1. Implementation of IP Mesh Network using ULE Protocol over DVB-S Links Wan Tat Chee Network Research Group School Of Computer Sciences Universiti Sains Malaysia Universiti Sains Malaysia 11800 USM, Penang, Malaysia. 11800 USM, Penang, Malaysia.tcwan@cs.usm.my

2. April 12 (c) 2006 TC Wan 2 Introduction Satellite-based Internet connectivity Satellite-based Internet connectivity Provides access to rural / underserved communitiesProvides access to rural / underserved communities Able to operate in areas without existing telecommunications infrastructureAble to operate in areas without existing telecommunications infrastructure Quick setup for disaster relief and recovery efforts (e.g., earthquakes, tsunami, etc.)Quick setup for disaster relief and recovery efforts (e.g., earthquakes, tsunami, etc.)

3. April 12 (c) 2006 TC Wan 3 Issues Existing satellite-link based Internet access equipment is expensive Existing satellite-link based Internet access equipment is expensive Existing technology has inefficient spectrum usage Existing technology has inefficient spectrum usage Existing hub-based network averages two hops among nodes (high latency) Existing hub-based network averages two hops among nodes (high latency) DVB-S is a cost-effective method used in satellite TV broadcast (e.g., Astro) DVB-S is a cost-effective method used in satellite TV broadcast (e.g., Astro) However, It is unidirectional in nature However, It is unidirectional in nature Unidirectional Link Mesh Network implements bidirectional network access using DVB-S technology Unidirectional Link Mesh Network implements bidirectional network access using DVB-S technology

4. April 12 (c) 2006 TC Wan 4 Existing Point-to-Point Satellite Links

5. April 12 (c) 2006 TC Wan 5 UniDirectional Link Mesh Networking Approach

6. April 12 (c) 2006 TC Wan 6 Hardware Requirements An ASI (Asynchronous Serial Interface) card to transmit MPEG2-TS packet (Linear Systems DVB Master FD). An ASI (Asynchronous Serial Interface) card to transmit MPEG2-TS packet (Linear Systems DVB Master FD). (N – 1) DVB receiver cards where N is the number of nodes in the UDL mesh network. List of supported DVB receiver cards: http://www.linuxtv.org/wiki/index.php/DV B-S_cards. (N – 1) DVB receiver cards where N is the number of nodes in the UDL mesh network. List of supported DVB receiver cards: http://www.linuxtv.org/wiki/index.php/DV B-S_cards. http://www.linuxtv.org/wiki/index.php/DV B-S_cards http://www.linuxtv.org/wiki/index.php/DV B-S_cards A DVB-S modulator (Newtec NTC2177). A DVB-S modulator (Newtec NTC2177).

7. April 12 (c) 2006 TC Wan 7 Node Configuration (for 3-Node WAN network)

8. April 12 (c) 2006 TC Wan 8 Configuration for 3 Nodes Test Bed

9. April 12 (c) 2006 TC Wan 9 Bidirectional DVB-S ULE Architecture

10. April 12 (c) 2006 TC Wan 10 Experiment and Result

11. April 12 (c) 2006 TC Wan 11 Experiment and Result (cont)

12. April 12 (c) 2006 TC Wan 12 Experiment and Result (cont)

13. April 12 (c) 2006 TC Wan 13 Experiment and Result (cont)

14. April 12 (c) 2006 TC Wan 14 Experiment and Result (cont)

15. April 12 (c) 2006 TC Wan 15 Experiment and Result (cont)

16. April 12 (c) 2006 TC Wan 16 Analysis of Result All UDL nodes are allocated 8Mbps of bandwidth for the tests. All UDL nodes are allocated 8Mbps of bandwidth for the tests. The throughputs of TCP and UDP traffic are about 1/2 and 1/8 of allocated bandwidth respectively. The throughputs of TCP and UDP traffic are about 1/2 and 1/8 of allocated bandwidth respectively. ASI card buffer queue affects the latency of packet sending. Less buffer queue decreases latency, but increases CPU usage due to more interrupts and context switches. ASI card buffer queue affects the latency of packet sending. Less buffer queue decreases latency, but increases CPU usage due to more interrupts and context switches.

17. April 12 (c) 2006 TC Wan 17 Analysis of Result (cont) Faulty ASI card firmware disables automatic null packets insertion. Thus bidirectional module need to insert null packets manually. Faulty ASI card firmware disables automatic null packets insertion. Thus bidirectional module need to insert null packets manually. Consequently, real data packets have to compete with null packets for resources. Thus the performance is less than ideal. Consequently, real data packets have to compete with null packets for resources. Thus the performance is less than ideal. Due to high latency, bigger TCP window size results in better throughput. Due to high latency, bigger TCP window size results in better throughput.

18. April 12 (c) 2006 TC Wan 18 Future Work Reimplemention of bidirectional module as a kernel space module to cut the cost of context switches and improve performance. Reimplemention of bidirectional module as a kernel space module to cut the cost of context switches and improve performance. Try to obtain an ASI card that properly insert null packets automatically. Try to obtain an ASI card that properly insert null packets automatically.

19. April 12 (c) 2006 TC Wan 19 Links & Contacts IP over DVB-S via ULE research page: http://nrg.cs.usm.my/satellite_ule.htm IP over DVB-S via ULE research page: http://nrg.cs.usm.my/satellite_ule.htm http://nrg.cs.usm.my/satellite_ule.htm Bidirectional module research page: http://nrg.cs.usm.my/ule.htm Bidirectional module research page: http://nrg.cs.usm.my/ule.htm http://nrg.cs.usm.my/ule.htm Coordinator: tcwan@cs.usm.my Coordinator: tcwan@cs.usm.mytcwan@cs.usm.my Developers: cwtan@nrg.cs.usm.my, chteh@nrg.cs.usm.my, wcang@nrg.cs.usm.my. Developers: cwtan@nrg.cs.usm.my, chteh@nrg.cs.usm.my, wcang@nrg.cs.usm.my.cwtan@nrg.cs.usm.my chteh@nrg.cs.usm.my wcang@nrg.cs.usm.mycwtan@nrg.cs.usm.my chteh@nrg.cs.usm.my wcang@nrg.cs.usm.my