Homeplug Technology As Backbone of the Future Home-Network
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Acknowledgement We would like to thank Dr. Luc Vandeurzen for making this thesis possible and intro- ducing the subject. He supported us and gave useful insight into the studied matter. His indispensable personal guidance has proved to be an asset for this thesis. Moreover, we would like to thank our families and friends who supported us throughout the making of this thesis. They gave moral support and gave us the possibility of using their infrastructure for our testing purposes. We wish to express our warmest thanks to Tom and Jelle who were there during the whole process. The pleasant and sometimes hilarious interactions lead to some creative solutions. We are also grateful to the makers of the open source programs we used to test the Home- Plug devices and typeset this text. In particular we like to mention LATEX and The GIMP. Without these tools no such result would be possible. The financial support of the GroupT engineering school is gratefully acknowledged. It gave us the possibility to purchase and test several HomePlug devices. i Contents Summary x 1 Introduction 1 2 HomePlug technology in a nutshell 5 2.1 The technology . 5 2.1.1 Location on the OSI network stack . 5 2.1.2 Problems with PLC . 6 2.1.3 Solutions . 8 2.1.4 Security and privacy . 11 2.2 Media Access Control (MAC) . 12 2.2.1 Collision avoidance . 13 2.2.2 Priorities and QoS . 14 2.2.3 HomePlug MAC frame structure . 16 2.3 Other HomePlug standards . 17 2.3.1 HomePlug 1.0 Turbo . 17 2.3.2 HomePlug AV . 18 3 HomePlug getting physical 20 3.1 The electricity grid . 20 ii Contents 3.1.1 Power Plant . 20 3.1.2 Substation . 21 3.1.3 Low-voltage lines . 21 3.1.4 Service Panel . 21 3.2 Classification and quantification of noise . 21 3.2.1 Iperf . 22 3.2.2 Test description . 23 3.2.3 Test setup . 23 3.2.4 Conclusion . 24 3.3 The phase issue . 25 3.4 Neighbours: possible intruders? . 26 3.5 Isolation of HomePlug signals . 27 3.5.1 Noise filtering . 27 3.5.2 HomePlug filtering . 28 3.6 HomePlug in a company . 29 4 HomePlug in home-networks 31 4.1 Varying throughput at each layer . 31 4.2 Measuring QoS parameters in a home situation . 32 4.2.1 Description . 33 4.2.2 Tools used . 33 4.2.3 Results . 35 4.2.4 Conclusion . 35 4.3 Multicast streaming . 44 iii Contents 4.3.1 Multicasting with Devolo adapters . 44 4.3.2 Multicasting with Topcom adapters . 47 4.3.3 Multicasting with Devolo AVdesk adapters . 48 4.3.4 Conclusion . 49 4.4 Broadcast . 50 4.5 Multiple concurrent streams . 51 4.5.1 Description . 52 4.5.2 Results . 53 4.5.3 Conclusion . 56 4.5.4 HomePlug AV and 1.0 concurrent streams . 57 4.6 Compatibility between HomePlug Turbo devices . 58 4.6.1 Conclusion . 59 4.7 Comparing throughput of HomePlug 1.0 turbo and AV devices . 59 5 Home-network applications 61 5.1 UPnP . 61 5.2 VoIP....................................... 63 5.2.1 Introduction . 63 5.2.2 VoIP within the home . 65 5.2.3 VoIP over the Internet . 66 5.3 Application anthology . 72 5.4 User Scenarios . 75 5.4.1 Use case 1 . 75 5.4.2 Use case 2 . 79 iv Contents 5.4.3 Conclusion . 80 6 Taking HomePlug to the next level 82 6.1 Extending the range of a HomePlug network . 82 6.1.1 Linux IP Repeater . 82 6.1.2 Extending range with two HomePlug adapters . 84 6.1.3 Placement of the range extender . 85 6.1.4 Comparing both range extenders . 86 6.1.5 Comparing performance . 86 6.1.6 A case-study . 88 6.1.7 A monitor for the Linux-based range extender . 89 6.2 A HomePlug switch . 90 6.2.1 An ethernet switch . 91 6.2.2 A HomePlug switch . 92 Conclusion 95 Bibliography 97 v List of Figures 1.1 HomePlug logo . 3 2.1 Long frame format . 12 2.2 Short frame format . 13 2.3 Priority resolution slots and contention period . 14 2.4 VLAN tag structure . 15 3.1 Noise impact on throughput . 25 3.2 Example of a Schaffner netfilter . 28 4.1 Coverage plot . 39 4.2 Measured upstream throughputs in a typical home . 40 4.3 Measured downstream throughputs in a typical home . 41 4.4 Throughput legend . 42 4.5 Correlation between up- and downstream throughput . 42 4.6 Correlation between throughput and round-trip-time . 43 4.7 Multicast streaming – setup . 44 4.8 Four-node test – setup . 52 4.9 Throughput with four nodes on the same logical network . 54 4.10 Throughput with four nodes on a different logical network . 55 vi List of figures 5.1 UPnP with Topcom adapters – setup . 62 5.2 VisualRoute – different hops and average RTT to www.cnnic.cn measured with HomePlug . 67 5.3 VisualRoute – different hops and average RTT to www.cnnic.cn measured with Ethernet . 68 5.4 Ethereal – Jitter analysis of VoIP call to echo test server with Ethernet . 69 5.5 Ethereal – Jitter analysis of VoIP call to echo test server with HomePlug . 69 5.6 Ethereal – Capture of a VoIP call between two VoIPCheap softphone users 71 5.7 Ethereal – Capture of a VoIP call between Express Talk and XLite . 71 5.8 Legend for user scenarios . 75 5.9 Home environment – downstairs . 76 5.10 Home environment – upstairs . 76 6.1 Linux range extender . 83 6.2 Topology monitor . 91 6.3 Ethernet switch . 92 6.4 HomePlug switch . 93 vii List of Tables 3.1 Effect of various noise sources on TCP throughput . 24 3.2 Powerstrip as HomePlug filter . 29 3.3 HomePlug measurements in GroepT . 30 4.1 Differences between PHY and MAC throughput . 32 4.2 Results from the QoS tests . 36 4.3 Summary of the measured throughputs . 37 4.4 Summary of the measured round-trip-times . 37 4.5 Summary of the measured jitter . 37 4.6 Multicasting a HDTV fragment with a Devolo adapter, three listeners . 45 4.7 Multicasting a HDTV fragment with a Devolo adapter, two listeners . 45 4.8 Multicasting a HDTV fragment with a Devolo adapter, one listener . 46 4.9 Multicasting a DivX fragment with a Devolo adapter, three listeners . 46 4.10 Multicasting a DivX.