Different spanning tree modes in 1 network

I've noticed that we use MST and PVST in our network, is this a good way to tackle spanning tree ? ( I guess not ) and how am I able to disable MST and use PVST instead.
Also, what impact will it have if I change MST to PVST ?

MST allows you to build multiple spanning trees over trunks. You can group and associate VLANs to spanning tree instances. MST converges faster than PVST.Refer the following URL for more information
http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a008007e71a.html#wp1050594

Similar Messages

Changing spanning tree modes / potential outages?

Hi All,
Our core / distribution / access layers are all currently configured to use Cisco's PVST+. We are now a fully populated Cisco network with no standards based STP so we can now migrate to Rapid PVST.
By simply changing the spanning tree mode on a an access switch to Rapid PVST will the vlans with spanning tree enabled suffer an outage ? If so will this be time be based on how the rest of the network is configured ? That is, if the rest of the network is still PVST+ and I change a switch to Rapid PVST will the outage deault to around 45 seconds based on PVST+ timers ?
Furthermore, as I understand it, even though this access switch would now be configured for Rapid PVST, the switch defaults back to PVST until the rest of the network (or VLAN) is configured for Rapid PVST.
My second question is this :
Assuming that all the access layer switches have been migrated to Rapid PVST, what would be the effect of then migrating the distributing and potentially core layer devices to Rapid PVST ? Will they also cause an outage on the VLAN on which STP is enabled ? Again, if so, what would the outage be ? Would this be based on PVST timers or Rapid PVST ?
Thanks in advance.
Chris.

Mike
No problem and please do come back if needed.
One thing I should have answered from your questions but didn't directly was the question of the mac address of the root switch.
The mac address that is important in the root switch election is the one contained in the BPDU not the source mac address of the BPDU. The source mac address is simply that of the port that transmitted the BDPU.
If a switch flushes it's mac address table it would remove that mac address but that would make no difference as to whether the switch believed it had lost it's path to root or not.
In terms of switch to switch communication BPDUs are sent with a multicast destination mac address so removing that mac address has no effect on BPDUs being exchanged.
So the fact that you are seeing the switch reporting it has lost it's path to root is not a direct consequence of the mac address being flushed because it doesn't need that to send and receive BPDUs.
However with all the flooding of end to end devices because of the flushing an indirect consequence may be that BPDUs are getting lost.
Apologies for not making that clearer.
Jon

Debug spanning-tree bpdu brought the network down

I'm troubleshooting a pair of Dell Power-Connect switches in a Dell blade chassis connected to a pair of Cisco 4900M switches. I have my 4900M switches set as spanning-tree root and backup root. The Dell switches are connected via LACP trunks to the 4900M's. Dell switch 1 to 4900 #1 and Dell switch 2 to 4900M #2. Both of the Dell switches are reporting as root switches.
I was trying to troubleshoot this yesterday and ran 'debug spanning-tree bpdu' on the primary 4900M. There was a masive amount of BPDU events scrolling by. This debug command actually took the network down. The primary 4900M was non-responsive and the secondary unit had it's CPU go to 100%. The fix was to power cycle the primary 4900M.
Why did this command take my network down?
--Patrick

Typically, the device prioritizes console output ahead of other functions. The debug spanning-tree bpdu generates a lot of output. That is what jumped the CPU to 100% and ultimately caused the device to crash.
You should be very careful with debug commands and log to the internal buffer, instead of the console.
See: http://www.cisco.com/c/en/us/support/docs/dial-access/integrated-services-digital-networks-isdn-channel-associated-signaling-cas/10374-debug.html.

