Mst is the cisco implementation of mstp, an ieee standard protocol that provides up to 16 instances of rstp. 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. For a layer 2 network to function properly, only one active path can exist between any two stations. 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. If you have not yet registered, you will be prompted to register, before proceeding to access this content. Root port is the port that is closest to the root bridge, which means it is the port that receiving the lowestcost bpdu from the root every nonroot bridge must have a root port. Spanning tree protocol timing protocol is timer driven too short timers can give loops and instabilities too long timers can give long convergence times until network reaches a stable spanning tree configuration proto id 2 root id 8 ver 1 bpdu type 1 flags 1 root path cost 4 bridge id 8 port id 2 msg age 2 max age 2 hello time 2. 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. Rapid spanning tree protocol rstp one big disadvantage of stp is the low convergence which is very important in switched network.
With the advent of layer 3 switching in lan environments, bridging now competes. Spanningtree protocol is a link management protocol that provides path redundancy while preventing undesirable loops in the network. Ccna training rapid spanning tree protocol rstp tutorial. Here you will find answers to spanning tree protocol questions. The spanning tree feature cannot be turned off in switches on a perport basis. Spanning tree protocol stp is a network protocol designed to prevent layer 2 loops. The classic spanning tree uses a max age timer 20 seconds for bpdus before they are discarded. Mst is commonly used in extremely large networks where running pvst would tax switch resources.
The spanning tree portfast is introduced to avoid the network connectivity issues. Mar 02, 2019 the spanning tree protocol stp is a network protocol that builds a loopfree logical topology in, the ieee introduced rapid spanning tree protocol rstp as w. Stp overview stp is a layer 2 link management protocol that prov ides path redundancy while preventing loops in the network. Vlan0005 spanning tree enabled protocol ieee root id priority 32773 address 00. These redundant paths cause the broadcast traffic to loop around indefinitely causing what is known as the broadcast storm. Lesson 122 where to place the spanning tree protocol root switch root bridge lesson 123 spanning tree protocol stp uplinkfast, backbone fast and portfast. Spanning tree protocol 90425 the cisco learning network. The main purpose of stp is to ensure that you do not create loops. Jul, 2019 the spanning tree protocol stp is a network protocol that builds a loopfree logical topology in, the ieee introduced rapid spanning tree protocol rstp as w. Jan 31, 2016 hi guys, this post got awarded best publication at the cisco support community.
See how it will also change the pathways to fit current link conditions to keep it operational. Can someone share videos and tutorials of advanced level stp with me personally please. The spanning tree protocol requires network devices to exchange messages to detect bridging loops. 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. How stp works video by sikandar shaik dual ccie rs.
One of the topics on the ccna rs version 3 exam is spanning tree protocol stp. To prevent loops, spa places some interfaces into forwarding state and some interfaces into blocking state. Lesson 124 what is spanning tree protocol stp uplink fast. On each switch, display the spanning tree table with the show spanning tree command. Cisco developed, implemented and published the per vlan spanning tree pvst proprietary protocol using its own proprietary inter switch.
The root path cost is used to elect root port and we will discuss in the next part. Stp will identify if there are any loops, and then disable or block. Configuring pervlan spanning tree protocol free ccna workbook. Join lazaro diaz for an indepth discussion in this video introducing spanningtree protocol, part of ccna cert prep.
In 2008 free ccna workbook originally started as a sharable pdf but quickly evolved into the largest ccna training lab website on the net. Digital equipment corporation created a protocol called spanning tree protocol stp to prevent broadcast storms and network loops at layer 2. Bridge id priority 32773 priority 32768 sysidext 5. This content is only accessible by registered users. Introduction to spanningtree spanningtree is a protocol that runs on our switches that helps us to solve loops. This article describes how stp spanning tree protocol works and what bpdus are.
Stp spanning tree protocol automatically removes layer 2 switching loops by shutting down the redundant links. If you are not sure how stp and rstp work, please read my stp tutorial and rstp tutorial. Lan switching configuration guide spanning tree protocol. This webcast shows you the stp topics for which youre responsible on the ccna rs 200125 or icnd2 200105. Rapid spanning tree protocol rstp, which significantly reduces the convergence time after a. Spanning tree protocol stp is a layer 2 protocol that runs on bridges and switches. Enabling the portfast causes the switch or trunk port to enter the stp forwardingstate immediately. You should have deep knowledge in basic networking. Many people struggle with stp so in this video, we try to break it down as much as possible.
Free cisco certified network associate ccna online. Review spanningtree protocol, which maintains a loopfree network by pruning redundant links and monitors the state of the network. Understanding and configuring spanning tree protocol stp on. Stp is a layer 2 link management protocol that provides path redundancy while preventing loops in the network. Just like every coin has two sides, a redundant link, along with several advantages, has some disadvantages. Sep 04, 2014 cbt nuggets trainer jeremy cioara explains how to configure spanning tree protocol as well as the different types of spanning tree protocols. Uplinkfast is used to improve the convergence time of stp in case of a link failure. Configuring pervlan spanning tree protocol free ccna. A computer network can be described as a system of interconnected devices that can communicate using some common standards called protocols. Stp spanning tree protocol step by step configuration. Ccna stp spanning tree protocol explained video from. We will focus on spanning tree protocol stp configuration and verification commands in this tutorial, as implemented on cisco.
