Spanning tree configuration on cisco switch

It is crucial to understand the impact of a default switch configuration on stp convergence and what configurations can be applied to adjust the default behavior. Configure spanning tree protocol stp on a switch cisco. Many people struggle with stp so in this video, we try to break it down as much as possible. To configure spanning tree protocol stp portfast on a switch running ios, run spanningtree portfast command as shown below. 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. Spanning tree interoperability between hp and cisco switches introduction this appendix explains and provides stepbystep configuration instructions for implementing multiple instance spanningtree protocol mstp and virtual router redundancy protocol vrrp on.

The basic function of stp is to prevent bridge loops and the broadcast radiation that results from them. Rootthe port given this role is the selected best path to reach the root switch. Configure spanning tree from hp to cisco hardware server fault. Huawei mstp and cisco multiple spanning tree mst are based on. Aug 20, 2019 if a network segment in the spanning tree fails and a redundant path exists, the spanning tree algorithm recalculates the spanning tree topology and activates the standby path. You configure the command spanningtree portfast on all the ports.

Portfast feature causes a switch port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states. 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. Overview of spanning tree protocols on huawei switches. Thats itjust one command will enable rapid spanning tree on our switches. Enabling loop protection for spanningtree protocols, configuring loop protection for a spanningtree instance interface, example. Catalyst 4500 series switch software configuration guide, 15.

The spanning tree feature cannot be turned off in switches on a perport basis. Configure stp spanning tree protocol in switches youtube. How to configure and verify spanning tree protocol stp portfast. First, it prevents problems caused by loops on a network. Sometime, it may necessary to change the spanning tree port priority value to fine tune spanning tree protocol we can change the spanning tree port priority value, using the interface configuration commad spanningtree vlan portpriority, as shown below you may change the spanning tree port priority value. Hello, in an ideal situation yes both switches should be in rstp however as it stands the 3750 will be currently working in pvst mode for the interconnects to the 6500 i would advise changing the stp mode of the 6500 at this time as you will cause outage to your lan. In this sample chapter from scaling networks v6 companion guide, explore potential redundancy problems, symptoms, and protocols to manage them. Both standards implement a separate spanning tree for every vlan. How to configure spanning tree on cisco switches youtube. Second, when redundant loops are planned on a network, stp deals with remediation of network. If the stack master fails, the stack members recalculate their bridge ids of all running.

Apr 28, 2012 mst multiple spanning tree is able to use a number of instances and maps multiple vlans to the same spanning tree calculation. Disabling spanning tree protocol stp can cause broadcast storms and layer 2 switching loops. Spanning tree interoperability between hp and cisco switches. Spanningtree bridge assurance is one of those stp features that help to prevent bridging loops in your network. Aug 29, 2017 spanning tree protocol stp is a big topic on the ccna exam. This switch does not need to be the most powerful switch, but choose the most centralized switch on the network. Catalyst 4500 series switch software configuration guide.

Youd like to use a spanning tree protocol that uses the 802. Spanning tree uses the extended system id, the switch priority, and the allocated spanningtree mac address to make the bridge id unique for each vlan. Cbt nuggets trainer jeremy cioara explains how to configure spanning tree protocol as well as the different types of spanning tree protocols. Spanning tree bridge assurance spanning tree bridge assurance is one of those stp features that help to prevent bridging loops in your network. Configuring loop protection to prevent interfaces from transitioning from blocking to forwarding in a spanning. When you enter spanningtree vlan root command, ios will check the switch priority values of the root bridges root switches for each vlan. To ensure that a switch has the lowest bridge priority value, use the spanningtree vlan vlanid root primary command in global configuration. Before you configure stp, select a switch to be the root of the spanning tree. Configuring spanning tree protocol costs on a cisco switch. Understanding and configuring spanning tree protocol stp cisco. This means that each vlan is mapped to a single spanning tree instance. Once the root switch is elected, each of the ports is given a role depending on its place within the stp topology.

Configuring loop protection to prevent interfaces from transitioning from blocking to forwarding in a spanning tree. To configure the stp maximum age, use the spanningtree maxage command in switch configuration mode. Spanning tree protocolsome links below may open a new browser window to. The switch with the highest priority will be elected as the root bridge. Learn how to configure the spanning tree protocol on cisco switches. Rstp allows switch port configuration so that the ports can transition to forwarding directly when the switch reinitializes. Follow the steps as we proceed from a blank scenario to one in which all the switches, mac addresses, ports, speeds, and costs are included. Spanning tree protocol concepts and configuration cisco press. Restricts the switch from sending unnecessary bpdus out access ports. When switches are interconnected via multiple paths, stp prevents loops from being formed. Dear all, regarding best practice related to spanning tree and etherchannel, we have decided to configure following.

