Re: New LINKTYPE_ for EPON

[Guy Harris <guy () alum mit edu>]

On Apr 21, 2014, at 3:24 PM, Philip Rosenberg-Watt <P.Rosenberg-Watt () cablelabs com> wrote:

> On 4/21/14 15:58 , "Guy Harris" <guy () alum mit edu> wrote:
>
> > OK, so frames for LINKTYPE_ETHERNET_P2MP, or whatever we end up calling
> > it, are:
> >
> >      the last 6 octets of the modified preamble as specified by 65.1.3.2
> > "Transmit" in 802.3-2012
>
> Correct.

OK - is LINKTYPE_ETHERNET_P2MP a good name, or might there be other flavors of point-to-multipoint in the future, so 
that we should call this LINKTYPE_ETHERNET_P2MP_EPON or something such as that?

> > followed by
> >
> >      a regular Ethernet frame (with the destination MAC being the MAC of the
> > splitter, rather than the MAC of the final destination?)?
>
> The destination MAC is the same as defined for Ethernet in IEEE 802.1. I
> can't find anything in the specification that says that the ONU/OLT will
> rewrite the destination MAC. The ONU/OLT has an internal mapping to
> associate LLIDs with MACs of connected devices, and uses it for forwarding
> packets to the appropriate Ethernet port.

So why doesn't the destination MAC suffice to determine which is the appropriate Ethernet port?

> > And those would be LINKTYPE_ETHERNET, with just a regular Ethernet frame
> > with the right destination MAC, and nothing preceding the destination MAC?
>
> Yes, because the sniffer would be connected downstream of the ONU/OLT

E.g., connected to the Ethernet in the subscriber's home?

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