate. Times are normalised dividing everything by the time needed to send a chunk (hence, the stream bitrate and the output bandwidths are equal to 1). 3) All the peers have a very large (modeled as infinite) input bandwidth 4) All the peers have the possibility to know the internal state of all the other peers in the system (the scheduling algorithms can be clairvoyant) Based on these assumptions, at every time unit: 1) Each peer receives all the chunks that have been sent to it at the previos time unit 2) The source selects a target peer (peer scheduling) and sends a new chunk to it 3) Each peer selects a chunk C (chunk scheduling) and target peer P (peer scheduling) and sends C to P. Note that the peer can select first the chunk and then the peer or vice-versa (or can select chunk and peer simultaneously, but these algorithms have not been tested yet). SSSim can generate a trace showing the chunks exchanged between peers at each time unit. To compile the simulator, just type "make" and a "sssim" executable should be built. To build the simulator with different scheduling algorithms, you can use the "PEER_SCHED" and "CHUNK_SCHED" variables: for example, "make CHUNK_SCHED=latest_blind_chunk". To remove the playout delay (and limited-size chunk buffer), compile with the "NO_BUFF" variable defined: for example, "make NO_BUFF=YesPlease". The program accepts a "-n " option to set the number of peers (100 is the default), while the number of chunks to send can be configured by using the "-c " option. The complete syntax for the sssim program is available by using the "-h" (help) option. It is possible to specify an optional argument indicates the name of a file where the trace of all the exchanged chunks is written, and an optional argument which indicates the name of a file where the chunks' diffusion times (the maximum time needed by a chunk to reach a peer) are saved as soon as chunks arrive.