Spanning-tree cost

I'm practicing spanning-tree with two 2950 switches (Ver 12.1). I have 3 trunks and 3 vlans. I try to change the cost of the interface (for the 3 vlans) and only 2 vlans change the value after I apply the command. The command is "spanning-tree cost 1" in interface mode. Is there any explanation as why only two of the vlans change the cost? I hope to be clear on the scenario.

Hello Francisco,
as Toshi has explained STP calculstes the cost to the root bridge but it does it by adding the local port cost that receives the BPDU to the path cost in the BPDU.
A switch advertises out its ports not in STP blocking state a BPDU modified in the following manner:
the sender bridge id is that of the local switch
the port id is that of the outgoing port
the total cost to reach the root bridge is:
cost received on root port + cost of root port
notice that only port-id changes from port to port.
This is different from what happens with routing protocols where the cost is added on the outgoing interface.
So as Toshi notes if one device is the root bridge for one vlan the cost (actually 0) doesn't change if you change the cost of one of its ports.
Hope to help
Giuseppe

Similar Messages

Method-long Spanning-Tree Cost - Nexus and VSS

Hi,
I'have a DC topology with 2x6509 VSS, 2 NX7K, 10xNX5548 and NX2K dual-homed.
My question is about spanning-tree cost in method-long
Between VSS(L2/L3) and NX7Ks(L2) i have 8x10giga links on a crossed VPC, from NX7K point of view, the pathcost to the root (wich is the VSS), is 200.
is this correct ?
what is the cost for 2 and 4x10g links ?
thanks for your replies
Franck

Yes one of the interfaces will be in blocking.

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.

IDSM2 spanning tree

Hi,
what is a default value of spanning tree cost for data port on IDSM2 module?
If we put command
intrusion-detection module 4 data-port 1 spanning-tree cost 1
what is changed?

Each link between spanning tree switches has a "cost" associated with the bandwidth of that link. This allows switchs to caculate the lowest "cost" (highest bandwidth) path to the root switch. Here's a table of the STP cost for each bandwidth:
http://en.wikipedia.org/wiki/Spanning_tree_protocol
I think that I shall never see
A graph as lovely as a tree.
A tree which must be sure to span.
So packets can reach every LAN.
First the root must be selected.
By ID, it is elected.
Least cost paths from Root are traced.
In the tree these paths are placed.
A mesh is made by folks like me.
Then bridges find a spanning tree.
- Radia Perlman

"Peer-switch" command on vPC domain and spanning-tree priority interaction

Hi guy,
We have 2 N7K (N7KA and N7KB) which will be running vPC in hybird and pure vPC environment.
I have a question about the Hybird and pure vPC environment. With the "peer-switch" command enable, should i tune the spanning-tree priority to be the same for all the vlan running on vPC on both N7KA and N7KB? This way, when i enter the "sh spanning-tree vlan X(vPC vlan) detail" command on N7K, it will list both N7K announc itself as "We are the root of the spanning tree".Also the switch running spanning-tree with N7K vPC vlan (Hybird), will see both N7K has the same priority (4096), and it is not desirable for a spanning-tree environment. Therefore, i used the "spanning-tree pseudo-information" on N7KB to tune the spanning-tree priority to "8192" and the switch running spanning-tree with N7K will list N7KB has a priority of 8192(perfect).
However, I notice some strange "show" output on the switch running Port-channel with the N7KA and N7KB. The "Designated bridge" priority is flapping as show on the switch. It is constantly changing between "4096 and 8192" with the same vPC system wide mac address.
Entering the "sh spanning-tree vlan X detail" command repeatly on switch with port-channel toward N7KA and N7KB.
>>sh spanning-tree vlan 10 detail
Port 65 (Port-channel1) of VLAN10 is root forwarding
Port path cost 3, Port priority 128, Port Identifier 128.65.
Designated root has priority 4106, address 0013.05ee.bac8
Designated bridge has priority 4106, address 0013.05ee.bac8
Designated port id is 144.2999, designated path cost 0
Timers: message age 15, forward delay 0, hold 0
Number of transitions to forwarding state: 1
Link type is point-to-point by default
BPDU: sent 5, received 603
one sec later.
>>sh spanning-tree vlan 10 detail
Port 65 (Port-channel1) of VLAN10 is root forwarding Port path cost 3, Port priority 128, Port Identifier 128.65. Designated root has priority 4106, address 0013.05ee.bac8 Designated bridge has priority 8202, address 0013.05ee.bac8 Designated port id is 144.2999, designated path cost 0 Timers: message age 15, forward delay 0, hold 0 Number of transitions to forwarding state: 1 Link type is point-to-point by default BPDU: sent 5, received 603
Configuration:
N7KA
spanning-tree vlan 1-10 priority 4096
vpc domain 200
peer-switch
N7KB
spanning-tree vlan 1-10 priority 4096spanning-tree pseudo-information vlan 1-10 designated priority 8192
vpc domain 200
peer-switch

