# Spanning Tree **URL:** https://forum.networklessons.com/c/routing-switching/spanning-tree/16.md [Latest](https://forum.networklessons.com/latest.md) · [Categories](https://forum.networklessons.com/categories.md) --- ## [About the Spanning Tree category](https://forum.networklessons.com/t/about-the-spanning-tree-category/22)
**Author:** [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Replies:** 0\ **Last updated:** [December 13, 2016, 12:33pm UTC](https://forum.networklessons.com/t/about-the-spanning-tree-category/22 "2016-12-13T12:33:22Z")
Spanning-Tree helps us to create a redundant, loop-free topology. Any STP related questions can be discussed here. --- ## [Rootguard and Bridge Assurance](https://forum.networklessons.com/t/rootguard-and-bridge-assurance/58824)
**Author:** [@akhilnr21](https://forum.networklessons.com/u/akhilnr21)\ **Replies:** 1\ **Last updated:** [July 13, 2026, 5:03am UTC](https://forum.networklessons.com/t/rootguard-and-bridge-assurance/58824 "2026-07-13T05:03:04Z")
We faced an issue: Access switch uplink interface was configured first as port type network, and as soon as we entered port type network and guard root on the Core switch towards the access switch, the vlans got blocked… --- ## [STP on a daisy-chained network](https://forum.networklessons.com/t/stp-on-a-daisy-chained-network/55774)
**Author:** [@rob.mekken](https://forum.networklessons.com/u/rob.mekken)\ **Replies:** 4\ **Last updated:** [March 11, 2025, 6:25pm UTC](https://forum.networklessons.com/t/stp-on-a-daisy-chained-network/55774 "2025-03-11T18:25:13Z")
Hi René and team, I recently had an issue on a small daisy-chained network with three devices and STP enabled. Topology: Switch\_01 STP MAC: CCCC Prio: 32768 Port\_25 connected over 10Gps to Port\_09@Switch\_02 Port… --- ## [MST convergence and Port type edge](https://forum.networklessons.com/t/mst-convergence-and-port-type-edge/54589)
**Author:** [@houssemeddineyaacoub](https://forum.networklessons.com/u/houssemeddineyaacoub)\ **Replies:** 4\ **Last updated:** [February 5, 2025, 11:23am UTC](https://forum.networklessons.com/t/mst-convergence-and-port-type-edge/54589 "2025-02-05T11:23:59Z")
Hello, when MST convergence occurs in the topology, are the ports configured as Spanning-Tree Edge Trunk impacted by the changes in the topology, i get these logs : Here is the text with the asterisks removed from the s… --- ## [vPC & Spanning-Tree](https://forum.networklessons.com/t/vpc-spanning-tree/51165)
**Author:** [@Wheelz1492](https://forum.networklessons.com/u/Wheelz1492)\ **Replies:** 1\ **Last updated:** [August 10, 2024, 6:51am UTC](https://forum.networklessons.com/t/vpc-spanning-tree/51165 "2024-08-10T06:51:11Z")
I have 2 Nexus core switches that are vPC peers. The downstream switches are Meraki switches that are LAG uplinked to the 2 cores in a vPC config. So there are no loops here since they are vPC. I have no issues with S… --- ## [BPDU Version ID 0x04 SPT BPDU](https://forum.networklessons.com/t/bpdu-version-id-0x04-spt-bpdu/41940)
**Author:** [@juanrequejosilva](https://forum.networklessons.com/u/juanrequejosilva)\ **Replies:** 1\ **Last updated:** [January 9, 2024, 5:15am UTC](https://forum.networklessons.com/t/bpdu-version-id-0x04-spt-bpdu/41940 "2024-01-09T05:15:58Z")
Hi, I’m learning the purpose of each BPDU field(also each option) to create my Anki flashcards, but there is an option in the Version ID(0x04 SPT BPDU) that i don’t find their purpose, please could you clarify in which … --- ## [Spanning tree dilemma](https://forum.networklessons.com/t/spanning-tree-dilemma/15104)
**Author:** [@Support1](https://forum.networklessons.com/u/Support1)\ **Replies:** 7\ **Last updated:** [August 19, 2021, 12:22pm UTC](https://forum.networklessons.com/t/spanning-tree-dilemma/15104 "2021-08-19T12:22:06Z")
Hi all, Here’s another dilemma. I currently have 2x separate RSTP networks that are physically separate. I’m setting up a Nexus VPC core and will need to connect both of these networks, since Internet access will be ar… --- ## [Rapid-pvst wiith pvst](https://forum.networklessons.com/t/rapid-pvst-wiith-pvst/14970)
**Author:** [@amiie00](https://forum.networklessons.com/u/amiie00)\ **Replies:** 3\ **Last updated:** [July 28, 2021, 5:19am UTC](https://forum.networklessons.com/t/rapid-pvst-wiith-pvst/14970 "2021-07-28T05:19:25Z")
Dear admin, I found issue interface up/down on core switch every time when I plug interface on access switch. Core switch was configured spanning tree mode pvst and Access switch with rapid-pvst. I’m not sure STP wit… --- ## [Mst with multiple region](https://forum.networklessons.com/t/mst-with-multiple-region/14865)
