Questions tagged [spanning-tree]

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Q: Arista, can you read spanning-tree status via SNMP

Is it possible to use SNMP to read the spanning-tree status from Arista switches? Although it is possible to set up SNMP traps for spanning-tree, I did not find anything related to spanning-tree in ...
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Spanning Tree Protocol: How are ports selected to be designated or non-designated?

I have read a lot about STP now. Perhaps not enough yet, but it starts to get difficult to get details. I have understood the mechanism how all bridges select their root port. After having exchanged ...
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Spanning tree causing packet loss between a Cisco switch C3560 and Linux server running on CentOs

I am working in a network environnement where I have some Cisco Switch WS-C3560X-48 and Linux Servers running CentOS 7.7. The linux servers are connected 3 times on my switches : one admin link, one ...
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Cisco spanning tree configuration

I need your support for my spanning tree configuration. I like to bridge my public network to a server and give him a public IP. I am using a virtual wire at the firewall to forward the public network....
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How do I stop STP from blocking ports assigned to different VLANs

I have a spanning tree issue on my Cisco SG500 SMB Switches that I could use some help solving. Here is a diagram of my setup: SW1 (ports 44-47, VLAN 10) connect to port 43 (VLAN 10) on SW2, SW3, SW4,...
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MSTP: choice of MSTs and "freezing" an active topology

The scenario: A network topology consiting of a few layer 2 switches with some end devices on the edges. The pairs of end devices are in the same VLAN, a spanning tree protocol like MSTP created ...
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4 answers
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enabling Spanning-Tree or not

do you think is wise or stupid keeping the rapid spanning tree enabled for just two switches in this image? https://imgur.com/a/XI1NI As you can see the switches are not redundant each other but are ...
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Cisco STP with SG550

I have created a lab connecting 4 switches like in the topology below to test a STP with cisco sg550xg, but somehow it's creating storm and gives me this error 1y22w: %SW_MATM-4-MACFLAP_NOTIF: Host ...
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What routing/topology protocol(s) should be used with P2P devices with sporadic, changing connectivity?

I have several IoT devices that will sporadically come into and out of range, and connect in a partial mesh topology. For illustration purposes, imagine the interconnectivity of a Web of Trust, or ...
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Does PVST allow to bridge two VLANs?

I am having a Switch Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version 12.2(50)SE4, RELEASE SOFTWARE (fc1) I have interface FastEthernet0/1 up to interface FastEthernet0/48 are ...
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Linux Spanning Tree between Bond and an interface

I try to do something with network virtualisation to get my Proxmox server ready for production in an HA environment i'm using openvswitch 2.5 the Setup that i try to reach: My Server which has 4 ...
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How to troubleshoot a MAC flapping between switch ports. (Cisco)

I'm working on a rather small Layer 2 network segment that contains a physical loop. (I have included a picture of the topology below). The core switches are stacked 3850s. The other switches are ...
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EX4550 and EX4300 speak different dialects of JunOS 13.2X51-D35.3?

I have four EX4300-48T switches -- two in a VC, and two stand-alone -- both running JunOS 13.2X51-D35.3. I have, because I miraculously found some budget, added to these switches a pair of EX4550-32F ...
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-1 votes
1 answer
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Point of Sale Terminal Crashing the Network

We look after a series of restaurants which is a collection of point of sale terminals and a typically a single workstation per site. We have one site that is causing a fair amount of head ache and ...
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527 views

Group Policy Application on Boot with MSTP & really really fast computers

The latest generation HP computers with solid state drives and Win 10 are booting so fast that Multiple Spanning Tree Protocol is not allowing network access in time for Group Policy to process on ...
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Dell Switches and Spanning-Tree Route ID Configuration

I am analyzing a network for a colleague. It's a fairly simple topology and all the switches have converged on a common root-bridge, however two of the non-root bridges have identified the root as the ...
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Cisco spanning tree commands

I have been immersing myself in the Cisco STP documentation, but for the life of me I am not able to find anything relating to the toppology changes (aka ports logically going down) when certain ...
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HP ProCurve Preventing Loops and Users Plugging in Unauthorized Switches/Access-Points

We have a HP ProCurve 2530-24-PoE (J9773A) switch, recently I had a user who plugged in an Apple wireless hardware device to the network - whenever it was connected I got a ton of broadcast warnings ...
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Spanning Tree Protocol on HP5406zl and Netgear edge switches

I have a simple star network setup, a core HP switch with servers and storage, and WAN uplinks on it, and then trunked 2 x 1GB uplinks to some crappy old Netgear switches (I know, but moving on). We ...
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Do you need STP on ProCurve trunks?

