RE: [EFM] EFM Requirements
Geoff,
I agree with Howard, and I apologize if my insistence on these questions
seems to be way out of the scope for the EFM group. I'm just trying to keep
a broad vision of the standard, thinking about the way some companies (such
as mine) will use it. Also bear in mind that, as non native english
speaker, it's sometimes hard for me to make my point as clear as I wish.
Concerning the frame format, my understanding is that we'll be using the
same format already used sucessfully by Ethernet in its many incarnations.
My remark was to remember that 802.1q is showing signs of age; the VLAN tag
field is no longer wide enough to acommodate some of the new applications
of the Ethernet (in fact, it was design with something completely different
in mind). As such, I believe that the 802.1q header will end up being
updated, and it will probably increase the maximum frame size. In the end,
silicon must be designed to allow for bigger frames to be transmitted at
the MAC level. It's as simple as this.
As for the interoperability requirement, it's something that I just began
to realize; I'm not completely sure if it's a good idea, or even if it's
something to be discussed at 802.3ah. My take is that all EFM compliant
equipment should support 802.1q, either the 1998 version or a future
update. The main reason is that support of VLANs on the access network is
very important as a way to provide multiple services to every customer,
while keeping all these services isolated into a separate logical network.
This requirement could either be stated as part of 802.3ah, or by another
standard group. I'm not an expert on standardization issues, though, so
I'll leave this as an open question.
Carlos Ribeiro
CTBC Telecom