## 1 Introduction
Despite this knowledge, the protocol does not define a procedure to establish and maintain this federation. Other authors have tried to define this procedure in [16]. The proposed solution is based on the combination of current Internet technologies with Delay Tolerant Network (DTN) ones [17]. Specifically, a complete protocol stack with existing technologies is presented, proposing the Saratoga protocol [18] to exchange data as in a federation. This file-oriented protocol was originally designed to download data performing hop-by-hop transfers between satellites. The achieved results of this approach demonstrate the benefits of having federations to download data. However, this solution does not take into consideration a key concept of a federation: the service nature. As previously indicated, a service from a satellite is available during a lapse of time, according to the use of the resources. This temporal availability needs to be reflected in the protocol. Moreover, as the satellite resources are valuable and limited, their consumption must be properly negotiated and agreed before establishing the federation. For that reason, this work presents a new protocol, the Federation Deployment Control Protocol (FeDeCoP), that deploys federations integrating a negotiation process to agree on the resources to be shared. To the best of authors' knowledge, this negotiation process has not been defined in a protocol for satellite federations previously. The FeDeCoP is based on a connection-oriented mechanism. Although connection-oriented protocols are typically not suitable for satellite networks (due to the disruption of the network), the deployment of a federation entails the use of a context that takes into consideration the service status. This protocol was experimented in a dedicated field campaign with three stratospheric balloons. The goal of this campaign was to establish federations to share downlink opportunities and storage capacity. A dedicated hardware system has been implemented for this purpose: the Federated Satellite System Experiment (FSSExp) payload. This payload integrates the OSADP and FeDeCoP protocols. This manuscript presents the details and the outcome of the campaign. A discussion of the FeDeCoP performance is performed evaluating it in different configurations: when balloons are on ground, raising, and flying. The results demonstrate that using the proposed protocol the federations can be correctly established, and it is possible to increase the communications range using intermediate nodes. As a global overview, this work mainly contributes by extending [19] with (1) a detailed description of the FeDeCoP protocol and its features, (2) an explanation of the stratospheric balloon campaign to conduct a proof of concept of a federation, (3) discussion of the generated metrics of different types of federations, and (4) evidence of the benefits of using the proposed protocol by evaluating the retrieved results of the stratospheric balloon campaign. The remainder of this work is structured as follows. First, Section 2 discusses the nature of the federations and presents the details about the FeDeCoP protocol. The concept of the experiment conducted with the stratospheric balloon campaign is presented in Section 3. The different scenarios evaluated in the campaign and the obtained results are discussed in Section 5. Finally, Section 6 concludes the work.