First Year Results and Lessons, and Project Directions for the Second Year Marco Conti Computer Networks Dept., IIT CNR

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, September 2003, Lecture Notes in Computer Science LNCS 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, 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) Scenario An IEEE 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 aspects are modelled, e.g., most simulators assume the same Tx range for unicast and broadcast frames. real 2.No calibration of simulators with real measurements 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 and network layer protocols wireless ad-hoc technologies power management cooperation model application 1application 2application 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-layer tasks Security Cooperation Energy Saving Application 2Application n BluetoothHyper 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 pp 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 Cons

MobileMAN IAB meeting (Helsinki, 7 Jun 2004) Applications Power Management Enhanced Wi-Fi cards Routing Users’ location Forwardin g (Simplified) Transport Protocol Socket API Middleware Network status Cooperation Performability 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 Year

MobileMAN IAB meeting (Helsinki, 7 Jun 2004) Berkley Sockets (stream, datagram) Transport (TCP, UDP) IEEE (MAC + Physical) NeSt NeSt API Network (Link-State routing, IP forwarding) Middleware (Subject-Based Routing) Common API Cross-Layering Ring 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 Year 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 Technologies Include 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 services Include the cross-layering view at network/transport layer Design/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 services Include 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 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 ?