We have a issue similar to this in our environment. I am trying to upgrade the existing 3750 stack router with 2 Nexus 5596 running VPC between them. For the transition I have planned to create a channel between 3750 stack and 5596's. Once this environment is set, my plan is to migrate all the access switches to N5k.
The issue is when I connect the 3750 port channel to both N5Ks, all the Vlans on 3750 started to flap. If I connect the port channel to only one N5K everything is normal; but when I connect the port channel to both N5K running VPC, vlans are flapping. Any idea what is going wrong here? Am I missing something?

SF 300 Serires switch not participating in spanning tree?

I just purchased an SF300-24 managed switch and I am running it in layer3 mode. I am testing it out right now and have it connected to two 2950 switches. The SF300 is connected to each 2950 with a four port etherchannel running LACP. When looking at spanning tree all three switches are configured the same when it comes to hello, forward, max age and all three are in RSTP mode. I adjusted the priorities so that the SF300 would be the root but that is not happening.
I only have one VLAN as of right now set up and connectivity between the three switches is fine. The only problem seems to be that the two 2950 switches are the only two switches involved in the determination of the root bridge. Additionally it was the same way before I configured the etherchannel and had the switches connected over single trunk lines.
I would appreciate if someone can expain to me why this is?
Thanks in advance.

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Thanks for your help but know I still cannot get the three devices to talk MST either,it is getting frustrating. If i add a redundant link and directly connect the two 2950's they immediately talk and configure MST. But when I remove that link no info is passed and both 2950's think they are the root even though the SF 300 priority is 0 on all three MST instances. On the SF300 I have the following settings:
Spanning tree: enabled
STP Operation Mode: Multiple STP
BPDU Handling: Flooding
Path Cost: Long
Region name: test
Revision: 1
Max Hops: 20
Max-age: 20
Hello Time: 2
Forward Delay: 15
MST instance 1 Vlan 100
Bridge Priority 0
Designated Root Bridge: Self
Root port: 0
Root path cost: 0
MST instance 2 Vlan 2-5
Bridge Priority 0
Designated Root Bridge: Self
Root port: 0
Root path cost: 0
MST instance 0 all vlans not in instance 1 and 2
Bridge Priority 0
Designated Root Bridge: Self
Root port: 0
Root path cost: 0
For MST interface Settings (both LAGs/instances are thesame)
Int Priority: 128
Path Cost: 20000
Port State: Boundary
Mode: RSTP
Type: Boundary
Designated port ID: 128
Designated Cost: 0
Remain Hops: 20
Forward Transitions: 1
The 2950 switches: (The only difference on the other switch is that the priority is 8192, and the MACs of course)
MST00 is executing the mstp compatible Spanning Treeprotocol
Bridge Identifierhas priority 4096, sysid 0, address 000b.460e.e040
Configured hello time 2, max age 20, forward delay 15
Current root haspriority 0, address 6c50.4dcb.334b
Root port is 65 (Port-channel1), cost of root path is 50000
Topology change flag not set, detected flag not set
Number of topology changes 7 last change occurred 00:18:54 ago
          from Port-channel1
Times: hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 65 (Port-channel1) of MST00 is root forwarding
   Port path cost 50000, Port priority 128, Port Identifier 128.65.
   Designated roothas priority 0, address 6c50.4dcb.334b
   Designatedbridge has priority 0, address 6c50.4dcb.334b
   Designated port id is 128.1000, designated path cost 0
   Timers: message age 4, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   Link type ispoint-to-point by default, Boundary RSTP
   BPDU: sent 571,received 568
MST01 is executingthe mstp compatible Spanning Tree protocol
Bridge Identifierhas priority 4096, sysid 1, address 000b.460e.e040
Configured hello time 2, max age 20, forward delay 15
We are the root of the spanning tree
Topology change flag not set, detected flag not set
Number of topology changes 9 last change occurred 00:18:55 ago
          from Port-channel1
Times: hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 65 (Port-channel1) of MST01 is boundary forwarding
   Port path cost 50000, Port priority 128, Port Identifier 128.65.
   Designated root has priority 4097, address 000b.460e.e040
   Designated bridge has priority 4097, address 000b.460e.e040
   Designated port id is 128.65, designated path cost 0
   Timers: message age 0, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   Link type ispoint-to-point by default, Boundary RSTP
   BPDU: sent 598,received 0
MST02 is executingthe mstp compatible Spanning Tree protocol
Bridge Identifierhas priority 4096, sysid 2, address 000b.460e.e040
Configured hello time 2, max age 20, forward delay 15
We are the root of the spanning tree
Topology change flag not set, detected flag not set
Number of topology changes 9 last change occurred 00:19:50 ago
          from Port-channel1
Times: hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0
Port 65 (Port-channel1) of MST02 is boundary forwarding
   Port path cost 50000, Port priority 128, Port Identifier 128.65.
   Designated root has priority 4098, address 000b.460e.e040
   Designated bridge has priority 4098, address 000b.460e.e040
   Designated port id is 128.65, designated path cost 0
   Timers: message age 0, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   Link type ispoint-to-point by default, Boundary RSTP
   BPDU: sent 611,received 0
I notice that on MST01 and 02 they are not receiving BPDU’s,but I am not sure why or if that is the problem. It appears that the SF 300 is not sending BPDU packets for MST01 and 02, but is sending them for MST00. I also attached a capture. I captured the VLAN info for VLAN 100 which is in MST1. on the SF300, it appears that the SF 300 is recieving STP traffic but not generating any.

