SOLAR Joy Ghosh, Sumesh J. Philip, Chunming Qiao

{joyghosh, sumeshjp, qiao}@cse.buffalo.edu

Sociological Orbit aware Location Approximation and Routing

A Random Orbit Model and its Parameters

Living

Kitchen Porch

Conf. Room

Cafe Cubicle

HomeSchool

Outdoors

Home Town

City 2Friends

City 3Relatives

MANET

Level 3

Level 2

Level 1

IntermittentlyConnectedNetworks

Sociological Orbits

Conference Track 1

Conference Track 3

Cafeteria

Lounge

Conference Track 2

Conference Track 4

PostersRegistration

Exhibits

Hub A

Hub C

Hub B

Green’s IHO: Hubs A, B, C

Hub D Hub E

Hub F

Blue’s IHO: Hubs D, F

Red’s IHO: Hubs E, F

IHM of individual nodes

IHM: Random Waypoint; IHO: P2P Linear

SOLAR Variations: Ongoing Research

• Non-probabilistic – Geographic forwarding to hubso SOLAR Sequential – to all hubs in sequenceo SOLAR Simulcast – to all hubs simultaneouslyo SOLAR Multicast – to a multicast tree of hubs

• Probabilistic – Intermittently connected networkso SOLAR-P – forward to hubs in probabilistic ordero SOLAR-KSP – K-shortest paths; store & forward routing

Key Concepts

• Every user periodically visits a list of places of social interests (i.e., hubs)• Can utilize such mobility information for location approximation and routing• Examples (at right):

• User 1 (green), User 2 (blue) and User 3 (red) attending a conference• User 3 queries User 2 for the hub list of User 1• User 3 sends data to User 1

• Advantage of Macro-level (hub-based) sociological orbital mobility profile• does not require continuous location monitoring• does not depend on exact movement in time or space• acquaintance-based soft location management• captures probabilistic routing in MANET & other networks (e.g., ICN)

Query Optimization – Subset of Acquaintances to query

• Acquaintance Ai has a Hub list Hi = {h1, h2, …, hm} where hi is a hub• H = {H1, H2, …, Hn} is the set of hub lists covered by A1, A2, …, An

• C = H1 U H2 U … U Hn is the set of all hubs covered by A1, A2, …, An

• Objective: find a minimum subset H’ of H such that:

• This is a minimum set cover problem – NP Complete• Possible solutions: Greedy Set Cover, Primal-Dual Schema, etc.• Minimizes the number of queries and optimizes the cache size

General Parameters

Simulation time 1000s Terrain size 1000m X 1000m

No. of nodes Vary, (Default = 100) Radio range Vary, (Default = 200m)

MAC protocol IEEE 802.11 Mobility model Random Orbit

SOLAR Parameters

Total hubs Vary, (Default = 15) Hub size Vary, (Default = 200m)

Hub stay time 50s – 100s IHO Timeout 250s – 500s

Hub list size 2 – Total hubs Inter-hub speed Vary,

(Default = 10m/s – 30m/s)

Intra-hub pause 1s Intra-hub speed 1m/s – 10m/s

Traffic Parameters

CBR connections

200 Random

(5 packets each)

Data payload 512 bytes per packet

Conference Track 2

SOLAR Simulcast: Location Query and RoutingConference Track 1

Conference Track 3

Cafeteria

Lounge

Conference Track 2

PostersRegistration

Exhibits

(b) Geographic forwarding of data to destination

Conference Track 4Conference Track 4

Conference Track 1

Conference Track 3

Cafeteria

Lounge

PostersRegistration

Exhibits

(a) Geographic forwarding of location query to acquaintance

Hub Centers

Research Issues:

• Routing Objectives: • Maximize data throughput (under energy and memory constraints)• Minimize control overhead (number of location queries/updates)• Minimize number of logical hops required for each location query• Minimize number of acquaintances maintaining throughput• Minimize the end-to-end delay (location query + data delivery)

• Routing Variable:• Cache size (number of acquaintances)• Logical hop threshold (acquaintance to acquaintance lookup)• Hub list discovery probability (reliability of location approximation)

• Optimization problems:• What is the minimum cache size required to achieve a desired discovery probability within a fixed number of search steps?• Given a fixed cache size, what is the minimum number of search steps required to achieve desired reliability?• What is the probability of Hub list discovery within a fixed number of search steps given a fixed cache size?

Performance of SOLAR vs. conventional protocols

SOLAR achieves high throughput, low control (signaling) overhead, and reasonable delay (even for destinations far away)

Laboratory for Advanced Network Design, Evaluation and Research (LANDER)