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74793
March 18th, 2011 17:00
MSTP and multiple uplinks between two switches.
I've got two Dell 5424 switches. On each switch, I have three VLANs: 1, 103, and 215. For reasons I won't go into now, I need to uplink both switches via their 103 and their 215 VLANs. The uplinks are untagged, not sharing any VLANs. That is port 1 on the first switch is on VLAN 103 only and that port 1 links to port 1 on the second switch, which is also only on VLAN 103. Same for the 215 uplink--one port to one port and each port only on VLAN 215. When I do this, however, spanning tree kicks in and blocks one of the uplinks, so either VLAN 103 traffic will traverse its link or VLAN 215 traffic will traverse its link, but not both. I've been looking into MSTP to get around this problem, but I don't know if it will actually help. So, that is my question: Does MSTP allow two switches to have multiple uplinks between them each of which handles separate VLAN traffic without any of the uplinks being blocked?
Thanks.
events found
Anaraendil
72 Posts
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March 19th, 2011 02:00
HI,
Yes, MSTP (or MST) is what you need in this case.
The solution here is to create 2 MST instances: first for VLAN 103 (and VLAN 1 probably) and second for VLAN 215.
Larry Mateo
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47 Posts
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March 21st, 2011 08:00
Thank you for your response. I had created two MST instances, one for VLAN 103 and one for VLAN 215. VLAN 103 being the first instance, 215 the second; I left VLAN 1 set for the default instance of 0. I'm still having my spanning tree blocking issue, though. This is the first time I've tried configuring MST, so I'm sure I'm missing something somewhere. I'll just do more research and keep plugging away on this.
You did, however, answer my question. I just wanted to make sure that I wasn't wasting my time pursuing MST to make this work.
Anaraendil
72 Posts
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March 21st, 2011 10:00
Can you post here output of show spanning-tree mst-configuration and show spanning-tree active of both your switches?
If nothing helps, you can manually turn off STP on inter-switch links.
Larry Mateo
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47 Posts
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March 21st, 2011 13:00
Your wish is my command.
Also, FYI: My goal is have VLAN 215 traffic traverse the two switches via ch1. VLAN 103 will traverse the switches via g23 on each switch; however, there will also be a VLAN 103 uplink from the first switch's g24 to another switch. This is an HP switch on our network; it is running STP, not MSTP. Don't know if that'll be an issue or not.
Thanks again for your time and continued assistance.
First Switch
------------
sh span mst
Gathering information ..........
Current MST configuration
Name: Dell5424Switches
Revision: 5
Instance Vlans Mapped State
-------- ------------------------------------------------ -----
0 1 enabled
1 103 enabled
2 215 enabled
console# sh span active
Spanning tree enabled mode MSTP
Default port cost method: short
Gathering information ..........
###### MST 0 Vlans Mapped: 1
CST Root ID Priority 32768
Address 5c:26:0a:99:5f:3f
The IST ROOT is the CST ROOT
Root Port g23
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
IST Master ID Priority 32768
Address 5c:26:0a:99:5f:3f
Path Cost 4
Rem hops 19
Bridge ID Priority 32768
Address 5c:26:0a:99:5f:57
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Max hops 20
Name State Prio.Nbr Cost Sts Role PortFast Type
------ -------- -------- --------- ------ ---- -------- -----------------
g1 enabled 128.1 4 Frw Desg No P2P Intr
g2 enabled 128.2 4 Frw Desg No P2P Intr
g5 enabled 128.5 4 Frw Desg No P2P Intr
g6 enabled 128.6 4 Frw Desg No P2P Intr
g14 enabled 128.14 19 Frw Desg No P2P Intr
g23 enabled 128.23 4 Frw Root No P2P Intr
ch1 enabled 128.49 4 Dscr Altn No P2P Intr
###### MST 1 Vlans Mapped: 103
Root ID Priority 32768
