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The author of the book thanked Radia Perlman for his time in helping to review the contents of this chapter. This chapter covers the following topics: What is spanning tree and why use spanning tree-a brief introduction to Spanning Tree Protocol (STP). Explaining why some loops avoid the presence of protocols is necessary for blocking broadcast storms and MAC Address Table exceptions (bridge table corruption). STP Forms 4 Steps--A selection calculation process that describes the spanning tree protocol. Initializes a three-step, detailed step of convergence of the STP convergence--STP on a loop-free topology. STP status-Describes the five states of STP and the process of switching algorithms between each state. The STP timers--discusses the three configurable timer used by the spanning tree protocol. STP Configuration Commands--provides a detailed explanation of the configured commands, and discusses some useful tips. bpdus--discusses the protocol data Bao topology change process of STP in detail--explains why the topology change after the physical network changes can allow the network to quickly re-converge. Setting up the root bridge--describes how to manually set up a network bridge to improve stability and performance. Spanning Tree per VLAN-explains how Cisco supports an STP instance on each VLAN. This feature makes the design very flexible, and the detailed information in the seventh chapter "Advanced STP".
Most network administrators and designers do not value the importance of Spanning Tree Protocol (STP). As routers became popular in the the 1990s, STP gradually became labeled "an unimportant protocol that is only obsolete". However, with the recent rise of exchange technology, spanning tree has become an important factor that has a great impact on network performance. In fact, STP often accounts for more than half of the configuration, error resolution, and tricky network maintenance in real life networks, especially in poorly designed networks. When I first faced exchange technology, I had the typical mindset: "How do I, as a three-storey expert, understand these complex things that digest stp?" ”。 However, I quickly found that STP, though complex, is basically not difficult to understand. I find it difficult to find information about collecting spanning trees, especially on current mainstream frontier applications (modern implementations). So, the purpose of this chapter is to make your STP learning process smoother. This chapter covers the mechanism of the spanning tree protocol, which is responsible for the basic functions of loop protection. This chapter passes "What is a spanning tree?" "and" Why do I need a spanning tree? "The two problems begin with STP learning to have a basic understanding of it. From here, this chapter will describe the spanning tree algorithm in detail from beginning to end. In the next chapter, the seventh chapter, "Advanced Spanning Tree", describes some complex topics such as load balancing and minimizing convergence time. In this chapter, the term bridge, switch, and tier two switches are used interchangeably. While some argue that these terms vary widely between different types of devices, these differences are not affected when we discuss spanning trees, especially when discussing STP standards that have been completed prior to the development of hardware switches. For example, you will learn the concept of "Root Bridge" (which is not a concern for now), although the term "root switch" is becoming more common, but I feel that the term is inappropriate for the first time I learned the Spanning Tree Protocol feature. The term "switch" is typically used when discussing a network deployment because it is rarely used on traditional, software-based "bridges".
Note: Please note that the example given in this chapter (and in the seventh chapter) is designed to illustrate the use of spanning tree protocol, and may not be very practical to use in design. The questions about design are highlighted in the following chapters: 11 chapters, three layers Exchange, 14 chapters, campus network design model, 15 chapters, campus network design and 17 case study: The realization of the Exchange network.
The classic "Cisco Lan switching" (i): Chapter 6. Understanding Spanning Tree
