Table of Contents
Abstract..............................................................................................................................1
Acknowledgements ...........................................................................................................2
Contributions ....................................................................................................................3
Table of Contents..............................................................................................................4
List of Figures....................................................................................................................6
List of Tables.....................................................................................................................7
Acronyms...........................................................................................................................8
1. Introduction...................................................................................................................9
1.1 What is VoIP?........................................................................................................... 9
1.2 Purpose.................................................................................................................... 10
1.2.1 Protocol design................................................................................................ 10
1.2.2 Software design................................................................................................ 10
1.2.3 Hardware design.............................................................................................. 10
1.3 Goals .......................................................................................................................11
1.4 Unique aspects of our system.................................................................................. 11
1.5 Real-world Impact ..................................................................................................12
2. Research and Network Testing..................................................................................13
2.1 Existing Voice over IP Systems.............................................................................. 13
2.1.1 Speak Freely .................................................................................................... 13
2.1.2 TeamSpeak.......................................................................................................13
2.1.3 Skype ................................................................................................................ 14
2.1.4 HawkVoiceDI...................................................................................................14
2.1.5 ITU Standards.................................................................................................. 14
2.1.6 Strengths of Existing Systems ..........................................................................14
2.1.7 Weaknesses ...................................................................................................... 14
2.2 Audio Codec Research............................................................................................15
2.2.1 µ -Law .............................................................................................................. 15
2.2.2 Adaptive Differential Pulse Code Modulation (ADPCM) ............................... 15
2.2.3 Global System for Mobile Communication (GSM) 6.10..................................15
2.2.4 LPC.................................................................................................................. 15
2.2.5 Codec Comparison .......................................................................................... 16
2.3 Network packet latency........................................................................................... 16
2.3.1 Internet-wide latency tests ............................................................................... 17
2.3.2 Wireless Tests .................................................................................................. 22
2.4 Packet Loss and Bit Error Rate ............................................................................... 24
2.4.1 Internet-wide Tests........................................................................................... 25
2.4.2 Packet Loss, Bit Errors and Wireless Networks .............................................. 28
2.4.3 Checksum-less UDP Packets ........................................................................... 29
2.5 Network Jitter.......................................................................................................... 29
3. Overview of Protocol Design......................................................................................32
3.1.1 Issues affecting Protocol Design ..................................................................... 32
3.1.2 Incorporation of Research into Protocol Design............................................. 33
4
henrychan1232013-09-09资料不错，可惜是英文版，研究中
wokeyi2052015-10-12正在研究学习。。。。
CHENFENGLI19852013-06-23不错，入门了解的资料