Address 5c:26:0a:99:5f:3f
Path Cost 4
Root Port g23
Rem hops 19
Bridge ID Priority 32768
Address 5c:26:0a:99:5f:57
Interfaces
Name State Prio.Nbr Cost Sts Role PortFast Type
-------- -------- -------- ------- ---- ---- -------- ----------
g1 enabled 128.1 4 Frw Desg No P2P Inter
g2 enabled 128.2 4 Frw Desg No P2P Inter
g5 enabled 128.5 4 Frw Desg No P2P Inter
g6 enabled 128.6 4 Frw Desg No P2P Inter
g14 enabled 128.14 19 Frw Desg No P2P Inter
g23 enabled 128.23 4 Frw Root No P2P Inter
ch1 enabled 128.49 4 Dscr Altn No P2P Inter
###### MST 2 Vlans Mapped: 215
Root ID Priority 32768
Address 5c:26:0a:99:5f:3f
Path Cost 4
Root Port g23
Rem hops 19
Bridge ID Priority 32768
Address 5c:26:0a:99:5f:57
Interfaces
Name State Prio.Nbr Cost Sts Role PortFast Type
-------- -------- -------- ------- ---- ---- -------- ----------
g1 enabled 128.1 4 Frw Desg No P2P Inter
g2 enabled 128.2 4 Frw Desg No P2P Inter
g5 enabled 128.5 4 Frw Desg No P2P Inter
g6 enabled 128.6 4 Frw Desg No P2P Inter
g14 enabled 128.14 19 Frw Desg No P2P Inter
g23 enabled 128.23 4 Frw Root No P2P Inter
ch1 enabled 128.49 4 Dscr Altn No P2P Inter
console#
***********************************************************************
Second Switch
-------------
sh span mst
Gathering information ..........
Current MST configuration
Name: Dell5424Switches
Revision: 5
Instance Vlans Mapped State
-------- ------------------------------------------------ -----
0 1 enabled
1 103 enabled
2 215 enabled
console# sh span active
Spanning tree enabled mode MSTP
Default port cost method: short
Gathering information ..........
###### MST 0 Vlans Mapped: 1
CST Root ID Priority 32768
Address 5c:26:0a:99:5f:3f
This switch is root for CST and IST master
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Max hops 20
Name State Prio.Nbr Cost Sts Role PortFast Type
------ -------- -------- --------- ------ ---- -------- -----------------
g1 enabled 128.1 4 Frw Desg No P2P Intr
g5 enabled 128.5 4 Frw Desg No P2P Intr
g23 enabled 128.23 4 Frw Desg No P2P Intr
ch1 enabled 128.49 4 Frw Desg No P2P Intr
###### MST 1 Vlans Mapped: 103
Root ID Priority 32768
Address 5c:26:0a:99:5f:3f
This switch is the regional Root
Interfaces
Name State Prio.Nbr Cost Sts Role PortFast Type
-------- -------- -------- ------- ---- ---- -------- ----------
g1 enabled 128.1 4 Frw Desg No P2P Inter
g5 enabled 128.5 4 Frw Desg No P2P Inter
g23 enabled 128.23 4 Frw Desg No P2P Inter
ch1 enabled 128.49 4 Frw Desg No P2P Inter
###### MST 2 Vlans Mapped: 215
Root ID Priority 32768
Address 5c:26:0a:99:5f:3f
This switch is the regional Root
Interfaces
Name State Prio.Nbr Cost Sts Role PortFast Type
-------- -------- -------- ------- ---- ---- -------- ----------
g1 enabled 128.1 4 Frw Desg No P2P Inter
g5 enabled 128.5 4 Frw Desg No P2P Inter
g23 enabled 128.23 4 Frw Desg No P2P Inter
ch1 enabled 128.49 4 Frw Desg No P2P Inter
console#
Larry Mateo
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47 Posts
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March 22nd, 2011 08:00
Just a follow-up to my last post: I started looking at config settings outside of MSTP, specifically the two switches' VLAN settings. I tried a bunch of stuff, but the problem persists--when the switches are uplinked via their ch1 and gi23 interfaces, the ch1 interface goes into discarding mode on one of the switches.
For now, I'm going to disable STP on the 215 VLAN, which should clear up the ch1 issue. VLAN 215 is a self-contained region on our network; it has no router interface and there will be no additional switches connected to it, just end-poing devices--server interfaces and iSCSI devices. VLAN 103 will be uplinked to our network to provide management of the two switches.
madpacket
5 Posts
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April 7th, 2011 15:00
After you have the two instances working, you'll need to make an adjustment to some factor if you want vlan 103 on one uplink and vlan 215 on another. MST will still pick a single spanning-tree path for all instances without your additional configuration.
