Congestion Detection Strategy for Hierarchical Services in The Integrated Space-Earth Network

Aiming at the congestion problem in the space-earth integration network based on DTN architecture, this paper proposes a congestion detection strategy CGR-Key based on key contact which is assessment. When data packets ─which is called bundle in Bundle Protocol─ are queued for transmission, the bundles may be queued for high-priority services. As a result, the topology based on which the route is calculated is invalid, and the route may be congested. CGR-Key evaluates the capacity of the key contacts that are likely to be congested, detects congestion in the whole data transmission cycle by a priori, and takes measures to avoid congestion before it occurs. Because the local node's knowledge of the global topology may be biased due to the transmission delay of topology information, the local node cannot learn the global service distribution. Therefore, the local node can set a threshold to retain some redundant capacity when using contact to reduce the probability of congestion caused by “collision” and improve the service arrival rate. Simulation results show that CGR-KEY has better performance.