When you disable spanning tree on a vlan, the switch does not participate in spanning tree and any bpdus that are received in that vlan are flooded on all ports. We can the show spanningtree vlan command to shows the. When creating new vlan 3, is it need to include spanning tree vlan 3 priority 8192 sw 1 and spanning tree vlan 3 priority 16384sw 2. Cisco spanning tree protocol guide stp examples and. For largescale distribution blocks, the network administrator can consider ieee mst as an alternate solution to simplify spanning tree instances. How to enable or disable spanning tree protocol stp. Lan switching configuration guide, cisco ios xe everest 16. Because the switch stack appears as a single switch to the rest of the network, all switches in the stack use the same bridge id for a given spanning tree. Esxvmware switch port configuration cisco community. Oct 12, 2011 hi jason, most of the time people will configure the port as a trunk to the esx host. We will focus on spanning tree protocol stp configuration and verification commands in this tutorial, as implemented on cisco switches. Bpdu guard is a safety feature for cisco switch ports that have portfast enabled. Hi jason, most of the time people will configure the port as a trunk to the esx host. All data flow across the network is from the perspective of this switch.

What will happen for those switch if didnt put in this command. Bridge priority switch priority value decides which switch can become root bridge root switch. Cisco introduced several enhancements to the standard stp operation that were later incorporated in rapid spanning tree protocol rstp defined as ieee 802. Stp configuration examples apply to some cisco catalyst switches like catalyst 2926g, 2948g, 2980g, 45004000, 55005000, and 65006000 switches that run catalyst os catos more related stp tips. To ensure that a switch has the lowest bridge priority value, use the spanning tree vlan vlanid root primary command in global configuration. All the switches exchange information for use in the root switch selection and for subsequent configuration of the network.

Spanning tree interoperability between hp and cisco switches introduction this appendix explains and provides stepbystep configuration instructions for implementing multiple instance spanning tree protocol mstp and virtual router redundancy protocol vrrp on specific hp and cisco catalyst switches. We can do that by using two global configuration commands. Understanding and configuring spanning tree protocol stp. Extreme care should be taken whenever you disable spanning tree because this creates layer 2 loops within the. Lan switching configuration guide spanning tree protocol cisco. To configure the cisco 3750 to use mstmultiple spanning tree use the following commands. Configuring pervlan spanning tree protocol free ccna workbook. 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.

Configure and troubleshoot cisco spanning tree stp. Also, choose the least disturbed switch in the network. In order to simplify the configuration of spanning tree on a switch, global settings are configured using what are known as spanning tree templates. Understanding and configuring spanning tree protocol. Spanning tree timers affect the spanning tree performance. Complete table 26 to show the default spanningtree configuration for a cisco catalyst 2960 series switch. The switch with the lower value has the higher priority. Spanning tree also allows a network design to include backup links providing fault tolerance if an active link fails as the name suggests, stp creates a spanning tree that. When you enter spanningtree vlan root command, ios will check the switch priority values of the root bridges root switches. Before configuring stp, the network topology should be carefully planned. Configure stp settings on a switch through the cli cisco. The following table lists some of the differences among the. Spanning tree protocol stp resolves redundant topologies into loopfree, treelike topologies. On ports connecting to other switches enable root guard.

Switch 15 enableshow spantree 1 vlan 1 spanning tree enabled spanning tree type ieee designated root 00100db17800. Network redundancy is a key to maintaining network reliability. To configure the stp protocol to run on the switch, enter the following. The priority is a parameter used to determine the root bridge for spanning tree. When two ports on a switch are part of a loop, the spanning tree port priority and port path cost setting determine which port is put in the forwarding state and which.

While i have posted a couple of blogs regarding spanningtree, the layer 2 loop prevention mechanism that runs on cisco switches, i wanted to post one with a few more switches and a bit more detail on the stepbystep process. If all switches are configured with the default priority value 32,768, the switch with the lowest mac address in the vlan becomes the root bridge. Complete table 26 to show the default spanning tree configuration for a cisco catalyst 2960 series switch. You need to configure spanning tree on a cisco 2960 switch. How to change spanning tree bridge root priority value and. The time spanning tree protocol stp takes to transition ports over to the forwarding state can cause problems.

