On each switch, display the spanning tree table with the show spanning tree command. Cisco ios cisco ios mode explained with examples download. Understanding and configuring spanning tree protocol stp. Feb 10, 2016 spanning tree protocol, from a future ccna. Cisco also published a proprietary version of rapid spanning tree protocol. Ccna semester 3 chapter 5 spanning tree protocol ccna exploration 4. 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. Configuring multiple spanning tree protocol mstp free. Spanning tree basic functions now including rstp 802. It lets you peek at the message header or download just a part of a messageyou can now. Jan 31, 2016 hi guys, this post got awarded best publication at the cisco support community. Ccna course gives you the basic knowledge to operate a computer network. Root selection varies depending on the bid of each switch in your lab resulting in varying outputs. Rstp is similar to stp in that it elects the root switch using the same parameters and tiebreakers.
During the exchange of bdpus, to choose the ports that will be forwarding and ports that will be blocked, the spanning tree algorithm on a switch may use which three components. Spanningtree protocol stp premium ccna exam questions. Stp will identify if there are any loops, and then disable or block. Configuring pervlan spanning tree protocol free ccna workbook. On each bridge, select a root port port with the least cost path to the root bridge. Spanning tree protocol in layer 2layer 3 environments.
Links that will cause a loop are put into a blocking state. Choose 3 best answers path cost subnet mask bridge id port id your answer answer explanation. Spanning tree protocol port states, stp port states,logical loop free topology,root bridge,forwarding, blocking port,switch priority,32768,lowest mac address,root port, designated port,nondesignated port,disabled port, pdf download, pdf, stp port states pdf. A redundant link is usually created for backup purposes. 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. This study guide is intended to provide those pursuing the ccna certification with a framework of what concepts need to be studied. Stp spanning tree protocol explained with examples. Cisco ccna routing and switching 200120 spanning tree protocol concepts. The spanning tree protocol stp is a network protocol that builds a loopfree logical topology for ethernet networks. Nov 16, 2016 one of the topics on the ccna rs version 3 exam is spanning tree protocol stp. The specification for spanning tree protocol is 802. Apr 27, 2019 the command spanningtree portfast bpduguard default was issued in global configuration mode. Ccnp switch chapter 4 exam answers version 7 score 100%. Vlans overview intervlan routing, collision domain broadcast domain and segments.
The node with the smallest id is selected the root bridge 2. Jul 05, 2014 rapid spanning tree protocol, spanning tree protocol stp is enabled by default for all vlans in a switch. Ccna routing and switching practice and study guide. Feb 22, 2012 a beginners tutorial on the function and purpose of stp spanning tree protocol in a local area network.
Stp path cost automatically changes when a port speedduplex is changed troubleshoot commands command summary related information introduction spanning tree protocol stp is a layer 2 protocol that runs on bridges and switches. The message that a switch sends, allowing the formation of a loop free logical topology, is called a bridge protocol data unit bpdu. Before we talk about spanning tree protocol, lets organize the different variants of stp. By default, the bridge priority value is set to 32768 in all cisco switches. To change the priority to a lower value for root switch elections, use one of the following commands. Understanding spanning tree protocol this section describes how spanningtree features work. Modern extensions of stp will be covered later in this guide. Spanning tree protocol assigns a root bridge, root ports for nonroot bridges, and designated port segments. In the firs part of this book, network basics, you will learn different network layers, and the protocols. Multiple spanning tree protocol gives you the ability to configure a hierarchical spanning tree topology where you have a common spanning tree instance known as the cist, technically instance 0 in mst configuration mode. Switching is the process of using the physical address of devices to perform forwarding decisions. Spanning tree protocol stp was developed before switches were created in order to deal with an issue that occurred with networks that were implementing network bridges. The spanning tree protocol is a link management protocol that is designed to support redundant links while at the same time preventing switching loops in the network. Stp spanning tree protocol step by step ciscoforall.
Read here what is ccna fee last updated december 2018. Dec 05, 2019 spanning tree protocol is a layer 2 protocol that works on bridges and switches. It vigilantly monitors the network to find all links, making sure that no loops occur by blocking any redundant ones. When two interfaces are part of a loop, the spanningtree port priority and path cost settings determine which interface is put in the forwarding state and which is.
The command spanningtree etherchannel guard misconfig was issued in interface configuration mode. Spanning tree protocol port states best cisco ccna ccnp and. Stp overview stp is a layer 2 link management protocol that prov ides path redundancy while preventing loops in the network. Stp spanning tree protocol cis 187 multilayer switched networks ccnp switch rick graziani spring 2010 2.
