Transcript End-Semester Poster

Technion
Israel Institute
of Technology
BlueTooth High-Level
Simulator
A Base Platform For Simulating Packets
Routing Algorithms Over A Bluetooth
Scatternet
Computer
Networks
Laborator
y
Students: Ehud Klugman
Eitan Peri
[email protected]
[email protected]
Instructor : Ran Cohen
comnet.technion.ac.il/~cn23s00
BlueTooth Background
BlueTooth is a technology specification.
 It describes how various electronic
products, can interconnect with each
other using a short-range wireless
connection, and establish a network.
 Some BlueTooth basic terms:

A BlueTooth Scatternet
Unit - The most primitive element in a BlueTooth
scatternet. It can be any electronic product which
implements the BlueTooth specification. At a single
piconet, a unit can be a master unit or a slave unit.
Piconet - A “mini-network”, with small coverage area,
which consist of one BlueTooth master unit, and
one to seven slave units. Slaves communicate
only with the master unit (and not with each other).
Scatternet - Group of piconets with overlapping area of coverage. A unit
can act as master & slave at the same time in different piconets or as slave
in those piconets. It is possible to route packets in a scatternet.
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Project Objectives
Base platform for simulating routing algorithms over a
scatternet.
 Simulates connecting/disconnecting of units to the
scatternet over the time axis.
 The behavior of the unit is pre-defined by the user
using different attributes.
 Supporting run-time tracing over unit’s connectivity to
the scatternet.
 User Interference during run-time, can be used to
connect/disconnect units form the piconet or the
scatternet.

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Our Implementation - General

Language: Java.
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Each unit is represented by a separate process.
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Our code implements a single unit, which can be executed
from the command prompt.
Running a few units simultaneously, can create a piconet/
scatternet.
The units communicate over the network using UDP:

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Code can run on any platform.
Ready classes for networking and threads.
UDP is best for simulation radio transmissions.
Units can run on different machines.
Packets loss is simulated in application level.
Acknowledge is needed for every packet transmissions
(except broadcast & SCO connection), and is implemented in
application level.
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Our Implementation – General (cont.)

Packets enumerating is used to distinguish packets:
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Avoiding duplicated packets/ack. to be executed more then once.
Use Responses Cache in order to save re-calculating a certain
response, when duplicating request is received.
Running the simulation can be done through script:
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Scripts Contain some attributes for each unit, in a single line.
It executes the processes/units one by one.
Script Line Example:
Btsim
Executable
Name

Role of
the unit
-master 2.3 7.5 132.68.55.1 2022 -if
Role’s
start time
Role’s
end time
IP address
of this role
Port number
of this role
Use user
interface
Command-line user interface can be used to change/see units’
attributes on run time:
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Changing the roles of a unit, means connecting disconnecting it
from a specific piconet, or destroying it completely.
Seeing the units connectivity, and other information.
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High Level Design – Classes Relations
Slave
Master
Inherited
BT_scheduler
BT_unitFunc
N
1
BT_userInterface
BT_unitFuncManager
BT_udpConnection
BT_requestsTable
BT_msgSendQueue
BT_send
BT_recv
BT_responseCache
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High Level Design – Main Classes
Description
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BTudpConnection - A single network connection.
BTrecv - Inherited from thread class, and handles received massages
from the network. There are two kind of received massages:
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Request - Contain a certain command that should be handled by the
receiving unit. For example, a request from new slave unit to the piconet’s
master to be added to this piconet.
Response – Contains the result of executing previous Request. There are
two kinds of responses:
– Immediate response – Indicates that the request and was received, and
the receiving unit started to process it. It is sent when the processing
time of the request might be long.
– Final replay – Indicates that the receiving unit finished processing the
request, and contains the requested data. As in the example above, the
master can replay to the new unit with its identification number in the
piconet or by denying the request
BTrequestsTable - Implements a table, that contains requests that were
sent on the network, but no acknowledgements were received for them.
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High Level Design – Main Classes
Description (continue)

BTresponseCache - Caching implementation of the responses that the unit
is sending to other units:
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BTmsgSendQueue - Implements a queue of massages that should to be
sent:
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When a request from the unit is received at the first time:
– It is passed to BTunitFuncManager that generates a response.
– The response is stored in the data structure of this class.
If this request is received again (response was lost):
– Its response is stored in the cache of receiving unit (BTrecv).
– The response is read from the cache, and is send immediately. The time of
computing the response again is saved.
BTrecv & BTunitFunc classes fill this queue with massages.
BTsend’, which run on separate thread, fetches the massages that is located on
the top of this queue, and send them.
BTsend -Inherited from thread class, and has two tasks:
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Sends to network the massages that are in BTmsgSendQueue. Each sent
massage is also added to BTrequestsQueue.
Re-send requests that weren’t acknowledged by the destination unit after a
certain time (using BTrequestsQueue).
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High Level Design – Main Classes
Description (continue)

BTunitFunc - Represents a single functionality of the unit in the
Bluetooth scatternet.
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BTunitFuncManager - Responsible for the following:
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Create a new BTunitFunc, or destroy an existing one.
– Creation or destruction of BTunitFunc is done, when a command is
passed to this class from BTscheduler or BTuserInterface classes.
Receive massages from BTrecv and deliver them to the right
BTunitFunctional object.
BTuserInterface - Inherited from thread class, & has the following tasks:
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Such a functionality is either master or a slave in a single piconet.
A unit can own more than one BTunitFunc, if it is in a few piconets.
Those two functionalities are inherited from this class.
Display unit’s information to the user on screen.
Receive from the user some basic commands.
BTscheduler - It is the main stream of the unit, & has two main tasks:
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Create all other objects on proccess initialization.
Schedule the creation and the destruction of BTunitFunc classes, by
using functions of BTunitFuncManager
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