We have 3 switches - a Core Switch, and 2 downstream switches. Each downstream switch has a 3 cable Trunk direct to the core switch. However - when we disconnected one cable in that trunk group (...
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cascading load on connected Alcatel-Lucent OmniSwitch units via VLANs

We are having an intermittent issue with a campus of Alcatel-Lucent Omniswitch switches, ranging from model 6000 to 6850. We are having a problem tracking down the root cause of our issue. The seems ...
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2 answers
426 views

Avoiding switch loop

Will I have loop problems with this topology because S2 and S3 are both connected to S1 and s4 ?
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Proper method for connecting multiple non-stackable network switches?

I deal with many clients in warehousing and industrial applications who have IT staff or local consultants. Many of these sites are still using a 10/100 Megabit switching backbone... I've managed to ...
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DHCP over PXE fails, but in the OS it works - with configured (R)STP

I'm trying to PXE-boot desktop-machines to install a new OS over the network, but it isn't picking up an IP address via DHCP during boot. When an OS is already booted on the machine, it is working ...
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1 vote
2 answers
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Portfast on a trunk port on a Cisco 3750

Good morning everyone! Some history, we have mixed environment of Dell Powerconnect 6248 switches and Cisco 3750 switches and a Cisco 6500 core for our Head office. We have two VLANs 1 & 20 ...
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Is grabbing multiple IP addresses from 1 link via a switch a good idea?

I need to connect several machines to the internet for work purposes. However, each workstation only has 1 LAN port. To get around this, I tried to connect a switch to the LAN port to "grab" multiple ...
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2 votes
1 answer
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Spanning-tree setup with incompatible switches

I have a set of eight HP ProCurve 2910al-48G Ethernet switches at my datacenter that are set up in a star topology with no physical loops. I want to partially mesh the switches for redundancy and ...
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3 votes
2 answers
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How to anticipate spanning-tree changes to prevent packet loss during convergence?

We have a LAN with Cisco switches, redundant cabling and spanning tree. If I understand it correctly, when I pull out a redundant cable (that is currently "used" by the spanning tree) it takes several ...
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8 votes
1 answer
11k views

Layer 2 Loop Avoidance: Three Switches in Series

I know this seems like a homework question, but it's actually part of a larger project (and network) and need to break it down into chunks so I'm clear with what I'm doing. I've never worked with [R/...
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4 votes
1 answer
250 views

STP in a mixed environment

Good day all, We have some a mixed environment of Dell Powerconnect and Cisco switches. On both brands of switches, I am seeing numerous STP topology changes. I've decided to try on work on the Dell ...
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3 dedicated wires for 3 VLANs between two switches: (M)STP failing

looking for a couple of hints from you we have a small but peculiar networking need: - 3 vlans, that are to be propagated among two L2 switches - we need to partition the vlans as much as possible, ...
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13 votes
5 answers
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If you turn on spanning tree, how do you know there is an issue with your network?

I have been learning about spanning tree protocol (STP/RSTP/MSTP) and was wondering, once I turn it on and it's protecting against for example network loops, how do I know there is a network loop? I ...
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2 votes
1 answer
685 views

Intermittent connectivity problems for servers on VLAN 1 with spanning tree

Recently we implemented spanning tree and redundant links in our infrastructure. This has resulted in systems on the default VLAN having intermittent connectivity problems when I plug in the backup ...
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9 votes
2 answers
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HP to Cisco spanning tree root flapping

Per a recent question I recently configured both my HP (2x 2900) and Cisco (1x 3750) hardware to use MSTP for interoperability. I thought this was functional until I applied the change to the third ...
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3 votes
2 answers
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Configure spanning tree from HP to Cisco hardware

