Reset Search
 

 

Article

Why do some ports that are in blocking state not show up when using "show spantree blockedports"

« Go Back

Information

 
TitleWhy do some ports that are in blocking state not show up when using "show spantree blockedports"
Question
Why do some ports that are in blocking state not show up when using "show spantree blockedports"
Environment
  • S-Series 
  • N-Series
  • 7100-Series
  • K-Series
Answer
When using the command "show spantree blockedports" the ports that are shown are in blocking state but but also the role is NOT disabled.

If you use "show spantree stats" active you will see some ports that are in blocking state but role disabled and that is most likely because the port is a member of a lag or is a port that has no link ( but has previously had a bpdu passed )

Example:
 
Bonded S4 Chassis(su)->show spantree stats active

Spanning tree status         - enabled
Spanning tree instance       - 0
Designated Root MacAddr      - 00-1f-45-fc-71-35
Designated Root Priority     - 0
Designated Root Cost         - 40000
Designated Root Port         - tg.1.24
Root Max Age                 - 30 sec
Root Hello Time              - 2  sec
Root Forward Delay           - 15 sec
Bridge ID MAC Address        - 00-1f-45-60-3b-54
Bridge ID Priority           - 32768
Bridge Max Age               - 20 sec
Bridge Hello Time            - 2  sec
Bridge Forward Delay         - 15 sec
Topology Change Count        - 3
Time Since Top Change        - 06 days 23:26:26
Max Hops                     - 20

SID   Port         State              Role          Cost        Priority
---   ----------   ----------------   -----------   --------    --------
0     tg.1.1       Blocking           Disabled      2000000     128
0     tg.1.2       Forwarding         Designated    20000       128
0     tg.1.24      Forwarding         Root          20000       128
0     lag.0.1      Forwarding         Designated    20000       128

Here we see that tg.1.1 is in a blocking state and Role is disabled. This is because the port is a member of lag.0.1 , which is forwarding. 

tg.1.1 will not show up in the output of "show spantree blockedports"


 
Additional notes

Feedback

 

Was this article helpful?


   

Feedback

Please tell us how we can make this article more useful.

Characters Remaining: 255