Re: [RPRWG] Gandalf - question on Framing
Pankaj,
The use of same physcial layer will be of the most benefit to test vendors.
I'm not sure of what level of equipment you describe, but most vendors will
have the flexibility to deal with new/different packet structures. They need
this ability for such activities as error generation/detection (i.e., CRC,
alignment, illegal frame size, frame capture). They do not use an off the
shelf Ethernet MAC. To be of any use, they will have to interpret the bits
of the RPR frame anyway (especially the header bits). The position of the DA
will not make their job any easier.
Regards,
Martin
Pankaj K Jha wrote:
> Question for Gandalf editors:
>
> I would like some understanding on benefits and rationale behind putting
> RPR header bytes in _front_ of Ethernet DA/SA fields in the Gandalf
> proposal. If an RPR header is put in using an Ethertype life would be
> much simpler, and we'd be able to use existing systems to test/monitor
> RPR packets. I don't know why header bytes are put in this way in the
> Gandalf proposal. For sure, a different MAC doesn't have to have an
> unusual format unless there was some benefit in doing so.
>
> Since the header scheme is essentially the SRP scheme, could the Gandalf
> editors consult original authors about the intent of doing so and then
> reply.
>
> Being able to look at RI, TTL, etc. very early ahead of MAC addresses
> isn't a valid reason since we're only talking about difference of a few
> bytes.
>
> In general, I'd like RPR WGers to start discussing different elements in
> different proposals so we can make informed choices on different issues
> at the January meeting.
>
> Regards,
> Pankaj