I have three switches I'd like to configure in a loop - a Cisco stack (3750s) and two HP 2900 series. Each is connected to the next with a 10 gig backplane of one form or another. How do I configure ...
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1 answer
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Spanning tree outage with root port removal

Today, A tech at a remote server site unplugged a single port from one of our fiber converters for our WAN uplink from a Dell PowerConnect Switch. We lost all networking on the 3 stacked 48 port ...
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spanning tree protocol(STP) bridge priority configuration

I'm trying to figure out the appropriate spanning tree protocol settings for a redundant network topology I'm in the process of implementing. The graphic demonstrates what the physical layer will look ...
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1 vote
2 answers
331 views

Spanning-Tree and redundant links

I have 2 switches which have redundancy between them, meaning fa0/1 on SW1 is connected to fa0/1 on SW2, and fa0/2 on SW1 is connected to fa0/2 on SW2. Both of the switches have the same BID, however ...
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1 answer
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Spanning Tree Protocol (STP) to prevent network loop back issues?

I have several locations with managed network switches - for example, one being a stack of 3com 4500's. On occasion we have an issue where a user somewhere in the building decides to plug in their ...
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0 votes
1 answer
132 views

Strange behavoir of PVST

: The spanning-tree root for vlan 1050(192.168.50.0) is Core2 : The spanning-tree root for vlan 1020(192.168.20.0) is Core1 I was trying to add some redundancy to my network and added the links from ...
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1 answer
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Does native vlan tagging work with voice vlan?

we hard-code native vlan tagging: vlan dot1q tag native then we configure a port like this: interface FastEthernet0/1 switchport access vlan 20 switchport mode access switchport voice vlan 500 mls ...
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0 votes
1 answer
3k views

Netgear GS724T port issue between two switches

We have three 24 port (Gigabit) Netgear GS724T switches which are connected in the following way: SW-003 > SW-001 > SW-002 The port on SW-002 that connects to Sw-003 is constantly ...
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1 vote
2 answers
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Spanning Tree blocking DHCP requests in Windows/BOOTP

We have a LAN with 3 Cisco switches (SLM2048), a handful of Windows Servers and some WinXP/Win7PRO workstations. All devices are on the same LAN, no VLANs, nothing special configured on the switch (...
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Stackwise and RSTP states of other uplinks

Assuming I've got four C3750X, each side stacked with Stackwise Plus and using RSTP: C1 -----10Gbit----- C2 | | | | SW SW | | ...
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1 vote
1 answer
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SSTP BPDU with bad TLV and macflap -- info please

I'm slowly locking down the network I've inherited and mac-flapping has been a problem in the past with customers doing all kinds of crazy things. Thats changing but I am now encountering this error: ...
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2 votes
3 answers
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Firewall that supports HighAvailability and Spanning Tree

I'm looking for a firewall appliance that supports high availability and spanning tree. I have two ha-cluster nodes and I'd like to protect them with a firewall. To avoid a single point of failure, I'...
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Spanning Tree Portfast in JUNOS

Can someone tell me what the Juniper JUNOS equivalent is for Cisco's spanning tree portfast command? My google-fu keeps leading me to long whitepapers on Spanning tree and not so much configuration ...
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1 vote
3 answers
5k views

Spanning Tree required/desired for Port-Channel?

I have two Dell PowerConnect switches I want to connect together via Port-Channel links (2 ethernet links). Spanning tree is enabled on both switches, so therefore applied to all interfaces unless ...
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3 votes
1 answer
213 views

Network topology, clearing congestion

Our networking components consist of (3) x D-Link DGS 1248T Switches, and a router. We have 4-5 servers running as VMWare Host, HTTPD, and Storage. The clients on the network are connected to the ...
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4 votes
3 answers
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Redundant Ethernet links from a Linux box

This could be an RTFM kind of question. If so, I'll gladly award the answer to whoever gives a link to TFM :) In my racks, I've got redundancy all over the place. Two sets of switches, two upstream ...
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