SSSim

This is the home of SSSim, the Simple & Scalable Simulator for P2P scheduling algorithms.

The Simulator

Actually, 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 [see details].

SSSim can generate a trace showing the chunks exchanged between peers at each time unit.

More details about SSSim can be found in a Technical Report.

Download:

Get the first release (v0.1)
A second version has been released, including the new Dl/ELp scheduling algorithm

Compiling and Using:

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 specified using the "-c " option. The complete syntax for the sssim program can be asked using the "-h" (help) command line option.

Assumptions and Constraints:

All peers are synchronised
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).
All the peers have a very large (modeled as infinite) input bandwidth
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)

How it Works:

Based on the assumptions highlighted above, at every time unit:

Each peer receives all the chunks that have been sent to it at the previos time unit
The source selects a target peer (peer scheduling) and sends a new chunk to it
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).