Assuring quality of service in the Columbus Ground Segment Network

Abstract

The ISS Columbus Ground Segment Network is a complex communication network which connects sites located in the USA (NASA), Russia (RSA), France (ATV-CC), Germany (COL-CC) and several user centers all across Europe. For the WAN communication between the different control centers and facilities MPLS technology is being used while the LAN setup employs Ethernet technology. One of the challenges within the IGS network is the simultaneous transport of different datastreams like TM/TC, voice, video, science data, etc., with separate and sometimes competing needs for quality of service parameters. While travelling from end to end, the datastreams cross different realms of the network. In addition limitations have been imposed by the wide area network provider. Some of those, well known in theory, have proven to yield surprising effects in reality. While most of the limitations were known at the design phase of the overall structure, a few have revealed themselves later during the test and implementation phases and had an impact on operations. The network in its present design is being used for more than two years. This article will present the building blocks and design parameters that shaped the setup of the network as it is being used today. Unused alternatives will be shortly discussed and the reasons for the choices that lead to the current setup will be given. A short outlook of the future development of the network will be presented together with a discussion of the limitations and consequences that cost driven technology changes imply.