On 2014-05-20, 11:03 AM, "Tantilov, Emil S" <[email protected]>
wrote:

>>-----Original Message-----
>>From: Fred Klassen [mailto:[email protected]]
>>Sent: Tuesday, May 20, 2014 10:32 AM
>>To: [email protected]
>>Subject: [E1000-devel] Spanning tree packets missing in
>>ixgbe (82599)
>>
>>Hi,
>>
>>I'm trying to understand why I cannot receive classic STP or
>>RSTP packets. When sending the STP_only.pcap file with
>>tcpreplay we see "rx_errors" with ethtool, and notice that
>>the 82599 RLEC (Receive Length Error Count) increments. If I
>>send the pattern to a 82574L (e1000e) the packets arrive.
>
>RLEC - this register increments if an incoming packet length field in the
>MAC header does not match the packet length. We see this all the time
>where some switches generate these packets. If you already have the
>packet you should be able to inspect it and check the length reported in
>the MAC header.

I have confirmed that these STP packets are 51 bytes, and have been padded
with an additional 9 bytes so as to not violate the 60 byte minimum
Ethernet size (excluding FCS). I guess that you are saying that the only
way to have 82599 receive STP packets is to violate the Ethernet standard
and sent runt frames.

Should these RLEC conditions lead be resulting in a dropped packet? In our
appliances it is important that STP packets be passed up to the bridging
protocol. This happens properly on our e1000e bridge. We have never
implemented STP on ixgbe adapters, but if did I would be concerned about
missing STP packets.
 
>
>This feature is new for 82599 - that is why these packets are not dropped
>in older HW.
>
>Thanks,
>Emil
>
>>
>>Also, we note that MSTP (802.1s) does appear to work on
>>82599.
>>
>>I am using the 3.18.7 ixgbe driver from Sourceforge.
>>
>>Thanks, Fred.
>>
>>
>


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