PRIN WOMEN PROJECT Research Unit: University of Naples Federico II G. Ferraiuolo

T3.6: Location management and routing in wireless ad hoc and mesh networks

Rome, WOMEN – 3° Meeting3 Mobility management WMNs mesh routers have low mobility: –monitoring the connectivity Mesh clients are mobile: –Mobility management is essential for the ad hoc domain Mobility management: location and handoff management

Rome, WOMEN – 3° Meeting4 Location management in MANETs Node’s identifier and node’s location can not be statically related in self organizing networks Location is retrieved and then routing is performed Routing based on location information can improve scalability respect to proactive/reactive approaches

Rome, WOMEN – 3° Meeting5 DHT based location management Distributed Dynamic management Low control message overhead P2P applications for locate information (scalability and resilience to failures) DHT based routing: –Location by GPS or other dedicated systems –Topology location (by dynamic addressing)

Rome, WOMEN – 3° Meeting6 Addressing in MANETs Twofold goal: –Assign a like-IP address in mobile environments –Solve the location management problem for supporting routing Mandatory requirements: –Distributed mechanism –Scalability

Rome, WOMEN – 3° Meeting7 Resume There are 3 problems to optimize: –Dynamic Address Allocation –Dynamic address based Routing –Distributed Hash Table Lookup There is still work to do toward the definition of a realistic scalable routing approach based on DHT and Dynamic Addressing

Rome, WOMEN – 3° Meeting8 Distributed Address Allocation Identifier: static (IP) Routing address: dynamic Each node can assign a valid address to a joining neighbor node The assigning node also delegates control over half of its address space to the requester Problems: network merge and partition yield to address duplication

Rome, WOMEN – 3° Meeting9 Distributed Address Allocation A level-k sibling of a given address is defined as the subtree that share the same immediate parent of the level-k subtree of the considered address. Example: sibling(100) = 101, 11X, 0XX

Rome, WOMEN – 3° Meeting10 Distributed Address Allocation Each node build a state table –The table stores an entry for each one of node’s level- k sibling subtree –If an entry is empty, the new node get an unoccupied address in that subtree –The new node chooses the largest unoccupied address set –Table dimension O(log n) The table is used also for routing

Rome, WOMEN – 3° Meeting11 Distributed Address Allocation Related works: –Stateless approach: flood the network for duplicate address detection –Stateful approach (DART): based on the underlying Neighbor Discovery Protocol Other stateful approaches dose not face effectively network partition problem –We use the identifier to detect partitions and solve the contention

Rome, WOMEN – 3° Meeting12 Routing Location information is embedded in the dynamic address: –Hierarchical distance-vector routing based on dynamic address –A node compare the address with its own, if the i-th bit is different, it forwards the packet toward the i-th sibling –Routing is a recursive descending through the address tree –Prefix subgraph constraint assures robustness

Rome, WOMEN – 3° Meeting13 Prefix subgraph constraint Nodes with a given address prefix form a connected graph The longer the shared address prefix between two nodes, the shorter the distance in the topology Routing entries for distance nodes can remain valid despite local topology changes Reduce size of routing tables and updates

Rome, WOMEN – 3° Meeting14 Routing optimization 1 Tree address structure –simple and manageable (+) –low route selection flexibility for routing (-) Optimization opportunities: –Enhancing address capability (-) –Increasing table dimension (+) Additional neighbor information in the routing table –Low increment of the table size, same routing overhead

Rome, WOMEN – 3° Meeting15 Routing optimization 1

Rome, WOMEN – 3° Meeting16 Routing optimization 2 Toward an effective routing protocol: –Cross layering is mandatory in MANETs –A simple interaction with MAC can be very useful –When a link failure is detected, the corresponding entry is removed from the state table –Routing is attempted using another available entry Resuming: –Routing protocol 1 (R1): minimum table size –Routing protocol 2 (R2): neighbor information –Routing protocol 3 (R3): minimum table size with cross layer –Routing protocol 4 (R4): neighbor information with cross layer

Rome, WOMEN – 3° Meeting17 Simulated scenario Network Simulator 2 Mobility model: –random waypoint; –speed [0.5;5] m/s, pause time [0;100] s; –density ≈ 121 nodes/km 2 ; Data traffic model: –Constant Bit Rate (CBR) on UDP; –throughput CBR = 0.25 throughput link

Rome, WOMEN – 3° Meeting18 Simulation results

Rome, WOMEN – 3° Meeting19 Simulation results

Rome, WOMEN – 3° Meeting20 Simulation results

Rome, WOMEN – 3° Meeting21 Simulation results

Rome, WOMEN – 3° Meeting22 Conclusions Preliminary results: –Address allocation scheme is effective in assigning valid addresses –Better performance in routing is achieved with slightly more complexity –Cross layering is necessary to achieve effective performance