Re: [802.3_NGECDC] EthType on Long Reach
Bob-
This is not an 802.3 question.
From the 802.3 point-of-view, all traffic is "directly-on-mac messaging"
The format of what is in the packet is determined by the protocol identification from the EtherType value which resides in the Type/Length field of the Ethernet packet.
The Ethernet MAC only looks at the EtherType to determine if it is MAC Control information, otherwise the packet just gets passed up to the next layer.
Further, I don't know what you mean by "directly-on-mac messaging".
Is it binary or ASCII?
If it is ASCII, is just plain text or is it HTML (or some other form of encoded ASCII)?
Does it have predetermined fields or is it free form?
So, in answer to your question.
Yes, there are lots of Layer 2 protocols don't involve IP, many of them not even from "the old days".
There probably even is an existing one for transporting CANBus data directly over Ethernet.
You need to pick one or define and type a new one.
This issue is appropriately addressed at the upper layers.
I hope this helps.
Best regards,
Geoff Thompson
> On Jan 31, 2016, at 7:14 AMPST, Robert Moskowitz <rgm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> In a conversation I had about the Long Reach work, there was a comment that not all sensors want to add IP, even with the work in IETF's 6lo for IPv6 over MS/TP (Bacnet).
>
> Is there an EthType that is used for directly-on-mac messaging, or one lying around from the old days that was used for this?
>
> Something that basically says here is a message that you know how to handle? Or looking at it in the ISO stack model of layer 5 (session) directly on layer 2. I will point out that is also basically what CANBus is.