We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Thank you!
Presentation is loading. Please wait.
Published byCassandra Cornish
Modified over 2 years ago
© De Montfort University, 20041 Protocols for multimedia transmission over the Internet Howell Istance Dept. of Computer Science De Montfort University
© De Montfort University, 20042 Overview… In order to understand differences between streaming services and download services over the Internet, it is necessary to understand the various protocols involved and the differences between them Chapter 15 – Chapman and Chapman HTTP UDPTCP IP RTSP RTP
© De Montfort University, 20043 Internet Protocol (IP) Transfer of datagrams between hosts Each host has an IP address Datagram headers contain source and destination IP addresses Each datagram treated separately – no connection between datagrams that make up a page Routers inspect destination address – if on same network modify it to native address format else pass on to another router Routers discard datagrams which have not reached their destination after a certain time
© De Montfort University, 20044 Transport Control Protocol (TCP) Clearly there is a need to order packets received from IP layer and request re-transmission of any that are missing TCP provides this service Sets up a connection between sender and receiver Uses a sliding window protocol – sender sends packets up to a limit and awaits acknowledgement from receiver – when acknowledgement received, sends more up to window limit If no acknowledgement received, packet is re-sent Transport address = IP address + port number, needed to ensure that packets is passed to appropriate application
© De Montfort University, 20045 User Datagram Protocol (UDP) No connection set up between sender and receiver No acknowledge/ retransmit procedure Packets have port number Suitable for delivery of streamed audio and video data
© De Montfort University, 20046 Realtime Transport Protocol (RTP) Adds sequence number to each packet to enable application to order packets or discard packets received out of order No guarantee of delivery Sets up a connection between sender application and receiver so that each stream is an identifiable entity Identifies payload (data) type e.g audio or video, Where several data types are to be sent, these are sent by individual RTP streams Synchronisation supported by adding timestamp to the header
© De Montfort University, 20047 Unicasting and Multicasting If several (many) users want to receive same data from same source at the same time, separate and duplicate data packets need to be sent to each user (receiver) unicasting leads to much duplication in this situation Multicasting – send a single copy from source and duplicate this en route only when necessary to ensure that each user receives it Hosts assigned to host groups, IP addresses now identify host groups rather a single hosts – range of IP addresses reserved for this
© De Montfort University, 20048 Hypertext Transfer Protocol (HTTP) Link between application (e.g. web browser) and TCP HTTP 1.0 – caused server TCP to close connection to client after each request HTTP 1.1 – client TCP closes connection to server after all requests have been processed Prescribes format of requests from client and responses from server
© De Montfort University, 20049 HTTP requests : http://www.cse.dmu.ac.uk/~hoi/index.html Browser sends HTTP request GET /~hoi/index.html HTTP/1.1 Host: www.cse.dmu.ac.uk User-Agent: Mozilla/4.0 Accept: image/gif, image/jpeg, text/* (blank line)
© De Montfort University, 200410 HTTP Server Responses Status followed by header followed by data HTTP/1.1 200 OK Server: Netscape-Enterprise/3.5.1G Date: Sat 25 Feb 2002 14:27:17 GMT Content-type: text/html …..(rest of data) … Status codes <200 – informative300-399 – redirect 200-299 - success 400-599 - error
© De Montfort University, 200411 Realtime Streaming Protocol (RSTP) HTTP – runs on top of TCP, overheads incurred by reliable transmission are unacceptable for streamed media RTP – does not provide functionality to start, stop, pause RTSP – provides these services, Internet VCR remote control Syntactically similar to HTTP, but requests require an absolute url – no Host header No data in RTSP responses, all data carried in RTP responses Used primarily by Streaming Quicktime, RealPlayer G2
© De Montfort University, 200412 Setting up a streaming session Before session is set up, client needs to obtain a presentation description – details of how presentation is to be controlled Typically contains media announcements including transport address and protocol (e.g RTP), type of data and type of encoding used Each stream will have a rtsp://URL Information to client about where to get presentation description passed to it somehow (usually by HTTP) –QuickTime – small movie –RealPlayer 5.0 and below -.ram file –RealPlayer 6.0 and above -.smil file
© De Montfort University, 200413 Setting up a streaming session (server)(player) DESCRIBE request to url provided Presentation description SETUP request Session identifier (arbitrary string) PLAY session request PAUSE session request TEARDOWN session request
© De Montfort University, 200414 Protocol Rollover Firewalls can prevent clients accessing external servers via ports or protocolls that have been disabled The player can attempt to access the server using a succession of protocols (protocol roll-over) Client Server Local Area Network firewall multicast HTTP RTSP/TCP? RTSP/UDP?
