2 Replies Latest reply on Nov 12, 2010 11:58 PM by Michael Thornburgh

    what is a peer introduction service?

    Pablo P.



      There are several terms related to RTMFP which I don't understand and couldn't find info about them.

      What is a peer introduction service?

      Do you need it to enable p2p between two users or only between a group of users?

      What is RTMFP unicast and RTMFP multicast?

      Is it possible to get the NearID and FarID from RTMFP unicast and use it for p2p between two users?



        • 1. Re: what is a peer introduction service?
          Michael Thornburgh Adobe Employee

          the RTMFP P2P APIs available on the Flash platform only deal with peerIDs (the cryptographically unforgeable pseudorandom identifiers that endpoints have; the nearID of a NetConnection is the local node's peerID).


          a peer introduction service, like Flash Media Server 4 or the Codename Cirrus service, acts as a kind of name server to initiate direct communications between peers based on the peerID.  an introducer translates a peerID to one (or more) IP addresses and UDP port numbers, and also forwards session initiation messages from an initiator to a target peer to facilitate NAT and firewall traversal using a technique called "UDP hole punching".


          FMS4 and Cirrus can also perform automatic group bootstrapping when requested (by enabling the "server channel" for the group).


          a peer introduction service is always needed for direct client-to-client connections.  in general one is also needed for P2P group communication, but RTMFP can be used in "serverless" mode for P2P group communication on a LAN, where peers can discover each other with IP multicast.  there's more information in the ActionScript documentation for the NetConnection.connect() method.


          RTMFP unicast refers to point-to-point communication, either client-server (where it's just like RTMP only encrypted, over UDP, and with lower latency possible for live mode with certain codecs), or direct connections between two peers.


          RTMFP multicast refers to both a native IP multicast streaming mode using packets specially formatted for the Flash platform and a P2P mesh mode (also called "application layer multicast" or "P2P simulated multicast"), as well as a simultaneous IP/P2P multicast mode that we call "multicast fusion".


          the nearID of a NetConnection is the local node's peerID.  the farID of a NetConnection is the identifier of the server to which the NetConnection is connected, and is not the identifier you would use for direct P2P between two users/clients.  you (the developer) must store and look up or otherwise discover the peerID of the party you wish to contact and use that to establish a direct connection.  the VideoPhoneLabs sample application uses a web service to do this (each user registers his nearID with his name; users can look up a name to find the associated peerID).

          • 2. Re: what is a peer introduction service?
            Pablo P. Level 1

            Only the Flash Media Enterprise Server has the peer introduction services capability



            influxis claim they managed to enable rtmfp p2p with the Flash Media Interactive Server that doesn't have the pee introduction service.



            How is it possible?

            Can I emulate the pee introduction service in FMiS and translate NearID to IP and port?