The easiest way to change the path for one instance or another should be to (on the non-root switch) adjust the interface root path cost to be "lower" for the instance that you want on that particular trunk.
e.g.:
interface g1
spanning-tree mst 1 cost 500
You can see the current cost per interface/portchannel with "show spanning-tree active" in the "cost" column.
HTH
gwharton
3 Posts
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June 9th, 2011 03:00
madpacket,
Ive run quite a few tests on MSTP and concur with what you said above. I tried the same on a pair of PC8024F's and a pair of PC6224's. They both do the same, however this is different from how the same test behaves on a pair of Cisco switches I have tested. Consider the example below.
Switch 1 and switch 2 are both
Vlan 101 Trunked up port 1
Vlan 102 Trunked up port 2
Vlan 103 Trunked up port 3
MST1 = vlan 101
MST2 = vlan 102
MST3 = vlan 103
and are connected together with port 1 to port 1 and port 2 to port2 and port 3 to port3
Dell
Spanning tree on Switch 1 shows that in MST1 port 1 is forwarding, port 2 is forwarding, port 3 is forwarding
Spanning tree on Switch 2 shows that in MST1 port 1 is forwarding, port 2 is blocking, port 3 is blocking
Spanning tree on Switch 1 shows that in MST2 port 1 is forwarding, port 2 is forwarding, port 3 is forwarding
Spanning tree on Switch 2 shows that in MST2 port 1 is forwarding, port 2 is blocking, port 3 is blocking
Spanning tree on Switch 1 shows that in MST3 port 1 is forwarding, port 2 is forwarding, port 3 is forwarding
Spanning tree on Switch 2 shows that in MST3 port 1 is forwarding, port 2 is blocking, port 3 is blocking
Cisco
Spanning tree on Switch 1 shows that in MST1 port 1 is forwarding
Spanning tree on Switch 2 shows that in MST1 port 1 is forwarding
Spanning tree on Switch 1 shows that in MST2 port 2 is forwarding
Spanning tree on Switch 2 shows that in MST2 port 2 is forwarding
Spanning tree on Switch 1 shows that in MST3 port 3 is forwarding
Spanning tree on Switch 2 shows that in MST3 port 3 is forwarding
There seems to a fundamental difference in the way that Dell and Cisco implement MSTP. Ciscos seem to take into account whether the VLAN is trunked over the link when it determines whether it should be forwarding within that MST or not, whereas Dell assume that all VLANs go region wide on all links, even when they don't. A review of HPs documentation for some of their switches shows they have also implemented it in the same was that Cisco have.
I guess what you want is auto setting the link cost to infinite on a link if the VLANs are NOT trunked across it. It would then behave in the same way as the Ciscos. The only way I have of making the Dell switches behave as planned is to do as you say, put maximum cost on the links that do not trunk that vlan and then lower costs on the links that do trunk the vlan but this means that you have to maintain the VLAN trunking topology and the MSTP link costs separately and make sure the two match up, otherwise the network isnt going to do what you expect it to, i.e you have MSTP blocking a port in which the vlan is trunked, and forwarding on a port where it isnt trunked, which isnt going to help anyone.
gwharton
3 Posts
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June 10th, 2011 15:00
Here is two Cisco 3560G switches back to back with ports 3,4,5,6 connected together.
