卫星ATM网络中跨层设计的星上缓存管理优化方案

为提高卫星ATM(异步传递方式)网络星上缓存资源的利用率,针对利用上层协议重传的非实时数据业务,采用跨层设计方法提出了一种缓存管理优化方案—错误信元尾丢弃(ECTD)。它把信道误码引起的错误信元及后续的属于同一协议数据单元的无效信元丢弃。以早分组丢弃为基础,进一步建立了采用ECTD和不采用ECTD的分析有效吞吐量的数学模型。数值分析结果表明,ECTD具有优化缓存管理、提高有效吞吐量的作用,而且信元错误率和协议数据单元的长度越大,ECTD对有效吞吐量的改善就越明显。

Cross-layer Designed on-board Buffer Management Strategy for Satellite ATM Networks

Erroneous cell tail drop(ECTD),a buffer management optimization strategy through crosslayer design as proposed in this paper,could improve the utilization of onboard buffer resources in asynchronous transfer mode over satellite networks.The strategy,in which erroneous cells caused by satellite channels and the following cells in the same protocol data unit(PDU) are discarded,applies to nonrealtime data services that use higher layer protocol for retransmission.Based on early packet drop policy,mathematical models were established with and without ECTD.The numerical results show that ECTD would optimize buffer management and improve goodput.And the larger the cell error ratio and the PDU length,the greater the increment of goodput.