Spanning tree ports

hi all
can anyone tell me why on my new switches, 3560's, the ports that are being blocked still light up ?

Hi Eric,
Your statement "LED is green when port is up even if a port is BLOCKING" is not correct. If the ports are merely an access port then the blocking port will show an amber LED.
BUT yes if the port is a trunk port and there are some vlans which are in fwding state on that trunk and some vlans are in fwding state on that trunk then the trunk port will show a GREEN LED.
Regards,
Ankur

Similar Messages

Do I configure spanning-tree port type ed trunk on LACP port-channels

Hello,
Can't seem to see a clear answer and wondering if something could offer some advice please?
We are using LACP aggregation across all our 10 gig attached servers and also trunking them. We're running a VPC pair of 5596 Nexus.
For a standard trunk port I always add the spanning-tree port type edge trunk to the interface config.
However I think I should be adding this to the overiding port-channel config. At present a colleague has configured the VPC below omitting the spanning-tree port type config.
interface port-channel100
description a-server
switchport mode trunk
switchport trunk allowed vlan 100
vpc 100
The port member configs are these which do contain the spanning tree port type:
interface Ethernet1/1
description a-server(1)
switchport mode trunk
switchport trunk allowed vlan 100
spanning-tree port type edge trunk
channel-group 100 mode active
I always try to keep the overiding port channel config the same as its members and obviously for most config, you can't have disparate configs anyway.
However for the spanning tree config the NexOS allows you to have the members with spanning tree port types and not have to reflect that in the port-channel.
However I have this issue with STP:
Switch1# show spanning-tree interface po100
Vlan Role Sts Cost Prio.Nbr Type
VLAN0100 Desg BKN*200 128.4996 (vPC) Network P2p *BA_Inc
Is this due to the inconsistency with my port channel to member configs?
Any advice would be gratefully accepted.
Thanks!

Hi Paul, there are some parameters you can define on individual ports and there are some of them that will be inherited from the port-channel configuration no matter what has been configured under the infidividual ports. Spanning-tree configuration is one of the inherited ones. As soon as the port joins into a port-channel, it will start to use spanning-tree settings under the port-channel. When it leaves the channel, then it can continue to use the individual configuration.
There is a nice summary here under NX-OS Interface Conf Guide > Port-Channel Conf:
http://www.cisco.com/en/US/docs/switches/datacenter/sw/6_x/nx-os/interfaces/configuration/guide/if_portchannel.html#wp1798338
Evren

Spanning-Tree Port Type Edge & Router

I am wondering if a switch trunk port that is facing a router that is connected with subinterface can be classified as an edge port in the eyes of Spanning-Tree.
Thanks.

Ricardo
You should configure the switchport as "spanning-tree portfast trunk"
As Glen says that is assuming you are not connecting to a switch module on the router.
Jon

Nexus spanning tree pseudo configuration

Hi
I am trying to understand the pseudo configuration commands in a Nexus hybrid topology.
I have vlans a, b and c only in the vPC side of the topology. I have peer switch configured and the same stp priority on both switches.
In the standard Spaning-tree topology I have completely seperate vlans x, y and z.
What should I be configuring in the pseudo config section ? Do I define a pseudo root priority for all vlans a, b, c and x, y, z or just for the standard spanning tree vlans x, y and z. I need to avoid and, even short, spanning tree outages if I take one Nexus out of service for a short time.
My thinking is that if one Nexus is out of service the physical mac will be used and potentially reduce the root priority of the vPC vlans causing a TCN and STP recalculation in vlans a, b and c. This can be avoided by configuring a pseudo root priority for all Vlans lower than the current spanning tree priority shared by the vPC peers. Is this correct ? However, since I have a shared priority of 8192 on current vPC vlans will configuring, for example, a pseudo root priority of 4096 on those vPC vlans won't this also cause the TCN and recalculation I am trying to avoid ? Is the benefit of the pseudo root config only obtained if it is configured at the start when the vPC is formed and prior to the peer switch command being issued ?
Thanks, Stuart.

