Dynamic Team Formation on Team-Oriented Multicast Yiguo Wu and Siavosh Bahrami Tutor: Yunjung Yi Prof. Mario Gerla CS 218 Advanced Computer Networks 12/05/2003

Outline LANMAR Previous work: Dynamic team formation Our modified dynamic team formation protocol Preliminary results Discussion

LANMAR MANET challenge: scalable routing Hierarchical Routing Protocol – Assumption: “group affinity model” – Benefit: scalable routing – Limitation: assumes logical subnets known in advance Logical Subnet Landmark

Dynamic Team Formation Xiaoyan Hong,Mario Gerla, " Dynamic Group Discovery and Routing in Ad Hoc Networks, " In Proceedings of Med-Hoc-Net 2002.Dynamic Group Discovery and Routing in Ad Hoc Networks No subnet assumption Two Phases: – Phase 1) Initialization: traveling companion discovery, K-Hop clustering (connectivity, lowest ID, heuristics), and initial elections – Phase 2) Maintenance: Hysteresis rule for stable landmark election Phase 1 stability issue?

Stability Problem C B A Rest of Network B elects C as landmark Propagation of inaccurate information A initially elects B

Confirmation & Advertisement C B A D Rest of Network B elects C as landmark Propagation of accurate information A elects the next lowest ID Node B: Failed Elect Node B: Failed Elect Node B: Failed Elect Node B: Failed Elect

Protocol Algorithm Details: Routing Table Exchange Exchange local routing tables with direct neighbors periodically How frequently should we exchange local routing tables?

Protocol Algorithm Details: Companion Identification Identify Companions - Routing Table entry not “stale” - Has been present in local routing table for at least time t (avoid roaming nodes)

Protocol Algorithm Details: Election Elect Clusterhead – Lowest ID Companion – Pros: Stable Simple Fast – Cons: Most likely not close to the minimum dominating set (optimal), i.e. many small clusters that may require further merging – Note: in current implementation, every election is independent of the previous one raising stability issues (add maintenance heuristics?)

Protocol Algorithm Details: Close Proximity Merge Small cluster problem - Clusters overlap each other Solution: Low Cost Merging -Observation: If landmarks can see each other directly, then their corresponding clusters overlap. - Action:Merge them !

Protocol Algorithm Details: Confirmation & Advertise Confirmation – Tentatively elected node can “respond” in 2 ways: If it is its own landmark, or has not elected anyone yet, implicitly accepts. If elected another node as landmark, rejects by broadcasting failure. Advertise – If candidate accepts election, then broadcast affiliation to entire network.

Protocol Highlights Routing Table Exchange & Companion Identification – Companions are chosen based on the duration and continuity of their presence within source’s K-hop range Confirmation and Advertisement periodically Node type capability also implemented

Implementation Details: Asymmetric Broadcast When a node casts its vote for landmark, it broadcast the message to compensate for high mobility. Do we really need to broadcast to everyone? Not really, only the presumed landmark needs the information.

Implementation Details: Asymmetric Broadcast cont. “Symmetric Broadcast” High overhead K-hop range Presumed Landmark

Implementation Details: Asymmetric Broadcast cont. “Asymmetric Broadcast” Intermediate nodes only forward the packet if they can deliver it within TTL. K-hop range Presumed Landmark

Demonstration Qualnet 3.6 Provided mobility trace file – 150 nodes – 6 types (2 mobile) – Terrain size: 1500 x 1350 – Duration: 250 seconds 1-Hop clustering

Preliminary Results 1 Same mobility settings as the demonstration K100s150s200s250s Number of Landmarks

Preliminary Results 2 No mobility traces yet, so assumed static model Tested on 200, 500, 1000 nodes with terrain sizes , , and , respectively Different K-values: 1 to 3 1 Type Duration 200 seconds

Preliminary Results 2 cont. K200 nodes500 nodes1000 nodes Number of Landmarks

Future Work Cluster maintenance (join, leave, hysterisis rules…) Parameter tuning – Empirically determine optimal/robust routing table exchange and election schedules Adaptive K Landmark supergroups: grouping of same-group landmarks Distibuted/redundant DNS for landmark members

References [1] Yunjung Yi, Mario Gerla, Joon-Sang Park, Dario Mazzorri, " Team- oriented Multicast: A Scalable Routing Protocolfor Large Mobile Networks, " NGC [2] Yunjung Yi, Xiaoyan Hong, Mario Gerla, " Scalable Team Multicast in Wireless Ad hoc Networks Exploiting Coordinated Motion, " NGC [3] Xiaoyan Hong,Mario Gerla, " Dynamic Group Discovery and Routing in Ad Hoc Networks, " In Proceedings of Med-Hoc-Net [4] Wu, F. Dai, M. Gao and I. Stojmenovic, " On calculating power-aware connected dominating sets for efficient routing in ad hoc wireless networks, " IEEE/KICS Journal of Communication Networks, Vol. 4, No. 1, March 2002, Team- oriented Multicast: A Scalable Routing Protocolfor Large Mobile NetworksScalable Team Multicast in Wireless Ad hoc Networks Exploiting Coordinated MotionDynamic Group Discovery and Routing in Ad Hoc NetworksOn calculating power-aware connected dominating sets for efficient routing in ad hoc wireless networks [5] G. Pei, M. Gerla, and X. Hong, " LANMAR: Landmark Routing for Large Scale Wireless Ad Hoc Networks with Group Mobility," In Proceedings of IEEE/ACM MobiHOC 2000, Boston, MA, Aug LANMAR: Landmark Routing for Large Scale Wireless Ad Hoc Networks with Group Mobility [6] J.T. Tsai and M. Gerla, “Multicluster, Mobile, Multimedia Radio Network”, ACM/Kluwer Journal of Wireless Networks, Vol.1, No.3, pp , 1995.