Spanning tree concepts 12 draw a redundant topology 12 purpose of spanning tree 12 spanning tree operation identify the 802. To change the vlan associated with a port, you need to go to each interface or a range of interfaces and tell it which vlan to be a part of. You can download the cisco packet tracer example with. Packet tracer pt is a powerful and dynamic tool that displays the various protocols used in networking, in either real time or simulation mode. How to create your first sample network design using. Configure and troubleshoot cisco spanning tree stp learn how to configure stp. Stp spanning tree protocol explained with examples. Spanning tree also allows a network design to include spare redundant links to provide automatic backup paths if an active link fails. Catalyst 4500 series switch software configuration guide. Configure s1 to be the primary root for vlans 1, 10, 30, 50, and 70. The switch port is temporarily not forwarding frames, while it goes through the stages for the spanning tree protocol stp process. The other requirement is that all leaves are connected. 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.
This is the way packet tracer tells us which ports spanning tree is blocking. Access the packet tracer tutorial videos by clicking help tutorials. Catalyst 4500 series switch software configuration guide, 15. Click the question mark icon in the top, righthand corner of the menu toolbar. 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. Stp spanning tree protocol automatically removes layer 2 switching loops by shutting down the redundant links. Spanning tree protocol in layer 2layer 3 environments. Stp configuration lab1 open the packet tracer scenario. This lesson is an introduction to spanningtree, you will learn why we need it, how it works and how you can check the spanningtree topology on your cisco switches. Mst is commonly used in extremely large networks where running pvst would tax switch resources. I discuss how stp mitigates layer 2 loops and layer 2 broadcast storms. It shows what changes are made to a packet from source to destination as its processed by l2 and l3 devices, as well as changes between l2 datalink encapsulated frame types. This is very necessary in large networks that are designed to have redundancy like backup switches and multiple paths across the network.
Edc0 hello time 2 sec max age 20 sec forward delay 15 sec aging time 20 interface role sts cost prio. A beginners tutorial on the function and purpose of stp spanning tree protocol in a local area network. In this section, i will provide you a detailed tutorial for creating a p2p network using packet tracer. Edc0 this bridge is the root hello time 2 sec max age 20 sec forward delay 15 sec bridge id priority 32769 priority 32768 sysidext 1 address 0001. Spanning tree has n1 edges, where n is the number of nodes vertices. Sep 09, 20 network and cisco packet tracer tutorial. A minimum spanning tree mst is a subset of edges of a connected weighted undirected graph that connects all the vertices together with the minimum possible total edge weight. This means that each vlan is mapped to a single spanning tree instance. In a graph, there may exist more than one spanning tree. Configuring multiple spanning tree protocol mstp free. Spanning treeenabled switches go through a root election process based on bridge p rotocol data unit.
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. A spanning tree is a subset of an undirected graph that has all the vertices connected by minimum number of edges if all the vertices are connected in a graph, then there exists at least one spanning tree. Aug 04, 2011 spanning tree protocol stp is standardized as ieee 802. First, it prevents problems caused by loops on a network. What is spanning tree protocol stp sysnettech solutions. A redundant link is an additional link between two switches. 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 leaves represent end stations, and there is one and only one path from a leaf to another leaf. Introduction to the spanning tree protocol expert network. We start with the graph where the vertices are the cells and the edges represent the neighbors we can move to in the maze. Introduction to spanning tree spanning tree is a protocol that runs on our switches that helps us to solve loops. To derive an mst, prims algorithm or kruskals algorithm can be used. The bridge id has two components its priority and the mac address of the switch.
Packet tracer enables you to create networks, visualize how packets flow in the network, and use basic testing tools to determine whether the network would work. Redundancy is a great thing for a network to continue reading stp. Before proceeding, save as stp configuration lab1working. Although these networks are purely adhoc in nature, but it is always a good practice to start from here. This includes layer 2 protocols such as ethernet and ppp, layer 3 protocols such as ip, icmp, and arp, and layer 4 protocols such as tcp and udp. Feb 22, 2012 a beginners tutorial on the function and purpose of stp spanning tree protocol in a local area network. Spanning tree protocol stp initialization stp is the ieee 802. Configure and troubleshoot cisco spanning tree stp. The purpose of this simulation is to understand the concept of the spanning tree protocol. The spanning tree priority occupies the most significant two bytes of the bridge id. Root selection varies depending on the bid of each switch in your lab. Rapid spanning tree protocol improved stp with faster convergence backward compatible with stp rstp ieee 802. This content is only accessible by registered users. Cisco 2960 can do pvst, rstp, mst mrv mr2228s2c can do sta, mstp hp 1810 can do rstp, stp two main ciscos are linked with.