Hi Ajay,
It is recommended that switch-to-switch links are configured with the spanning-tree port type normalcommand. The one exception is the vPC peer-link which is recommended to configure with the spanning-tree port type network command.
Take a read of the Best Practices for Spanning Tree Protocol Interoperability from page 56 of the vPC Best Practice Design Guide for further information on this.
Regards

Triangle Link - Spanning Tree

Hi All,
We tried to create a redudancy link between 3 building. When we connect the 3rd link (Red Line) and keep receiving the following error message.
*Nov 3 19:27:44.932: %SW_MATM-4-MACFLAP_NOTIF: Host 6c41.6a13.3580 in vlan 17 is flapping between port Gi4/0/44 and port Gi1/1/1
*Nov 3 19:27:44.957: %SW_MATM-4-MACFLAP_NOTIF: Host 001e.0b66.8561 in vlan 19 is flapping between port Gi4/0/44 and port Gi1/1/1
*Nov 3 19:27:44.965: %SW_MATM-4-MACFLAP_NOTIF: Host 88ae.1dad.2fd3 in vlan 19 is flapping between port Gi1/0/4 and port Gi1/1/1
*Nov 3 19:27:45.032: %SW_MATM-4-MACFLAP_NOTIF: Host 0013.2304.49f6 in vlan 25 is flapping between port Gi1/1/1 and port Gi4/0/44
*Nov 3 19:27:45.074: %SW_MATM-4-MACFLAP_NOTIF: Host 0013.2304.4a1b in vlan 25 is flapping between port Gi1/1/1 and port Gi4/0/44
*Nov 3 19:27:45.091: %SW_MATM-4-MACFLAP_NOTIF: Host a01d.48b7.dcdb in vlan 19 is flapping between port Gi4/0/44 and port Gi3/0/28
*Nov 3 19:27:45.166: %SW_MATM-4-MACFLAP_NOTIF: Host 0050.569e.6d67 in vlan 2 is flapping between port Gi4/0/44 and port Gi1/1/1
*Nov 3 19:27:45.234: %SW_MATM-4-MACFLAP_NOTIF: Host 0013.2307.764a in vlan 25 is flapping between port Gi1/1/1 and port Gi4/0/44
*Nov 3 19:27:45.275: %SW_MATM-4-MACFLAP_NOTIF: Host 28d2.4476.172f in vlan 17 is flapping between port Gi4/0/44 and port Gi1/1/1
I cannot figure out what is wrong with the setting. Any advise?

Hey,
I suggest locating the original location of any of these machines from SW85 and then start looking the STP port states in other direction.
Say originally users are reachable over link G3/1/1 so ideally as per STP link G4/0/44 needs to be blocking for these user/vlans. Keep tracing the spanning tree port states over the other link and i am sure you will find something useful.
HTH.
Regards,
RS.

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

2960X 15.0(2)EX5 Stack Bug? Master Switch Ports link in Orange, no spanning Tree

Is anyone aware of a bug in version 15.0(2)EX5 for 2960X Switches that would cause a switch in the master role to stop linking in new ports in green (and passing traffic). I have 2 2960X-48FPD-L Switches in a stack and whichever switch I designate master will only link new connections in orange and not pass traffic. All ports linked in show up/up and can be seen in a show cdp neighbor but won't pass any other traffic.
If I unplug the Stacking cables both switches become masters and ports linked in green on the previous member switch stay green, but after it switches to master any new connections plugged in only link in orange.
If I switch priorities and reboot the problem switches to the new master switch and the problem goes away on the member switch.
Also, a switch in the master role does not show any spanning tree instances for ports in the orange link state.
Has anyone seen this issue and do you know of a solution?
Jim

A quick update for those with this same problem.
1. 15.2(3)E turned out to be very unstable causing my switch stack to randomly lockup/reboot one of the switches about once a week.
2. I downgraded back to 15.0(2)EX5 but found a workaround. It turns out the switch stack with the 15.0 versions does not like the switchport voice vlan command on any of the interfaces on the master switch. I simply removed the voice vlan configuration on the interfaces and all the switch ports linked in just fine. I would prefer to run the phones on a voice vlan, but it still works without, just the PC's and phones are on the same vlan.
Jim

Blocked Stack Ports on 2960X-48FPD-L Stack (Unstable Switch Stack!) Spanning Tree?

