Multiple spanning tree protocol was developed to reduce the number of. In 1990, the ieee published the first standard for the protocol as 802. Dec, 2006 spanning tree protocol enhancements using loop guard and bpdu skew detection features. It is quite useful and should be enabled on the switch interfaces. It is recommended to read understanding rapid spanning tree protocol 802.
Although this document uses cisco catalyst 5500 5000 switches, the spanning tree principles that the document presents are applicable to almost all devices that support stp. Stp will identify if there are any loops, and then disable or block. Vlan0005 spanning tree enabled protocol ieee root id priority 32773 address 00. Configuring pervlan spanning tree protocol free ccna workbook. I have seen spanning tree being configured on switches to prevent switching loops.
Stp spanning tree protocol automatically removes layer 2 switching loops by shutting down the redundant links. Catalyst 4500 series switch software configuration guide. Dec 09, 2017 spanning tree protocol utilizes the fact that just like the spanning tree from the graph theory, this network protocol can calculate the least cost path from any node to the root bridge. May 24, 2016 user already knows cisco ios format and wants translation to mstpd spanning tree daemon for linux. Vrrp is configured on the hp 8200zl switches in the core. Spanning tree protocol stp is a layer 2 protocol that runs on bridges and switches. You can find the cisco configuration guide used to interpret their commands here. Lldp configuration example cisco lldp configuration example huawei multiple.
Refer to understanding multiple spanning tree protocol 802. As shown in example 310, the show spanningtree active command displays spanningtree configuration details for the active interfaces only. Understanding and configuring spanning tree protocol. Please refer to the spanning tree protocol documentation for more information. This lab will discuss and demonstrate the configuration and verification of 802. Understanding and configuring spanning tree protocol stp. Aug 29, 2017 spanning tree protocol stp is a big topic on the ccna exam. This is because with rstp each state has a much shorter timer. Spanning tree protocolsome links below may open a new browser window to display the document you selected. There are no specific requirements for this document.
Portfast feature causes a switch port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states. 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. For example, a broadcast or multicast packet that transmits from station m and is. Stp spanning tree protocol step by step configuration. Ospfopen shortest path first configuration in cisco packet tracer duration. Spanning tree protocol explained step by step youtube. Spanning tree interoperability between hp and cisco switches. For example, if all devices in a network have the bridge priority for vlan 100 set to the default value of 32768, entering the spanningtree vlan. Based on the exchanged bpdu information, the spanning tree algorithm selects one of the switches on the network as the root switch for the tree topology. Rapid spanning tree protocol rstp is the second stp type. Rstp bypass the blocking state and listenning state of stp, and provide forwarding state in 15 seconds. Stp can take up to a minute to converge, while rstp typically converges under 10 seconds in normal operation.
It was first introduced as cst common spanning protocol then ieee introduced its advanced version as stp with specification ieee 802. Cisco introduced several enhancements to the standard stp operation that were later incorporated in rapid spanning tree protocol rstp defined as ieee 802. This will be discussed in lab 415 configuring multiple spanning tree protocol. Rstp excellent summary of rapid spanning tree protocol. Lan switching configuration guide spanning tree protocol cisco. However, this setup creates the possibility of a bridging loop. Cisco saw the need for spanning tree on all vlans and create the proprietary pvst and. Spanning tree protocol stp spanning tree protocol stp was developed to prevent the broadcast storms caused by switching loops. Understanding spanningtree instance interfaces techlibrary. Stp spanning tree protocol explained with examples. For what reasons would we want to configure spanning tree on router.
Multi spanning tree protocol allows for resource conservation by now requring an instance for every single vlan in the layer 2 network. Configuring multiple spanning tree protocol mstp free. Cisco network troubleshooting spanning tree lab 01. Learn how to configure the spanning tree protocol on cisco switches. A redundant link is an additional link between two switches. Switches running stp will build a map or topology of the entire switching network. Many people struggle with stp so in this video, we try to break it down as much as possible.
To enable spanning tree, connect to your switch and type spanning tree mode while in global configuration mode. Catalyst 4500 series switch software configuration guide, 15. Remember, every time we modify the spanning tree topology, like changing priorities, spanning tree will need to converge. For example, if the idlefree interfaces are closed by the system administrator, you will be able to view only the active interfaces with this command. 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.
