An Analysis of Instant Messaging and E- mail Access Protocol Behavior in Wireless Environment IIP Mixture Project Simone Leggio Tuomas Kulve Oriana Riva Jarno Saarto Markku Kojo March 26, 2004 University of Helsinki - Department of Computer Science i TABLE OF CONTENTS 1 Introduction ..................................................................................................................................... 1 PART I: BACKGROUND AND PROTOCOL ANALYSIS ............................................................. 1 2 Instant Messaging............................................................................................................................ 1 3 ICQ.................................................................................................................................................. 3 3.1 Overview ................................................................................................................................. 3 3.2 Protocol Operation .................................................................................................................. 4 3.2.1 Client to Server................................................................................................................4 3.2.2 Client to Client ................................................................................................................5 3.2.3 Normal Operation............................................................................................................ 5 3.2.4 Abnormal Operation........................................................................................................ 5 3.3 Discussion ............................................................................................................................... 6 3.3.1 Advantages of ICQ.......................................................................................................... 6 3.3.2 Disadvantages of ICQ ..................................................................................................... 6 4 AOL/Oscar ...................................................................................................................................... 7 4.1 Overview ................................................................................................................................. 7 4.2 Protocol Operation .................................................................................................................. 7 5 MSN Messenger.............................................................................................................................. 9 5.1 Overview ................................................................................................................................. 9 5.2 Protocol Operation ................................................................................................................ 10 5.3 Discussion ............................................................................................................................. 11 6 Yahoo ............................................................................................................................................ 12 7 IRC ................................................................................................................................................ 13 7.1 Overview ............................................................................................................................... 13 7.2 Protocol Operation ................................................................................................................ 13 7.3 Discussion ............................................................................................................................. 15 8 SILC .............................................................................................................................................. 15 8.1 Overview ............................................................................................................................... 15 8.2 Protocol Operation ................................................................................................................ 16 8.3 Discussion ............................................................................................................................. 17 9 Jabber ............................................................................................................................................ 17 9.1 Overview ............................................................................................................................... 17 9.2 Protocol Operation ................................................................................................................ 18 9.3 Discussion ............................................................................................................................. 20 10 Other Protocols.......................................................................................................................... 21 ii 10.1 TOC....................................................................................................................................... 21 10.2 Napster .................................................................................................................................. 22 10.3 Zephyr ................................................................................................................................... 24 11 The Internet Message Access Protocol...................................................................................... 25 11.1 The mail access paradigms.................................................................................................... 26 11.2 Description of IMAP features ............................................................................................... 27 11.3 Discussion on IMAP ............................................................................................................. 28 11.4 The IMAP state machine....................................................................................................... 29 12 Detailed analysis of the selected protocols................................................................................ 31 12.1 Detailed analysis of IRC........................................................................................................31 12.2 Detailed analysis of SILC...................................................................................................... 33 12.3 Detailed analysis of Jabber.................................................................................................... 34 12.3.1 Discussion on the deployment of XMPP in a wireless link .......................................... 40 12.3.2 Analysis of session establishment sequence.................................................................. 42 12.3.3 Behaviour in disconnected environments and in case of packets losses ....................... 46 12.4 Detailed analysis of the Internet Message Access Protocol .................................................. 46 12.4.1 Discussion on the deployment of IMAP in a wireless link ........................................... 50 12.4.2 Behaviour in disconnected environments and in case of packet losses......................... 52 13 Protocols Comparison ............................................................................................................... 52 PART II: JABBER TEST REPORT................................................................................................. 55 14 Test environment....................................................................................................................... 55 14.1 Best-case scenario ................................................................................................................. 57 15 Test case 1: Delay in the downlink direction ............................................................................ 58 16 Test case 2: Delay in the uplink direction ................................................................................. 65 17 Test case 3: Reconnection of a client ........................................................................................ 69 18 Test case 4: Delay in reconnection. Downlink direction........................................................... 70 19 Test case 5: Delay in reconnection. Uplink direction................................................................ 74 19.1 Connection of the fixed client after message delivery to the server...................................... 75 19.2 Reconnection of the fixed client during message delivery to the server ............................... 77 20 Other test cases.......................................................................................................................... 80 20.1 Tests with the older server version........................................................................................ 80 20.2 Preliminary tests with the Jabberd2 server............................................................................ 82 20.3 Tests with two source clients................................................................................................. 83 21 Discussion on Jabber experiments............................................................................................. 84 21.1 The pacing of message sending............................................................................................