About Spanning tree problem

I am a newbie for cisco switch.
I need a failover solution for both switch and AP Bridge link on both side.
I have 2 of location (Location A and Location B)
Location A
There has 3 set of cisco 2960 switch.
switch C is active switch
switch A is redundancy switch , it will be active when primary Wi-FI Link and switch C is failure.
Location B
There has 3 set of cisco 2960 switch
switch D is active switch
switch B is redundancy switch ,it will be active when primary Wi-Fi Link and switch D is failure.
I would like to use spanning tree protocol for this case.
As show my diagram, Can it achive failover for both switch and AP bridge link if I use this network design
Please help to comment
Thanks
John

Hi John,
This is achievable. The best way to do this is, If you can control the client switches,
make the Client switch at location A, the root primary for the STP domain.
On the Client switch at location B, make the STP cost high on the port towards the Switch B.
Assuming all other STP settings are on default values, this should block the link between LocationB client switch and Switch B. So all your traffic will take the path through switchC-SwitchD.
If the Wifi Bridge fails (AP3-AP4), the blocked link will start forwarding (make sure you are using rapid spanning tree for fast transition)
Now the most important thing in this design is to make sure that the Wifi bridges pass STP BPDU traffic, if they don't, this will not work.
Even if one of the switches fails on the active path, the backup path would still kick in..
Let me know how you go with this..
please rate helpful posts.. :)

