Simulation in Large Scale Sensor Networks

Transcription

1 Simulation in Large Scale Sensor Networks Barney Maccabe University of New Mexico The University of New Mexico Santa Fe, New Mexico 17 Oct 2006

2 I have finally reached the point in my career where I can live on the results of my graduate students Collaborators UNM sensor network systems software James Horey, PhD Student Jean-Charles Tournier, Postdoc Eric Nelson, MS student LANL sensor network system simulation Sean Brennan, MTS (& UNM PhD student) Angela Mielke, project lead SNL multi-scale system simulation for MPPs Rolf Riesen Keith Underwood

3 Multiscale Simulation for Systems Software Use simulation to study systems software approaches fault tolerance: simulate a large system and inject faults impact and viability of systems software at scale: how does it work More emulation than simulation, for now Traditional use of simulation in sensor networks application testing ad-hoc routing protocols

4 Basic simulation tools ns-2 network simulation packet level simulation, great for studying changes to TCP/IP plug-ins for wireless protocols ad-hoc wireless routing protocols Simple Scalar processor simulation instruction set simulation great for studying branch prediction and out-oforder execution Mambo

5 More Tiny OS simulation (TOSSIM) develop applications, small number of nodes EmStar sensor networks involving Linux-based platforms SWANS like ns2, better scalability, Java apps and a whole host of others...

6 Sensor Network Environment s sensing Stargate Stargate Stargate 1,000 s limited compute, communication and, power Stargates compute 100 s more compute, memory, power, and communication Computation in the network

7 Software Stack Composability Application Spreadsheet Programming Active Management Kensho Kaizen Micro Services Hardware Language Mapping policy Mapping mechanism Quality of service Hardware abstraction Programming writing the functions that will run on the nodes of a sensor network Tasking distributing functions to the nodes of a sensor network Groups Static and dynamic Collective operations

8 Basic Simulation Goal: evaluate software stack Kensho API library Each sensor simulated by a process (linked with the Kensho library) Wireless communication provided by a broadcast daemon Sensor reads come from environment simulator Kensho Node Kensho Node Broadcast Send Message Read Sensor Kensho Node Environment Kensho Node

9 Fire Detection: Group Operations smaller groups: higher resolution, more communication

10 The University of New Mexico Motion Tracking: Dynamic Groups Group is defined by magnetometer activation Tracking Accuracy Fig. 6. The object starts at position (5, 5) and moves at a velocity of 1.35 units per time interval. The circles indicate the triggered by the presence of the object. The horizontal line in the right figure represents the normalized path of the object, indicate how far from the actual object the algorithm predicted the object to be. Fig. 6. The object starts at position (5, 5) and moves at a velocity of 1.35 units per time interval. The circles indicate the sensors th triggered by the presence of the object. The horizontal line in the right figure represents the normalized path of the object, while the indicate how far from the actual object the algorithm predicted the object to be. osition (5, 5) and moves at a velocity of 1.35 units per time interval. The circles indicate the sensors that are

11 N-Sim: Scalable Simulation Goal: run large scale sensor network applications without modification Be able to control communication and node faults Order of magnitude speedup Initial focus on typical software stack: TinyOS and Linux Long term will be used to study the Kensho/ Kaizen stack

12 Virtualization using Xen Xen provides base level virtualization sharing CPU between multiple OSes Dom 0 provides access to other resources (e.g., network) Type 1 para-virtualization Dom 0 Host OS 1 Virtual Machines App App App App Host OS 2 Xen Virtualization Layer Hardware Host OS 3 Host OS 4

13 N-sim: Scalable simulation for sensors Simulate each sensor or stargate using a separate virtual machine Direct execution of applications On modified operating systems Simulation daemon runs in Dom 0 network and sensing Dom 0 Daemon Virtual Stargates App App App Xeno Xeno Linux Linux Linux Linux Xen Virtualization Layer Hardware Tiny Tiny OS OS wedge Virtual s App Tiny Tiny OS OS wedge

14 Scaling: Cluster of nodes Use multiple cluster nodes Simulation Daemons coordinate and exchange communications MPI for communicaiton and coordination Daemon Daemon Daemon Daemon Daemon

15 Full system simulation for MPP design Network Simulator Library Process Library Process Library Process

16 Multiscale issues Want full, cycle accurate, simulation from detailed processor simulation device drivers to large scale application including all software layers impact of changing implementation of services Also want simple, proof of concept simulation fast, clean and simple

17 Thanks LANL & NNSA SSL UNM Prof Patrick Bridges Postdocs Patricia Crowley (now at Gonzaga) Patrick Widener