first year results and lessons, and project directions for the second year
DESCRIPTION
First Year Results and Lessons, and Project Directions for the Second Year. Marco Conti Computer Networks Dept., IIT CNR [email protected] http://cnd.iit.cnr.it/mobileMAN. Methodology. 2200 papers (citeseer), but no mainstream products - PowerPoint PPT PresentationTRANSCRIPT
First Year Results and Lessons, First Year Results and Lessons, and Project Directions for the and Project Directions for the Second YearSecond Year
Marco ContiComputer Networks Dept., IIT CNR
[email protected]://cnd.iit.cnr.it/mobileMAN
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
2200 papers (citeseer), but no mainstream products
More than 10 years of research but this area is far from being consolidated
Three Areas where Ad Hoc lacks “Realism” (*):
1. Integration (lack of)2. Implementations/Testbeds (lack of)3. Experimentation (lack of)
(*) Christian Tschudin, Henrik Lundgren, Erik Nordström, “Embedding MANETs in the Real World“, Personal Wireless Communications”, Proceedings of the 8th IFIP-TC6 Conference, Venice, Italy, 23-25 September 2003, Lecture Notes in Computer Science LNCS 2775.
Methodology
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
1. Integration (lack of)
Focus was mostly on revising routing Internet Draft. Current ID revision numbers: v13 (AODV, now an RFC), v9 (DSR), v11 (OLSR), v10 (TBRPF)
Main other areas have been analyzed (and new areas are continuously added), see (*):
- Most works focus on a single layer/issue (MAC, Routing, TCP, middleware, etc.); or
- Studies of the interation among few layers (TCP and MAC, TCP and routing, energy and topology control, …)
Lack of an overall view of MANET architecture and protocols
(*) I. Chlamtac, M.Conti, J. Liu, “Mobile Ad hoc Networking: Imperatives and Challenges”, Ad Hoc
Networks Journal, Vol.1 N.1, 2003.
State of the Art: open issues
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
2. Implementations/Testbeds (lack of)
Only limited hands-on experience available(typically 4 to 10 nodes, up to 37 at Uppsala)
3. Experimentation (lack of)
Internet Drafts production cycle mainly driven by simulation work: “implementations can come later, simulations tell the truth”
Few attempts to validate/calibrate simulative studies with measurements
Can we trust the protocols inside the simulators?
State of the Art: open issues
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
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Scenario
An IEEE 802.11 network with 50 nodes moving according to the Random Waypoint mobility model in a 1500m x 300m closed rectangular area. The nodes maximum speed is equal to 1 m/sec.
In the considered scenario there are 3 FTP sessions (1460 bytes per packet), and ten CBR sessions (512 bytes per packet).
Results
Figures show the sum of the 3 FTP-session throughput by varying the length of the pause in the Random Waypoint model
Results are highly dependent on the simulation tool.
Can we trust the protocols inside the simulators?
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
3. Not all 802.11 aspects are modelled, e.g., most simulators assume the same Tx range for unicast and broadcast frames.
2 Mbps data rate
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NS2QualNetrealereal
2. No calibration of simulators with real measurements
MS
FS2FS1GW
Brodcast Range
Unicast Range
Gray Zone
The Communication Gray Zones Problem
Can we trust simulative results?
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Experimentation
Use of real testbeds:
• to validate the developed solutions whenever possible or, (at least),
• to calibrate/validate the simulation models to be used for architecture and protocols desgin
Implementations
• Whenever possible, hardware/software implementation of the MobileMAN solutions
• The integration of the developed solutions in a testbed.
MobileMAN: Experimentation & Implementation
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
The development, and validation, of effective integrated solutions for the relevant technical issues of self-organizing networks: routing and medium access control protocols, power management, security, and location.
middleware
transport andnetwork layer protocols
wireless ad-hoc technologiespow
er
man
ag
em
en
t
coop
era
tion
mod
el
application 1 application 2 application k
MobileMAN: Integration
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Experimentation
• We will see some experimental results in the following presentations
Implementation
• The main activity of the second year of the project
Integration
• A preliminary integration will be performed in the last months of the II year.