spanning-tree mode mst
spanning-tree mst configuration
instance 1 vlan 101
instance 2 vlan 102
instance 3 vlan 103
instance 4 vlan 104
name region1
revision 1
exit
vlan 101 trunked over port 3
vlan 102 trunked over port 4
vlan 103 trunked over port 5
vlan 104 trunked over port 6
Switch1#show spanning-tree
MST0
Spanning tree enabled protocol mstp
Root ID Priority 32768
Address 001e.f625.7900
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768 (priority 32768 sys-id-ext 0)
Address 001e.f625.7900
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/3 Desg FWD 20000 128.3 P2p
Gi0/4 Desg FWD 20000 128.4 P2p
Gi0/5 Desg FWD 20000 128.5 P2p
Gi0/6 Desg FWD 20000 128.6 P2p
MST1
Spanning tree enabled protocol mstp
Root ID Priority 32769
Address 001e.f625.7900
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 001e.f625.7900
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/3 Desg FWD 20000 128.3 P2p
MST2
Spanning tree enabled protocol mstp
Root ID Priority 32770
Address 001e.f625.7900
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32770 (priority 32768 sys-id-ext 2)
Address 001e.f625.7900
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/4 Desg FWD 20000 128.4 P2p
MST3
Spanning tree enabled protocol mstp
Root ID Priority 32771
Address 001e.f625.7900
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32771 (priority 32768 sys-id-ext 3)
Address 001e.f625.7900
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/5 Desg FWD 20000 128.5 P2p
MST4
Spanning tree enabled protocol mstp
Root ID Priority 32772
Address 001e.f625.7900
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32772 (priority 32768 sys-id-ext 4)
Address 001e.f625.7900
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/6 Desg FWD 20000 128.6 P2p
Switch2#show spanning-tree
MST0
Spanning tree enabled protocol mstp
Root ID Priority 32768
Address 001e.f625.7900
Cost 0
Port 3 (GigabitEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768 (priority 32768 sys-id-ext 0)
Address 001e.f634.2700
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/3 Root FWD 20000 128.3 P2p
Gi0/4 Altn BLK 20000 128.4 P2p
Gi0/5 Altn BLK 20000 128.5 P2p
Gi0/6 Altn BLK 20000 128.6 P2p
MST1
Spanning tree enabled protocol mstp
Root ID Priority 32769
Address 001e.f625.7900
Cost 20000
Port 3 (GigabitEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 001e.f634.2700
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/3 Root FWD 20000 128.3 P2p
MST2
Spanning tree enabled protocol mstp
Root ID Priority 32770
Address 001e.f625.7900
Cost 20000
Port 4 (GigabitEthernet0/4)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32770 (priority 32768 sys-id-ext 2)
Address 001e.f634.2700
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/4 Root FWD 20000 128.4 P2p
MST3
Spanning tree enabled protocol mstp
Root ID Priority 32771
Address 001e.f625.7900
Cost 20000
Port 5 (GigabitEthernet0/5)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32771 (priority 32768 sys-id-ext 3)
Address 001e.f634.2700
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/5 Root FWD 20000 128.5 P2p
MST4
Spanning tree enabled protocol mstp
Root ID Priority 32772
Address 001e.f625.7900
Cost 20000
Port 6 (GigabitEthernet0/6)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32772 (priority 32768 sys-id-ext 4)
Address 001e.f634.2700
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/6 Root FWD 20000 128.6 P2p
gwharton
3 Posts
0
June 10th, 2011 15:00
And the same exact test run on a pair of 8024F's showing a different outcome.
Switch1#show spanning-tree active
Spanning tree Enabled BPDU flooding Disabled Portfast BPDU filtering Disabled mode mst
CST Regional Root: 80:00:00:25:64:2C:E5:32
Regional Root Path Cost: 0
###### MST 0 Vlan Mapped: 1
ROOT ID
Priority 32768
Address 0025.642C.E532
Path Cost 0
Root Port
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec
Bridge ID
