During a test session i did find a very nasty bug between Router OS and a Procurve Aruba 2530 switch. the kind of bug that can fully break an entire network.
This is the first time i have a problem with STP, but this one is a big one ! I've heard some tech guys inside Datacenters complaining about STP, Now i know why
The bug is not directly related to Mikrotik, but it was triggered by a Mikrotik Router where i did left enable RSTP in a bridge.
After adding a Mikrotik router in the setup, i did loose all connectivity in my network. Everywhere even inside the telephony and other Vlans.
After scratching my hairs during a couple hours, i did watch with Wireshark and did see GVRP and RSTP frames on the link. Then i did check the switch settings and saw that STP was fully disabled in the switch. But GVRP enabled. GVRP frames were going to the Mikrotik bridge, and RSTP frame were going to the Procurve switch.
STP was disabled on the switch, but GVRP enabled. GVRP is a protocol to exchange VLAN configuration data automatically between all switches of the Network.
The switch was fully mad, mixing VLANS and breaking connectivity on all VLANS. Then i did disable RSTP on the Mikrotik and bam ! no more problems.
I think that the switch was missinterpreting the RSTP frames as GVRP frames, probably sending RSTP information in the VLAN tables !!
Then i did enable again RSTP on the Mikrotik and again the same madness on the switch, breaking all connectivity.
Then i did enable MSTP in the switch (there is no more STP or RSTP in those switches), and problem solved.
The only explanation is that when the 2530 switch (latest firmware) is receiving RSTP frames, it takes them as GVRP frames, corrupting the VLAN tables. !!
It does this only if STP is disable on the switch !
After checking in details the frames, RSTP and GVRP frames are very similar, they are 802.2 Ethernet frames with a LLC header that have the same 0x42 number for DSAP and SSAP. Weird.
Because the RSTP packet is very small compared to GVRP, i think that the switch were resseting the VLAN table when it did take erroneously RSTP frames for GVRP data.
Morals : sometimes it's better to leave STP enabled
It's definitely a Procurve switch bug not related to Mikrotik.