ApplyingApplying Ulysses to Ulysses to BluetoothBluetooth

Alvise BoniventoAlvise Bonivento

Mentor: Marco SgroiMentor: Marco Sgroi

Outline Motivations The Ulysses methodology Introduction to Bluetooth Bluetooth from an Ulysses

perspective Extensions to Ulysses Conclusions and future works

MOTIVATIONS: PROTOCOL DESIGN METHODOLOGY

•Traditional design approaches are informal•Early partition of the system behavior increases number of errors•Need of a formal approach enabling IP reuse •Scenario based specifications

Ulysses Design Flow

Scenario Specification(Message Sequence Charts + relations)

Synthesis of Petri Nets(MSC Covering)

Scenarios composition

Mapping and Optimization

Bluetooth

Applications

ACL SCO

Baseband

LMP

HCI

L2CAP

RFCOMM

OBEX WAPSDP

•Services: Asynchronous Connection-Less (ACL) and Synchronous Connection Oriented•Service Discovery Protocol (SDP): table of services•L2CAP: Adaptation layer, segmentation and reassembly•Host Control Interface: Interface HW and SW•Link Manager Protocol (LMP): a CPU implemented on HCI•Baseband: LLC + PHY•Radio:2.4 GHz (IMS), FHSS, 79 Channels, of 1 MHz each •Piconets with a master and a maximum of 7 active slaves

verifier LM claimant LM

verifier LM claimant LM

AuthenticationM1

M2verifier LM claimant LM

M3

1.1

2.1 3.1

c c

Verifier LMClaimant LM

!1.1

?1.1

! 2.1

? 2.1

! 3.1

? 3.1

Authentication PN

Bluetooth: examples

Authentication

Encryption

\failure

M2

2.1

2.1 HCI_conn_complete

H A LM ALMB

HostB

H A LM ALMB

HostB

M3

\

1.1 LMP_setup_complete

H A LM ALMB

HostB

1.1

1.1

\

ACL_Ecryption

M1

masterLM

SlaveLM

1.1

Encryption

M1

masterLM

SlaveLM

masterLM

SlaveLMM2

M3

3.12.1

masterLM

SlaveLM

4.1

masterLM

SlaveLM

5.1

masterLM

SlaveLM

4.1mast

erLM

SlaveLM

5.1

M4

M5

M6

M7

masterLM

SlaveLM

8.1

M8.1

masterLM

SlaveLM

9.1

M9

From M5 From M7

9.2

masterLM

SlaveLM

10.1

masterLM

SlaveLM

5.1

masterLM

SlaveLM

8.1

M10

M11M12

masterLM

SlaveLM

8.1

M8

masterLM

SlaveLM

8.1

M8.2

failure

Bluetooth: example

Encryption and connection set-up

Connectionestablishment&detachment

t1T1:HCI_ConnectionReque

stfailure

T2:HCI_ConnectionSetUpt2

failure

t3T3: HCI_Encryption

failure

Detach

EnableNewOperation

Do you want to connectanyway ?Y

N

Op. Service 1

Op. Service nDataEchangeSCO enable

SCO disable

No SCO

ALL THIS TRANSITIONS CAN BE CONSIDERED PATTERNS

Bluetooth: example

HIGH LEVEL SCENARIO COMPOSITION !!!!!

DESCRIBE THIS TRANSITIONS WITH OTHER PNs

Starting from Ulysses

•Authomatic synthesis of communication protocols not effective: layer by layer refinement very hard•Next generation protocols: 4G (beyond 3G) ? New key parameters•OSI type protocol stack may not be the most appropriate solution•Need to provide an authomatic synthesis tool able to deploy “super networks” •A new methodology with higher level of abstraction

Platform based design

Specifications + constraints (power, area, latency, QOS ...)

Translation into a labeled PN model

Optimized labeled PNs

Library of architectures (SW/HW) + performances

Bottom-up abstraction of resources

Mapping

Labeled MSN

Simulations and synthesis tool: Metropolis

At this level they can talk !!!

Conclusions Ulysses: a new approach

Scenario based PNs as MoC pattern

Case study: Bluetooth: MSN description, PN translation, Metropolis.

Platform based design for communication protocols Future work: A LOT !!!

More patterns and examples Extend the model in order to capture more aspetcs (i.e.

power, area, latency ... Environment ?) Implement authomatic PNs generation from MSNs

Covering AlgorithmCovering Algorithmtj=t0Repeat

BeginCoverMRepeat

Select ei s.t. Ei is a cutif ei is receive add ChannelSelectPatternLabelPatternComposePatterni++

Until all e in Mj are coveredif all e in Mj are covered mark tjEndCoverMSelect next transition tj with all predecessors covered or a marked

predecessor placeUntil all transitions are coveredFor every choice add a synchronizerAdd initial marking Tokens