Understanding and configuring spanning tree protocol stp. It treats a port as joining the active topology when it becomes. Stp configuration lab 1 open the packet tracer scenario. Spanning treeenabled switches go through a root election process based on bridge p rotocol data unit. Spanning tree protocol stp determines the least cost path from the root bridge to other nodes in the networks. In this exercise, we will explain how does the spanningtree protocol work. Spanningtree protocol is a link management protocol that provides path redundancy while preventing undesirable loops in the network. A redundant link is an additional link between two switches. The spanning tree protocol stp is a network protocol that builds a loopfree logical topology for ethernet networks. Pdf the stp spanning tree protocol which is standardized as ieee 802.
Pvst can load balance traffic at layer 2 of the osi model without causing a loop. Spanning tree protocol typically runs on switches like the transition networks management aggregation converter smacf100. This protocol is used between switches, that will sometimes be called bridges in this lab. Spanning tree enabled protocol ieee root id priority 32773 address 00. But there is a protocol called spanningtree protocol stp that is used to stop switching loops in a layer2 switched network. The predecessor lan of b2 is a, so the link joining b2 to ashould stay.
This will be discussed in lab 415 configuring multiple spanning tree protocol. Cisco ccnp switch advanced spanning tree certificationkits. The basic function of stp is to prevent bridge loops and the broadcast radiation that results from them. Mst configuration is manual as there no current method to propagate this info as in vtp. Consider, city network as a huge graph and now plans to deploy telephone lines in such a. This topology makes more meaningful and challenging stp and vtp lab as compared to a single or switch pair topology. Root selection varies depending on the default bid of each switch. Root selection varies depending on the bid of each switch in your lab resulting in varying outputs.
In the first chapter, you were introduced to bit of switching and switches. Spanning tree protocol stp is a layer 2 network protocol used to prevent looping within a network topology. Spanning tree protocol online class with example and. Change the hello timer on all switches for vlan 10 to 4 seconds. Understanding spanning tree protocol this section describes how spanningtree features work. This lab is a continuation from the earlier set up exercise, and the lab layout is identical. Example of a bridged network with a loop, and the minimum spanning tree with the loop removed. To overcome this problem, in 2001, the ieee with document 802. Stp was created to avoid the problems that arise when computers compete for the ability to use the shared telecommunications path on a local area network. I e e e s standards are rapid spanning tree protocol rstp and multiple stp mstp. Chapter 6 switching and spanning tree protocol freeccna 20150921t14. Spanning tree also allows a network design to include backup links to provide fault tolerance if an active link fails as the name suggests, stp creates a. Layer 2 switching and spanning tree protocol stp kumar.
This lab will take youre understanding of spanning tree just a bit further. Spanning tree is basically used to find a minimum path to connect all nodes in a graph. Stp configuration lab1 open the packet tracer scenario. This unsettling scenario just described is called a broadcast storm and can be avoided completely by using a layer 2 protocol sent among switches called the spanning tree protocol. Spanning tree protocol this document descibes spanning tree protocol stp in a wireless environment. Before proceeding, save as stp configuration lab 1working. Chapter 3 lab 31, spanning tree protocol stp default behavior. Configuring pervlan spanning tree protocol free ccna. Once a proprietary protocol from dec, spanning tree protocol stp was standardized and blessed by the ieee specification, 802. For a layer 2 network to function properly, only one active path can exist between any two stations. We have some costly hardware test tools, but if you company is implementing spanning tree protocol, the chances are you will have any of these tools in ypur lab. If e is not in the spanning tree, then, indeed, we dont need it. Lecture notes on spanning trees carnegie mellon school. Spanning tree protocol stp spanning tree protocol stp was developed to prevent the broadcast storms caused by switching loops.
On each switch, display the spanning tree table with the show spanningtree command. Introduction to spanningtree spanningtree is a protocol that runs on our switches that helps us to solve loops. Stp spanning tree protocol step by step configuration. Stp, rstp, and mstp page 3 overview of spanning trees overview of spanning trees the concept of the spanning tree protocol was devised to address broadcast storming. Spanning tree protocol stp is standardized as ieee 802. Troubleshooting spanning tree protocol topology diagram addressing table device. What is spanning tree protocol with stp lab youtube.
