Team Members

Atcharawan Jansprasert Padmoja RoyRana AlmakabiEhsan EslamlouevanManya 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

o Provide mechanisms to ensure timely deliveryo Prevent out-of0order delivery of packeto Give any Quality of Service(QoS) Guarantee.

RTP Header Format

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?

1.provides feedback on the quality of reception and data distribution

2.synchronizes media streams 3.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?o 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?o RTCP Packet Types:

Sender Report (SR) Receiver Report (RR) Source Description Items (SDES) End of Participation Indicator (BYE)

SIPSession Initiation Protocol  

ByEhsan Eslamloueyan

• SIP makes two end points able to Establish , Modify and Terminate a session .

• SIP provides these services:o  User-Locationo  User-Availabilityo  User-Capabilityo  Session SetupoSession Management

•  SIP network elements:oUser Agent  (UA)o  Proxy Servero  Registrar Servero  Redirect ServeroLocation Server

• Each UA has a Uniform Resource Identifier(URI)

    sip:bob@biloxy.com

Session Establishment 

SIP/2.0 200 OKVia: SIP/2.0/UDP server10.biloxi.com;branch=z9hG4bKnashds8;received=192.0.2.3Via: SIP/2.0/UDP bigbox3.site3.atlanta.com;branch=z9hG4bK77ef4c2312983.1;received=192.0.2.2Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bK776asdhds ;received=192.0.2.1To: Bob <sip:bob@biloxi.com>;tag=a6c85cfFrom: Alice <sip:alice@atlanta.com>;tag=1928301774Call-ID: a84b4c76e66710@pc33.atlanta.comCSeq: 314159 INVITEContact: <sip:bob@192.0.2.4>Content-Type: application/sdpContent-Length: 131

SIP Message

SDPSession Description Protocol

ByManya Tarawalie    

SDP

• Main function Format standard representation

1.Media details2.Transport address3.Session description

Convey media detail Transport address Session initiation

• Transport media o Use by transport protocols to carry information

1. SIP, SAP1. 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 o Determine by transport protocolo Inform participant of encryption

• Session description content o Session description

Version Name Initiator

o Timing Description (Active time) Start and end times

o Media description (Type of media) Media type Session bandwidth information Session initiator contact info. Encryption (if any)

                                          QUESTIONS?