RE: [EFM] T.V. broadcast / unicast
I think a lot of this depends on how the relative cost of CWDM optics
develops over the next two-three years. It would be far simpler technically
to put b'cast TV (and / or user selected TV channels) on a separate lambda
(may be not using an 802 protocol). I thought that was why we are proposing
to leave some of the lambda bands vacant.
I thought that the email from Ingvar was very informative.
'Broadcasting' only the channels selected by users (probably from a
selection system at the POP, not at the CO) is a change of system
architecture from the traditional cable T.V. model. It also requires powered
POPs. Powered POPs map well into the star / fan-out p2p systems (which maps
into my positioning well, so I am in favour of it).
Best regards
Bob
-----Original Message-----
From: owner-stds-802-3-efm@majordomo.ieee.org
[mailto:owner-stds-802-3-efm@majordomo.ieee.org]On Behalf Of
carlosal@xxxxxxxxxxxxxxxxxx
Sent: 20 November 2001 19:55
To: John Pickens
Cc: Norman Finn; stds-802-3-efm@ieee.org; stds-802-3-efm-p2mp@ieee.org
Subject: [EFM] Re: [EFM-P2MP] Point-to-Point plus Shared Media
Two comments:
1) John Pickens said:
> I know there is a contingent within the working group that does not
> consider it a requirement to access the single-copy-broadcast attribute
of
> the media, so probably we should poll this question at some point.
Although I'm the first to acknowledge that my opinion is *not*
representative of all carriers (far from it :-), I can say that the
single-copy-broadcast is one of the *great* potential advantages of using
Ethernet PON in the access network. Of course, it all depends on whether
will we be able to provide broadcast-based services such as digital video.
I believe that many carriers will be of the same opinion.
So my vote is already cast - single-copy-broadcasts are a requirement.
2) Norman Finn's idea is really neat from a technical *and* political
standpoint, as it sounds as a reasonable compromise between the two fields;
however, I'm not sure that it's actually feasible in practice due to
administrative reasons, as John pointed out. It is highly probable that
most carriers will end up using only one of the modes.
[For instance, this already happened with DSL; almost nobody uses the two
transmission modes of DMT modems (interleaved and fast). Although it is
technically possible to use the two at the same time, almost everybody uses
only the interleaved one, mainly because of the complexity, and also
because of potential compatibility issues]
Anyway, just to explore the alternatives, we could deploy completely
separate IP networks, each over a separate MAC address (of course this
assume that we are going to run IP over Ethernet, but who bets otherwise?).
Each IP network could 'opt' for some particular mode of operation.
p.s. There are also some security issues that we should analyze in this
case; the two kinds of traffic would be received at every node, and this is
could pose a different security problem. Not sure about it, just wondering.
Carlos Ribeiro
CTBC Telecom