Design And Implementation Of The Space-Based Link Emulator

The space-based network is space wireless network system, interconnecting through the inter-satellite link by different kinds of orbits and satellites. With the rapid growth of the satellite network technology, the new network protocols become more and more complex. These protocols need to conduct strict testing before putting into operation. Network emulation combines the merits of network simulation and live testbed. It can not only provide a controllable and reproducible environment, but also can exchange network data with the outside in real time using real protocol implementations. Network emulation can implement in several layers, we chose the link layer because network link emulation can get relatively high measuring accuracy with lower costs, it is very suitable for the requirements of satellite network testing, and has important theory and practice value.This thesis first analyzes the techniques relative to the implementation of link-emulator, then designs a distributed link-emulator architecture, using Emulation Node(EN) to simulate the satellites, ethernet interface to simulate the link channel, Configuration-Management Server(CMS) to configure and manage the Emulation Nodes.In order to implement the reconstruction of the link topology and the dynamic update of link properties, we propose a model of the link properties and the Virtual-Link Association Talbes(VLAT).This paper uses Linux Virtual Interface and Queuing Discipline mechanisms to implement the distributed link-emulator. Link-emulator runs on the Emulation Nodes and emulates the space-based network link by controlling the forwarding of packets between the network interfaces.In the end, we test and validate the Link-emulator. According to the results, the link-emulator can simulate the satellite link well.