Placement of plug-and-play network managers in SpaceWire networks: SpaceWire networks and protocols, long paper

Satellite onboard control systems have changed significantly towards of complexity of control algorithms. Network operation must be flexible and adapt easily to configuration and composition changes of the onboard network. Plug-and-Play should solve this problem. Plug-and-Play technology is aimed for network monitoring, should promptly detect changes in it and correctly handle any network situation. Due to size increase of onboard networks, one center (Plug-and-Play Manager), which would quickly react to changes in the entire network, is not enough, one must have several such centers. Thereby there is the problem of Plug-and-Play manager's placement in the network, to provide rapid response and efficient management of other devices in the network. Depending on the SpaceWire network functions and requirements, it must be taken into account in its design, in determining position for the Plug-and-Play managers. In the paper, we consider some reference variants of SpaceWire/GigaSpaceWire networks: ; Network designer chooses the number of Plug-and-Play managers according to the network size and others parameters. The network is not clustered, not divided into subnetworks. : Network designer chooses the number of Plug-and-Play managers according to the network size and others parameters. However, the network that is initially undivided into subnets, in the search for of the network managers location is divided into subnets. : Network designer clusters the network, divides it into subnets. For each subnet, the manager's placement problem is solved separately in accordance with the requirements to particular subnet. In this paper, we will consider in details two approaches to determining location of Plug-and-Play centers in SpaceWire/GigaSpaceWire networks. The first approach is based on a method of graph partitioning into subgraphs. The second approach is based on a P-median graph search algorithm. Both approaches are described in details. Advantages and disadvantages of these methods will be presented; their computational complexity will be evaluated. In network managers placement it is important, what will be characteristics of data transfer from Plug-and-Play managers to nodes. These characteristics include data transmission time, data transmission delay, etc. It is important how the network nodes are distributed among the Plug-and-Play managers for control. The network managers loading should be as uniform as possible. All these parameters directly affect the quality of the Plug-and-Play technology. We assess transmission characteristics between the Plug-and-Play manager and network nodes for each of these approaches, give recommendations of using these approaches for Plug-and-Play managers placement, taking into account various features of the construction and administration of SpaceWire/GigaSpaceWire networks.