A Multi-protocol Framework for Ad-hoc Service Discovery Carlos Flores, Gordon Blair, Paul Grace {c.florescortes, gordon, 28th November 2006 MPAC 2006

Agenda 1.Motivation 2.Research Goal 3.Ad-hoc Service Discovery Protocols Architecture 4.Ad-hoc Service Discovery Framework 5.Future Work 6.Conclusions

Highly Heterogeneous Mobile Environments WEATHERWEATHER TRAFFIC TOURISM Taxi (GSD) Taxi (SSD) Weather (ALLIA) Traffic (GSD) Tourism (SLP-B) Middleware platforms should have the following requirements: Discover services irrespectively of the discovery platform used. Discover services in diverse mobile scenarios and environmental conditions. Provide efficient mechanisms to interact with different SDPs simultaneously (i.e. configurability, dynamic re-configurability) Discover services featuring low performance overhead in terms of resource usage of the device, and network bandwidth consumption.

Research Goal  Development of a configurable and dynamically reconfigurable multi-personality discovery middleware for operation in both nomadic and MANET style operation.  Common Interaction Pattern  Ad-hoc Service Discovery Protocols.  A component framework approach for the development of a configurable and dynamically reconfigurable multi- personality discovery middleware. Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-Hoc SDPs Architecture  Agents  User Agent  Performs service discovery on behalf of the clients.  Service Agent  Represents and advertise services.  Directory Agent  Collects service advertisements and matches incoming requests against collected service descriptions.  Architecture  Directory-based (Centralized)  Directory-less (Distributed) Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-Hoc SDPs Architecture Directory-based Architecture Interaction Pattern UA SA UA SA DA UA SA UA SA UA SA UA SA DA UA SA 1.- DAs advertise its presence (multicast) 2.- SAs register their services (unicast) 3.- DAs manage service advertisement 4.- UAs request a service (unicast) 5.- DAs match requested service description 6.- DAs send service reply (unicast) Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-Hoc SDPs Architecture Directory-less Architecture, Interaction Pattern UA SA UA SA DA UA SA UA SA UA SA UA SA DA UA SA 1.- SAs advertise their services (multicast) 2.- DAs store service advertisements 3.- UAs perform local service request 4.- UAs send service requests (multicast) 5.- DAs match requested service description 6.- DAs send service reply (unicast) DA S1 S2 … CACHE Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