© De Montfort University, 200415 Sequence in a streaming session urls in.smil files reference RealServer Server sends page.wav clips RealProducerRealPlayer Web Browser Access database Client requests page.smil file ram file RealServer Web Server (IIS).rm file.html..smil files Streaming server Web server Client Network
© De Montfort University, 200416 Quality of service… Delay (latency) in network will cause intervals between packet arrival to vary continuously (jitter) Why will this cause problems? In addition, there may be packet loss Delay, jitter and packet loss are all measurable – amount which an application can tolerate can be quantified These parameters + bandwidth required define Quality of Service required by application ATM (Asynchronous transfer mode) networks – high speed which offer guarantees of a level of QofS to applications which use them
Digital Multimedia, 2nd edition Nigel Chapman & Jenny Chapman Chapter 17 This presentation © 2004, MacAvon Media Productions Multimedia and Networks.
Multimedia and Networks. Protocols (rules) Rules governing the exchange of data over networks Conceptually organized into stacked layers – Application-oriented.
Chapter 15 Chapter 15 Multimedia and Networks Multimedia Systems.
Chapter 1: Introduction to Web Applications. This chapter gives an overview of the Internet, and where the World Wide Web fits in. It then outlines the.
© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 Network Services Networking for Home and Small Businesses – Chapter 6.
The Inter-network is a big network of networks.. The five-layer networking model for the internet.
CS 218 F 2003 Nov 3 lecture: Streaming video/audio Adaptive encoding (eg, layered encoding) TCP friendliness References: r J. Padhye, V.Firoiu, D.
Data and Computer Communications Chapter 2 – Protocol Architecture, TCP/IP, and Internet-Based Applications.
Communication Networks NETW 501 Tutorial 2
03/11/2015 Michael Chai; Behrouz Forouzan Staffordshire University School of Computing Streaming 1.
CIS679: RTP and RTCP r Review of Last Lecture r Streaming from Web Server r RTP and RTCP.
McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Chapter 28 Real-Time Traffic over the Internet.
Presented by Rebecca Meinhold But How Does the Internet Work?
© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ITE PC v4.0 Chapter 1 1 Network Services Networking for Home and Small Businesses – Chapter.
CCNA – Network Fundamentals
Multimedia Streaming I. Fatimah Alzahrani. Introduction We can divide audio and video services into three broad categories: streaming stored audio/video,
Data and Computer Communications Eighth Edition by William Stallings Lecture slides by Lawrie Brown Chapter 2 – Protocol Architecture, TCP/IP, and Internet-Based.
1 Networking Chapter Distributed Capabilities Communications architectures –Software that supports a group of networked computers Network operating.
Network Protocols A network protocol defines the structure of messages sent over the network We will only talk about the Internet Network protocols need.
Voice Over Internet Protocol (VoIP) Copyright © 2006 Heathkit Company, Inc. All Rights Reserved Presentation 5 – VoIP and the OSI Model.
Transport Layer COM211 Communications and Networks CDA College Theodoros Christophides
Individual Project 1 Sarah Pritchard. Fran, a customer of your company, would like to visit your company’s website from her home computer… How does your.
Lecture 2 TCP/IP Protocol Suite Reference: TCP/IP Protocol Suite, 4 th Edition (chapter 2) 1.
Jaringan Komputer Dasar OSI Transport Layer Aurelio Rahmadian.
1 Transport Protocols Relates to Lab 5. An overview of the transport protocols of the TCP/IP protocol suite. Also, a short discussion of UDP.
Introduction to Transport Layer. Transport Layer: Motivation A B R1 R2 r Recall that NL is responsible for forwarding a packet from one HOST to another.
Multimedia Over IP: RTP, RTCP, RTSP “Computer Science” Department of Informatics Athens University of Economics and Business Λουκάς Ελευθέριος.
Networking Basics CCNA 1 Chapter 11.
Review of Chapters 12, 13 & 14 Transport Layer Session Layer Presentation Layer.
29.1 Chapter 29 Multimedia Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
TCP/IP Protocol Suite 1 Chapter 25 Upon completion you will be able to: Multimedia Know the characteristics of the 3 types of services Understand the methods.
Fundamentals of Computer Networks ECE 478/578 Lecture #19: Transport Layer Instructor: Loukas Lazos Dept of Electrical and Computer Engineering University.
1 CCNA 2 v3.1 Module Intermediate TCP/IP CCNA 2 Module 10.
1. Layered Architecture of Communication Networks: TCP/IP Model
1 Semester 2 Module 10 Intermediate TCP/IP Yuda college of business James Chen
Fall 2005 By: H. Veisi Computer networks course Olum-fonoon Babol Chapter 6 The Transport Layer.
1 7-Oct-15 OSI transport layer CCNA Exploration Semester 1 Chapter 4.
INTERNET AND PROTOCOLS For more notes and topics visit: eITnotes.com.
Chapter 9: Transport Layer
Chapter 3: Transport Layer Our goals: r understand principles behind transport layer services: m multiplexing/demultipl exing m reliable data transfer.
© 2017 SlidePlayer.com Inc. All rights reserved.