Spanning tree protocol explained step by step youtube. Enabling bpdu guard allows the switch to monitor for the reception of bpdu frames spanning tree configuration frames on the port configured for portfast. The need for the spanning tree protocol stp arose because switches in local. By default, all cisco switches has a bridge priority switch priority value of 32,768. Most modern cisco switches default to a protocol called pervlan rstp. The spanning tree protocol stp is a network protocol that builds a loopfree logical topology. An stp loop or forwarding loops can occur when the entire network fails because of a hardware failure, a configuration issue, or a network attack. When you enable spanning tree protocol stp, every port in the switch, vlan, or network goes through the blocking state and transitory states. When a bpdu is received on a switch port with portfast and bpdu guard enabled, bpdu guard will cause the switch port to errdisable shut down. Configuring pervlan spanning tree protocol free ccna.

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. These templates include settings such as bridge priority, hello interval, and so forth. How to configure spanning tree on exos switch to connect. Like alwaysit depends, lets take a look at an example. Catalyst 2960x switch layer 2 configuration guide, cisco. Portfast is a feature which can be used to speed up convergence on ports which are connected to a workstation or a server which will not cause layer 2 loops. The spanning tree protocol stp is a network protocol that builds a loopfree logical topology for ethernet networks. How to configure spanning tree protocol root primary and. If a network segment in the spanning tree fails and a redundant path exists, the spanning tree algorithm recalculates the spanning tree topology and activates the standby path. Nov 22, 2014 dear all, regarding best practice related to spanning tree and etherchannel, we have decided to configure following.

Portfast is a cisco network function which can be configured to resolve this problem. Presentation et configuration du protocole spanning tree stp. We can use the same command to change the spanningtree mode i. Sep 09, 20 network and cisco packet tracer tutorial. On a cisco 1900 switch, up to four templates can be.

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. Never disable spanning tree protocol stp if there is no valid reason to disable it. Understanding loop protection for spanningtree instance interfaces, eliminating bridge loops in ethernet lans with spanning tree protocol, example. Cisco refers to this as rapid pervlan spanning tree rpvst. When an interface doesnt receive a bpdu for a certain time, the interface goes into the blocking state. Spanning tree protocol stp is a big topic on the ccna exam. Loop protection for spanningtree protocols techlibrary. Youd like to take advantage of fast convergence when the trunk link goes down and fast transition to forwarding state for edge links. Nexus 7000 stp priority change in peer switch setup impact assessment. Unless the config digest on two or more switches are configured the same the switches will be in different regions and behave like a rapid spanning tree 802. Understanding loop protection for spanning tree instance interfaces, eliminating bridge loops in ethernet lans with spanning tree protocol, example. Sonos, cisco, stp, mst, and spanning trees sonos community.

We are calculating a rapid spanning tree for each vlan. When creating new vlan 3, is it need to include spanningtree vlan 3 priority 8192 sw 1 and spanningtree vlan 3 priority 16384sw 2. Enabling loop protection for spanning tree protocols, configuring loop protection for a spanning tree instance interface, example. If you configure an exos switch to use rapid spanning tree it will require the configuration of an untagged vlan to. This is the mac address of the root switch for vlan 1. The valid value is from 0 to 61440, which are divisible by 4096. Every bridge switch participating in a spanning tree protocol network is assigned with a numerical value called bridge priority switch priority value. In stprstp, the value is the priority of the switch in spanning tree. This factor of time is not an issue for many people, but it can cause problems for. This article aims to show you how to configure stp on sx250, sx300, sx350, sg350x, sx500, and sx550x series switches. Mst multiple spanning tree lab on cisco catalyst switches. When you have 20 vlans, it means there are 20 instances of spanning tree. Although it is not recommended, you can turn off stp on a pervlan basis, or globally on the switch.

How to configure and verify spanning tree protocol stp. How to configure spanning tree protocol root primary and root. Mst multiple spanning tree is able to use a number of instances and maps multiple vlans to the same spanning tree calculation. Configure spanning tree from hp to cisco hardware server. In some other cases, we might want to turn these features on by default on all ports. How to configure spanning tree protocol stp on catalyst. To enable spanning tree, connect to your switch and type spanningtree mode while in global configuration mode. To configure a switch to become the spanning tree protocol stp root bridge root switch for a vlan, you can use the spanningtree vlan root command from the global configuration mode.

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