The Research On Network Video Live-broadcasting Model Based On PIM-SSM

With the rapid development of Internet technology,Internet services have been became the rapidest in development and the most drastic in competition fields of multimedia transportation.Commonly, multimedia transportation needs high bindwidth. While the multicast transport model could reduce the load of the servers and save the bandwidth of backbone network. So it can solve the problems of the unicast.The protocol of PIM-SSM uses the source address S and the group address G to identify a channel to solve the problem of the discovery of multicast source,so it is suitable for video services of point-to-multipoint.The protocol of PIM-SSM doesn't solve some problems of traditional multicast model,such as user control,multicast accounting and QoS etc. Aiming at these problems,based on the thorough research of the protocol of PIM-SSM,this thesis gives a live-broadcasting video model. It is based on PIM-SSM including the functions of the user authentication,the packets filter and the accounting.It is implemented by java language and verified.This thesis first introduces the concept and principle of multicast and then multicast,unicast and broadcast have been compared in each suitable circumstance,the merits and the defects.At mean time,it describes the key techniques in detail and makes a thorough study on some problems of current multicast model.This thesis describes the live-broadcasting video model and the implementation prototype in detail.The model implements the user authentication at the client end.Only these users who pass the authentication could get the source address and group address to join the multicast group;Secondly ,nowadays some routers don't support the protocol of the PIM-SSM,therefore,the model considers filtering the packets at the client end and uses source IP address,source port and TTL value of the packet as the filter conditions.Those packets filtered by these conditions could be presented to the users by JMF(Java Media Framework);Finally, when the users login and quit,the registration server will record the time.So this thesis takes accounting by time.Considering of the illegal exit, the registration server sets a counter for each user,users need send the "live" message to the registration server.When the registration server gets it,it will update the counter.When the counter expires,the model holds that the user is offline,then records the time.This model is designed based on IPv4,IPv6 is the next work that needs to be done.Besides,the QoS problem of the multicast in the video broadcasting needs the further study, too.