It also includes the contents as well as explanation for certain sections of the bpdu. Free cisco certified network associate ccna online tutorials and study guides. The transmitting switch port id, will be discussed later 2. Ccna stp spanning tree protocol explained video from accelerated coaching program. First, it prevents problems caused by loops on a network. In this spanning tree protocol tutorial, i will present in simplest terms the operation of stp and indicate how this protocol prevents the creation of bridging loops. Rootthe port given this role is the selected best path to reach the root switch. Lesson 120 topology changes in spanning tree protocol stp lesson 121 spanning tree protocol stp convergence. Understanding and configuring spanning tree protocol stp on catalyst switches contents introduction prerequisites requirements components used background theory network diagram concepts description of the technology stp operation task stepbystep instructions verify troubleshoot stp path cost automatically changes when a port speedduplex is.
So if you are not sure about stp, please read my article about spanning tree protocol tutorial first. Stp spanning tree protocol explained with examples. Spanning tree protocol stp for ccna rs 200125 and icnd2. 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. I have studied much about stp but still there are many ques 90425. 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. Free cisco certified network associate routing and switching ccna routing and switching online tutorials and study guides. Spanning tree protocol is standardized as ieee 802. 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. The spanning tree protocol constructs a topology that has one path for reaching every network node. Spanning tree protocol introduction 11012015 jonathan leave a comment this is the first in a series of posts on spanning tree, in this post i will be describing the need for spanning tree protocol stp in modern lan environments.
How does stp decides in which state to port will be placed. The collective set of forwarding ports creates a single path over which frames are sent between ethernet segments. Spanning tree protocol concepts and configuration spanning. All the ports in forwarding state are considered to be in the current spanning tree. Learn stp features and functions in detail with examples. The golden rule of spanningtree protocol is lower is better. For an ethernet network to function properly, only one active.
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. Fundamentals of stp spanning tree protocol part i the logic. This is because layer 2 ethernet frameshave no time to live or time out mechanismbuilt into the frame. It is quite useful and should be enabled on the switch interfaces. And so, dont be too confused when we say root switch or root bridge, they are the same, they are the same.
Spanning tree protocol explained step by step youtube. With stp in place, you can have redundant links between switches in order to provide redundancy. Before we talk about spanning tree protocol, lets organize the different variants of stp. Spanning tree protocol stp is standardized as ieee 802. Configuring multiple spanning tree protocol mstp free. So the same nomenclature for the different reference points lives to this day. Root selection varies depending on the bid of each switch in your lab.
Protocols are covered in great detail in other guides. The spanning tree algorithm places each bridgeswitch port in either a forwarding state or a blocking state. I have attached the complete document in pdf format at the end, for download. On each switch, display the spanning tree table with the show spanningtree command. The resulting tree originates from the root bridgeswitch. Edc0 hello time 2 sec max age 20 sec forward delay 15 sec aging time 20 interface role sts cost prio. Spanning tree protocol ccnax 200120 ccna practice tests. Spanning tree protocol stp is a big topic on the ccna exam. Here is an example network consisting of two computers connected together. Spanning tree 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. Best printed in landscape mode ccna network simulator ccna exam simulator ccent network simulator ccent exam simulator juniper simulator 10 spanning tree protocols a. Understanding spanning tree protocol this section describes how spanning tree features work. Stp uses the spanning tree algorithm spa to create a topology database of the nework. So therefore, if there is a tie in our value with spanningtree protocol, there has to be a tiebreaker mechanism. Tutorial on stp, spanning tree protocol algorithm, which finds the minimum spanning tree for packet forwarding between switches in a network. This document descibes spanning tree protocol stp in a wireless environment. To overcome this problem, in 2001, the ieee with document 802. Vlan, trunking, vtp, stp, rstp, switch security and.
The main purpose of stp is to ensure that you do not create. Stp uses the spanningtree algorithm spa to create a topology database of the network. Pervlan spanning tree protocol is the default stp mode on cisco catalyst series switches. Switches running stp will build a map or topology of the entire switching network. Cisco spanning tree protocol guide stp examples and.
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. Spanning tree protocol this document descibes spanning tree protocol stp in a wireless environment. Once the root switch is elected, each of the ports is given a role depending on its place within the stp topology. 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. Spanning tree protocol stp spanning tree protocol stp was developed to prevent the broadcast storms caused by switching loops. Stp blocks some ports on switches with redundant links to prevent broadcast storms and ensure loopfree topology. Bpdus are now used as a keepalive mechanism similar to what routing protocols like ospf or eigrp use. The site was designed to help you pass the ccna exam 200125, but it can also be used as a reference site for anything networking related. Before reading this article you should understand how stp works. Root selection varies depending on the bid of each switch in your lab resulting in varying outputs. This standardized solution is called spanning tree protocol stp. Understanding spanning tree protocol this section describes how spanningtree features work.
A redundant link is usually created for backup purposes. If a switch misses three bpdus from a neighbor switch it will assume connectivity to this switch has been. Understanding and configuring spanning tree protocol stp. This section describes how spanningtree features work. As the name implies, stp, spans all switches in a network or subnet. Consists of bridge priority 2byte and macaddress 6byte. Rapid spanning tree protocol rstp is based on the ieee standard 802. The problem is that when we create redundancyat a layer 2 level of our networks,we create loops that traffic will traverse indefinitely. 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 stp uplinkfast, backbone fast and portfast. Cisco introduced several enhancements to the standard stp operation that were later incorporated in rapid spanning tree protocol rstp defined as ieee 802.
This tutorial explains what the stp protocol is and how it removes loops from the network. This protocol was created by radia perlman for bridges, ethernet transparent bridges. Jul 03, 2014 spanning tree protocol stp tutorial premium tutorial to provide for fault tolerance, many networks implement redundant paths between devices using multiple switches. However, providing redundant paths between segments causes packets to be passed between the redundant paths endlessly. It vigilantly monitors the network to find all links, making sure that no loops occur by blocking any redundant ones.