A redundant link is usually created for backup purposes. 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. Spanning tree enabled protocol ieee root id priority. The information in this document was created from the devices in a specific lab environment. This lab has been developed as a packet tracer activity but can be completed with gns3 or real hardware. Spanning tree protocol stp you are the network administrator of ranet, and would like. Chapter 6 switching and spanning tree protocol free ccna. Spanning tree protocol stp is a layer 2 protocol that runs on switches. Lab 6 spanning tree protocol res 841 october 20 introduction in this lab, you will discover the spanning tree protocol, which is speci. Learn why do we need stp, spanning tree protocol and what it does to save your network from the loop and broadcast storm with lab example.
Im now able to create spanningtree protocol stp and vlan trunking protocol vtp lab using the famous switch triangle topology. Cisco ccnp switch rapid spanning tree protocolrstp. Make sure switch grasshopper is the root bridge for vlan 40, switch butterfly should be the backup in case switch butterfly fails. One big disadvantage of stp is the low convergence which is very important in switched network. Stp spanning tree protocol automatically removes layer 2 switching loops by shutting down the redundant links. This lab will explain the functions of the ieee standard multiple spanning tree protocol also referred to as mst. Ranetcoresw to be the root bridge port fa02 of ranetsw2 to be in the blocking state please config spanningtree parameter on both ranetcoresw and ranetsw2 via its console to be as the requirement above. Spanning treeenabled switches go through a root election process based on bridge p rotocol. As the name suggests, it creates a spanning tree within a mesh network of connected layer2 bridges typically ethernet switches, and disables those links that are not part of the spanning tree, leaving a single active path between any two network nodes. He also developed several training and lab sessions for. The purpose of this lab is to introduce the spanning tree protocol and how to configure priorities of core, distribution and access switches appropriately. When working with a switch that has been previously configured, any new commands entered will be merged. Just like every coin has two sides, a redundant link, along with several advantages, has some disadvantages. Observe and explain the default behavior of spanning tree protocol stp, 802.
Rapid spanning tree protocol rstp, which significantly reduces the convergence time after a topology change occurs in the network. Mst is commonly used in extremely large networks where running pvst would tax switch resources. Read how do all the operations happen and what are the chief components of the same. Root selection varies depending on the bid of each switch in your lab. Stp will identify if there are any loops, and then disable or block. All of the devices used in this document started with a cleared default configuration. Stp spanning tree protocol explained with examples.
The multiple spanning tree protocol mstp is an stp variant that allows multiple and independent spanning trees to be created over the same physical network. Switches running stp will build a map or topology of the entire switching network. 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. The multiple spanning tree protocol mstp and algorithm, provides both simple and full connectivity assigned to any given virtual lan vlan throughout a bridged local area network.
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. It was first introduced as cst common spanning protocol then ieee introduced its advanced version as stp with specification ieee 802. Before proceeding, save as stp configuration lab1working. The possible states that a spanning tree port can be.
The spanning tree protocol stp is designed to prevent layer 2 loops. Ciscos per vlan spanning tree pvst provides a significant step up from. Cisco saw the need for spanning tree on all vlans and create the proprietary pvst and. Configuring multiple spanning tree protocol mstp free. Stp overview stp is a layer 2 link management protocol that prov ides path redundancy while preventing loops in the network.
As jonathon mentioned, there are so many devices that combine. The spanning tree protocol run my experiment on geni. Complex protocol that is generally poorly understood. This lab is complete when all wired trunks are carrying traffic, and all three switches are participating in. Spanning tree protocol stp stp often accounts for more than 50 % of the configuration, troubleshooting, and maintenance headaches in real world campus networks especially if they are poorly designed. In addition, you will design an addressing scheme based on host requirements. Stp is a layer 2 link management protocol that provides path redundancy while preventing loops in the network. For an ethernet network to function properly, only one active. This section describes how spanningtree features work.
To create a loopfree tree, bridges in the network exchange bpdus, and execute the spanning tree protocol as follows. Clear the configuration of a standalone switch to prepare it for a new lab. 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. You can build the bpdu packet using the tool and test. You are not allowed to use the spanningtree root command. In this lab scenario, you will configure a redundant network with vtp, multiple vlans, and stp. Ccnp switch chapter 4 lab 42 multiple spanning tree. The purpose of this lab is to introduce the spanning tree protocol and how to configure priorities of core, distribution and access switches.
Pervlan spanning tree protocol pvst is maintaining a spanningtree instance for each vlan configured in the network and uses ciscos proprietary isl trunking protocol. The stp module transmits and receives bpdus bridge protocol data units which permit the module to learn the topology of the network and disable ports if necessary. You use an algorithm called the spanning tree protocol just one of the. In this lab, you will discover the spanning tree protocol, which is specified in the ieee 802. Principles of imperative computation frank pfenning lecture 24 november 18, 2010 1 introduction.
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