# Networking of Multi-Robot Systems: Architectures and Requirements
## 5 Networking for Cloud and Fog-Based Multi-Robot Systems
### Cloud-Based Multi-Robot Systems  
Cloud computing could be incorporated as an important component of robotics applications as it can provide many powerful and advanced services needed to effectively operate these applications [47; 48; 49]. Cloud computing offer powerful processing capabilities, large and scalable data storage, and advanced software services that can be used to build different support services to be used in diverse robots and MRS applications. Cloud computing can be used as the main control and management platform to execute MRSs. Different robots, sensors and actuators of an application can be connected to cloud computing services to collect, process, store the robots and sensors' data and perform management tasks for different robots and MRS applications [50]. As the collected data from MRS and other related systems can become big data, cloud computing can be used to provide the necessary powerful platforms for storing and processing this big data to enhance operations and planning of the robots and MRS applications.  
The communication between robots of MRS applications and cloud computing involve different requirements to smoothly support these applications. These requirements should be supported by the network architectures deployed in the MRS. Cloud robotics and MRS applications rely on the integration between different robots on one side and the cloud on the other and cannot perform well unless there is a well-designed network that provides efficient and reliable communication services connecting both sides. Another issue that arises when using cloud computing for MRS applications is that the cloud services are either offered at a centralized location or across multiple distributed platforms in various locations. The distributed cloud computing approach can provide better quality and reliability support for different applications [51]. However, there is usually a need to provide good communication links among the distributed cloud computing facilities in these distributed locations. Another issue arising when using the cloud is the reliability and performance of the networks connecting all components on both sides [52]. With the Internet in the mix, there are problems with delays, lost packets, and unstable connections. Careful planning and management of network resources and communication models in addition to the design and architecture of the MRS application is necessary to account for these issues. Some of these issues may be resolved by the design efforts, yet there are some unavoidable aspects such as the transmission delays.  
One emerging networking technology that can provide some solutions for networking challenges in cloud-based MRS is software-defined networking (SDN) [53]. SDN offers some features for configuring cloud-based MRS to support different applications. These include improving QoS, reliability, latency, scalability, and security between MRS and the cloud computing components. While there are some efforts in investigating this approach for supporting other applications such as smart cities [54], there is very limited work to provide similar customized solutions for cloud-basedMRS. Therefore, there is plenty of room for developing more advanced management and networking mechanisms in SDN for efficient, reliable, and secure network configurations in cloud-based MRS.