Spanning-tree modes: PVST vs RAPID-PVST

I am upgrading an old network and as I add switches, I would like them to run rapid-pvst, instead of just pvst which is what the older switches are running.
Last I checked (with a Cisco techie at Networkers 2006), it was OK to have trunked switches with different modes (pvst and rapid-pvst)... but now I'm hearing differently from a few other sources.
Can someone please verify if this is a concern and if so, how should one proceed?
Cheers...

rapid-pvst+ can be migrated into your pvst+ environment.
rapid-pvst+ configured switches revert to pvst+ to provide interoperability.
cisco recommends configuring the rapid-pvst+ and pvst+ for different STP instances. the rapid-pvst+ root switch must be running rapid-pvst+ and the pvst+ root switch must be running pvst+; as well, the pvst+ switches should be at the edge of the network.
(this being said, upgrade your core first and move outward. keep your pvst+ root switch out of the core where rapid-pvst+ will be running)
please see the following link for more info:
http://www.cisco.com/en/US/products/hw/switches/ps5206/products_configuration_guide_chapter09186a00801ce264.html#wp1150840

Different spanning tree protocols behavior

Hi,
This is my first time posting a question, so apologies if I missed something.
My question is...
I noticed a weird setup at my workplace and i'm unsure of how STP will interact. We have about 15 switches spread around the network, and I have noticed some run PVST and others run RSTP. I also noticed that there will two root bridges for a particular VLAN. However one root bridge will be running PVST and the other one will be running RSTP. What happens in that time of scenario?
Is it that only PVST switches will look at the root bridge running PVST and the ones running RSTP will look at the root switch running PVST.

It usually happens when people add additional switches over time and configure them using RSTP.
You then end up with a mix of the two.
As Reza has said, schedule a maintenance window and get them all over to RSTP (or Per Vlan-RSTP). There could well be a blip during this time so I would avoid doing it unless you have advised users of potential down time.
You may find things improve after you change it, you could well have some sub optimal traffic flows if you have root bridges all over the place.

Spanning tree loops

Hi we are having regular spanning tree issues in our network.
On our config we do not have bpduguard configured from what I can see? Could this be an issue?
What can be done centrally on the core switches to remove this threat? Are their default configs that a wise network administrator would apply as standard?
HELP!

HI Mike [Pls Rate if HELPS]
Refer link below for examples and identify redundant links, root and backup root bridge etc..
http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a0080136673.shtml#intro
Refer link for usage guidelines in implementing loopguard, bpdu guard etc..
http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/7.4/configuration/guide/stp_enha.html#wp1019943
A Cisco router will give you a warning when you configure PortFast:
SW1(config)#int fast 0/5
SW1(config-if)#spanning-tree portfast
%Warning: portfast should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc... to this interface when portfast is enabled, can cause temporary bridging loops. Use with CAUTION
%Portfast has been configured on FastEthernet0/5 but will only
have effect when the interface is in a non-trunking mode.
SW1(config-if)#
Not only will the switch warn you about the proper usage of PortFast, but you must put the port into access mode before PortFast will take effect.
But there is a chance - just a chance - that someone is going to manage to connect a switch to a port running Portfast. That could lead to two major problems, the first being the formation of a switching loop. Remember, the reason we have listening and learning modes is to help prevent switching loops. The next problem is that there could be a new root bridge elected - and it could be a switch that isn't even in your network!
BPDU Guard protects against this disastrous possibility. If any BPDU comes in on a port that's running BPDU Guard, the port will be shut down and placed into error disabled state, shown on the switch as err-disabled. A port placed in err-disabled state must be reopened manually.
BPDU Guard is off on all ports by default, and is enabled as shown here:
SW1(config)#int fast 0/5
SW1(config-if)#spanning-tree bpduguard enable
It's a good idea to enable BPDU Guard on any port you're running PortFast on. There's no cost in overhead, and it does prevent the possibility of a switch sending BPDUs into a port configured with PortFast - not to mention the possibility of a switch not under your control becoming a root switch to your network!
Refer link below for Understanding Spanning Tree Protocol:
http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/sw_ntman/cwsimain/cwsi2/cwsiug2/vlan2/stpapp.htm
Hope i am Informative and this HELPS.
PLS RATE if HELPS
Best Regards,
Guru Prasad R

