Questions tagged [spanning-tree]
For questions about Spanning Tree Protocol (STP), originally defined by IEEE 802.1D, to prevent bridge loops at OSI layer-2.
0
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2answers
20 views
RSTP recovery time with Ethernet ring
I am trying to test Rapid Spanning Tree on an Ethernet ring. Most of what I found does not seem to apply to my specific situation, but I am happy to be pointed elsewhere.
Specifically, I have one ...
1
vote
2answers
41 views
Spanning tree protocol
I have a questions regarding STP and i would like to know if STP is only a feature of layer 2 switches? i am on GNS3 and i am trying to enable STP but it tells me that there is no spanning tree ...
6
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1answer
144 views
MSTP and Rapid-PVST+
We have a medium sized network running all Juniper except for one building. This building is shared with another group, and is completely Cisco. We just trunk our VLANs up there.
Our Juniper network ...
0
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3answers
44 views
Using VRRP instead of XSTP
Suppose there is a ring with two routers (L3 switch) and 3 switches. All devices are configured properly.VRRP is configured on both routers and one virtual gateway is introduced to switches and their ...
0
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1answer
35 views
designated ports and root ports in STP
I am just a bit confused about designated ports in STP, i know how to determine them and the confusion is about the say " designated port is the only port in charge to forward traffic on a segment ". ...
0
votes
1answer
38 views
Disable STP and force port state on a Avaya 4950 switch port
I know how to connect a switch on a router Avaya VSP 7200 by disabling STP with the command :
no spanning-tree mstp force-port-state enable
but how to force port state on a switch Avaya 4950?
...
0
votes
0answers
24 views
Spanning tree priority values on port-channel
Group Port-channel Protocol Ports
-------------------------------------------------------------------------
1 Po1(U) LACP Gi0/3(P),Gi0/9(P)
4 Po4(U) LACP ...
2
votes
2answers
188 views
Spanning tree Priority values
show spanning-tree interface gigabitethernet 0/2
Switch default
Instance Role State Cost Prio type
-------- ---- ----- ---- ---- ----
MST00 ...
1
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2answers
88 views
Fastest spanning tree in multiple-ring topology
I have a topology in which there is a main ring and some nodes in the main ring have a minor ring.
1- which STP configuration has the fastest convergence time? How would you configure spanning tree ...
9
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3answers
2k views
I have a single ethernet switch. Should I use spanning tree?
I have a single ethernet switch. Should I use spanning tree?
If there is a redundant link, definitely need to enable STP.
In a single switch, how is it possible to have a redundant link?
Any other ...
1
vote
2answers
37 views
Spanning tree - per vlan spanningntree vs rapid spanning tree
Which spanning tree protocol is link state and which one is vector state. We have stp and rapid spanning tree !!
4
votes
2answers
250 views
Network Redundancy with LACP Trunking
I would like to set up a redundant link between two switches. I have four ports available to accomplish this.
Scenario A: Switch 1 has ports 1+2 trunked together via LACP. They are plugged into ...
3
votes
1answer
47 views
Cascading a switch interface to another switch
We have a service provider switch which has an interface that we use to connect to other users over.
We have been advised by the SP that we can use this interface how we wish (i.e. feed it into a ...
4
votes
2answers
227 views
spanning tree RootGuard question on vPC switches
I have following diagram and two distribution switch connected back to back over vPC
Related spanning-tree question is it ok to use RootGuard on both distribution switch where access switch is ...
4
votes
1answer
256 views
How does STP convergence work?
Consider the IEEE 802.1D (first revision) Spanning Tree Protocol. I have read a lot of articles and forum entries about STP convergence. Often I do find contradictions about the convergence mechanics. ...
1
vote
1answer
137 views
PVST + MST + RSTP network. Possible to make it work?
I have got a network (around 100 switches) which looks like this:
Cisco 2960 - can do PVST, RSTP, MST
MRV mr2228-s2c - can do STA, MSTP
HP 1810 - can do RSTP, STP
Two main Ciscos are linked with ...
2
votes
2answers
166 views
OpenvSwitch Spanning-tree priority for specific Vlan ID
I'm new to the SDN technology,
I have 12 year's experience working with Cisco products,
On Cisco devices, a user can set different STP priority Per VLAN ID
Like :
Switch(config)#spanning-tree VLAN ...