I am having an issue where 2 2960X-48FPD-L Switches in a redundant flexstack (stack port 1 SW1 to port 2 SW2 and port 2 SW1 to port 1 SW2) ring.
At first running the 15.0(2).EX5 (and earlier EX3, and EX4) version IOS yielded all the ports on the stack master switch refusing to run spanning tree and would only link in amber and not pass any traffic other than CDP information (the slave switch linked in fine).
I upgraded to 15.2(3)E and this solved the problem of the ports not linking in green and participating in spanning tree.
Now, however, about every week or two I lose connectivity to the switch stack and I was able to go to the switch stack locally and found that for some reason the switch stack is blocking and unblocking VLANs on StackPort1 frequently (see below). When I was at the site, I sometimes had connectivity, sometimes not. A stack hard reboot brought everything back up, but this is the second time this has occurred and I would expect the same problem in the next week or so.
Has anyone else run into these issues, and have you found a solution?
I'm guessing that if I either get rid of the redundancy on the switch stack or stack using Ethernet cables between switches the problem will go away, but then what is the point of using stackable switches in a non redundant low speed stack. It seems to me that Spanning tree thinks that I have a spanning tree loop going on with the stack ports which I didn't even think was possible.
What do you think?
Jim
_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:02:59: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking StackPort1 on VLAN0307. Port consistency restored.
Mar 11 09:03:16: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:03:27: %SPANTREE-2-BLOCK_PVID_PEER: Blocking StackPort1 on VLAN0307. Inconsistent peer vlan.
Mar 11 09:03:42: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking StackPort1 on VLAN0307. Port consistency restored.
Mar 11 09:03:46: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:03:47: %SPANTREE-2-BLOCK_PVID_PEER: Blocking StackPort1 on VLAN0307. Inconsistent peer vlan.
Mar 11 09:04:12: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking StackPort1 on VLAN0307. Port consistency restored.
Mar 11 09:04:22: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:04:56: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:05:13: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 207 on StackPort1 VLAN307.
Mar 11 09:05:13: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking StackPort1 on VLAN0307. Inconsistent local vlan.
Mar 11 09:05:30: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:06:00: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:06:04: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking StackPort1 on VLAN0307. Port consistency restored.
Mar 11 09:06:32: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:07:02: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:07:03: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 207 on StackPort1 VLAN307.
Mar 11 09:07:03: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking StackPort1 on VLAN0307. Inconsistent local vlan.
Mar 11 09:07:34: %SPANTREE-2-RECV_BAD_TLV: Received SSTP BPDU with bad TLV on StackPort1 VLAN1.
Mar 11 09:07:45: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking StackPort1 on VLAN0307. Port consistency restored.

Jim,
We have also the same problem with our 2960-X switches (access) connecting to a pair of 4500x (VSS) except our issue is with Portchannel with 2 physical links connecting the 2960xs to the 4500.
If we disconnect one of the physical links from the portchannel everything works fine, but when we connect the same physical link back all users lose connectivity and the physical link starts flapping. Here are some of the messages we see in the logs when both physical links are in the portchannel:
Mar 10 18:00:43 EST: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 1 on Port-channel5 VLAN90.
Mar 10 18:00:43 EST: %SPANTREE-2-BLOCK_PVID_PEER: Blocking Port-channel5 on VLAN0001. Inconsistent peer vlan.
Mar 10 18:00:43 EST: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking Port-channel5 on VLAN0090. Inconsistent local vlan.
Mar 10 18:00:58 EST: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel5 on VLAN0001. Port consistency restored.
Mar 10 18:00:58 EST: %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking Port-channel5 on VLAN0090. Port consistency restored.
Mar 10 18:01:29 EST: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/1, changed state to down
Mar 10 18:01:37 EST: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/1, changed state to up
Mar 10 18:01:48 EST: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/1, changed state to down
Mar 10 18:01:51 EST: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/0/1, changed state to up
We have upgraded to 15.0(2a).EX5 and still have the same issue.
We have a ticket open with Cisco and have sent them all the logs and debugs and waiting to hear back from IOS developers.
HTH

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 root ports in back to back VPC