Priority 32768
Address 0025.642C.E532
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Desg No
Te1/0/4 Enabled 128.4 2000 FWD Desg No
Te1/0/5 Enabled 128.5 2000 FWD Desg No
Te1/0/6 Enabled 128.6 2000 FWD Desg No
###### MST 1 Vlan Mapped: 101
ROOT ID
Priority 32769
Address 0025.642C.E532
Path Cost 0
Root Port
Bridge ID
Priority 32768
Address 0025.642C.E532
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Desg No
Te1/0/4 Enabled 128.4 2000 FWD Desg No
Te1/0/5 Enabled 128.5 2000 FWD Desg No
Te1/0/6 Enabled 128.6 2000 FWD Desg No
###### MST 2 Vlan Mapped: 102
ROOT ID
Priority 32770
Address 0025.642C.E532
Path Cost 0
Root Port
Bridge ID
Priority 32768
Address 0025.642C.E532
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Desg No
Te1/0/4 Enabled 128.4 2000 FWD Desg No
Te1/0/5 Enabled 128.5 2000 FWD Desg No
Te1/0/6 Enabled 128.6 2000 FWD Desg No
###### MST 3 Vlan Mapped: 103
ROOT ID
Priority 32771
Address 0025.642C.E532
Path Cost 0
Root Port
Bridge ID
Priority 32768
Address 0025.642C.E532
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Desg No
Te1/0/4 Enabled 128.4 2000 FWD Desg No
Te1/0/5 Enabled 128.5 2000 FWD Desg No
Te1/0/6 Enabled 128.6 2000 FWD Desg No
###### MST 4 Vlan Mapped: 104
ROOT ID
Priority 32772
Address 0025.642C.E532
Path Cost 0
Root Port
Bridge ID
Priority 32768
Address 0025.642C.E532
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Desg No
Te1/0/4 Enabled 128.4 2000 FWD Desg No
Te1/0/5 Enabled 128.5 2000 FWD Desg No
Te1/0/6 Enabled 128.6 2000 FWD Desg No
Switch2#show spanning-tree active
Spanning tree Enabled BPDU flooding Disabled Portfast BPDU filtering Disabled mode mst
CST Regional Root: 80:00:00:25:64:2C:E5:32
Regional Root Path Cost: 2000
###### MST 0 Vlan Mapped: 1
ROOT ID
Priority 32768
Address 0025.642C.E532
Path Cost 0
Root Port Te1/0/3
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec
Bridge ID
Priority 32768
Address A4BA.DB6D.98FB
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Root No
Te1/0/4 Enabled 128.4 2000 DSC Altn No
Te1/0/5 Enabled 128.5 2000 DSC Altn No
Te1/0/6 Enabled 128.6 2000 DSC Altn No
###### MST 1 Vlan Mapped: 101
ROOT ID
Priority 32769
Address 0025.642C.E532
Path Cost 2000
Root Port Te1/0/3
Bridge ID
Priority 32768
Address A4BA.DB6D.98FB
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Root No
Te1/0/4 Enabled 128.4 2000 DSC Altn No
Te1/0/5 Enabled 128.5 2000 DSC Altn No
Te1/0/6 Enabled 128.6 2000 DSC Altn No
###### MST 2 Vlan Mapped: 102
ROOT ID
Priority 32770
Address 0025.642C.E532
Path Cost 2000
Root Port Te1/0/3
Bridge ID
Priority 32768
Address A4BA.DB6D.98FB
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Root No
Te1/0/4 Enabled 128.4 2000 DSC Altn No
Te1/0/5 Enabled 128.5 2000 DSC Altn No
Te1/0/6 Enabled 128.6 2000 DSC Altn No
###### MST 3 Vlan Mapped: 103
ROOT ID
Priority 32771
Address 0025.642C.E532
Path Cost 2000
Root Port Te1/0/3
Bridge ID
Priority 32768
Address A4BA.DB6D.98FB
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Root No
Te1/0/4 Enabled 128.4 2000 DSC Altn No
Te1/0/5 Enabled 128.5 2000 DSC Altn No
Te1/0/6 Enabled 128.6 2000 DSC Altn No
###### MST 4 Vlan Mapped: 104
ROOT ID
Priority 32772
Address 0025.642C.E532
Path Cost 2000
Root Port Te1/0/3
Bridge ID
Priority 32768
Address A4BA.DB6D.98FB
Hello Time 2 Sec Max Age 20 sec Forward Delay 15 sec TxHoldCount 6 sec
Name State Prio.Nbr Cost Sts Role RestrictedPort
------ -------- --------- --------- ---- ----- --------------
Te1/0/3 Enabled 128.3 2000 FWD Root No
Te1/0/4 Enabled 128.4 2000 DSC Altn No
Te1/0/5 Enabled 128.5 2000 DSC Altn No
Te1/0/6 Enabled 128.6 2000 DSC Altn No
madpacket
5 Posts
0
June 10th, 2011 15:00
When you do "show spanning-tree active" on the Ciscos, I would expect to see the ports on the root switch (per instance) all forwarding, on the non-root switch ports show as "root" or "blocking". Can you paste the output from those here?
Thanks