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Learning Outcome

EEC4113 Data Communication & Multimedia System Chapter 11: Application Layer – Networked Multimedia by Muhazam Mustapha and contributions by class members, October 2010. Learning Outcome. At the end of this chapter, the students are expected to have the knowledge about

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Learning Outcome

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  1. EEC4113Data Communication &Multimedia SystemChapter 11: Application Layer – Networked Multimediaby Muhazam Mustapha and contributions by class members,October 2010

  2. Learning Outcome • At the end of this chapter, the students are expected to have the knowledge about • Application Layer Protocols • Formats and Compression schemes of Multimedia Data • Some available multimedia techniques for the internet

  3. Chapter Content • Application Layer Protocols • HTTP, FTP, SMTP, POP(3) • Multimedia Transfer Techniques • Multimedia Transfer in Practice • VoIP, IPTV, Video & Audio Streaming • Compression of Multimedia Data

  4. Application Layer Protocols

  5. Application Layer Application Layer is the top most layer in OSI Network Model It interacts with the end users through via network application software It consists of a large number of protocols that is used by the application to make network / web communication That is why the application is named web application (like browsers, email client, etc)

  6. Application Layer Almost all protocols are made of plain text except for secured ones like HTTPS and FTPS If any binary data needed to be sent through HTTP, it will be encoded with some binary-to-text encoding scheme like Base64

  7. Application Layer Protocols The protocols are also called process-to-process protocols as they actually bind the processes running on the end machines Examples of TCP/IP standard application layer protocols: HTTP, FTP, SMTP, POP(3), IMAP, telnet, DNS, DHCP, RPC, etc Examples of non-TCP/IP standard protocols: Bit Torrent, NFS, NIS, DDS, etc

  8. HTTP Hypertext Transfer Protocol – the protocol that transfers web content Heart of WWW data transfer Almost all other technologies created for the web is designed around HTTP protocol e.g. The concept of sessions in web programming is nothing more than cookies in HTTP protocol Consists of a request that is followed by a response

  9. HTTP The request and response are of the following format sequence: Request/Response line Header Blank line Body HTTP 1.1 major upgrade: Allowing requests to be made to domains that share the IP address

  10. HTTP HTTP connection is non-persistent Means throughout the web download, if there is any extra files required, there will be separate connections made Example: An HTML file has 3 images First HTTP connection is made to download the HTML, then disconnected It will be followed then by 3 more connect-disconnect sessions of HTTP to download the 3 images

  11. HTTP Header The header in the request or response will provide more information about the request or the response This includes: User agent: browser type and operating system Accepted language, encoding, MIME types Content length, last modified

  12. HTTP Request Most widely used HTTP requests: GET: request for a file with extra info in query string POST: request for a file with extra info in STDIN PUT: request to upload file HEAD: request for header sample

  13. HTTP Request GET Request examples: GET /images/logo.png HTTP/1.0User-Agent: Mozilla/5.0 (Linux; X11)Accept-Language: en GET /images/logo.png HTTP/1.1Host: www.muhazam.comUser-Agent: Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 6.0Accept-Language: en GET /script/student.asp?name=ain HTTP/1.0User-Agent: Mozilla/5.0 (Linux; X11)Accept-Language: en Request Header Blank line Specific domain name Query string

  14. HTTP Response Responses are given as status codes Some of the most common ones: 200: OK – request done 401: Unauthorized – password wrong 403: Forbidden – access to protected area 404: Not found – the isn’t in server 500: Internal server error – due to some coding error

  15. HTTP Response GET Response example: HTTP/1.1 200 OK Date: Mon, 23 May 2005 22:38:34 GMT Server: Apache/1.3.3.7 (Unix) (Red-Hat/Linux) Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT Etag: "3f80f-1b6-3e1cb03b" Accept-Ranges: bytes Content-Length: 438 Connection: close Content-Type: text/html; charset=UTF-8 <html> <head> . . . . . Response Header Blank line Content

  16. FTP File Transfer Protocol – the protocol that transfers arbitrary file content FTP connection is persistent Means the user can perform many tasks during a single session Needs a proper FTP client to operate fully WS FTP, CuteFTP, etc Nowadays browsers are already equipped with some FTP capabilities

