Stratix 5700 PortFast

[patrickmoneyy]

Hi All,

I've been playing with 2 stratix switches in my test bench and seeing how different configurations affect the behaviour when 2 managed switches are connected.

The default config is MSTP with the options for BPDU Gaurd and BPDU Filter on.

Question 1: Are those options applied globally to access ports, or are they only applied to the individual ports you turn PortFast on for?

Question 2: If I understand them correctly is there any reason to have both options enabled? It seems like they achieve very different goals, and if PortFast was enabled you would only want BPDU Gaurd.

Just beginning to dip my toes into the different features related to spanning tree and would appreciate some opinions

Edit: The behavior I don't like out of the box is that connecting the two switches puts all of my ports into blocking state for around 10 seconds. Enabling PortFast on access ports and trunking between the two switches seems to fix that.

 

[patrickmoneyy]

Ok so I was playing around and disabled BPDU filtering to see if there was any behavior change, and when I went to enable it I got the message "BPDU Gaurd and BPDU Filter can't be enabled at the same time"
So that makes more sense to me, I just wonder why it shows them both globally enabled out of the box?

 

[rkukl]

both BPDU Guarding and Filter can and should be on. I believe this is a GUI issue. leave them checked it will work. BPDU is important protection.

 

[CornCobBob]

BPDU Filter effectively negates BPDU guard on a per port basis. It's used in special cases when you want to plug a switch into that port, but do not want it to participate in STP and do not want BPDU Guard to shut it down upon receiving a BPDU, so it just filters any BPDU packets out.

I'm not so sure that it is actually enabled globally. It may be worth using the CLI and seeing if you can find that specific configuration line in the config. Everyone of these that I have dealt with out of the box will go into err-disable on a portfast enabled macro assignment.

I would generally never connect anything to them straight out of the box and at least give the ports applicable macro assignments.