Spanning-tree not working: SG500 to Cat3650

Hi All,
Trying to turn up a new site. I have 2 switches: Cat 3650 & SG500-52P. I want to connect up two ethernet cables between these switches in the event one fails, STP will put the blocked one in forwarding. However, when I connect up the 2nd ethernet cable, I get the following:
IPADTBL-N-IPDUPLICATE: Duplicate IP address 192.168.5.232 from MAC a0:ec:f9:ef:6a:18 was detected on VLAN 1, port gi1/1/24
This log message is then followed by the network locking up & crashing until I remove the 2nd cable (i.e. STP Loop). Removing the redundant cable solves the problem. This is because STP is allowing both links to transitioning to forwarding state (confirmed in show spanning-tree & show cdp neighbor).
Why is spanning-tree not correctly blocking one of the lines? Is that type of architecture not supported when there is an SG300/500 in the equation?
Configs below:
Core 3650: (box configs basically)
Switch#show run
Building configuration...
Current configuration : 2686 bytes
! Last configuration change at 10:01:53 UTC Thu Jan 22 2015
! NVRAM config last updated at 09:24:03 UTC Thu Jan 22 2015
version 15.0
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
service compress-config
hostname Switch
boot-start-marker
boot-end-marker
vrf definition Mgmt-vrf
address-family ipv4
exit-address-family
address-family ipv6
exit-address-family
logging console emergencies
enable secret 5 $1$Qi5N$u/5q1HESY/TyQsPFNKVah1
no aaa new-model
clock timezone UTC -6 0
clock summer-time UTC recurring
switch 1 provision ws-c3650-24ts
ip device tracking
diagnostic bootup level minimal
spanning-tree mode pvst
spanning-tree extend system-id
spanning-tree vlan 1 priority 24576
redundancy
mode sso
class-map match-any non-client-nrt-class
match non-client-nrt
policy-map port_child_policy
class non-client-nrt-class
bandwidth remaining ratio 10
interface GigabitEthernet0/0
vrf forwarding Mgmt-vrf
no ip address
negotiation auto
interface GigabitEthernet1/0/1
interface GigabitEthernet1/0/2
interface GigabitEthernet1/0/3
interface GigabitEthernet1/0/4
interface GigabitEthernet1/0/5
interface GigabitEthernet1/0/6
interface GigabitEthernet1/0/7
interface GigabitEthernet1/0/8
interface GigabitEthernet1/0/9
interface GigabitEthernet1/0/10
interface GigabitEthernet1/0/11
interface GigabitEthernet1/0/12
interface GigabitEthernet1/0/13
interface GigabitEthernet1/0/14
interface GigabitEthernet1/0/15
interface GigabitEthernet1/0/16
interface GigabitEthernet1/0/17
interface GigabitEthernet1/0/18
interface GigabitEthernet1/0/19
interface GigabitEthernet1/0/20
interface GigabitEthernet1/0/21
interface GigabitEthernet1/0/22
interface GigabitEthernet1/0/23
interface GigabitEthernet1/0/24
interface GigabitEthernet1/1/1
interface GigabitEthernet1/1/2
interface GigabitEthernet1/1/3
interface GigabitEthernet1/1/4
interface Vlan1
ip address 192.168.5.230 255.255.255.0
ip default-gateway 192.168.5.1
ip http server
ip http secure-server
line con 0
exec-timeout 0 0
stopbits 1
line aux 0
line vty 0 4
password scrubbed
login
line vty 5 15
password scrubbed
login
wsma agent exec
profile httplistener
profile httpslistener
wsma agent config
profile httplistener
profile httpslistener
wsma agent filesys
profile httplistener
profile httpslistener
wsma agent notify
profile httplistener
profile httpslistener
wsma profile listener httplistener
transport http
wsma profile listener httpslistener
transport https
ap group default-group
end
SG500 Switch:
switchff1182#show run
config-file-header
switchff1182
v1.3.0.62 / R750_NIK_1_3_647_260
CLI v1.0
set system mode switch queues-mode 4
file SSD indicator encrypted
ssd-control-start
ssd config
ssd file passphrase control unrestricted
no ssd file integrity control
ssd-control-end cb0a3fdb1f3a1af4e4430033719968c0
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e075 Polycom/Veritel_phone___
voice vlan oui-table add 00e0bb 3Com_phone______________
hostname switchff1182
no passwords complexity enable
username cisco password encrypted scrubbed privilege 15
ip ssh server
snmp-server server
no ip http server
ip telnet server
interface vlan 1
ip address 192.168.5.231 255.255.255.0
no ip address dhcp
exit
ip default-gateway 192.168.5.1