Ok so I have a question about back to back VPC configuration.
I have a back to back VPC from core to agg layer so that I have 2 logical switches in my path.
However I am seeing an issue on the agg layer. Traffic is traversing the VPC peerlink instead of being sent up to the core which is where the spanning-tree root is configured.
Po1 is my uplink from the agg
Po4 is my vpc peerlink on the Agg
Po1              Root FWD 200       128.4096 (vPC) P2p
Po2              Desg FWD 200       128.4097 (vPC) P2p
Po4              Root FWD 330       128.4099 (vPC peer-link) Network P2p
Eth2/6           Altn BLK 2000      128.262 P2p

a little more info.
Po1 is my uplink to the core
Po4 is my agg vpc peer.
I see 2 paths to root on one swith. it is choosing Po4 (vpc peerlink) instead of Po1 (uplink to core)
MST0000
Spanning tree enabled protocol mstp
Root ID    Priority    4096
             Address     0023.04ee.be01
             Cost        0
             Port        4099 (port-channel4)
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority    8192   (priority 8192 sys-id-ext 0)
             Address     547f.eea6.d2c1
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface        Role Sts Cost      Prio.Nbr Type
Po1              Root FWD 200       128.4096 (vPC) P2p
Po2              Desg FWD 200       128.4097 (vPC) P2p
Po4              Root FWD 330       128.4099 (vPC peer-link) Network P2p
MST0000
Spanning tree enabled protocol mstp
Root ID    Priority    4096
             Address     0023.04ee.be01
             Cost        0
             Port        4096 (port-channel1)
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority    8192   (priority 8192 sys-id-ext 0)
             Address     547f.eea6.ce41
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface        Role Sts Cost      Prio.Nbr Type
Po1              Root FWD 200       128.4096 (vPC) P2p
Po2              Desg FWD 200       128.4097 (vPC) P2p
Po3              Desg FWD 200       128.4098 (vPC) P2p
Po4              Desg FWD 330       128.4099 (vPC peer-link) Network P2p

Enable BPDUGuard on Spanning-tree Portfast Trunk Port: Yes or No?

Hello to all the Cisco Experts,
I have been searching around to get a confirmed answer as per my subject, but yet unable to come into any conclusion that could help me.
This is all started when I configured the switchport configuration for my ESXi Server which is a dot1q trunk port. The reference will be as below URL:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006628
The configuration of the switchport will be as below:
interface GigabitEthernet1/0/1
description ESXi
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 11,15
switchport mode trunk
spanning-tree portfast trunk
end
The catch is, I had the bpduguard enabled on the global level in my switch = spanning-tree portfast bpduguard default.
This will enable the bpduguard on the trunk port above due to the switchport is in portfast (the command: spanning-tree portfast trunk).
Some of the guys in this forum mentioned that it is not recommended to have bpduguard on trunk port and some mentioned it is okay to have this.
So, what do you all think on this? Any real life experience dealing with this kind of situtation that can be shared to us over here?
Thank you in advance.

Hi Leo,
First of all, I would never, ever, consider any comment of yours as being offensive so don't worry, none taken. :)
Enabling portfast on a trunk is so "yesterday", in my opinion. If a trunk port(s) or an etherchannel is configured correctly, there's a significant chance portfast is irrelevant. The speed to get the ports to go from down to passing traffic is really boils down to one or two seconds.
Perhaps this is at the core of our different views. To my best knowledge, without the PortFast, a trunk - be it a single port or an EtherChannel - will become forwarding 30 seconds after entering the up/up state, not less. This is valid for STP, RSTP, and MSTP. In addition, if a new VLAN is created or added to the list of enabled VLANs on the trunk, it may take additional 30 seconds for that VLAN to become operational (forwarding) on that trunk. There is nothing besides PortFast and Proposal/Agreement that can cut down this time: the STP must go over the Listening-Learning-Forwarding sequence, and RSTP/MSTP must go through the Discarding-Learning-Forwarding sequence. The "one or two seconds" you have mentioned is perhaps the combined delay incurred by autonegotiation, LACP/PAgP, and DTP, but STP will take its own time and will not be deterred by any of these mechanisms.
I see no benefit but mischief when you enable BPDU Guard on an inter-switch link.
Absolutely agree. That is why it doesn't make any sense to put a BPDU Guard on an inter-switch link, and I have never suggested doing that. The original post, however, deals with enabling PortFast on a trunk link that does not go to another switch but rather connects to an ESXi server on which, obviously, different virtual machines are bridged onto different VLANs.
So what is the reaction of the port if you do happen to enable portfast and BPDU guard on an inter-switch link? Wouldn't the two be a "Jekyll & Hyde", wouldn't it?
It would be just the same as enabling PortFast and BPDU Guard on an access port that happens to be connected to another switch. Upon link-up, the port would become forwarding immediately, and after receiving a BPDU, it would be shot down to err-disabled. The fact the port is an access port or a trunk port makes no difference here. Just as before, I stress that this kind of configuration simply isn't meant to be used on inter-switch links. However, on trunks connected directly to routers, servers, autonomous APs supporting several SSIDs mapped to different VLANs, even to IP phones (remember the mini-trunk config used on old switches on which the switchport voice vlan command only instructed CDP to advertise the voice VLAN but did not cause the port to accept tagged frames in the voice VLAN so it had to be configured as a trunk?) - in all these situations, the PortFast can be beneficial. The BPDU Guard is a natural protective companion to the PortFast - wherever PortFast is eligible to be configured, the BPDU Guard is a natural additional protection to be activated as well.
But given the complexity of interconnection of different switches to various stuff going around, we're happy with leaving portfast on a trunk port disabled.
No argument here - but again, this is about trunks between switches on which I would never suggest using the PortFast or the BPDU Guard. The original post is talking about trunks to end hosts (i.e. edge trunk ports if we extend the terminology a little).
Best regards,
Peter