**Author:** [@Binishkurup](https://forum.networklessons.com/u/Binishkurup)\ **Replies:** 1\ **Last updated:** [July 13, 2021, 7:08am UTC](https://forum.networklessons.com/t/mst-with-multiple-region/14865 "2021-07-13T07:08:56Z")
want to know how mst with multiple region operate and connect to external non-mst region with an example . from the perspective of non mst (like pvst,rstp,stp) do all region look like a single switch or a group of swit… --- ## [RSTP root with MSTP](https://forum.networklessons.com/t/rstp-root-with-mstp/14376)
**Author:** [@netdevpak](https://forum.networklessons.com/u/netdevpak)\ **Replies:** 1\ **Last updated:** [May 19, 2021, 5:33am UTC](https://forum.networklessons.com/t/rstp-root-with-mstp/14376 "2021-05-19T05:33:39Z")
Hello, I am studying for CCNP ENCOR and I could not get clear understanding how RSTP and MST can speak with each other. Specifically how it’s possible to make RSTP switch a root bridge. So this is the scenario: I have… --- ## [Doubts on PVSTP, RPVSTP and MST](https://forum.networklessons.com/t/doubts-on-pvstp-rpvstp-and-mst/13614)
**Author:** [@arya1981](https://forum.networklessons.com/u/arya1981)\ **Replies:** 1\ **Last updated:** [February 16, 2021, 6:06am UTC](https://forum.networklessons.com/t/doubts-on-pvstp-rpvstp-and-mst/13614 "2021-02-16T06:06:16Z")
Hi all, Still have many generic doubts about STP behavior. Hope you can Help me: During first syncronization, every switch things it is the root, so everyone sends bpdus. So, no port still begin in blocking state but… --- ## [RPVST and RSTP](https://forum.networklessons.com/t/rpvst-and-rstp/5716)
**Author:** [@william.touze](https://forum.networklessons.com/u/william.touze)\ **Replies:** 4\ **Last updated:** [January 25, 2021, 9:15am UTC](https://forum.networklessons.com/t/rpvst-and-rstp/5716 "2021-01-25T09:15:28Z")
Hello, I would like to know if i can mix RSTP ( other switch ) with RPVST with mutiple vlan. I seen on the network that i mix with the vlan 1 because the bpdu destination mac is similar to rpvst but with the other vlan … --- ## [(R)STP Topologe change and Convergence(synchronization) process. They are different?](https://forum.networklessons.com/t/r-stp-topologe-change-and-convergence-synchronization-process-they-are-different/11152)
**Author:** [@michael3.chung](https://forum.networklessons.com/u/michael3.chung)\ **Replies:** 1\ **Last updated:** [May 12, 2020, 7:21am UTC](https://forum.networklessons.com/t/r-stp-topologe-change-and-convergence-synchronization-process-they-are-different/11152 "2020-05-12T07:21:24Z")
Hi. Can anybody clarify my questions? please correct my misunderstanding if any. Q1) I’m confused if topology change process(TCN) and Convergence process progress simultaneously. As far as I know Topology change means… --- ## [Topology Change Notification (TCN)](https://forum.networklessons.com/t/topology-change-notification-tcn/9069)
**Author:** [@simtastic](https://forum.networklessons.com/u/simtastic)\ **Replies:** 0\ **Last updated:** [December 3, 2019, 9:25pm UTC](https://forum.networklessons.com/t/topology-change-notification-tcn/9069 "2019-12-03T21:25:50Z")
Simple question with an equally simple answer I am sure: When a non-root switch port transitions from blocking to forwarding a TCN will be generated so that all switches will know of the change and can readjust as neces… --- ## [Debug spanning-tree events](https://forum.networklessons.com/t/debug-spanning-tree-events/8827)
**Author:** [@neuralping](https://forum.networklessons.com/u/neuralping)\ **Replies:** 0\ **Last updated:** [November 11, 2019, 5:56pm UTC](https://forum.networklessons.com/t/debug-spanning-tree-events/8827 "2019-11-11T17:56:36Z")
I don’t get any immediate screen output from the debug spanning-tree events commands showing changes when I plug a host into the switch. Disabled spanning globally - no spanning tree default. I do see the number of topo… --- ## [Spanning tree network type](https://forum.networklessons.com/t/spanning-tree-network-type/8389)
**Author:** [@michaelby1](https://forum.networklessons.com/u/michaelby1)\ **Replies:** 1\ **Last updated:** [October 2, 2019, 11:02am UTC](https://forum.networklessons.com/t/spanning-tree-network-type/8389 "2019-10-02T11:02:54Z")
HI I have discover an issue that I need to change. I have 7 nexus and 4 Nexus 5 K connected however these port-channels are configured for spanning-type network, I need to make these spanning tree type normal , do i ju… --- ## [Spanning Tree Cost Calculation Page Question](https://forum.networklessons.com/t/spanning-tree-cost-calculation-page-question/8050)
