## 1 Introduction  
A mobile ad hoc network (MANET) is a set of autonomous mobile devices connected by wireless links that cooperate with each other to achieve network functionalities in a distributed way and without a fixed infrastructure. Since mobile devices are free to move arbitrarily, this makes the network topology change dynamically [1; 2]. This work is based on our previous proposal named multipath multimedia dynamic source routing (MMDSR), which was previously presented in [3; 4]. The goal of this article is to further improve our proposal considering the social dimension by including a new tie strength (TS) metric as a measure of the interaction among users in social networks. As a result, our new proposal named QoS-aware and social-aware multimetric routing protocol for video-streaming services over MANETs (QSMVM) is able to offer a good trade-off between QoS and confidence in the forwarding nodes involved in the path. Providing multimedia services over MANETs represents a very attractive application of wireless networks for many cases, for instance in a disaster scenario or for entertainment purposes. The growth and big interest in ad hoc wireless networks has brought the development of new routing protocols and applications in many research areas such as the governmental or commercial sector, where ad hoc networks can be used in emergency or rescue operations for natural disasters (an earthquake, flood, etc.) where it is very likely the network infrastructure get destroyed [5]. Also, video-streaming services allow citizens to report any incident in the city (e.g., a traffic accident or a traffic jam), so that city authorities could have a better idea of the situation with a short and light video than just with a text message [6]. Another example for entertainment purposes is a video-streaming service to watch movies over MANETs [7; 8]. On the other hand, social web technologies, where people actively interact online with others through social networks, share multimedia contents, post comments and so on, are leading to a socialization of networks. Nowadays, users not only ask for information but also produce it. Currently, information of interaction among users in social networks is used to provide socially-enhanced software, always aware of the social environment of the users. To achieve this, we need to know the strength of the relationship between a given user and each user they interact with. The concept of tie strength (TS) was firstly introduced by [PERSON] in 1973 [9] as a function of duration, emotional intensity, intimacy and exchange of services. He distinguished two kinds of ties in social networks: strong and weak ties [10]. The TS concept summarizes the idea of social closeness between human beings. We claim that TS could also be used as a measure of trust in network communications. This aspect is relevant when information travels throughout different actors/elements, since trust (or closeness) may be used to assure the information travels through actors or elements that the two ends of the communication (i.e., sender and receiver) trust. Thus, considering together a social metric like the TS along with traditional QoS metrics (e.g., packet losses, packet delay, bandwidth, etc.) in the design of routing protocols, can offer a clear benefit to individuals concerned not only by the QoS level but also by the privacy of their communications. Motivation of our proposal: Our main motivation is to jointly consider several QoS metrics together with a new social metric in the design of a multimetric routing protocol for MANETs. The goal is to provide video-streaming services over MANETs improving not only the QoS offered to the end user, but also improving the trust on the intermediate forwarding nodes along the path from source to destination. Thus, our multimetric routing protocol for MANETs focuses on maximizing both the QoS and the trust of the forwarding path.