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Report on Sensor Networks and Degrading DOS. By Ganesh Godavari Tuesday, January 27, 2004. Sensor Networks. Basic Subsystems of Motes Power: sensor motes don’t have the ability to monitor an environment for unlimited time as they only have limited energy.
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Report onSensor Networks and Degrading DOS By Ganesh Godavari Tuesday, January 27, 2004
Sensor Networks • Basic Subsystems of Motes • Power: sensor motes don’t have the ability to monitor an environment for unlimited time as they only have limited energy. • Computation: Sensor motes are required to process sensor data and communicate with others. Their computation power of the motes is very less compared to any desktop. • Sensors: sensor motes have the basic sensors for sensing the environment like temperature, pressure, humidity, sound, acceleration. • Communication: communication must be possible between the motes separated by a range of few meters.
Ad-hoc Networking classification • Adhoc Networking Classification • Static Value Added: this is the simplistic network where a user terminal specifies the network structure: perhaps even assigning a X, Y, Z spatial coordinates to each mote. Routing in this case takes a form of calculating which node to forward a packet to based on a spatial XYZ address • Query Processing: A query processing network facilitates the computation of aggregate functions (e.g. min, max, mean) and creates a one to many spanning tree topology to facilitate this. • Collaborative processing: A network for collaborative processing requires Network Embedded System Technology services to provide time synchronization, localization and service coordination.
Focus of our project • Goals of First Responder Sensor Network (FRSN) • Information Gathering : get information about temperature from each mote and display information • Tracking : ability to monitor movement of motes
Equipment Used • Stargate: XScale Network Interface and Single Board Computer used as gateway. • Wireless Measurement System • Mica2 • Micadot Stargate MICA2DOT MICA2
Contd.. • Programming Interfaces Available • MIB500 – Parallel Port Programming Interface Board • MIB510 – Serial Port Programming Interface Board
Stargate • Operating System : Linux 2.4.19-rmk7-pxa1 • Network Interfaces : wired Ethernet 10/100 Base-T port
Information Gathering • Application must have • Ability to form a network dynamically (ADHOC) • provide information to the Gateway • Role of Gateway • Must gather information • Send information to a set of Wired/wireless clients
Existing applications/libraries • TinyOS-1.1 provides adhoc routing libraries which use • Shortest Path First algorithm • Active two-way link estimation • Example Surge Application • Limitations : higher message frequency can lead to data congestion
Contd.. • Application • SerialForwarder : read data from the serial port • Listen: connects to the SerialForwarder and displays the information • Surge: displays information in GUI format for better visualization
Applications Stargate • Stargate came with • “Hello World” Application • Networking Application • File System Application • Webcam video-capture application • Mote Application • Missing is the forwarder application.
Current work • Working on writing a forwarder application that forwards data received on the serial port. • Did preliminary analysis on the working of serialforwarder. • Failed to port wonka jvm onto stargate. • http://wonka.acunia.com/ doesn’t seem to be right.
Message structure TOS_Msg typedef struct TOS_Msg { uint16_t addr; uint8_t type; uint8_t group; uint8_t length; int8_t data[TOSH_DATA_LENGTH]; uint16_t crc; } TOS_Msg;
Message Structure TOS_MHopMsg typedef struct MultihopMsg { uint16_t sourceaddr; uint16_t originaddr; int16_t seqno; uint8_t hopcount; uint8_t data[(TOSH_DATA_LENGTH - 7)]; } TOS_MHopMsg
Captured data analysis Captured a multihop message of surge 7E 42 7D 5E 0 11 33 C 0 0 0 0 0 0 0 0 EC 0 7D 5E 0 13 6C 7E 7E indicates the beginning of the frame 42 indicates A data packet that does not require a subsequent ACK packet (tinyos documentation) 7D indicates that the preceding byte needs to escaped i.e preceding byte needs to be xor with 0x20 and is not counted 5E 5E xor 20 = 7E // beginning of the tos packet 0 00 the second part of the tinyos message 11 decimal value 17 indicates its a multi hop packet 33 group id c decimal value 12 is the length of the data so the data is
Contd.. 0 0 source address of the multihop message 0 0 original address of the multihop message 0 0 sequence number 0 hop count 0 EC 0 7D 5E data part of the multihop message 0 13 is the CRC of the tinyos message 6C 7E is the part of the frame
Work for the next week • Complete the forwarding program on the stargate