1. Simulators for Sensor Networks
Sagnik Bhattacharya
9/12/2001

2. Overview What we need? How much effort should we put? Simulators :
JavaSim
GlomoSim
NS - 2
SensorSim
Comparison

3. What we want?
It should perform simulations of our algorithms. (obviously)
It should have models for wireless transmissions and battery models.
It should be extremely scalable.
It should be efficient for large simulations.
There should be technical support.

4. How much effort should we put in?
Build battery and wireless models? (Preferably no)
Implement routing?
How much learning is involved?
Change basic modules or just add our own modules?

5. JavaSim Pros Cons Very modular Easy to use
Geared for wired internetworks
No wireless support

6. GlomoSim Specific for mobile wireless networks.
Built as a set of libraries. The libraries are built in Parsec( a C-based discrete event simulation language).
Layered architecture with easy plug-in capability.

7. Application Processing
GloMoSim Library
Data Plane
Modular, extensible library for network models
Model each layer using abstract or detailed model
Built-in statistics collection at each layer
Application Processing
Propagation
model
Radio
MAC Layer
Network IP
Transport
Application
Link Layer
RTP Wrapper
TCP, UDP, RSVP IP
OSPF, AODV, …
Packet Store/Forward
IEEE , 802.3, …
EPLRS, WaveLAN, ...
Free space, TIREM

8. NS - 2 De facto standard for network simulations
Does support wireless simulations
A primitive energy model is present.
Lots of documentation.
Uses Tcl to specify the Components, and Otcl to glue them together.

9. NS - 2 (contd.) Cons : Difficult to use and learn
Supposedly more useful for getting statistics for lower level protocols.
Originally built for wired networks, later extended for wireless.
Supposedly, does not work well for large topologies.

10. SensorSim Extension to NS - 2.
Provides battery models, radio propagation models and sensor channel models.
Provides a lightweight protocol stack.
Has support for hybrid simulation.
To be integrated with NS - 2.

11. SensorSim Architecture
app
monitor and control
hybrid network
(local or remote)
real sensor apps on
virtual sensor nodes
app
GUI
app
socket
comm
serial
comm ns
GUI Interface
HS Interface
Ethernet
RS232
gateway V V R V V
Gateway Machine R
modified event scheduler
Proxies for real
sensor nodes
Simulation Machine

12. Sensor Node Model in SensorSim
Node Function Model
Micro Sensor Node
Applications
Power Model
(Energy Consumers and Providers)
Middleware
State
Change
Network
Protocol Stack
Sensor
Protocol Stack
Radio Model
Network Layer
Sensor Layer
CPU Model
Battery
Model
Status
Check
MAC Layer
Physical Layer
Sensor #1 Model
Physical Layer
Sensor #2 Model
Wireless Channel
Sensor Channel

13. Power Management Model
BZR event
Off
BZR event
BZR event
BZR event
Off
BZR event
Transmit
transmit
Receive
Transmit
BZR event
Receive
transmit
done
receive
done
transmit
Idle
transmit
receive done
Idle
timeout
receive
transmit
done
Sleep
timeout(3 sec)
Without Power Management
With Power Management

14. SensorSim Problems
Still at pre-release stage.
No Documentation.

15. Comparison
On paper : SensorSim looks really good. Their DNS group has already done a lot of work.
Effort : GlomoSim seems better.
Track Record : NS wins. (GlomoSim was built by UCLA, but still they built SensorSim)