Hi Peter,
Thanks for replying. Unfortunately (or fortunately if it worked), STP is running and BPDU's are flooding below:
SW500A#show spanning-tree
Spanning tree enabled mode RSTP
Default port cost method: long
Root ID Priority 24577
Address a0:ec:f9:ef:6a:00
Cost 20000
Port gi1/1/43
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address 2c:3e:cf:ff:11:82
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
SW500A#show spanning-tree bpdu
Global: Flooding
I guess I'm doing etherchannels instead of redundant links :-/
This is one of many reasons why I regret these small business models being made; A lot of things that are polished and functional in the enterprise grade (i.e. real switches) just don't seem to work on these units. But unfortunately, as the price is significantly cheaper, companies will continue purchasing these over the better quality units, and engineers like myself will be stuck working with the cut-corners version of a Cisco switch.

NI PXI 8176 broadcasting Version 2 Spanning Tree Updates

I am not the owner of this device, but I am in IT. We had an NI PXI8176 suddenly start broadcasting version 2 spanning tree protocols over the network... this is a mystery to us. Has anyone ever seen this, or have theories why it would do this?
thanks
Nan

I'm not very familiar with spanning tree protocols, but I thought that they were for network bridges and switches.
Have you had any viruses on that PXI-8176? Think of the PXI-8176 as a laptop in a different form factor when troubleshooting this kind of stuff. This sounds like an OS/virus/network issue.
Good luck.
Jack

Spanning tree for VLANS

Hi,
I need an answer to this puzzling scenerio i have been asked to work with.I have two vlans with about 10 switches on each end and there is a link switch that has a connection to both sides of the VLAN. I have been asked to create a singular spanning tree for the entire scenerio. how can i go about this.
please i am awaiting the opinions of anyone knowledgable in this line. thanks.

Hi, I agree you can config MST on your router to reduce the number of spanning tree instances runing on the switch from one per vlan. You will have to map your vlan range to the MST, useful CLI commands are
spanning-tree mode mst
spanning-tree mst configuration
name (name)
revision( revision number)
instance (number) vlan (vlan range)
check your config using
show spanning-tree mst configuration.
Hope thsi will hlep you get started.
DW

Spanning Tree Reconfiguration - If Root Port is down.

Hello All,
I have some doubt on STP reconfiguration if Root port is down ...Can any one help...?
As per my understanding, if any port is down due to any reason, the corresponding bridge shall sends a TCN to the root bridge through the root port.
Lets say if a root port is down on a bridge, and so, the topology has to be re-established. As the root port itself is down, how does the Bridge convey the TCN to the root bridge ?
Thanks,
RajaSekhar

Hi Raja, if the root port is down, the TCN notification can't make it to the root bridge since the link is down. The affected device will rely on the last known good bpdu. When the affected device has it's designated port down, it will remove the alternate port from discard once it hits the max age table then progress through the listening, learning, forwarding, at this time the new tcn is sent through the spanning tree topology. Once the TCN reached the root bridge, the root bridge will send a configuration bpdu then the whole spanning tree topology will update.
It can take up to 52 seconds to have the topology update in the entirety depending on spanning tree mode and size of topology.
-Tom
Please rate helpful posts

Spanning Tree on 2950 (High CPU)

Just swapped out a 2924 with a 2950 (Copying config as closely as the 2950 would allow), and now icmp to Management IP is extremely latent (200m/sec+ from server connected directly to it)....icmp through the 2950 is unaffected.
Spanning tree appears to be the culprit:
36 12275368 3206214 3828 4.99% 4.07% 4.05% 0 Spanning Tree
2950 connects to Cat4k on multiple ports (Both trunks/Non Trunks)
spanning-tree mode is pvst on 2950.
Hoping someone has come across this before :)
Regards,
MB

