30 lines
4.2 KiB
TeX
30 lines
4.2 KiB
TeX
% !TEX root = ../bachelor-thesis.tex
|
||
|
||
% 中英文摘要和关键字
|
||
|
||
\begin{abstract}
|
||
跨域覆盖网络需要为用户提供稳定的低延迟、高带宽和低丢包传输服务的同时降低运营成本。传统方案通常依赖专线链路保证服务质量，但专线成本较高。已有链路调度方法尝试在公网质量较好时使用公网分流，但实际测量表明，公网链路质量下降时段往往与用户流量高峰重合，难以有效削减专线峰值成本。已有端到端冗余编码方法能够缓解丢包影响，但未区分不同链路片段的质量差异，容易在质量良好的片段上引入额外带宽开销。
|
||
|
||
针对上述问题，本文提出一种面向跨域公网覆盖网络的分段链路质量修复方法。该方法在全公网互联的前提下，仅对低质量链路片段启用前向纠错编码。本文设计了交织XOR分组编码方案，以承载各类数据流并降低连续丢包的影响；建立三状态丢包信道模型，根据解码端上报的丢包统计动态选择编码参数；同时设计基于PI控制器的输出速率控制机制，缓解FEC解码按组恢复导致的突发输出问题。
|
||
|
||
本文使用Rust语言实现了原型系统，并在模拟跨域低质量链路的实验环境中进行验证。实验结果表明，本文方法能够正确识别低质量链路片段并启用FEC修复，在无丢包链路片段上保持普通转发。在0至~\SI{2}{\percent}链路丢包率范围内，与直接转发方案相比，本文方法最高达到约3.6倍吞吐提升，验证了分段链路质量修复方法的有效性。
|
||
|
||
% 关键词用“英文逗号”分隔，输出时会自动处理为正确的分隔符
|
||
\thusetup{
|
||
keywords = {覆盖网络, 前向纠错编码, 公网链路优化, 链路质量修复},
|
||
}
|
||
\end{abstract}
|
||
|
||
\begin{abstract*}
|
||
Cross-domain overlay networks need to provide users with stable low-latency, high-bandwidth, and low-loss transmission services while reducing operational costs. Traditional approaches usually rely on dedicated links to guarantee service quality, but such links are expensive. Existing traffic scheduling methods try to offload traffic to public Internet links when their quality is good. However, real-world measurements show that quality degradation of public Internet links often overlaps with user traffic peaks, making it difficult to effectively reduce the peak bandwidth cost of dedicated links. Existing end-to-end redundancy coding methods can mitigate packet loss, but they do not distinguish quality differences among individual link segments and may introduce unnecessary bandwidth overhead on high-quality segments.
|
||
|
||
To address these problems, this thesis proposes a segment-level link quality repair method for cross-domain public-Internet overlay networks. Under an all-public-Internet interconnection setting, the method applies forward error correction only to low-quality link segments. It consists of three key components. First, an interleaved XOR block code generates independent repair packets and spreads burst losses across different recovery groups, making the scheme suitable for diverse traffic flows. Second, a three-state packet loss channel model estimates link conditions from decoder-side loss statistics and guides the adaptive selection of coding parameters. Third, a PI-controller-based pacer smooths the bursty packet output introduced by group-based FEC recovery before the packets are delivered to upper-layer protocols.
|
||
|
||
This thesis implements a prototype system in Rust and evaluates it in an experimental environment that emulates low-quality cross-domain links. The results show that the proposed method correctly identifies low-quality link segments and enables FEC repair on them, while keeping normal forwarding on loss-free segments. With link loss rates from 0 to \SI{2}{\percent}, the proposed method achieves up to about 3.6x throughput improvement compared with direct forwarding, demonstrating the effectiveness of segment-level link quality repair.
|
||
|
||
% Use comma as separator when inputting
|
||
\thusetup{
|
||
keywords* = {overlay network, forward error correction, public Internet link optimization, link quality repair},
|
||
}
|
||
\end{abstract*}
|