MobileMAN Status
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
MANET IETF WG proposes a view of mobile ad hoc networks as an evolution of the Internet [1]:
• IP centric view (“solve mobile routing problems at the IP layer”), and
• use of a layered architecture
Advantages: It guarantees that the TCP/IP protocol stack can efficiently operate on a large set of heterogeneous technologies.
Drawbacks: layers independence makes difficult to fix some ad hoc networks, see for example TCP-MAC interaction problems.
MANET Architecture
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
MANET reference architecture
Medium Access Control, Antennas, Power Control
Transport and Network layer protocols
TCP, IP routing, Forwarding, Addressing, Interconnection
Middleware
Service location, Group communication, DSM
Application 1
Inter-layertasks
Security
Cooperation
EnergySaving
Application 2 Application n
802.11 Bluetooth Hyper LAN
Applications
&
Middleware
Networking
Enabling
Technologies
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Efficient solutions for ad hoc networks require a more strict cooperation among protocols belonging to different layers [2]:
for example, from the energy management standpoint, power control and multiple antennas at the link layer are coupled with scheduling at MAC layer, and with energy-constrained and delay-constrained routing at network layer
The question is to what extent the pure layered approach needs to be modified?
• Extension of the layered architecture: layer triggers
Layer triggers are pre-defined signals to notify some events to the higher layer, e.g., failure in data delivery.
• “Violation” of the layered architecture: full cross layering design
Neglecting the layers separation principle by a joint design of the protocols
[2] A.J. Goldsmith, S.B. Wicker, “Design Challenges for Energy-Constrained Ad Hoc Wireless Networks”, IEEE Wireless Communications, Volume 9, Number 4, August 2002. pp. 8- 27.
Cross layers’ Dependencies in MANET Design
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Cross Layer optimization for all network functions. Cross layering is a must for functions such as energy management, but provides benefits for all network functions.
Both local and global adaptation can be performed to adapt the system to highly variable ad hoc network conditions, and to better control the system performance
Full Context Awareness at all layers. At each layer, protocols can be designed to be aware of the network status, energy level, etc. Cross layering makes easy to achieve context awareness at the application layer.
Reduced overhead for collecting the network status information avoiding data duplication at different layers.
Cross Layering Pros
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
• Protocols re-design (?)
minimal re-design is desirable
• No Layers independence (?)
“spaghetti” style in protocols design must be avoided
Vikas Kawadia, P.R. Kumar, "A Cautionary Perspective on Cross Layer Design", Technical reports
Cross Layering ConsCross Layering Cons
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Applications
Pow
er
Managem
en
t
Enhanced Wi-Fi cards
RoutingUsers’ locationForwarding
(Simplified) Transport Protocol
Socket API
MiddlewareN
etw
ork
sta
tus
Coopera
tion
Perf
orm
abili
ty
Network Layer
MobileMAN Cross Layer Architecture
MobileMAN approach to cross layering tries to balance performance optimization with protocols’ stack adatability
the kernel of the architecture is a shared memory (“Network Status” in the figure) that is a repository of all the network status information collected by the network protocols. All protocols can access this memory to write the collected information, and to read information produced/collected from the other protocols.
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Allows for a full compatibility with standards, as it does not touch the core functions of each layer.
Is robust to upgrading, and protocols belonging to different layers can be added/removed from the protocol stack without modifying the operations at the other layers.
For example, using the legacy TCP protocol as the transport protocol of the MobileMAN
architecture only imply that cross-layer optimizations will not occur at this layer.
It maintains all the advantages of a modular architecture.
Layer separation is achieved by standardizing the access to the Network Status.
MobileMAN Cross Layering Architecture
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
1. Continue along the construction of a MANET following the IETF approach to be used for experimental tests (internal and with users)
2. Refine the MobileMAN Architecture and Protocols to include the Cross Layering principle
Directions for the Second YearDirections for the Second Year
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Berkley Sockets (stream, datagram)
Transport(TCP, UDP)
IEEE 802.11 (MAC + Physical)
NeStN
eSt
AP
I
Network (Link-State routing, IP forwarding)
Middleware(Subject-Based Routing)
Common API
Cross-LayeringRing overlay for subject-based routing
Socket-based networking
MobileMAN protocol stack architecture with Cross Layering
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
• How should the network status information managed?
