25xx not forwarding BPDU frames (STP)

[Jeff Allen_5]

I have a 2512 with 2 links plugged into an HP Proliant GbE2 switch (same vlan). I left the 2512 to the default of STP disabled and left STP enabled on the GbE2. I expected to see the GbE2 disable one of the ports connected to the 2512 as soon as it received its own BPDU back. However, it doesn't and eventually causes a loop.

The reason this is a Procurve issue and not a GbE2 issue is because if I take a patch cable and loop the same 2 ports on the GbE2 switch, it does indeed block one of the ports. This tells me that the Procurve is not forwarding the BPDU packets it is receiving when STP is disabled. This is not the way it should be - these 2 features (forwarding BPDU's and disabling STP) should not be mutually exclusive.

Is this a bug? Thanks for any feedback

[Ralph Bean_2]

Jeff -

There was a fix for a problem like this in Switch 2512 firmware F.05.05. What version of f/w are you running?

Regards,
Ralph

[Jeff Allen_5]

I am running version F.05.17, so I guess it isn't really fixed?

[Stuart Teo]

Hi,

I did an experiment with a setup like the one below

+-----------+
| |
2524 2524
| |
+-----------+

One of the 2524 running 5.17 has RSTP turned on, the other has RSTP turned off. The one with RSTP turned on recognized the loop immediately and blocked the port.

I then changed the version to STP and it still blocked correctly. The 2524 without STP turned on DID forward the BPDUs.

[Stuart Teo]

OK that diagram didn't come out right. Let's try this one:

2524
| |
| |
| |
| |
2524

[Stuart Teo]

OK, this drawing ought to do it.

[Ardon]

Hi,

I am pretty sure that the 25XX DOES forward BPDU's even with STP/RSTP disabled. I will test this tomorrow when back into the office as follows.

25XX (STP ON)===25XX(STP Off)====25XX(STP On)

If you theory is right I would end up with two instead of one Root as they would not see eachother right?

What happens if you set up the same senario but using two times 25XX?

I will let you know my results tomorrow.

Regards, Ardon

I will let you know

[Ardon]

Hi Hwee Liang Teo,

Sorry I did not not read you post correctly as it confirms my idea as well (that 25XX DOES formward BPDU's even with STP disabled). Shame on me:-(

Can we get an Ethereal Trace of the BPDU's sent out by the HP Proliant GBE2 Switch?

Thanks, Ardon

[Jeff Allen_5]

I will send a trace when I get the equipment again - it will be a week or 2. You are correct in the theory, however - both GbE2's did think they were root when STP was disabled on the 25xx. When STP was enabled, all worked fine.

[Ardon]

Jeff,

Please also send me the used config of the 25XX and GbE2. I do not want to be a pain but normally speaking you enable STP on all switches or was this simply something you noticed as we have STP Disabled by default.
My collegue tested my poposed setup this morning so:

25XX(STP on)===25XX (STP Off)====25XX(STP On)

and did NOT end up in a looped environment caused by two STP Root Switches. I wonder what is so special on these BPDU's from the GbE2. I understand you reasoning and want to find out where things go south.

Regards, Ardon