These two protocols operate with the same end goal in mind, yet one has a much more rapid convergence time rstp. This table shows the support of mst in catalyst switches and the minimum software required for that support. Cisco spanning tree protocol guide stp examples and configuration spanning tree protocol stp ensures a loopfree topology in a local area network lan made up of switches. One for network vlan, two for isolated subscriber vlans and another two for nonisolated subscriber vlans. A number of cisco ios command parameters are associated with the show spanning tree command.
The problem is that when we create redundancyat a layer 2 level of our networks,we create loops that traffic will traverse indefinitely. On ports connecting to other switches enable root guard. It is a fast converged version of spanning tree protocol as its name implies. This is because layer 2 ethernet frameshave no time to live or time out mechanismbuilt into the frame.
This chapter describes how to configure the spanning tree protocol. Configuring vstp protocol techlibrary juniper networks. Introduction to spanning tree spanning tree is a protocol that runs on our switches that helps us to solve loops. The following table lists some of the differences among the. I recently noticed that show spanning tree command works on a cisco 1841 router as well. Cisco spanning tree protocol guide stp examples and. Three spanning tree modes can be configured on cisco switches as shown in the output below. As shown in example 310, the show spanning tree active command displays spanning tree configuration details for the active interfaces only. Configure and troubleshoot cisco spanning tree stp. Multiple spanning tree mst is an ieee standard inspired from the cisco proprietary multiple instances spanning tree protocol mistp implementation.
Spanning tree protocol stp is a layer 2 protocol that runs on switches. Nov 22, 2014 dear all, regarding best practice related to spanning tree and etherchannel, we have decided to configure following. Bridge id priority 32773 priority 32768 sysidext 5. In some cases, rapid spanning tree protocol is similar to. Just like every coin has two sides, a redundant link, along with several advantages, has some disadvantages. Spanning tree protocol stp is a link management protocol that provides path redundancy while preventing undesirable loops in the network. The main purpose of stp is to ensure that you do not create loops when you have redundant paths in your network. Configure spanningtree on cisco router network engineering. Portfast on switch ports connected to a single workstation or server allows those devices to connect to the network immediately, instead of waiting for the port to transition from the listening and learning. Configuring vstp on a trunk port with tagged traffic, reverting to rstp or vstp from forced ieee 802.
Spanning tree protocol states when the stp is enabled, every bridge and switch in the network starts in the blocking state and transitions to the listening and learning states. This document assumes that the reader is familiar with rapid stp rstp 802. Spanning tree protocol configuration examples and technotes. For example, assume that one port on switch b is a fiberoptic link, and. The main purpose of stp is to ensure that switches do not create loops when they have redundant paths in a network. For an ethernet network to function properly, only one active path can exist between two devices. First, it prevents problems caused by loops on a network.
A number of cisco ios command parameters are associated with the show spanningtree command. The first spanning tree protocol was invented in 1985 at the digital equipment corporation by radia perlman. Supermicro l2l3 switches configuration guide 5 spanning tree enabled switches exchange spanning tree protocol messages bpdu to form a loopfree topology. To enable spanning tree, connect to your switch and type spanningtree mode while in global configuration mode. Configure stp spanning tree protocol in switches youtube. Mst was developed to reduce the number of spanning tree instances to reasonable value thus reducing cpu cycles needed to calculate stp for each vlan separately. If properly configured, the ports then stabilize to the forwarding or blocking state until a change in the network is made. Once the root switch is elected, each of the ports is given a role depending on its place within the stp topology.
Configuration examples and technotes view documents by topic choose a topic multiple instance stp mistp 802. A console cable that is suitable for the supervisor engine in the switch. An example of pvst per vlan spanning tree configuration on. Rootthe port given this role is the selected best path to reach the root switch. This way, we are setting the priority for both vlan 1 and 10. The following is the topology for this configuration example where 5 switches are full mesh connected. Spanning tree protocol concepts and configuration cisco press.
This table shows the support for mst in various catalyst switches. Understanding vstp, global and specific vstp configurations for switches, example. 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. Lan switching configuration guide spanning tree protocol. Nexus 7000 stp priority change in peer switch setup impact assessment and configuration example.
You can use the debug spanning tree bpdu command to view bpdus are are sent or received. Understanding and configuring spanning tree protocol stp cisco. We will focus on spanning tree protocol stp configuration and verification commands in this tutorial, as implemented on cisco switches. It is desirable to have redundant links in a switched lan so that a single link failure cannot interrupt normal operation of the network. Second, when redundant loops are planned on a network, stp deals with remediation of network.
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