Does unicast need handshake before streaming?

[kevintcore]

I have programs using VLC libraries that do 2 things. Both are working fine.
1) Transcode a wav file to muLaw and send a multicast stream to an ipaddress and port using rtp. The ipaddress sent to is a decoder.
2) Play a stream using http/ipaddress/path/filename.sdp where ipaddress is an encoder streaming to a multicast address and port.

I am trying to figure out what kind of changes / additional steps I need to make if I start using unicast addresses instead of multicast addresses.

From our understanding, multicast just spews out the stream onto the network regardless if anything is listening and anything that wishes can listen. But with unicast, you need somekind of handshake event before the streaming from one ipaddress:port to another can occur. In otherwords, something needs to listen for a packet, pull the ipaddress and port from that packet's header then it can begin sending / listening to the stream. Are we on track or off base? If we are on track, how might we go about implementing this? We would also like to be able to support DHCP addresses on our server and encoder / decoder devices.

[Rémi Denis-Courmont]

Noo. With unicast, it just spews the packets to the destination, regardless of whether the destination wants them.

However, if the destination does not want them, it will likely emit ICMP Port Unreachable errors, which might confuse the sender.