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所在平台: Udemy |
课程主页: https://www.udemy.com/course/complete-spanning-tree-protocol-stp-course-by-arash-deljoo/
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**课程名称：** 跨越树协议 (STP) **主讲人：** Arash Deljoo **课程概述：** 本课程深入探讨了网络领域中至关重要的跨越树协议 (STP)。STP 是一种网络协议，旨在为以太网网络构建无环路的逻辑拓扑。其核心功能是有效防止桥接环路及其引发的广播风暴，同时通过引入备份链路提供故障容错能力，确保在活动链路发生故障时网络仍能稳定运行。 课程将详细解析 STP 的工作原理，包括它如何通过算法选择最优路径，并禁用非必需的冗余链路，从而在网络节点之间仅保留一条活动的通信路径。STP 的基础算法由 Radia Perlman 在 Digital Equipment Corporation 任职期间发明。 此外，课程还将介绍 STP 的发展历程，重点包括 2001 年 IEEE 推出的快速跨越树协议 (RSTP)，即 802.1w。RSTP 在网络变化或故障发生时提供显著更快的恢复速度，其引入的全新收敛行为和桥接端口角色，使其成为 STP 的重要升级。RSTP 被设计为向后兼容标准 STP。 最初，STP 标准化为 IEEE 802.1D，但其功能（包括 802.1D、802.1w 的 RSTP 以及多跨越树协议 802.1s）现已整合到 IEEE 802.1Q-2014 标准中。 课程将阐述 STP 产生的背景和必要性。在局域网 (LAN) 中，交换机常通过冗余链路互联以提高网络的弹性。然而，这种配置可能导致交换回路，进而引发广播风暴和 MAC 地址表不稳定。为了规避这些问题，STP 被部署在交换机上，用于监控网络拓扑，记录交换机间的链路，尤其是冗余链路。通过跨越树算法，STP 会屏蔽冗余链路的转发功能，在局域网交换机之间建立一条首选链路，仅在首选链路失败时才启用非首选冗余链路。 在具体实现层面，STP 会指定一个二层交换机作为根桥。所有其他交换机将根据其连接根桥的最佳路径选择以及阻止其他冗余链路来确定自己的角色。所有交换机通过发送桥协议数据单元 (BPDU) 与其局域网内的邻居持续通信。 **教学大纲：** 无
The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include backup links providing fault tolerance if an active link fails.As the name suggests, STP creates a spanning tree that characterizes the relationship of nodes within a network of connected layer-2 bridges, and disables those links that are not part of the spanning tree, leaving a single active path between any two network nodes. STP is based on an algorithm that was invented by Radia Perlman while she was working for Digital Equipment Corporation.In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides significantly faster recovery in response to network changes or failures, introducing new convergence behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with standard STP.STP was originally standardized as IEEE 802.1D but the functionality of spanning tree (802.1D), rapid spanning tree (802.1w), and multiple spanning tree (802.1s) has since been incorporated into IEEE 802.1Q-2014.The need for the Spanning Tree Protocol (STP) arose because switches in local area networks (LANs) are often interconnected using redundant links to improve resilience should one connection fail. However, this connection configuration creates a switching loop resulting in broadcast radiations and MAC table instability If redundant links are used to connect switches, then switching loops need to be avoided.To avoid the problems associated with redundant links in a switched LAN, STP is implemented on switches to monitor the network topology. Every link between switches, and in particular redundant links, are catalogued. The spanning-tree algorithm then blocks forwarding on redundant links by setting up one preferred link between switches in the LAN. This preferred link is used for all Ethernet frames unless it fails, in which case a non-preferred redundant link is enabled. When implemented in a network, STP designates one layer-2 switch as root bridge. All switches then select their best connection towards the root bridge for forwarding and block other redundant links. All switches constantly communicate with their neighbors in the LAN using bridge protocol data units (BPDUs).
