With stp in place, you can have redundant links between switches in order to provide redundancy. Configuring switchport spanning tree portfast free ccna. In 2008 free ccna workbook originally started as a sharable pdf but quickly evolved into the largest ccna training lab website on the net. Cbt nuggets trainer jeremy cioara explains how to configure spanning tree protocol as well as the different types of spanning tree protocols. Introduction to stp, spanning tree protocol, broadcast storm, topological loop, switch macaddress table corruption,stp pdf file download, pdf file download, ethernet bridge, ethernet switch,layer 2 topological loop,ieee 802. Stp blocks some ports on switches with redundant links to prevent broadcast storms and ensure loopfree topology. Before we talk about spanning tree protocol, lets organize the different variants of stp. This section describes how spanningtree features work.
Free cisco ccna tutorial cisco ccna spanning tree basics. Stp spanning tree protocol automatically removes layer 2 switching loops by shutting down the redundant links. Stp spanning tree protocol explained with examples. Once the root switch is elected, each of the ports is given a role depending on its place within the stp topology. On each switch, display the spanning tree table with the show spanningtree command. Stp is a layer 2 link management protocol that provides path redundancy while. Spanning tree protocol stp cisco ccna certification. Stp is a layer 2 link management protocol that provides path redundancy while preventing loops in the network. The bpdus communicate and compute the spanningtree topology.
Blocking during blocking state, the port is listening to and processing bpdus after 20 seconds, the switch port changes from the blocking state to the listening state. One of the topics on the ccna rs version 3 exam is spanning tree protocol stp. In 2008 free ccna workbook originally started as a sharable pdf but quickly evolved into. So therefore, if there is a tie in our value with spanningtree protocol, there has to be a tiebreaker mechanism. At this time there were no switches yet, only bridges, but. Chapter 6 switching and spanning tree protocol free ccna. Spanning tree protocol stp is enabled, every switch in the network starts in the blocking state and later changes to the listening and learning states. The unique bridge id wireless bridge priority and mac address associated with each vlan on each wireless bridge the spanningtree path cost to the spanningtree root the port identifier port priority and mac address associated with each layer 2 interface. This document descibes spanning tree protocol stp in a wireless environment. Just like every coin has two sides, a redundant link, along with several advantages, has some disadvantages. How does stp decides in which state to port will be placed. In preparation of your ccna exam, we want to make sure we cover the various concepts that we could see on your cisco ccna exam.
Change the hello timer on all switches for vlan 10 to 4 seconds. Path of packet i count this as a technology topic because it involves the forwarding mechanisms for the various catalyst platforms, spanning tree protocol, multicast, and quality of service. Ccna 200120 chapter 1 spanning tree protocol flashcards. Start studying ccna 200120 chapter 1 spanning tree protocol. The bridges send configuration bpdus through the ethernet and radio ports. Furthermore, cisco loves to give you really complex topologies like the one we created. A redundant link is usually created for backup purposes.
By default, the bridge priority value is set to 32768 in all cisco switches. Spanning tree protocol variants best cisco ccna ccnp and. Stp uses the spanningtree algorithm spa to create a topology database of the nework. Vlan0005 spanning tree enabled protocol ieee root id priority 32773 address 00.
The flavor of spanning tree protocol, we have been discussing, so far in this module has been the traditional 802. The original stp was developed by radia perlman while working for dce back in 1990. As you prepare for your ccna certification exam, you will be called upon to merge multiple concepts you learned into one exam question. This content is only accessible by registered users. Spanning tree protocol stp spanning tree protocol stp was developed to prevent the broadcast storms caused by switching loops. Spanning tree algorithm is used to calculate a loopfree path. Root selection varies depending on the bid of each switch in your lab. In this exercise, we will explain how does the spanningtree protocol work. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Switches running stp will build a map or topology of the entire switching network. The main purpose of stp is to ensure that you do not create loops when you have redundant paths in your network. For an ethernet network to function properly, only one active. Understanding and configuring spanning tree protocol stp cisco.
