Hello, friday we had the first working "real" testbed of the OBAMP plugin. I mean that instead of trying the obamp protocol with Netkit (UML virtualization) we configured a few routers and laptops to test.
The plugin works, but there is a major problem with the maximum bandwidth of the multimedia stream we are able to handle. We have a host streaming to a multicast address a mp3 file, we tried both UDP and RTP. The UDP stream travels correctly within the network encapsulated in the OBAMP tunnels and it gets decapsulated to the receivers. We experienced no packet loss. However, the problem is that the audio is very chunky with a stream of 5Kb/s. We used VLC to stream and to receive the media file. Looks like the packets arrive with a eccessive jitter to the receiver and not at a constant rate. We believe that the problem is bounded to the fact that the OBAMP capture socket, that intercepts the multicast traffic, is handled by the default OLSR scheduler. This choice was done to avoid the use of libpthread. Probably the OLSR scheduler is not fast enough and introduces this jitter in the multimedia stream. We are going to investigate further in the following days. Is it possible to control if a packet arrives on a socket without registering the socket descriptor to the OLSR scheduler and without using libpthread ?? If we don't find a solution we are thinking of introducing the use of libpthread to see if handling the media stream with a different thread solves the problem. Saverio _______________________________________________ Wireless mailing list [email protected] http://ml.ninux.org/mailman/listinfo/wireless
