Cloud and IoT-Based Vehicular Ad Hoc Networks. Группа авторов

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Cloud and IoT-Based Vehicular Ad Hoc Networks - Группа авторов


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resources (services) as per the IOV user’s requirements. In a 5G-VANET milieu, the service discovery implementations include the VANET users and service providers.

      Service Consumers (SC) or VANET users: Service consumers request for the services.

      Service Providers (SP): SP publishes its services in the registry for access to SC.

      2.4.1 Service Discovery Methods

      The literature distinguished three types of service discovery methods such as,

      1 Push-based Service Discovery (PUSD)

      2 Pull-based Service Discovery (PLSD)

      3 Hybrid-based Service Discovery (HSD)

      PUSD: In PUSD, the service provider disseminates the services to all vehicles in the VANET milieu, does not wait for the requests from the VANET users. The PUSD is a proactive mode [15–22].

      PLSD: In PLSD, the vehicle user transmits a request towards the service provider to find the specific service. The PLSD is a reactive mode [23–25].

      HSD: The HSD uses both the PUSD and PLSD. HSD uses both proactive and reactive mode [26–29]. Table 2.1 depicts the characteristics of service discovery methods.

      2.4.2 A Framework of Service Discovery in the 5G-VANET Milieu

      Table 2.1 Characteristics of service discovery methods.

Characteristics PUSD PLSD HSD
Mode Proactive Reactive Proactive and reactive
Architecture Centralized Centralized Centralized
Routing Broadcast On-demand routing Unicast/Broadcast/ Geocast
Mobility Periodic update Not required Periodic update/event-driven update
Discovery Spatial distribution Context-based/Spatial distribution Context-based/Spatial distribution
Bootstrapping Broadcast Geographical Routing/Computationbased Geographic dissemination/Broadcast
Accuracy High High High
Scalability Yes No guarantee Yes
Reliability Yes Yes Yes

      Table 2.2 illustrates the difference between the routing unit and service unit. Both the routing and service units come under the discovery agents but they differ in the form of processing behavior of an approach, service discovery works on the service line to accomplish the effective services to the users and the route discovery is majorly spotlight on the defining route from vehicle user to the target for smooth transversal between nodes. The two units such as, routing, and service are used for the overall improvement of the framework in the form of operational and conceptual deportment.

      The routing unit protocol is distinguished based on their characteristics are Table-Driven Routing Protocol (TDRP), On-Demand Routing Protocol (ODRP), and Hybrid Routing Protocol (HRP) [30]. The definition of routing unit protocols based on their characteristics is as follows:

      Figure 2.2 A framework of service discovery.

      Table 2.2 Comparison of routing unit and service unit.

Characteristics Routing unit Service unit
Protocols Routing protocols Service protocols
Leaned on Process-Oriented Resource-Oriented
Discover Finds the superlative path Finds the superlative services
Parameter for Discovery Distance, energy, cost, and so on. Accuracy and efficiency.
Mechanism Route discovery mechanism Service discovery mechanism
Information Routing information Service information
Layer Network layer Network layer
Protocols PUSD, PLSD, and HSD [13–27]. TDRP, ODRP, and HRP [28].
Reliability Yes Yes

      ODRP: This protocol reads the topological information when it requires.

      HRP: Hybrid uses the features of both TDRP and ODRP.

      The few important network characteristics to be considered while designing the service discovery architecture for 5G-VANET are dense, mobility, scalability, collision, failure, congestion, reliability, service availability, and latency. The services provided by the service discovery mechanism are classified into two types such as fixed services and moving services. The definitions of fixed and moving services are as follows:

      Fixed Services:


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