In time-sensitive networks, bounds on worst-case delays are typically obtained by using network calculus and assuming that flows are constrained by bit-level arrival curves. However, in IEEE TSN or IETF DetNet, source flows are constrained on the number of packets rather than bits. A common approach to obtain a delay bound is to derive a bit-level arrival curve from a packet-level arrival curve. However, such a method is not tight: we show that better bounds can be obtained by directly exploiting the arrival curves expressed at the packet level. Our analysis method also obtains better bounds when flows are constrained with g-regulation, such as the recently proposed Length-Rate Quotient rule. It can also be used to generalize some recently proposed network-calculus delay-bounds for a service curve element with known transmission rate.
翻译:在具有时间敏感性的网络中,最坏情况延误的界限通常是通过使用网络微积分和假设流动受比特级抵达曲线的制约而获得的。然而,在IEEE TSN 或 IETF DetNet 中,源流量受包数限制,而不是比特的限制。获得延迟约束的共同办法是从包级抵达曲线中得出一个比特级的抵达曲线。然而,这种方法并不紧凑:我们表明,直接利用在包级显示的抵达曲线可以取得更好的界限。我们的分析方法在流动受g-管制(例如最近提议的“长线”引文规则)限制时,也会获得更好的界限。还可以使用这种方法将最近提出的一些网络量曲线延迟幅度用于已知传输速率的服务曲线要素。