Stp overview stp or spanning tree protocol is a protocol used on switches that prevents layer 2 switching loops and layer 2 broadcast storms. Adding one edge to the spanning tree will create a circuit or loop, i. I have got a network around 100 switches which looks like this. Spanning tree selects the switch with the lowest bridge id as the root switch. The spanning tree protocol stp is a network protocol that ensures a loopfree topology for any bridged ethernet local area network. Spanningtree concepts 12 draw a redundant topology 12 purpose of spanning tree 12 spanningtree operation identify the 802. Oct 28, 2012 introduction to packet tracer packet tracer is a protocol simulator developed at cisco systems. Understanding spanning tree protocol in packet tracer to better understand the spanningtree protocol, we will examine the stp details by adding 4 switches in the cisco packet tracer program.
On each switch, display the spanning tree table with the show spanning tree command. If you have not yet registered, you will be prompted to register, before proceeding to access this content. When you see the packet tracer activity icon, you can use packet tracer with the listed file to perform a task suggested in this book. Download pdf stp spanning tree protocol step by step configuration tutorial when sw3 start receiving inferior bpdus at its interface from sw2, switch3 would ignore the inferior information until the bpdus stored with the blocked port expires max age timer 20 seconds. Use the spanningtree mode command to configure the switches so they use pvst as the stp mode.
Spanning tree protocol stp is standardized as ieee 802. Access the packet tracer help pages, tutorial videos, and online resources. Spanning tree protocol stp in packet tracer part 1. For all packet tracer examples and files, you can check packet tracer labs page. Just like every coin has two sides, a redundant link, along with several advantages, has some disadvantages. Nov 06, 2012 computer communication and networks, networking tutorial, networks tutorial, networking stuff, networks, vlan, vlan tutorial, vlan implementation, spanning tree protocol, virtual local area network, virtual lan, vlocal area network, spanning tree protocol on packet tracer, stp packet tracer, stp on pt, stp pt, stp on packet tracer. Root selection varies depending on the bid of each switch in your lab resulting in.
Rafat khandaker packet tracer spanning tree protocolpvst rstp 050516 abstract in this lab simulation, four switches have been set up to separate multiple hosts on a network. Spanning tree protocol protocol to calculate a spanning tree convergence all bridges should reach a unified view of the spanning tree special frames sent between neighbour switches bridge protocol data units, bpdus not forwarded. The spanning tree feature cannot be turned off in switches on a perport basis. Like alwaysit depends, lets take a look at an example. 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. Tree topology to avoid loops we need a tree topology consisting of a root, a succession of branches and then leaves. On each switch, display the spanning tree table with the show spanningtree command. In this example, we will configure rstp rapid spanning tree protocol with packet tracer. The spanning tree protocol stp is designed to prevent layer 2 loops. You can create a simple peer to peer network of simply two computers. A redundant link is usually created for backup purposes. Spanning tree protocol stp spanning tree protocol stp was developed to prevent the broadcast storms caused by switching loops.
Second, when redundant loops are planned on a network, stp deals with remediation of network. Understanding and configuring spanning tree protocol stp on. Therefore, the tree is free of loops that can cause havoc in a network. Lecture notes on spanning trees carnegie mellon school. If a port is green on one side, but amber on the other, it is blocked by the switch on the amber side. Root selection varies depending on the bid of each switch in your lab resulting in varying outputs.
Stp will identify if there are any loops, and then disable or block. Understanding spanning tree protocol in packet tracer to better understand the spanning tree protocol, we will examine the stp details by adding 4 switches in the cisco packet tracer program. If a port is green on one side, but amber on the other, it is. Spanning tree enabled switches go through a root election process based on bridge p rotocol data unit. Section 4 life of a packet quiz uses packet tracers simulation mode to gather the information necessary to answer the quiz questions listed in the topology diagram. Stp spanning tree protocol step by step configuration. When you have 20 vlans, it means there are 20 instances of spanning tree. When we examine the network topology above, we can see that all switches have the same priority values. The basic function of stp is to prevent bridge loops and ensuing broadcast radiation. Switches running stp will build a map or topology of the entire switching network.
1111 1486 1186 4 564 296 509 304 1206 873 897 480 549 151 477 1134 285 231 331 421 1530 1100 420 870 315 51 993 193 676 1429 81 261 571 354 261 329 1039 857 1327 904 371 698 124 1194 406