Team Members Atcharawan Jansprasert Padmoja Roy Rana Almakabi Ehsan Eslamlouevan Manya Tarawalie
Transport Protocols REAL-TIME TRANSPORT PROTOCOL (RTP) REAL-TIME CONTROL PROTOCOL (RTCP) SESSION INITIATION PROTOCOL (SIP) SESSION DESCRIPTION PROTOCOL (SDP)
RTP REAL-TIME TRANSPORT PROTOCOL By Atcharawan Janprasert And Padmoja Roy
RTP : Introduction Was first develop by the Audio-Video Transport Working Group of the IETF Defines a standardized packet format Internet standard for real-time data Provides end-to end transport functions for real-time applications Application-level Framing The end-to-end principal
Introduction Achieving flexibility Protocol architecture: usually work over UDP/IP RTP Issues: The protocol itself does not Provide mechanisms to ensure timely delivery Prevent out-of0order delivery of packet Give any Quality of Service(QoS) Guarantee.
RTP Header Fields The RTP header has a minimum size of 12 bytes. Version(V,2 bits)-Indicates the version of the protocol. Padding(P,1 bit)- if it is set, last byte of payload is padding size. Extension bit (X,1 bit), – it indicates the presence of an extension header between standard header and payload data. Marker (M, 1 bit)-defined in profile, marks significant events.
RTP Header CSRC count (CC,4 bits)-number of contributing sources(CSRC) identifiers. Payload type (PT,7 bits)- It indicates what type of multimedia data is carried in this packet Sequence number(16 bits)- It is used to enable the receiver of an RTP stream to detect missing and miss-ordered packets. The sequence number increments by one for each transmitted RTP data packet. Timestamp( 32 bits)– It is used to enable the receiver to play back the received samples at appropriate intervals and to enable different media streams to be synchronized.
RTP header When a packet is lost, RTP doesn’t do anything like TCP rather it is left in the application to decide what to do depending on the application. SSRC: 32 bits - Synchronization source identifier identifies the source of a stream and will be unique within the same RTP session. CSRC list: 0 to 15 items, 32 bits each -The CSRC list identifies the contributing sources for the payload contained in this packet.
RTCP By: Rana Almakabi
RTCP Protocol What does RTCP stand for? RTCP is the real-time control protocol What is RTCP? It is control protocol extends the RTP protocol with control functionality What are RTCP’s functions? provides feedback on the quality of reception and data distribution synchronizes media streams Keeps track of participants in an RTP session
RTCP Protocol Why is RTCP used in addition to RTP? This protocol depends on RTP, in that its basic functionality and packet structure are stored in RTP. It uses its unique canonical name (CNAME) in keeping track of participants in a session and identifying the identity of senders on a user interface
RTCP Protocol What is the structure of RTCP headers? RTCP’s headers consist of six parts: Version number (V) Padding indicator (P) Reception report count (C) RTCP packet type RTCP packet length SSRC of report sender
RTCP Protocol What is the structure of RTCP’s packets? RTCP Packet Types: Sender Report (SR) Receiver Report (RR) Source Description Items (SDES) End of Participation Indicator (BYE)
SIPSession Initiation Protocol By Ehsan Eslamloueyan
SIP makes two end points able to Establish , Modify and Terminate a session . • SIP provides these services: • User-Location • User-Availability • User-Capability • Session Setup • Session Management
SIP network elements: • User Agent (UA) • Proxy Server • Registrar Server • Redirect Server • Location Server • Each UA has a Uniform Resource Identifier(URI) • sip:firstname.lastname@example.org
SIP Message SIP/2.0 200 OK Via: SIP/2.0/UDP server10.biloxi.com ;branch=z9hG4bKnashds8;received=192.0.2.3 Via: SIP/2.0/UDP bigbox3.site3.atlanta.com ;branch=z9hG4bK77ef4c2312983.1;received=192.0.2.2 Via: SIP/2.0/UDP pc33.atlanta.com ;branch=z9hG4bK776asdhds ;received=192.0.2.1 To: Bob <sip:email@example.com>;tag=a6c85cf From: Alice <sip:firstname.lastname@example.org>;tag=1928301774 Call-ID: email@example.com CSeq: 314159 INVITE Contact: <sip:firstname.lastname@example.org> Content-Type: application/sdp Content-Length: 131
SDP Session Description Protocol By Manya Tarawalie
SDP Main function Format standard representation Media details Transport address Session description Convey media detail Transport address Session initiation Transport media Use by transport protocols to carry information SIP, SAP General purpose Used different protocol and network (Unicast and Multicast) Communication session existence Provide sufficient information to enable participant to join the session.
SDP SDP Encryption Determine by transport protocol Inform participant of encryption Session description content Session description Version Name Initiator Timing Description (Active time) Start and end times Media description (Type of media) Media type Session bandwidth information Session initiator contact info. Encryption (if any)