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Spanning Tree and Ports

Mattycnl
Occasional Visitor

Spanning Tree and Ports

Hi. I have a mesh network topology whose switches are connected through fiber optic, with RSTP enabled.

Usually when a new switch comes in I only give the following commands regarding STP:

#spanning-tree

#spanning-tree force-version rstp-operation

 

Everything works fine, I have no problem in my network, but I wonder if it's a best practice to only enable spanning-tree on the SFP ports which are connected to the other switches, thus disabling spanning tree on all the other ports which are connected to end-nodes (PCs, printers and so on). So it would be like:

#no spanning-tree 1 auto-edge-port

#no spanning-tree 2 auto-edge-port

...

leaving spanning tree enabled only on the SFP ports.

 

What do you think? 

Thanx

6 REPLIES
Pete W
Valued Contributor

Re: Spanning Tree and Ports

In my experience STP is there for 2 main reasons.

  1. To allow you to engineer L2 loops into the network for resiliance, and have them block/unblock in a deterministic way.
  2. To protect your ass from L8 issues such as users plugging IP phones into the wall using both ports.

I say leave it on. HP STP converges as fast as any I have seen, so if you are not seeing any issues - leave it alone.

 

:)

 

Regards,

 

Pete

MASE
CCNP
Meru MCSE
Vince_Whirlwind
Trusted Contributor

Re: Spanning Tree and Ports

I agree, leave it on.

 

On the other hand, you are asking a very good question - investigate BPDU Protect and BPDU Guard, I think you will like what either one or both of those have to offer.

Mattycnl
Occasional Visitor

Re: Spanning Tree and Ports

Was asking the question also because in the 'Event log' of all STP enabled switches I normally find these type of events:

 

I 07/16/13 05:15:37 00077 ports: AM1: port B15 is now off-line
I 07/16/13 05:15:39 00435 ports: AM1: port B15 is Blocked by STP
I 07/16/13 05:15:41 00076 ports: AM1: port B15 is now on-line
I 07/16/13 05:15:54 00077 ports: AM1: port B15 is now off-line
I 07/16/13 05:15:55 00435 ports: AM1: port B15 is Blocked by STP
I 07/16/13 05:15:58 00076 ports: AM1: port B15 is now on-line
I 07/16/13 07:05:02 00077 ports: AM1: port B8 is now off-line
I 07/16/13 07:05:05 00435 ports: AM1: port B8 is Blocked by STP
I 07/16/13 07:05:07 00076 ports: AM1: port B8 is now on-line
I 07/16/13 07:48:34 00435 ports: AM1: port C6 is Blocked by STP

....

 

Those are all end-node ports, and I don't understand why they get involved with STP operations.

thx

Richard Brodie_1
Honored Contributor

Re: Spanning Tree and Ports

It's just a short delay ~3 seconds after the port comes online to see if there is a switch connected. Except for the last entry, which appears to be something else.

Vince_Whirlwind
Trusted Contributor

Re: Spanning Tree and Ports

Change the ports to "admin-edge-port" instead of the default "auto-edge-port" and see if you like the result.

 

Spanning-tree a1-a20 admin-edge-port

 

Mattycnl
Occasional Visitor

Re: Spanning Tree and Ports

Thanx everyone