3
votes
3answers
79 views
Are the Switches not direct connect to the root-bridge need select root port in the STP circuit?
In the STP circuit like bellow, will the Router2 select a root port? or just the Router1 and Router3 select root port?
in a tutorial it says "all the non-root bridge node will select a root-port, ...
2
votes
2answers
67 views
Does Switch need its own MAC address?
I saw a post say Switch do not need its MAC address, unless it's an administrable Switch for managing.
but I found the spanning-tree protocol need a MAC address of Switch to form STP Root Bridge ID. ...
5
votes
4answers
1k views
Do layer 3 protocols use layer 2 protocols?
I saw the STP on layer 2. The guy that made the tutorial says at the end :
Even though it seems that Layer 2 access layer solutions are slowly
being replaced by blazing fast Layer 3 solutions.
...
4
votes
2answers
418 views
Spanning Tree on the interface that resides at end users
I do not understand why we use portfast and in fact STP on the interface of a switch that is directly connected to end users. Indeed, a user can interfere with the STP election and perform DDoS (that ...
1
vote
1answer
37 views
Does STP create a minimum spanning tree?
From the algorithm described in P&D textbook it looks to be minimum (if all edge weights are 1). Can't find mentions on Wikipedia or a quick google search.
1
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1answer
152 views
Spanning-tree MSTR port role
What is the MSTR port role in Spanning-tree ?
It shows up on boundary ports between MST regions and switches running (R)PVST+. Note that it shows up only on the switches running MST.
It seems to ...
2
votes
0answers
83 views
How to set portfast default on Dell FTOS Switches?
I'm configuring a Dell S3148 switch running FTOS 9.14.0.1 and I would like to achieve similar functionality of the following Cisco IOS commands:
spanning-tree portfast default
spanning-tree portfast ...
3
votes
1answer
345 views
How to solve a BKN* Port Issue on a cisco catalyst
There is a Cisco ISR 4451 connected with Portchannel to a Catalyst 3850 Stack and there are some VLANs enabled, but only one does not come up for a Portinconsistence. I figure out an Issue on the ...
2
votes
1answer
70 views
As a Spanning Tree Protocol Programmer, how will I know when the root bridge ID election is over?
I am trying to implement IEEE 802.1D. I know how the root bridge id is elected.
Initially, every switch will advertise that they are the root bridge.
Next, it will check whether the bridge ID received ...
5
votes
1answer
351 views
Is Per Vlan Spanning Tree or RPVST an open standard or can it only be implemented by Cisco?
I know there are some standards that are CISCO proprietary but have become open standards. CISCO has also updated the RFC to reflect this. So, is this also true for PVST?
Does Juniper or other ...
1
vote
2answers
247 views
spanning tree loop with bpdufilter on acces port but not on trunk?
┌─────┐ ┌─────┐
| A ┼------┼ B |
└─────┘ └┬───┬┘
└---┘ <-- loop
behold the above drawing. this is a test setup connectin switch A and B, and a test loop
A: cisco ...
5
votes
1answer
257 views
How to resolve a spanning tree issue on a server trunk port?
I am having a very strange spanning-tree issue with Cisco Nexus switches.
My server is connected to the TOR switch with trunk configuration because we have multiple VLANs on the server. When I reboot ...
2
votes
2answers
247 views
How should (per-vlan) STP behave when interconnecting access ports from different vlans on the same switch?
Half of the ports of a switch are in vlan 10, the other half in vlan 20, all untagged. In some specific situations, we need someone in the field to be able to interconnect both vlans without access to ...
3
votes
1answer
258 views
Add links to a port channel group without downtime
There are two trunk links with the same configuration connecting two switches. Currently they are independent links and one is blocked with spanning-tree. I would like to convert these to a single ...
2
votes
1answer
67 views
Spanning tree behaviour - topology change
Regarding a next change we have to do, we are studying spanning tree behaviour.
Does the following statement is true ?
In the case of topology change, if a new BPDU is received:
Currently: Root ...
1
vote
1answer
56 views
Replacing a pair of switches and stp
We need replace to a pair of switches with new ones without interrupting traffic.
In order to do that , for some minutes all 4 switches will be interconnected between them - but we need to avoid stp ...