  17. FTP Consists of a number of commands PWD – current working directory LIST – list the current directory DEL – delete a file MKDIR – make directory CHDIR – change to a directory etc

  18. FTP Specifying URL: ftp://[<user>[:<password>]@]<host>[:<port>]/<url-path> Example: ftp://public.ftp-servers.example.com/mydirectory/myfile.txt ftp://user001:secretpassword@private.ftp-servers.example.com/mydirectory/myfile.txt FTP clients are capable of taking username and password discreetly, but for browsers normally we need to specify it as plain text

  19. SMTP Simple Mail Transfer Protocol – the protocol that transfers email It transfers both outgoing and incoming emails – despite some misconceptions Consists of some commands to talk between SMTP servers: HELO, MAIL FROM, RCPT TO, etc

  20. SMTP Example: S: 220 smtp.example.com ESMTP Postfix C: HELO relay.example.org S: 250 Hello relay.example.org, I am glad to meet you C: MAIL FROM:<bob@example.org> S: 250 Ok C: RCPT TO:<alice@example.com> S: 250 Ok C: RCPT TO:<theboss@example.com> S: 250 Ok C: DATA S: 354 End data with <CR><LF>.<CR><LF> C: From: "Bob Example" <bob@example.org> C: To: "Alice Example" <alice@example.com> C: Cc: theboss@example.com C: Date: Tue, 15 Jan 2008 16:02:43 -0500 C: Subject: Test message C: C: Hello Alice. C: This is a test message with 5 header fields and 4 lines in the message body. C: Your friend, C: Bob C: . S: 250 Ok: queued as 12345 C: QUIT S: 221 Bye {The server closes the connection}

  21. POP Post Office Protocol – the protocol that transfers email to email client Email clients like, MS Outlook, Netscape Mail, Thunderbird, etc use this protocol to download emails from server to local machine Some of commands: LIST, STAT, RETR, DELE, etc

  22. Multimedia TransferTechniques

  23. Multimedia Transfer Techniques The main problem in multimedia transfer over the internet is the speed and efficiency Speed required to reduce delay and buffering Efficiency required to reduce packet loss and jittering A few techniques employed Web server Streaming server RTSP

  24. Web Server Technique Web browser makes the request After the server responds the browser delegates the play process to a media player The media player will then communicate directly to the web server to play the content

  25. Web Server Technique Browser Request Web Server Delegation Streaming Media Player

  26. Web Server Technique Advantage: Easiest to implement and least costly Disadvantage: Still rely on normally slow web servers

  27. Streaming Server Technique Web browser makes the request After the web server responds with the information about the streaming server, the browser delegates the play process to a media player The media player will then communicate directly to the streaming server to play the content

  28. Streaming Server Technique Web Server Browser Request Delegation Streaming Server Media Player Streaming

  29. Streaming Server Technique Advantage: Speedier and more reliable, even though still as HTTP transfer Disadvantage: Requires an extra and more expensive server

  30. RTSP Technique Real Time Streaming Protocol Just like the streaming server, but now it is using a dedicated protocol RTSP is a protocol the has some capabilities of a media player, like play, pause, stop, etc

  31. Reducing Delay There is an interleaving technique used to reduce delay in video streaming The in-sequence packets are re-arranged into interleaving groups, then transferred in that sequence At receiver, the interleaving groups are re-arranged back to the original sequence If any group lost, it only causes small distributed jittering instead of a long wait for that lost group

  32. Reducing Delay Interleave Streaming LOST Re-arrange Small less annoying but distributed jitters

  33. Multimedia Transfer in Practice

  34. Radio over Internet Protocol(RoIP) RoIP takes Internet Protocol (IP) input that convert communications stream to IP RoIP is not just about linking radios Enables interoperable communications between new and legacy public safety radio systems, commercial wireless and wired phones Allows a dispatcher to dynamically drag and drop parties and channels to form and dissolve talk groups remotely RoIP Slides contributed by: ABDUL MUIZ BIN SHAHIDAN,MUHAMMAD ATIQ B CHE MOHD ROSLI