Why the host ports are also seen in the spanning-tree output ?

Why the host ports are also seen in the spanning-tree output ?
Switch1#show spann
VLAN0001
Spanning tree enabled protocol ieee
Root ID    Priority    32769
             Address     0000.0CA2.138B
             This bridge is the root
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority    32769 (priority 32768 sys-id-ext 1)
             Address     0000.0CA2.138B
             Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 20
Interface        Role Sts Cost      Prio.Nbr Type
Fa0/1            Desg FWD 19        128.1    P2p
Fa0/2            Desg FWD 19        128.2    P2p
Fa0/15           Desg FWD 19        128.15   P2p
interface FastEthernet0/15
description PC0 Interface
switchport mode access
spanning-tree portfast
interface FastEthernet0/16
I read somewhere that all the ports of a switch will participate in STP by default. Is there any way to remove the STP operation on host ports ?
Regards,
Chandu

All ports participate in Spanning Tree by default.
Spanning tree is there to block redundant L2 paths in order to prevent loops. All ports are capable of causing a loop so you would not want to turn spanning tree off, in fact I don't think you can switch it off on a per port basis. You can switch it off on a per vlan basis.
You are already using portfast which allows host ports to transition into a forwarding state without going through the listening and learning states of STP. If you switch off STP on a port, you risk the chance of a L2 loop.
https://supportforums.cisco.com/docs/DOC-5180

SGE2010 switches, VLAN's and a blocked port in spanning-tree

Folks,
I have 2 switch groups.
2 SGE2010's with VLAN's defined as 10,20 and 30
Vlan 10 is the management VLAN, and it uplinks to our border router.
Vlan 20 is the workstation VLAN, and all workstations point to the switch as their default GW
Vlan 30 is the ip phone VLAN, and all phones use this as their gateway.
I would like to put a LAG between said switches, we have some servers on the ip phone switch that need to be accessed by the workstation clients, and the single 100mb link through the router is probably not going to be enough.
As I understand it, because the switches have different networks on them, a simple lag will not work. I did create a lag, and assign ip addresses to each side, however in that mode, it doesn't appear I can block vlan 10 from transiting the LAG, and with out that block I will end up with a logical loop, and spanning-tree will block one of the uplinks, or the LAG itself.
I have attached an image with a diagram of our current set up.
Any help/advice would be much appreciated.