2
votes
1answer
43 views
Edge detection on designated ports
If a switch doesn't receive a BPDU on a particular port it marks this port as "Edge Port". But any designated port won't receive any BPDU even though it was connected to other switches since their ...
2
votes
2answers
198 views
redundant vpn to remote location with redundant links
I have this situation:
Remote location with 6 devices collecting data and each connected to two VPN routers. Bonding is set up for those computers and data is sent to multicast address. Each VPN ...
3
votes
1answer
108 views
Does a bridge have the three STP timers per port or per bridge (one per bridge)?
I was trying to understand Spanning Tree Protocol and I got confused on some points, so I want to ask for some and double check for others:
Do the three timers(including max_age) exist in the bridge ...
2
votes
2answers
90 views
I CAN'T ping PC7
So... I have a set up as below. I ping PC7 from the router. obviously an ARP is sent to determine PC7's MAC address. but it doesnt work. i then decide to set packettracer to simulation mode. i ping ...
2
votes
1answer
108 views
Best way to connect Vlan's / STP / LAG
Am having a problem connecting these concepts together , like when i try thinking of them being ran on the same network. am able to understand each of them separately, But am not able to connect them ...
0
votes
1answer
764 views
What is the EtherType of a BPDU frame sent by a switch which runs Spanning Tree Protocol
I want to know what is the EtherType field of a BPDU frame in various versions and variants of the Spanning Tree Protocol.
2
votes
1answer
1k views
Bridge Assurance with vPC on port type network
I'm running two Nexus 3048 switches as network core and I got an issue when linking another switch (specifically a 2960-X) on the vPC links. Consider the scenario:
+-------+ +-------+
| NX #1 |===|...
5
votes
2answers
430 views
High availability LAN segment with Cisco ISR4451X and 2 x Netgear GS724 - Port-channel vs. BDI vs. BVI?
I have a customer that is getting a new 1Gbps ISP connection and wants his servers connected across two switches for redundancy and protection from:
failure of a router port
failure of a network ...
2
votes
1answer
66 views
Trying to configure STP on a small network and have a few questions
I am trying to configure the switches on a network to use STP or RSTP but I'm confused about how to do this. The network consists of 3 switches, all on the default subnet, so a fairly simple setup. ...
1
vote
2answers
421 views
What could cause network to duplicate packets? STP during convergence?
I have understood that real networks have routing changes, leading to out-of-order delivered IP packets. Real networks also have frequent packet loss.
However, what I have not understood is why could ...
1
vote
1answer
449 views
Cabling two access ports on the same switch from different VLANs
Theoretically would I be able to connect two switch ports together with a simple straight/cross cable on the same switch. If the two ports are in different VLANs (eg. 2 and 22) and ports are in ...
1
vote
1answer
243 views
root port election in STP
I have a question about root-port election in STP.
How to determine root-port on switch 3, both fa0/1 and fa0/2 have port-cost back to root switch (switch 0) of 38, receive BPDU from port fa0/3 of ...
3
votes
2answers
175 views
MSTP - different VLAN mapping in different regions
Regarding MSTP, is it possible to have different VLAN mapping for different regions ?
Example:
Region 1:
Instance 1: VLAN 10,20,30
Instance 2: VLAN 40,50,60
Region 2:
Instance 1: VLAN 10,50,60
...
1
vote
0answers
236 views
Adding new switch to Spanning Tree network
Currently studying Spanning Tree, I'm not sure about the behaviour when we add a new switch to an existing STP topology (with cisco pvst+).
Assuming we plug this new bridge called S4 with only one ...
1
vote
3answers
210 views
Doesn't a router stop broadcast?
Well I was at work.
And one of our customers connected a new device to that router. Additionally a switch was already connected to the router.
So there was only the switch connected to the router, ...
2
votes
1answer
283 views
Rapid Spanning Tree Protocol - RSTP Bridge Id isn't RSTP-Priority + Ethernet-MAC
what is the difference between the eth.src Address and the Bridge-System-Id? Sometimes they are the same but mostly not. Attached you will find a screenshot where they are the same.
1
vote
1answer
293 views
Why forward delay in spanning tree
I would have a really basic question... Why the spanning tree have forward delay ? (listening=15s and learning=15s).
Why initially the protocol has been designed like this ?
30 seconds before ...