  35. Radio over Internet Protocol(RoIP) Session Initiation Protocol - SIP System Diagram RoIP is not just about linking radios

  36. Radio over Internet Protocol(RoIP) HTML code for hot FM radios: <embed name="mediaplayer1" pluginspage="http://www.microsoft.com/Windows/MediaPlayer/" src="http://rs9.radiostreamer.com:10000" type="application/x-mplayer2" controller="true" loop="0" transparentstart="1" autostart="true" enablecontextmenu="false" showstatusbar="1" width="320" height="80"></embed>

  37. Radio over Internet Protocol(RoIP) List of stations:

  38. Radio over Internet Protocol(RoIP) Malaysia Listing: • Radio MMU (Multimedia University) • iRadio OUM (Open University Malaysia) • IIUM FM (International Islamic University Malaysia) • UFM (Universiti Teknologi Malaysia) • Putra FM (Universiti Putra Malaysia) • UMS KKFM (Universiti Malaysia Sabah) • Radio Malaysia Johor • Sinar FM • Hot FM

  39. Radio over Internet Protocol(RoIP) Users: • In the US military. • Increasingly in business. • Emergency agencies across the US. • Network that joins 42 federal, state, tribal, transit, and utility agencies without buying a single new radio.

  40. Voice over IP (VoIP) • Voice over Internet Protocol (VoIP)-technology that allows you to make voice calls using a broadband Internet connection instead of a regular (or analog) phone line. • Some VoIP services may only allow you to call other people using the same service, but others may allow you to call anyone who has a telephone number - including local, long distance, mobile, and international numbers. • Some VoIP services only work over your computer or a special VoIP phone, other services allow you to use a traditional phone connected to a VoIP adapter. VoIP Slides contributed by: NURUL MARLIANA BT MUSA,SUHANA BINTI MOHD TAHIR

  41. Voice over IP (VoIP) • Providers: • Skype (peer to peer program – both side must have Skype installed) • Zamir Telecom Limited • Google Voice

  42. Voice over IP (VoIP) • Protocols: • MEGACO (H.248) • MGCP • MIME • RVP ( Remote Voice protocol ) • SDP • SIP • SGCP • SKINNY

  43. Voice over IP (VoIP) • Advantages: • Operational cost • Routing phone calls over existing data networks to avoid the need for separate voice and data networks • Flexibility • The ability to transmit more than one telephone call over a single broadband connection.

  44. Voice over IP (VoIP) • Advantages (continued): • Location independence • Only a sufficiently fast and stable Internet connection is needed to get a connection from anywhere to a VoIP provider

  45. Voice over IP (VoIP) • The operation: • VoIP services convert your voice into a digital signal that travels over the Internet. • If you are calling a regular phone number, the signal is converted to a regular telephone signal before it reaches the destination. • VoIP can allow you to make a call directly from a computer, a special VoIP phone, or a traditional phone connected to a special adapter. • Wireless "hot spots" in locations such as airports, parks, and cafes allow you to connect to the Internet and may enable you to use VoIP service wirelessly.

  46. Voice over IP (VoIP) • Example of residential network including VoIP:

  47. IPTV • IPTV – Internet Protocol Television • It is digital television delivered on TV (or PC) through high speed internet connection (broadband) • Channels are encoded to IP format and delivered to TV through a Set Top Box (STB) IPTV Slides contributed by: WAN AHMAD GHAZLY BIN MD GHAUZ, MUHAMMAD FARHAN BIN SHAHROM

  48. IPTV • How IPTV works • IPTV converts television signal into small packets of computer data • The packets is the same like any other form of online traffic such as webpages or emails. • IPTV was first used in 1994 • ABC’s World News Now was the first television show to be broadcast over the internet, using the CU-SeeMe video conferencing software

  49. IPTV • Three main components: • TV and content head end • where the TV channels are received and encoded • Delivery network • Consists of broadband and landline network provided by telecom operator

  50. IPTV • Three main components (cont): • Set Top Box (STB) • Required at customer location • STB reassembles data packets into TV programs • Connected between internet modem and the customer’s TV

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