Tom,
I remember our conversation a few weeks ago. I did not get a chance to have a go at MSTP, mainly because I have no expierence with it, and looking at the configuration properities, it looks a little daunting.
It has also been a very busy few weeks with the deployment of 200+ phones across several sites, and the system is functioning great with out the LAG trunk, I am just trying to plan for the future.
I made a few postings a few weeks ago, one here and one on the Cisco forums on reddit, and a user there gave me some advice I have been unable to make work (I think it's just wrong), but I would love to go this route if it is in fact possible.
Here is the thread : http://www.reddit.com/r/Cisco/comments/x91tc/vlan_trunks_spanning_tree_and_a_port_blocked/c5kskch
This user implies it's possible to block a VLAN across the LAG which would end the logical loop problems.
It looks like his advice is to make the LAG into a trunk, and then block specific VLAN's from transiting it, but in trunk mode, I can't assign it an IP, so I am sorta wondering how exactly you transport packets across it.
Can you confirm that his advice is in fact incorrect?
If MSTP is my only route, then I suppose it's time to dig into the docs and see If I cant get it up and running.

Spanning Tree and Admin mac address issues srw2048

Ok, I have a somewhat complex problem and hopefully someone may shed some light or have an idea as to whats wrong.
First the scenario:
I have two Cisco Cat 6509's etherchanneled to each other via two fiber cables. One of these is the STP/RSTP root. I have two SRW2048's.. one trunked to each of these 6509 switches. There is also a trunk between the SRW2048's. All this is to create a redundant topology so that if one of the switches fail's the others can still forward packets to each other. Of course the scenario described is in fact a loop that should be handled by STP/RSTP. I have RSTP enabled on all the switches in the scenario (PV RSTP on the cisco switches as they only do Cisco's brand of per vlan spanning tree). There are 3 vlan's configured on each of the srw2048's (2,55,96). There are corresponding vlan's also on the 6509's. I have put the srw2048's management interface into vlan 2.
The problem:
I need to forward packets between the srw2048's primarily and only use the 6509 that is not the root when a failure happens. I have configured the non-root 6509's spanning tree cost on the etherchannel to be higher then the alternate path through the srw's to the root. I can hook everything up and view the spanning tree and see that the srw2048's interface that goes to the non-root 6509 is blocked, and all other interfaces on the other switches are forwarding. I can in fact ping and get to the admin interface on all the switches. Then for some strange reason the admin interface of the srw2048 plugged into the non-root 6509 stops responding. If I disable either the interface its plugged into on the 6509 or the other srw2048 everything starts working again. Sometimes it responds after many failures for no apparent reason. I looked into the mac-address table on the 6509's and they are conflicting, pointing to each other for the mac-address of the broken srw2048. When I clear the mac-table the admin port comes back for about 5 seconds then again goes dark. When reviewing mac-table on the 6509's they are back to pointing to each other. The odd thing (although I haven't confirmed this completely) is that hosts placed into vlan 2 on that same srw2048 seem to work fine. If there was an STP loop or something misconfigured, I would expect it to effect any host in vlan 2 or the other vlan's for that matter on the srw2048 that stops responding. Alas, I am stuck because I need to manage this switch remotely. My only thought is that for some reason even when the STP status is blocked the broken srw2048 is still sending out arp's of its admin interface and bypassing the STP protocol. I have no way to confirm this, but maybe someone has an idea as to what I'm doing wrong, or otherwise offer a solution. For now, I simply removed vlan 2 from the 6509 that the broken srw2048 is plugged into and everything seems fine.
My apologies for such a long post, but this is somewhat complicated. Thanks in advance for any info.
-Geoff
Message Edited by gmyers on 08-19-2008 10:35 PM

To follow up, I had a ticket open with Linksys about this for about 3 months with no resolution. I submitted packet captures, stp outputs, etc and no luck. I gave up and basically had to revert to a manual failover for redundancy. It's no perfect or fast, but it works every time.
Unless linksys issues a firmware upgrade with this as a fix, I doubt we will be able to ever resolve this on our own.

Can I disable spanning-tree in a vpc domain ?

i have two N7718s in a vpc domain and each have a vpc connection to 300+ TORs(non cisco switch).
each 7718 have 300+ trunk port and a trunk port carring 80 vlans . so the logical port number is 300*80 = 24000
the problem is n7k r-pvst logical ports limit is 16000,it causes the vpc primary 7718 ping latancy time exceed 1000ms
2 ways to solve this problem : use mst instead of rpvst or disable spanning-tree
if i use mst , the logical ports limit is 90000, the problem will appear one day
so i want to disable spanning-tree . 7718s' vpc link to TOR use lacp ,it will prevent some layer2 loops. can i do it?

I have the same problem. :)

Spanning tree ports

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