**Author:** [@chris.plesco](https://forum.networklessons.com/u/chris.plesco)\ **Replies:** 0\ **Last updated:** [August 26, 2019, 7:40pm UTC](https://forum.networklessons.com/t/spanning-tree-cost-calculation-page-question/8050 "2019-08-26T19:40:40Z")
Hello, Looking at the Spanning Tree Cost Calculation Page, it says: SW3 will forward BPDUs to SW4. The root path cost field will be 100. SW4 receives a BPDU from SW2 with a root path cost of 19. SW4 receives a BPDU f… --- ## [Spanning-tree Rootguard contradiction](https://forum.networklessons.com/t/spanning-tree-rootguard-contradiction/4645)
**Author:** [@timopoelen](https://forum.networklessons.com/u/timopoelen)\ **Replies:** 1\ **Last updated:** [August 17, 2018, 4:06pm UTC](https://forum.networklessons.com/t/spanning-tree-rootguard-contradiction/4645 "2018-08-17T16:06:49Z")
Hello! I’ve come across some info while doing CCNP labs which kinda contradicts what i’ve learned in CCNA. Here goes: “Inside your network, using rootguard would actually be harmful. Your network can be considered trust… --- ## [Introduction to Spanning-Tree | NetworkLessons.com](https://forum.networklessons.com/t/introduction-to-spanning-tree-networklessons-com/3466)
**Author:** [@kingsnetworks3](https://forum.networklessons.com/u/kingsnetworks3)\ **Replies:** 1\ **Last updated:** [April 10, 2018, 3:24pm UTC](https://forum.networklessons.com/t/introduction-to-spanning-tree-networklessons-com/3466 "2018-04-10T15:24:12Z")
Hi I have one doubt why Sw3 is port priorities are showing 128 + port number, actually the port ID = default port priority + Interface number + 2 right ..? Interface Role Sts Cost Prio.Nbr Type -----------… --- ## [Rapid Spanning-Tree Config](https://forum.networklessons.com/t/rapid-spanning-tree-config/2801)
**Author:** [@dembeleboukalo1](https://forum.networklessons.com/u/dembeleboukalo1)\ **Replies:** 1\ **Last updated:** [January 28, 2018, 8:55am UTC](https://forum.networklessons.com/t/rapid-spanning-tree-config/2801 "2018-01-28T08:55:01Z")
I would like to know when i use show spanning-tree | begin interface commande. what does the column: Prio.Nbr mean --- ## [RSTP and portfast,uplinkfast,backbones)](https://forum.networklessons.com/t/rstp-and-portfast-uplinkfast-backbones/2287)
**Author:** [@anguiano.ojeda.08](https://forum.networklessons.com/u/anguiano.ojeda.08)\ **Replies:** 2\ **Last updated:** [October 16, 2017, 4:25pm UTC](https://forum.networklessons.com/t/rstp-and-portfast-uplinkfast-backbones/2287 "2017-10-16T16:25:38Z")
If I enable RSTP (SW1(config)#spanning-tree mode rapid-pvst) on all switches from LAN do I need to enable portfast,uplinkfast,backbonest also or is inbuilt? Or these ( portfast,uplinkfast,backbones)only applies when … --- ## [Bridge Assurance](https://forum.networklessons.com/t/bridge-assurance/1780)
**Author:** [@chrisnewnham17](https://forum.networklessons.com/u/chrisnewnham17)\ **Replies:** 1\ **Last updated:** [July 7, 2017, 9:48am UTC](https://forum.networklessons.com/t/bridge-assurance/1780 "2017-07-07T09:48:41Z")
Would be good to see a walkthrough of this technology - not sure if this is exclusive to NX-OS or not --- ## [Both switches thinks they are root](https://forum.networklessons.com/t/both-switches-thinks-they-are-root/667)
**Author:** [@lars](https://forum.networklessons.com/u/lars)\ **Replies:** 4\ **Last updated:** [May 25, 2016, 8:34pm UTC](https://forum.networklessons.com/t/both-switches-thinks-they-are-root/667 "2016-05-25T20:34:34Z")
Hi I have 2 S3048-ON configured with VLT (virtual link trunk), and a Dell 5548 connected to one of the S3048-ON (tried both one and two cables). All switches are configured with RSTP, and have configured priorities. B… --- ## [STP queries](https://forum.networklessons.com/t/stp-queries/673)
**Author:** [@ashwinmartis](https://forum.networklessons.com/u/ashwinmartis)\ **Replies:** 1\ **Last updated:** [May 22, 2016, 5:25pm UTC](https://forum.networklessons.com/t/stp-queries/673 "2016-05-22T17:25:14Z")
Could anyone please let me know , how the BPDUS are exchanged in STP Are the BPDUs exchanged only with their neighbors to which they are connected --- ## [MST Problems](https://forum.networklessons.com/t/mst-problems/548)
**Author:** [@trevorhubbard](https://forum.networklessons.com/u/trevorhubbard)\ **Replies:** 1\ **Last updated:** [December 3, 2015, 11:00am UTC](https://forum.networklessons.com/t/mst-problems/548 "2015-12-03T11:00:23Z")
Rene, I am trying to test multi-region MST and I’m having issues pinging between the regions. SW1 Questions: What does the type “p2p bound (RSTP)” mean? What does the port role “b…