Audio Delay or No audio using FMS 4.5 and adobe flash player

Our company provide live chatting with flash player and FMS 4.5. Our application provide chat room for 4 or 5 clients to join the room to chat. One of the clients will be the presenter. The presenter will publish his/her audio and video to other clients, but other clients only publish their audio to others. Since this is live communication, we set bufferTime to 0. However, we need to save the chatting materials. We are publishing the streams with

   ns.publish(“video”, “append”);

If the networks are good, we will have no problem. However, it the network became bad, the audio will delay and even lost. We use rtmp, and I believe the protocol is TCP. I understand since the communication is TCP, the data will arrive late and cause audio delay. But can we explain why there is no audio sometimes?

For some typical usage like this:

One presenter and 3 audiences in the room. The presenter publish his/her video/audio to the audiences, audience receiver the presenter’s A/V and the other two’s Audio. When that audience network has jitter, his/her audio/video have problems. 

My questions –

1. What does the FMS do if the rtmp packets cannot send to clinet due to network jitter? (re-sent otr drop it?)
2. After the network jitter, the particular client will lag or lost the presenter’s A/V. Will FMS know there is a jetter and try to recover it?
3. If 2 is not, what can the user (I mean the client) do to re-sync with others.

Thanks,

Jim