Illegal STP BPDU format

[Alexander_Bauer]

Hi,

does anyone know what this log messages mean?

<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 188
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 188
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 188
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 196
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 196
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 196
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 196
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 193
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 193
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 28
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 28
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 193
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 193
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 39
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 39
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 193
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 193
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 188
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 188
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 188
<Erro:STP.InBPDU.Drop> Slot-1: Port=1:25: Illegal STP BPDU format 188

Port 1:25 is a Uplink Port, configured as sharing with port 2:25.

This messages comes every 30 seconds.

Thanks,

Alexander

[FredrikB · Accepted solution]

It may be due to a proprietary spanning tree format on the switch connected to port 1:25. I have seen a very similar error in LACP when connected to HP switches. The HP would send a proprietary LACP BPDU but when it discovered the standard BPDU from the Extreme switch, it reverted from proprietary to standard format. Is STP active on the switch that is connected to port 1:25 or can it be STP frames from some other device in the network?