On Thu, Oct 29, 2020 at 02:40:55PM +1100, Matthew P. Grosvenor wrote:
> I think you’re missing the point here. You made two assertions:
> The NIC MAC should either strip the CRC, or should drop a packet with a bad
> CRC.
No, that is not what I meant. The job of the MAC is to check the CRC
and d
Hi Richard,
I think you’re missing the point here. You made two assertions:
The NIC MAC should either strip the CRC, or should drop a packet with a bad
CRC.
It is completely useless for a NIC to forward the CRC to the host.
I am saying that I disagree with you on both of those assertions.
It ma
On Wed, Oct 28, 2020 at 06:27:42AM +1100, mgrosve...@gmail.com wrote:
> Furthermore, some switches (Eg Arista and and Cisco) use the CRC to convey
> timestamps in packets.
If that is true, then their device drivers should strip off the time
stamp and provide it via the SO_TIMESTAMPING mechanism.
On Wed, Oct 28, 2020 at 06:27:42AM +1100, mgrosve...@gmail.com wrote:
> Furthermore, some switches (Eg Arista and and Cisco) use the CRC to
> convey timestamps in packets. It would be absolutely necessary to be
> able to see the “CRC” for this this use case, on the same interface
> that PTP traffi
> AFAICT, receiving the FCS is totally useless. After all, it must be
> correct, otherwise the MAC would drop the frame.
I don’t know the context of this argument, but what I can say for a fact is
that this is not not a true statement. A NIC is free to decide to filter out
the CRC if it wants,
On Tue, Oct 27, 2020 at 11:12:54AM +, Matt Sanders (matt8) wrote:
> and uses the mechanisms that the standard implies to resolve the
> problem.
I disagree with your intrepretation of the what the standard "implies".
> What’s
> your objection to going down this path?
Check the list archives.
On 10/23/20 2:13 AM, Richard Cochran wrote:
> On Thu, Oct 22, 2020 at 11:17:51AM +, Matt Sanders (matt8) via
Linuxptp-devel wrote:
>
>> It is possible for 802.3 Ethernet adapters to be configured include
the Ethernet
>> CRC value in the raw frame which will be returned by the PF_PACKET /
On Thu, Oct 22, 2020 at 11:17:51AM +, Matt Sanders (matt8) via
Linuxptp-devel wrote:
> It is possible for 802.3 Ethernet adapters to be configured include the
> Ethernet
> CRC value in the raw frame which will be returned by the PF_PACKET / SOCK_RAW
> interface used by Linux PTP. This is con
Section 13.3 of the 1588 specification* discusses the common message header
format. In particular, the messageLength field is defined in 13.3.2.4 as
“The total number of octets that form the PTP message. The counted octets start
with the first octet of the header and include and terminate with the