Ccna in 21 hours it ebooks welcome to download ebooks. Just like every coin has two sides, a redundant link, along with several advantages, has some disadvantages. Redundancy is a great thing for a network to continue reading stp. Follow along with packet tracer download the following packet tracer file from my web site. Spanning tree protocol port states best cisco ccna ccnp.
Understanding spanning tree protocol this section describes how spanning tree features work. Spanning tree protocol concepts and configuration spanning. This is very necessary in large networks that are designed to have redundancy like backup switches and multiple paths across the network. Spanningtree protocol stp is a layer 2 protocol that utilizes a specialpurpose algorithm to discover physical loops in a network and effect a logical loopfree topology. All switches from cisco ship with spanning tree protocol stp enabled by default, but if stp is misconfigured for any reason, you can easily enable it. A redundant link is an additional link between two switches. This document descibes spanning tree protocol stp in a wireless environment.
This way, we are setting the priority for both vlan 1 and 10. Stp overview stp or spanning tree protocol is a protocol used on switches that prevents layer 2 switching loops and layer 2 broadcast storms. In this exercise, we will explain how does the spanning tree protocol work. For more information and to download the packet tracer files used in the video go to. This section describes how spanningtree features work. Rootthe port given this role is the selected best path to reach the root switch. Configure and troubleshoot cisco spanning tree stp. Spanning tree protocol this document descibes spanning tree protocol stp in a wireless environment. Switchb receives the packet on fa010 and sends it out on every port except that one. The spanning tree protocol requires network devices to exchange messages to detect bridging loops.
For a layer 2 network to function properly, only one active path can exist between any two stations. The main purpose of stp is to ensure that you do not create. So, each broadcast domain is a unique bridged internetwork that includes how the spanning tree protocol works. I discuss how stp mitigates layer 2 loops and layer 2 broadcast storms. Remember, every time we modify the spanning tree topology, like changing priorities, spanning tree will need to converge. To enable spanning tree, connect to your switch and type spanning tree mode while in global configuration mode. Second, when redundant loops are planned on a network, stp deals with remediation of network. Mst is commonly used in extremely large networks where running pvst would tax switch resources. In a converged network, ports are either in forwarding or blocking state. On each switch, display the spanning tree table with the show spanningtree command.
The flavor of spanning tree protocol, we have been discussing, so far in this module has been the traditional 802. Protocols are covered in great detail in other guides. Stp creates a loopfree tree structure consisting of leaves and branches that span the entire layer 2 network. This tutorial explains what the stp protocol is and how it removes loops from the network. Stp spanning tree protocol automatically removes layer 2 switching loops by shutting down the redundant links. Spanning tree protocol stp was developed to prevent the broadcast. To elect a root bridge from all switches of the network, stp uses two. The basic function of stp is to prevent bridge loops and the broadcast. The bridge id is made up of the mac address and priority. Spanning tree protocol stp spanning tree protocol stp was developed to prevent the broadcast storms caused by switching loops.
The spanning tree protocol prevents loops in a redundant network. May 28, 2008 this document descibes spanning tree protocol stp in a wireless environment. First, it prevents problems caused by loops on a network. Spanning tree protocol overview the plugandplay spanning tree protocol stp, a layer 2 protocol that ensures a loopfree topology in bridged lans, has been around for decades. The command no spanningtree backbonefast was issued in global configuration mode. Spanning tree protocol vs rapid spanning tree protocol. Configuring pervlan spanning tree protocol free ccna.
But there is a protocol called spanning tree protocol stp that is used to stop switching loops in a layer2 switched network. This webcast shows you the stp topics for which youre responsible on the ccna rs 200125 or icnd2 200105. It is quite useful and should be enabled on the switch interfaces. Spanning tree protocol stp in packet tracer part 1 youtube. This exam tests a candidates knowledge and skills related to network fundamentals, network access, ip connectivity, ip services, security fundamentals, and automation and programmability.
Stp is a layer 2 link management protocol that provides path redundancy while preventing loops in the network. Once the root switch is elected, each of the ports is given a role depending on its place within the stp topology. This section describes how spanning tree features work. Spanning tree protocol stp in packet tracer part 1. Spanning tree protocol stp for ccna rs 200125 and icnd2. 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. Spanning tree protocol variants best cisco ccna ccnp and. Vlan0005 spanning tree enabled protocol ieee root id priority 32773 address 00.