Chapter 1-16. Introduction to Congestion in Storage Networks

Lack of Buffers for the Distance, Frame Size, and Speed of a Link

In lossless networks, the required number of buffers on a port increase as the length of its link increases, the speed increases and the average frame size decreases. 在无损网络中，随着链路长度的增加、速度的提高和平均帧大小的减小，端口所需的缓冲区数量也会增加。

In Fibre Channel fabrics, the lack of buffers reduces the amount of traffic that can be sent on a port. This results in lower link utilization and congestion spreading. In lossless Ethernet networks with PFC, lack of sufficient buffers may result in packet drops (which goes against the basic principle of a lossless network) or lower link utilization. The following chapters bring more clarity to this aspect based on the flow control mechanism such as B2B flow control and PFC. 在光纤通道结构中，缺乏缓冲区会减少端口上可发送的流量。这会导致链路利用率降低和拥塞蔓延。在使用 PFC 的无损以太网网络中，缺乏足够的缓冲区可能会导致丢包（这与无损网络的基本原则相悖）或降低链路利用率。以下各章将根据 B2B 流量控制和 PFC 等流量控制机制进一步阐明这方面的问题。

Lossy networks do not spread congestion. In some cases, when traffic crosses from a lossless to a lossy network, congestion in the lossy network may spread to the lossless network, for example when transporting Fibre Channel traffic via FCIP. Refer to Chapter 8, section on Fibre Channel over TCP/IP (FCIP) for more details on this scenario. 有损网络不会传播拥塞。在某些情况下，当流量从无损网络传输到有损网络时，有损网络的拥塞可能会扩散到无损网络，例如通过 FCIP 传输光纤通道流量时。有关这种情况的更多详情，请参阅第 8