Further investigation revealed that all the cat4k's vlans where in the 2950's dynamic table (show mac-address-table dynamic) - These vlans where definitely not supposed to be there, so I checked out the interconnecting ports(On Cat4k) to discover that about 5 had turned into trunk ports!(Does CatOS automagically enable trunking on ports in certain circumstances?)
Systematically disabling trunking on these ports stopped all the cat4k's vlans being advertised to the 2950, and also reduced the cpu of spanning tree:
36 15213172 3875075 3925 1.14% 1.37% 1.61% 0 Spanning Tree
icmp had now also dramatically reduced.
Regards,
MB

Spanning tree loop

Hi,
How to identify spanning tree loop in switched network.
I want to know all the possible ways.
Regards
skrao

Hi Skrao,
One thing that happens when you have a loop in a switched network is that you get a broadcast storm. Since Ethernet has not "Time To Live" field, if you have a loop in your network then the broadcasts get transmitted round the loop forever, saturating all the links.
Spanning Tree is a protocol designed to identify the loops and to cut them. There is not really any such thing as a "Spanning Tree loop", because Spanning Tree actually prevents loops. Do NOT disable it unless you are 110% sure that you have no physical loops in your network.
So, if you have a network that is looping, how do you identify where Spanning Tree is not working? It is made difficult by the fact that your network has stopped functioning correctly. The switches may be too busy to give you access to the management functions.
In most cases, the loop is due to a very recent change. Usually, creating a loop makes the network go down immediately, or exactly 90 second later. What has changed recently?
If you can access the management functions, then find out which VLAN has the traffic storm, and trace it out.
If your access switches have redundant uplinks, then disconnect them, leaving one uplink per access switch, and see if the storm stops. You should have uplinkfast running anyway, so this should not disrupt your traffic any more than it is already.
Know your network before the loop happens! In this case, prevention is really better than cure. If you can, put a broadcast limit on all your trunks. Enable BPDU guard on all your access ports.
Sniff the storming broadcasts, and look at the source MAC addresses. Use these brodcasts to identify the access switch involved.
Anyone else got any techniques they use to identify the loops?
Kevin Dorrell
Luxembourg

Challenge: Spanning Tree Control Between 2 links from Switch DELL M6220 to 2 links towards 2 switches CISCO 3750 connected with an stack (behavior like one switch for redundancy)

Hello,
I have an Spanning tree problem when i conect 2 links from Switch DELL M6220 (there are blades to virtual machines too) to 2 links towards 2 switches CISCO 3750 connected with an stack (behavior like one switch for redundancy, with one IP of management)
In dell virtual machine is Spanning tree rapid stp, and in 3750 is Spanning tree mode pvst, cisco says that this is not important, only is longer time to create the tree.
I dont know but do you like this solutions i want to try on sunday?:
Could Spanning tree needs to work to send one native vlan to negociate the bdpus? switchport trunk native vlan 250
Is it better to put spanning-tree guard root in both 3750 in the ports to mitigate DELL to be root in Spanning Tree?
Is it better to put spanning- tree port-priority in the ports of Swicht Dell?
¿could you help me to control the root? ¿Do you think its better another solution? thanks!
CONFIG WITH PROBLEM
======================
3750: (the 2 ports are of 2 switches 3750s conected with a stack cable, in a show run you can see this)
interface GigabitEthernet2/0/28
description VIRTUAL SNMP2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 4,13,88,250
switchport mode trunk
switchport nonegotiate
logging event trunk-status
shutdown
interface GigabitEthernet1/0/43
description VIRTUAL SNMP1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 4,13,88,250
switchport mode trunk
switchport nonegotiate
shutdown
DELL M6220: (its only one swith)
interface Gi3/0/19
switchport mode trunk
switchport trunk allowed vlan 4,13,88,250
exit
interface Gi4/0/19
switchport mode trunk
switchport trunk allowed vlan 4,13,88,250
exit

