## 1 Introduction  
MANET consists of autonomous mobile nodes, which are capable of self-organizing and frequently reconfiguring due to the mobility in their nature. Therefore, the nodes are incapable of sharing services to other nodes available in the surrounding area [1, 2]. Generally, web-service composition enables application-to-application interactions over networks by comprising functional and non-functional characteristics. Functional requirements are related to the conformance of web-service composition to the conditions of its functionality. In contrast, nonfunctional requirements are associated with the QoS, e.g., response time, availability, and cost [3]. It provides interoperability because a single service cannot satisfy user requirements. The system requires composite services to achieve interoperability, consisting of many existing atomic services. These services may be hardware, software, raw data, etc. For example, you can consider that a laptop, which has software to be exchanged, can act as a service. Service composition is the integration of any existing e-services communicated over the Internet through wired media [4]. Recently, the research [5; 6; 7; 8; 9; 10; 11] on service composition over infrastructure-less networks has evolved enormously. Most of the works in the literature deliberate that the services available on the wired network are easily accessible; whereas, the services offered by the wireless network can be accessed by matching service composition protocols with infrastructure-less protocols. In addition, these services need brokers to exchange services among the requester and provider nodes in MANET. So, the research follows on providing service composition based on non-functional QoS parameters such as throughput, end-to-end delay, and packet-delivery ratio in MANET. A dynamic service composer is assigned based on QoS metrics among nodes, to compose various services for a wireless network based on user requirements. The various challenges in developing a dynamic service broker are due to node mobility, link failure, and topology changes in MANET, as discussed in [12]. The mobile nodes are grouped to form clusters, and each cluster is capable of assisting the scalability of the mobile nodes. A mobile node is selected to act as a cluster head based on the Multiple Cluster Head Gateway (MCHG) [13]. QoS is the term used to measure the objectives of both service provider and service requester; the QoS composition process will select the task based on metrics and aggregate the services that have obtained the maximum value by satisfying the user's requirement. Selection of the protocol for routing based on the QoS metrics in MANET is required. The research problem of embedding service composition in pervasive environments is divided into two approaches. The first approach is based on developing a language and workflow approaches such as BPEL4 WS, DARPA, and Web Services Flow Language discussed in [14]. The second approach is based on constructing architecture for discovering and integrating composite services in an infrastructure-less environment. This paper deals with the second approach, since it is indeed important to consider QoS parameters for the pervasive environment. The main contributions of this paper are presented below:  
1. Initially, an efficient cluster formation mechanism, namely the MCHG algorithm, is introduced to balance the load in the network. 2. A dynamic broker selection based on the QoS metrics is formulated to select an active broker and routing path. 3. A secured communication link within the intra-cluster is designed based on symmetric encryption and key-exchange protocol to prevent intrusion in the network. The rest of the paper are organized as follows. Section 2 discusses the various literature works. Section 3 illustrates the problem definition, and Section 4 deals with the overview of the QoSDSBS model. Further, a detailed discussion of the QoSDSBS model is presented in Section 5. Experimentation and result analysis are carried out in Section 6.