x Ad-Hoc SDPs Architecture Agents Tasks Advertise its presence Manages service advertisements Service description matching Multicast Unicast DA Advertise its services Multicast Unicast SA Send service requests Local Multicast Unicast x x x x x x x x x x x x x x x x x x TASKDirectory-basedDirectory-less Generates service replies xx Listen service replies xx UA Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Component Framework Architecture Policy Network Reply Cache Advertiser Request PolicyCacheAdvertiser Manages policies. Manages cache entries. Add. Replace. Update. Remove. Stores local service descriptions in cache. Generates service advertisements. Manages protocol control messages. Stores service advertisements and protocol messages in cache. (Confiurability) Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Component Framework Architecture Policy Network Reply Cache Advertiser Request ReplyNetwork Generates service requests. Processes incoming requests (matching). Forwards service requests. Sends service replies Notifies applications of received replies IP Unicast routing. IP Multicast routing. Bordercast routing Ad-hoc routing Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Service Agent Configuration Advertise its services Multicast Unicast SA x x x x TASKDirectory-basedDirectory-less Policy Network Cache Advertiser (Re-configurability) Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework User Agent Configuration Send service requests Local Multicast Unicast x x x x x x x Listen service replies xx UA TASKDirectory-basedDirectory-less Policy Network Reply Cache Request (Re-configurability) Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Service Discovery Framework Directory Agent Configuration Policy Network Reply Cache Advertiser Request x Advertise its presence Manages service advertisements Service description matching Multicast Unicast DA x x x x x x x TASKDirectory-basedDirectory-less Generates service replies xx Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Multi-protocol Support UA SA UA SA DA UA SA UA SA UA SA UA SA DA UA SA UA Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Implementation  PROTOCOLS  Group Service Discovery (GSD)  A novel group-based service discovery protocol for manets  Dipanjan Chakraborty, Anupam Joshi, Yelena Yesha, Tim Finin  University of Maryland, Baltimore County  Scalable Service Discovery (SSD)  Scalable service discovery for MANET  Francoise Sailhan, Valérie Issarny  INRIA-Rocquencourt, France  Alliance Based Service Discovery (ALLIA)  Allia: Alliance-based service discovery for ad-hoc environments  Olga Ratsimor, Dipanjan Chakraborty, Anupam Joshi, Timothy Finin  Univeristy of Maryland, Baltimore County  SLP-Based Service Discovery (SLP-B)  SLP-based service management for dynamic ad-hoc networks  Stefan Penz  Aachen University, Germany  UNDERLYING COMPONENT TECHNOLOGY  OpenCOM  It is a lightweight, reflective component model  Maintains a system graph of components currently in use in order to support introspection of a platform’s structure. Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Implementation Policy Network Reply Cache Advertiser Request Advertisement Request Reply Cache Policy Network Once Individual Once Stores local service descriptions in cache. Generates service advertisements. Manages protocol control messages. Stores service advertisements and protocol messages in cache. Heterogeneous service description languages Heterogeneous messages types and structure Directory presence advertisements Directory election advertisements (SSD) Advertisement Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Implementation Policy Network Reply Cache Advertiser Request Advertisement Request Reply Cache Policy Network Once Individual Once Request Service description matching Heterogeneous service descriptions Matching algorithms GSD Services are matched based on service groups SSD Services are also matched against others directories’ summaries Generates service requests. Processes incoming requests (matching). Forwards service requests. Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Implementation Policy Network Reply Cache Advertiser Request Advertisement Request Reply Cache Policy Network Once Individual Once Execution of additional process Hit-rate statistics of successful service requests Use of a reverse-route table to forward replies Reply Sends service replies Notifies applications of received replies Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Evaluation - Configurability Policy Network SLPB-Reply Cache SLPB-Advertiser SLP-BRequest ALLIA-Reply SSD-Reply GSD-Reply ALLIA-Request SSD-Request GSD-Request ALLIA-Advertiser SSD-Advertiser GSD-Advertiser Simplified configuration Same component types Same connection bindings Same configuration algorithm Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Evaluation - Configurability FRAMEWORK CONFIGURATION ServiceDiscovery Advertiser Advertiser_Network Network Network.INetwork Advertiser_Cache Cache Cache.ICAche …. Policy Network Reply Cache Advertiser Request Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Evaluation - Configurability AGENT CONFIGURATION ServiceAgent Advertiser Advertiser_Network Network Network.INetwork Advertiser_Cache Cache Cache.ICAche …. Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Evaluation - Configurability PROTOCOL CONFIGURATION GSD Advertiser GSD.Advertiser Request GSD.Request Cache Commons.Cache …. Policy Network Cache GSDRequest GSDReply GSDAdvertiser Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Evaluation – Re-configurability UA SA DA SLP-B SSD GSD ALLIA Protocol X XX X X UA SA DA SLP-B SSD GSD ALLIA Protocol X XX X Configuration A Configuration B UA Framework Description SA Framework Description SLP-B Protocol Description SSD Protocol Description GSD Protocol Description GSD Protocol Description Configurator.load(UA, SLP-B) Configurator.unload(SA, GSD) Configurator.load(UA, ALLIA) Simple re-configuration algorithms Well known configuration pattern Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Evaluation – Component re-use Policy Network SLPB-Reply Cache SLPB-Advertiser SLP-BRequest ALLIA-Reply SSD-Reply GSD-Reply ALLIA-Request SSD-Request GSD-Request ALLIA-Advertiser SSD-Advertiser GSD-Advertiser Simplifies development effort and time Reduces resource usage Enhances configurability Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Ad-hoc Service Discovery Framework Evaluation – Framework overhead ALLIASSDGSDSLP-B SIZE(KB) Framework SIZE(KB) Side by side Size of framework personalities X X X X X X X X X X X X X FrameworkSide by side Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Future work  Fine-grained architecture  Service description heterogeneity  Interaction heterogeneity (Set of message types)  Directory maintenance Matching algorithm A Lookup Policy Network Reply Cache Advertisement Request Parser AParser BMatching algorithm BMatching algorithm C  SDP Interoperability  Monitor component  Consider service discovery protocols from different network styles e.g. fixed, sensor, overlay etc. Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

Conclusions  Ad-hoc Service Discovery Protocols  SSD, GSD, ALLIA, SLP-B  Common functionality.  Ad-hoc Service Discovery Framework  Evaluation with the implementation of 4 existing ad-hoc service discovery protocols  Benefits:  Common component architecture  Component re-use  Minimize resource usage for multiple concurrent protocols  Simplify development  Code re-use  Future work  Fine-grained architecture  Evaluate our framework with discovery protocols from different network styles  Development of a middleware to provide service discovery interoperability across different network styles Research Goal Ad-hoc SDPs Architecture Ad-hoc SD Framework Future work Conclusions

? Carlos Flores, Gordon Blair, Paul Grace {c.florescortes, gordon,