F.Y.I for catylyst heroes - here is the equivalent config for SG-300 - Vlan1 is required on the allowed list on the catylyst side (3xxx/4xxx/6xxx)
In this example:
VLANS - Voice on 188, data on 57, management on 56.
conf t
hostname XXX-VOICE-SWXX
no passwords complexity enable
username xxxx priv 15 password XXXXX
enable password xxxxxx
ip ssh server
ip telnet server
crypto key generate rsa
macro auto disabled
voice vlan state auto-enabled !(otherwise one switch controls your voice vlan….)
vlan 56,57,188
voice vlan id 188
int vlan 56
ip address 10.230.56.12 255.255.255.0
int vlan1
no ip add dhcp
ip default-gateway 10.230.56.1
interface range GE1 - 2
switchport mode trunk
channel-group 1 mode auto
int range fa1 - 24
switchport mode trunk
switchport trunk allowed vlan add 188
switchport trunk native vlan 57
qos advanced
qos advanced ports-trusted
exit
int Po1
switchport trunk allowed vlan add 56,57,188
switchport trunk native vlan 1
do sh interfaces switchport po1
!CATYLYST SIDE
!Must Explicitly allow VLan1, this is not normal for catalysts - or spanning tree will not work ! Even though it’s the native vlan on both sides.
interface Port-channel1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,56,57,189
switchport mode trunk

Cisco Switches and HP Interoperability with Spanning-Tree (RSTP)

Hello All.
I read a lot of information from this forum about Spaning-Tree interoperability between HP Switches and Cisco Switches.
Rather than having questions I would like to post that I manage to configure successfully HP and Cisco using RSTP (802.1w).
SWPADRAO]display stp root
MSTID Root Bridge ID        ExtPathCost IntPathCost Root Port
  0    32768.cc3e-5f3a-2939 0           0
[SWPADRAO]display stp brief
MSTID      Port                         Role STP State     Protection
  0        GigabitEthernet1/0/47        DESI FORWARDING    NONE
  0        GigabitEthernet1/0/48        DESI FORWARDING    NONE
[SWPADRAO]display stp instance 0
-------[CIST Global Info][Mode RSTP]-------
CIST Bridge         :32768.cc3e-5f3a-2939
Bridge Times        :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC      :32768.cc3e-5f3a-2939 / 0
CIST RegRoot/IRPC   :32768.cc3e-5f3a-2939 / 0
CIST RootPortId     :0.0
BPDU-Protection     :enabled
Bridge Config-
Digest-Snooping     :disabled
TC or TCN received :17
Time since last TC :0 days 0h:1m:52s
SWNHAM17#show spanning-tree VLAN0001
Spanning tree enabled protocol rstp
Root ID    Priority    32768
            Address     cc3e.5f3a.2939
            Cost        4
            Port        26 (GigabitEthernet0/2)
            Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec  Bridge ID Priority    61441 (priority 61440 sys-id-ext 1)
            Address     001b.54db.7200
            Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
            Aging Time 300 Interface        Role Sts Cost      Prio.Nbr Type
Gi0/1            Altn BLK 4         128.25   P2p
Gi0/2            Root FWD 4         128.26   P2p
SWNHAM18#show spanning-tree VLAN0001
Spanning tree enabled protocol rstp
Root ID    Priority    32768
            Address     cc3e.5f3a.2939
            Cost        4
            Port        26 (GigabitEthernet0/2)
            Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec  Bridge ID Priority    61441 (priority 61440 sys-id-ext 1)
            Address     001b.0cbc.4300
            Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
            Aging Time 300 Interface        Role Sts Cost      Prio.Nbr Type
Gi0/1            Desg FWD 4         128.25   P2p
Gi0/2            Root FWD 4         128.26   P2p

Hello, David.
Your command doesn't work because it's made only for tha ports that has command "spanning-tree portfast" in them. Try change spanning tree mode at the HP switch to MSTP if this is possible.

Spanning-Tree MST

Hi,
we have the following configuration on our switches
spanning-tree mode mst
spanning-tree extend system-id
spanning-tree mst configuration
name test
spanning-tree mst forward-time 4
when we have a failover convergence time was about 8-10 seconds outage is there anything on the above config that suggest's this could be causing the delay? i thought MST was fast convergence times?
Thanks

i will try and you this later on. Not sure it was already in place what are the difference's between them both i thought MST can have multiple vlans per region so better design. Is RSTP not the same as PVST? not done much spanning tree as of yet. so not had chance to look at the differences?
Thanks

Different spanning tree modes in 1 network

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