The spanning-tree add strange value when I create new Vlans

Hi,
On all switchs access, the spanning-tree add strange value when I create new Vlans from Distrib Layer,
and no association is created with any interface with spanning-tree vlan 700, see below in this exemple,
until I reboot the switch.
somebody already saw this values ?
DSFDS112#sh span sum
Switch is in rapid-pvst mode
Root bridge for: none
EtherChannel misconfig guard is enabled
Extended system ID           is enabled
Portfast Default             is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default            is enabled
UplinkFast                   is disabled
Stack port is StackPort1
BackboneFast                 is disabled
Configured Pathcost method used is long
Name                   Blocking Listening Learning Forwarding STP Active
VLAN0001                     0         0        0          3          3
VLAN0002                     0         0        0         22         22
VLAN0006                     0         0        0          3          3
VLAN0007                     0         0        0          8          8
VLAN0009                     0         0        0          4          4
VLAN0010                     0         0        0          3          3
VLAN0011                     0         0        0          3          3
VLAN0012                     0         0        0          3          3
VLAN0013                     0         0        0          3          3
VLAN0090                     0         0        0         15         15
VLAN0109                     0         0        0          3          3
VLAN0200                     0         0        0          4          4
VLAN0300                     0         0        0         26         26
VLAN0302                     0         0        0          4          4
VLAN0700               -   253 -1872756560 2087191206 -1872756549 2080375982
VLAN0702               -   253 -1872756560 2087191206 -1872756549 2080375982
VLAN0704                     0         0        0          4          4
VLAN0710               -   253 -1872756560 2087191206 -1872756549 2080375982
VLAN0816                     0         0        0          3          3
VLAN0820                     0         0        0          3          3
20 vlans               -   759 -1323302384 1966606322 -1323302237 1946160764
DSFDS112#sh span vlan 700
VLAN0700
Spanning tree enabled protocol rstp
Root ID    Priority    4796
             Address     0008.e3ff.fcbc
             Cost        10000
             Port        608 (Port-channel1)
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority    62140 (priority 61440 sys-id-ext 700)
             Address     885a.9213.6880
             Hello Time   2 sec Max Age 20 sec Forward Delay 15 sec
             Aging Time 300 sec
Interface           Role Sts Cost      Prio.Nbr Type
Po1                Root FWD 10000     128.608 P2p
DSFDS112#sh run int Gi1/0/25
Building configuration...
Current configuration : 194 bytes
interface GigabitEthernet1/0/25
description Station12
switchport access vlan 700
switchport mode access
end
DSFDS112#sh span interface Gi1/0/25
no spanning tree info available for GigabitEthernet1/0/25
DSFDS112#sh int status interface Gi1/0/25
Port      Name               Status       Vlan       Duplex Speed Type
Gi1/0/25 Station12          connected    700          full    100 10/100/1000BaseTX
Thanks for your help,
Regards.

Venki,
The ORA-00942 is okay because there is no existing object. But what stuck me is the ORA-01921 error which may indicate that this might not be a new database.
CREATE ROLE exp_full_database
ERROR at line 1:
ORA-01921: role name 'EXP_FULL_DATABASE' conflicts with another user or role name
CREATE ROLE imp_full_database
ERROR at line 1:
ORA-01921: role name 'IMP_FULL_DATABASE' conflicts with another user or role name
Are there any existing databases on this server? Have you tried to create it on other machine?I searched on Metalink too and found Doc ID: 237486.1 ORA-29807 Signalled While Creating Database using DBCA which say that eroror could be ignored. You may want to review that as well.
Ittichai

Spanning tree guard root

                  Hi,
We have 45xx switch & we enabled spanning tree root guard on ports connected with access switch via fiber uplink
& we enable spanning tree loop guard on access switch side
One of my core switch port connected to Juniper Netscreen Firewall
Whether I need to enable spanning tree guard root on the same port on core switch side ? or not
In case of yes, any config changes required on JUniper Netscreen box
Br/Subhojit

Hi, Pls find the output
Port 130 (GigabitEthernet3/2) of VLAN0054 is designated forwarding
   Port path cost 4, Port priority 128, Port Identifier 128.130.
   Designated root has priority 8246, address 001b.d474.8a40
   Designated bridge has priority 16438, address 001b.0cee.0440
   Designated port id is 128.130, designated path cost 3
   Timers: message age 0, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   Link type is point-to-point by default
Bpdu filter is enabled
   Root guard is enabled on the port
   BPDU: sent 5847158, received 0
Present the bold config enabled on the port
Br/Subhojit

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 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

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.

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.

Rapid Spanning Tree, 802.1w

Do any SBTG switches support Rapid Spanning Tree? It appears the 3560x does, but looking for more "cost effective" solution.

Hi Art,
The new and improved 300 series (SRWxxx-K9-NA) which is a refresh for the older SRW series, shows that it supports STP, RSTP and MSTP.
http://www.cisco.com/en/US/products/ps10898/prod_models_comparison.html
regards and seasons greetings
Dave Hornstein

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 cost

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