Spanning Tree - Blocking Port

[chalithcp]

Hi.

With a HP 2530-8 Switch I created two VLANs and configured two access ports for each VLAN. Then I looped these two interfaces using an UTP cable. One of the port is going to blocking state in spaning tree. 

I just want check, as those ports are in 2 seperate VLANs, why it is blocking one port.

Thanks. 

[akg7]

Hi,

Which STP you are using here?

Is it rapid-pvst?

Can you please share the config?

[aybra]

Hello,

by default Procurve uses MSTP and all vlans are in the same instance, so it bhaves like RSTP (non vlan aware), to avoid blocking the ports of different vlans you have tow options, the first is using different instance of each vlan and the second one is using PVST.

Hope this help you

Best regards

[chalithcp · Accepted solution]

Hi aybra,

 I change spanning tree mode to RPVST. Please find the config below.

vlan 1
name "DEFAULT_VLAN"
no untagged 1,5-6
untagged 2-4,7-10
ip address 10.1.1.1 255.255.255.0
ip address 10.10.10.1 255.255.255.0
ip igmp
exit
vlan 5
name "test"
untagged 5-6
ip address 10.10.20.1 255.255.255.0
exit
vlan 100
name "VLAN100"
untagged 1
no ip address
exit
spanning-tree
spanning-tree mode rapid-pvst

Now both ports seems to be blocked as shown below.

HP-2530-8-PoEP# show spanning-tree vlan 1

Spanning Tree Information

STP Enabled [No] : Yes
Mode : RPVST
Extended System ID : Enabled
Ignore PVID Inconsistency : Disabled
Switch MAC Address : e0071b-464ac0

VLAN ID : 1
RPVST Enabled : Enabled

Root MAC Address : e0071b-464ac0
Root Priority : 32,768
Root Path Cost : 0
Root Port : This switch is root
Operational Hello Time (secs) : 2
Topology Change Count : 0
Time Since Last Change : 2 hours

Root Inconsistent Ports :
Loop Inconsistent Ports :
PVID Inconsistent Ports : 2

Designated
Port Type Cost Priority Role State Bridge
----- ---------- --------- --------- ---------- ---------- ---------------
2 10/100TX 200000 128 Designated Blocking e0071b-464ac0
3 10/100TX 0 128 Disabled Disabled
4 10/100TX 0 128 Disabled Disabled
7 10/100TX 0 128 Disabled Disabled
8 10/100TX 0 128 Disabled Disabled
9 100/1000T 0 128 Disabled Disabled
10 100/1000T 0 128 Disabled Disabled

HP-2530-8-PoEP# show spanning-tree vlan 5

Spanning Tree Information

STP Enabled [No] : Yes
Mode : RPVST
Extended System ID : Enabled
Ignore PVID Inconsistency : Disabled
Switch MAC Address : e0071b-464ac0

VLAN ID : 5
RPVST Enabled : Enabled

Root MAC Address : e0071b-464ac0
Root Priority : 32,768
Root Path Cost : 0
Root Port : This switch is root
Operational Hello Time (secs) : 2
Topology Change Count : 0
Time Since Last Change : 2 hours

Root Inconsistent Ports :
Loop Inconsistent Ports :
PVID Inconsistent Ports : 5

Designated
Port Type Cost Priority Role State Bridge
----- ---------- --------- --------- ---------- ---------- ---------------
5 10/100TX 200000 128 Designated Blocking e0071b-464ac0
6 10/100TX 0 128 Disabled Disabled

I can not undersatand the logic behind it. 

Thanks. 

[chalithcp]

Hi,

Is there anyone who can help me ?

Thanks. 

[aybra]

Hello

can you please provide network diagram and which ports are looped with the show tech files so we can identify what happened exactly.

best regards