topic bpdu protection in Switches, Hubs, and Modems

bpdu protection

Simon Merckx — Tue, 27 May 2008 06:31:13 GMT

I have STP enabled on my procurve switches.
I have also some cisco switches that are running PVST. I am going to switch tot Rapid STP when al the cisco are gone.
I heard that RSTP en PVST are not compatible.

I want to enale bpdu protection on my edge ports to prevent loops. But the command seems only available when a procurve is in RSTP mode.
I this true?
Loop protect is always available, but does it work when there is a loop between two switches?
Two adjacent wall connections don't always go to the same switch.

Re: bpdu protection

Jeff Carrell — Tue, 27 May 2008 13:07:38 GMT

yes, PVST is not compatible with standard STP/RSTP/MSTP...

hard to provide absolute info not knowing which procurve switches you have...

reading in the 5400 manual, bpdu protection appears to be available in STP,RSTP,MSTP modes...

pvst filtering/protection is only available in MSTP mode...

loop protection might work if one of the switches drops STP packets...but if the 2 switches connected together have STP (one of the protocols) enabled, then bdpu filtering/protection will/could work...

you may need to work on the physical layer a bit to resolve some of your potential loop issues...i know not the best answer, but it may be what has to be done...

hth...jeff

Re: bpdu protection

Jeff Carrell — Tue, 27 May 2008 13:08:10 GMT

yes, PVST is not compatible with standard STP/RSTP/MSTP...

hard to provide absolute info not knowing which procurve switches you have...

reading in the 5400 manual, bpdu protection appears to be available in STP,RSTP,MSTP modes...

pvst filtering/protection is only available in MSTP mode...

loop protection might work if one of the switches drops STP packets...but if the 2 switches connected together have STP (one of the protocols) enabled, then bdpu filtering/protection will/could work...

you may need to work on the phica layer a bit to resolve some of your potential loop issues...i know not the best answer, but it may be what has to be done...

hth...jeff

Re: bpdu protection

Simon Merckx — Tue, 27 May 2008 15:24:47 GMT

I am using 2950 procurve switches.

You say that BPDU protection is available in STP mode on the 5400. But when I put a 2950 in STP mode, the BPDU protection command is not available. Only when I put it in RSTP mode.
That protection can also work in STP mode I presume? Why is the that command not available in that mode?

I also tested loop protect on a 2950 with the latest firmware (10.50) and enabled it with:
loop-protect 1-48. When I make loops it doesn't detect them.
Show loop-protect says that loop-protect is running and that there are no detected loops.
This was an isolated switch with no traffic on it. Is that the reason?

Re: bpdu protection

Jeff Carrell — Tue, 27 May 2008 17:25:03 GMT

ok...

according to the 2650 10.50 rel notes, bpdu protection is only available in RSTP/MSTP mode...can't say why, that's what the docs indicate...

loop protect only works when you have another device that drops bpdu pkts connecting between 2 switches that do pass/understand bdpu pkts...so connecting a loop on the same switch w/LP enabled, doesn't meet the criteria...then you would need bpdu protection...

confusing at best i agree...

Re: bpdu protection

Simon Merckx — Wed, 28 May 2008 08:02:54 GMT

I did some more testing with loop protect.
It only works reliable when you set the transmit interval to 1 second. You also have to set a disable interval.
If you set the interval to 0, loop-protect doesn't seem to work.

With the above settings, it works if you make a loop between to switches and also when you make a loop on the same switch.

Thanks for your advice.