• How protocols belonging to different layer access to the common information?
• Make protocols cross-layer aware
• Protocols overheads cannot be evaluated in isolation but new cross-layer metrics need to be defined.
MobileMAN Cross Layering Architecture: II MobileMAN Cross Layering Architecture: II Year Open IssuesYear Open Issues
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
NeSt Hypothesis
We have a language, that the NeSt and the protocols can use for:
Describing data
Writing functions to analyse/monitor data
The NeSt manages abstractions of data and events, internally maintained by protocols
Example: topology information collected at the routing layer is exported in a graph structure in the NeSt
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
NeSt functionalities
NeSt groups and controls all cross-layer interactions
It implements two models:Synchronous interactions, to allow data sharing among protocols
Asynchronous interactions, to allow network event subscription and notification
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
a. Register
b. Seize an abstraction
with PID, AID and callback
NeSt register()
seize()
access()
subscribe()
notify()
monitor()
P1
P2
1. Generate PID 2. Return PID
1. Verify callback 2. Grant or reject seizing
•register : (void) ProID
•seize : (ProID, AbsID, CallBack()) result
Registering and seizing of an abstraction
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
NeSt register()
seize()
access()
subscribe()
notify()
monitor()
P1
P2
a. Access an abstraction with PID, AID and
Filter()
b. Abstract internal data in NeSt
format
INTERNAL DATA
1. Invoke callback for AID
2. Apply Filter() on AID
3. Return Filter() result
•access : (ProID, AbsID, Filter()) result
Synchronous interaction
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
NeSt register()
seize()
access()
subscribe()
notify()
monitor()
P1
P2
a. Subscribe event with
PID and EID
b. Notify event with PID, EID and info
regarding the occurrence
Catch e
1. Check EID on the subscription list
2. Deliver the occurrence to matching subscribers
1. Register subscription (PID, EID)
•subscribe : (ProID, EvID) result
•notify : (ProID, EvID, EvInfo) result
Asynchronous interaction: internal events
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
NeSt register()
seize()
access()
subscribe()
notify()
monitor()
P1
P2
a. Monitor event with PID, AID and
Monitor()
b. Abstract internal data in NeSt format
Internal data
1. Verify Monitor()
2. While (true) 2a. Invoke callback for AID 2b. Apply Monitor() to AID 2c. If match found notify PID
•monitor : (ProID, AbsID, Monitor()) result
Asynchronous interaction
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Wireless TechnologiesInclude the cross-layering view at datalink layer.Design and implement a full datalink layer that includes the enhanced MAC protocol for ad hoc networks as designed during the first year.
Networking servicesInclude the cross-layering view at network/transport layerDesign/Implementation of packet forwarding schemes suitable for MobileMAN. Development and testing of an ad hoc network
Co-operation Model Implementation and validation of the cooperation models and mechanisms defined during the first year.
Second Year Objectives
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
Middleware Adaptation of Pastry middleware for the MobileMAN environment to exploit cross layering.
Development of new solutions for P2P information delivery based on Pastry.
New applications and servicesInclude the cross-layering view at application layer
Adaptation of existing applications, identified, during the first year, to run on top of MobileMAN.
Socio-economic Model Apply the developed methodology for evaluating social, anthropological potential of MobileMAN, and provide the results for improving the technical parts.
To investigate market-based mechanisms for exploiting the self-organised paradigm
Second Year Objectives (cont.)
MobileMAN IAB meeting (Helsinki, 7 Jun 2004)
References
MobileMAN: Deliverable D5
M. Conti, S. Giordano, G. Maselli, G. Turi, “Cross Layering in MANET: the MobileMAN Approach”, IEEE Computer, February 2004.
M. Conti, J. Crowcroft, G. Maselli G. Turi, “A Modular Cross Layer Architecture for Ad Hoc Networks”, in “Theoretical and Algorithmic Aspects of Sensor, Ad Hoc Wireless and Peer-to-Peer Networks”, Jie Wu (Editor) CRC Press, 2004
Thank You !
Questions ?