Configuring pervlan spanning tree protocol free ccna. Spanningtree protocol is a link management protocol that provides path redundancy while preventing undesirable loops in the network. The basic function of stp is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree protocol stp ensures a loopfree topology in a local area network lan made up of switches. The stable, active spanningtree topology of a network is determined by the following factors. Configure and troubleshoot cisco spanning tree stp. How is the ttl field used to prevent indefinite looping of ip datagrams.
Cisco ccna spanning tree basics this is a course that will start from the very beginning of spanning tree and you will walk away with how it begins. Make sure switch grasshopper is the root bridge for vlan 40, switch butterfly should be the backup in case switch butterfly fails. Root selection varies depending on the bid of each switch in your lab resulting in varying outputs. This tutorial explains what the stp protocol is and how it removes. The spanning tree protocol stp is a network protocol that builds a loopfree logical topology for ethernet networks. Stp will identify if there are any loops, and then disable or block. Spanning tree protocol stp is a layer 2 protocol that runs on bridges and switches. Ccna in 21 hours about this book introduction this book gives a basic illustration for ccna cisco certified network associate, 640802 syllabus, which is a prerequisite certificate for most of the cisco certifications. This webcast shows you the stp topics for which youre responsible on the ccna rs 200125 or icnd2 200105. To prevent loops, spa places some interfaces into forwarding state and some interfaces into blocking state. What is the byte order used for transmitting datagram headers in the tcpip protocol suite.
For a layer 2 network to function properly, only one active path can exist between any two stations. Digital equipment corporation created a protocol called spanning tree protocol stp to prevent broadcast storms and network loops at layer 2. The following image shows how the stp changes a physically looped topology into a virtually looped free topology. As layer 2 networks grew, it quickly became evident that a system to prevent loops was needed if lans were to continue to function. This will be discussed in lab 415 configuring multiple spanning tree protocol. Understanding and configuring spanning tree protocol stp.
You already know that the layer 2 of the osi model deals with switching frames in the local network and that switches work at this layer. To view the information about the stp operation, you can use the show spanning tree command from the privilegedexec mode. The spanning tree protocol was created by dec digital equipment corporation now compaq. Cisco spanning tree protocol guide stp examples and. 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. With the advent of layer 3 switching in lan environments, bridging now competes. Spanning tree protocol understanding spanning tree protocol 3 cisco 3200 series wireless mic software configuration guide when the bridges in a network are powered up, each br idge functions as the stp root. Multiple spanning tree multiple spanning tree protocol mstp network organized in regions regions have their own multiple spanning tree instances spanningtree topologies vlans are associated to mstis one common spanning tree cst for the entire network mstp based on rstp rapid stp. Chapter 6 switching and spanning tree protocol freeccna 20150921t14. Ccna course gives you the basic knowledge to operate a computer network. On each switch, display the spanning tree table with the show spanning tree command. Thats where we can have a convergence time of 50 seconds and that where even, if we have multiple vlans, all of the vlans are using the same instances of spanning tree protocol, its called a cst or common spanning tree. As you already know, what we have just seen is a loop and such loops can bring a network to a grinding halt. The output of this command can be divided into three subsets.
It is desirable to have redundant links in a switched lan so that a single link failure cannot interrupt normal operation of the network. It vigilantly monitors the network to find all links, making sure that no loops occur by blocking any redundant ones. If you have not yet registered, you will be prompted to register, before proceeding to access this content. In the first chapter, you were introduced to bit of switching and switches. So to assist you, below we will discuss one of the more difficult ccna concepts.
Configure and troubleshoot cisco spanning tree stp learn how to configure stp, portfast and bpduguard on cisco switches free ccna course handson lab networking fundamentals switching troubleshooting written by alessandro maggio. Cisco ccna spanning tree protocol stp spanning tree protocols stps main task is to stop network loops from occurring on your layer2 network bridges or switches. We block fa02 and so we know now that we could cable two switches together, but spanningtree protocol hits us with a mallet and it says, you know what, you cant have your cake and eat it too, you cant add extra throughput to these two switches. The golden rule of spanningtree protocol is lower is better. A redundant link is an additional link between two switches. Spanning tree protocol stp is a network protocol designed to prevent layer 2 loops. This is where an understanding of stp spanning tree protocol comes into play.
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