A Transport Protocol for Multimedia Wireless Sensor Networks Duarte - PDF document

technology from seed A Transport Protocol for Multimedia Wireless Sensor Networks Duarte Meneses, António Grilo, Paulo Rogério Pereira Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 1 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011 Introduction – technology from seed Wireless Sensor Networks Typically a high number of autonomous nodes with sensors and RF • communications. Cooperate in a common task retrieving sensor data such as: • temperature, humidity, light, image, video, etc. • Data is normally forwarded wirelessly to a sink node • • Used in surveillance and security, industrial process control, military Used in surveillance and security, industrial process control, military applications, domotics, monitoring, etc. Other networks Mobile devices Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 2 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011

Motivation technology from seed Protection of critical infrastructures, namely electrical energy • distribution infrastructures Multimedia data from cameras is routed multi-hop to the sink • • WSN advantages: ease of installation, configuration, flexibility, low power TCP: end-to-end, loss assumed as congestion, RTT delays TCP: end-to-end, loss assumed as congestion, RTT delays • • New transport protocol tailored for WSN: DTSN. • Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 3 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011 Objectives technology from seed Transport protocol for WSN with the following characteristics: • Adapted to embedded systems • Battery operated • Runs on Linux • Support reliability • Support reliability • Optimize multimedia data transfers, particularly real-time video • Support several simultaneous applications • Support security mechanisms • Ease of use through an API Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 4 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011

Transport Protocols for WSN technology from seed Purpose: Reliability Guarantee and/or Congestion Control Several different characteristics and mechanisms: • upstream/downstream communication • Loss feedback through: ACK, NACK, iACK • Lost segment detection: sequence number continuity or timers for each segment timers for each segment • end-to-end or hop-by-hop ������������������������ recovery • Two types of target applications: sending ������������������ ��������������������� events or sending large data volumes ������������� ���� ���������� ��������������������� ���������!�� Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 5 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011 DTSN technology from seed Node 2 Node 3 Node 4 Node 1 • Sessions identified by DATA 0 a Session Number, DATA 1 DATA 2 DATA 3 DATA 2 Application ID, source DATA 4 DATA 3 DATA 5 DATA 4 DATA 3 DATA 6 and destination DATA 5 DATA 7 + EAR DATA 4 DATA 6 DATA 5 DATA 8 DATA 7 + EAR DATA 6 DATA 9 addresses DATA 7 + EAR DATA 10 DATA 9 DATA 11 NACK 0, <0,1,2,3> DATA 10 DATA 12 Feedback when DATA 11 • NACK 0, <0,1,2> DATA 3 DATA 13 EAR DATA 12 DATA 10 DATA 14 Timeout DATA 13 DATA 11 requested by the DATA 15 + EAR DATA 14 DATA 12 DATA 13 DATA 14 source through an source through an EAR 15 EAR 15 Explicit EAR 15 Acknowledgement EAR 15 NACK 0, <0,1,2,8,9,10,12,15> Request (EAR) NACK 0, <0,1,2,8,9,15> DATA 10 DATA 12 NACK 0, <0,1,8,15> DATA 2 DATA 9 DATA 0 DATA 2 Losses detected • Flow DATA 1 DATA 9 DATA 0 Control DATA 8 DATA 1 Timeout DATA 0 through the sequence DATA 15 DATA 8 DATA 1 EAR 15 DATA 15 EAR 15 number continuity DATA 15 EAR 15 NACK 7, <8,10,12> Selective Repeat • NACK 7, <8,12> DATA 10 retransmission hop- NACK 7, <> DATA 8 DATA 12 by-hop : intermediate DATA 16 DATA 8 DATA 17 DATA 12 DATA 16 DATA 18 DATA 17 nodes cache packets DATA 16 DATA 19 DATA 18 DATA 17 DATA 20 DATA 19 DATA 18 DATA 21 DATA 19 t Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 6 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011

Probabilistic Model technology from seed Expected number of links crossed: Success probability: Expected number of transmissions per packet: Generalized formulas for different losses in each link: Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 7 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011 Probabilistic model 2 technology from seed Expected number of transmissions when packets are cached with 50% probability: "$ ������������� "" ����������������������� "# "# ' & % #(#" #(#$ #(#) #(#* #(#+ #(#, #(#% #(#& #(#' #(" ������������������������������������ ���-����.������.��$+/����������-����������0 ���-����������.��$+/����������-����������0 ���-����1��-�+#/������������ ���-����������. ���-����.������. Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 8 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011

Development Platform technology from seed • The protocol is generic: can work over several wireless technologies and hardware • The Silex SX-560 was used. • Supports Wi-Fi 802.11a/b/g. • 200 MHz 32-bit ARM processor • 16 MB RAM • 16 MB RAM • 8MB Flash • Runs Linux • 792 mW average power • 49.6 x 34.3 x 9.65 mm • Developer’s daughtercard with USB, serial, SPI, GPIO, Ethernet, power Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 9 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011 General Architecture technology from seed DTSN implemented as a single daemon process for all node • types: source, receiver and intermediate nodes. • Clients use the protocol through a library that connects to the daemon through UNIX sockets Several configuration parameters may be adjusted in a • configuration file Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 10 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011

API technology from seed • Dynamic library • Interface similar to the Unix sockets interface • Simple operation, with most work done centrally in the daemon • The application can receive asynchronous events • Threads, blocking and exclusive access implemented • Threads, blocking and exclusive access implemented through the pthread library Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 11 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011 DTSN Sessions 1 technology from seed • Header present in all packets: Bit Flag 0 ACK 1 NACK 2 EAR 3 DATA 4 RESEND 5 ENDSESSION 6 (not used 7 7 (not used) (not used) • Soft unidirectional sessions, identified by <App ID, Session No, Src Addr, Dest Addr>. No connection establishment: the applications just creates the session and start sending packets • A complete session description is maintained with buffers, timers, ID, mode, etc. • The session can be kept internally after being closed by the application Instituto de Engenharia de Sistemas e Computadores Investigação e Desenvolvimento em Lisboa 12 NGI'2011: A Transport Protocol for Multimedia Wireless Sensor Networks 27-06-2011