ProCurve / ProVision-Based
cancel
Showing results for 
Search instead for 
Did you mean: 

Spanning tree Which switch is root?

Wikusg
Visitor

Spanning tree Which switch is root?

Hi, I have 2 switches that claim to be root on spanning tree. THe switches are linked on a 1gbps fiber with gbics. Why are both switches showing as root?

The config on the core is

spanning-tree
no spanning-tree bpdu-throttle
spanning-tree root primary priority 0 force-version rstp-operation

The config on the link switch 

spanning-tree root secondary priority 1 force-version rstp-operation

See below for info from "sh span" for both

My core

Multiple Spanning Tree (MST) Information

STP Enabled : Yes
Force Version : RSTP-operation
IST Mapped VLANs : 1-4094
Switch MAC Address : 2c59e5-25c700
Switch Priority : 0
Max Age : 20
Max Hops : 20
Forward Delay : 15

Topology Change Count : 620,526
Time Since Last Change : 12 mins

CST Root MAC Address : 2c59e5-25c700
CST Root Priority : 0
CST Root Path Cost : 0
CST Root Port : This switch is root

IST Regional Root MAC Address : 2c59e5-25c700
IST Regional Root Priority : 0
IST Regional Root Path Cost : 0
IST Remaining Hops : 20

Root Guard Ports :
Loop Guard Ports :
TCN Guard Ports :
BPDU Protected Ports :
BPDU Filtered Ports :
PVST Protected Ports :
PVST Filtered Ports :

Root Inconsistent Ports :
Loop Inconsistent Ports :

And  my link switch at my main high site for our WAN

Multiple Spanning Tree (MST) Information

STP Enabled : Yes
Force Version : RSTP-operation
IST Mapped VLANs : 1-4094
Switch MAC Address : d89d67-85af00
Switch Priority : 4096
Max Age : 20
Max Hops : 20
Forward Delay : 15

Topology Change Count : 0
Time Since Last Change : 128 days

CST Root MAC Address : d89d67-85af00
CST Root Priority : 4096
CST Root Path Cost : 0
CST Root Port : This switch is root

IST Regional Root MAC Address : d89d67-85af00
IST Regional Root Priority : 4096
IST Regional Root Path Cost : 0
IST Remaining Hops : 20

Root Guard Ports :
Loop Guard Ports :
TCN Guard Ports :
BPDU Protected Ports :
BPDU Filtered Ports : 1-24
PVST Protected Ports :
PVST Filtered Ports : 6

Root Inconsistent Ports :
Loop Inconsistent Ports :

 

 

 

1 REPLY
16again
Respected Contributor

Re: Spanning tree Which switch is root?

Check:
-mst settings on both switches. Only if they match, it'll be a single mst area
-the status of link between switches.  Also run show commands for stp on those ports.  
afaik, it's best to have vlan1 present untagged on this link