AW: [EFM] Wavelength allocation
Yes, this is a very important topic. I think that from the
way things have been progressing in the group that
this will be a topic for discussion within the next sessions.
I know that as a component vendor that we have a strong
interest in this field and we would also be in favour
of allocating dedicated wavelength bands for extended services etc.
What are your feelings on how such a specification might look?
Von: Carlos Ribeiro [mailto:cribeiro@xxxxxxxxxxxxxxxx]
Gesendet am: Dienstag, 17. Juli 2001 13:20
Betreff: [EFM] Wavelength allocation
I've tried to send this message a few times over the weekend, but I didn't
get through. I'm trying again, because this is a very important topic,
looking from the carrier's perspective.
Most EPON proposals are P2MP. You have to use a sophisticated arbitration
mechanism to control the use of the upstream channel. Although complex and
initially expensive, DOCSIS did this before, and with high volume the cost
of CPEs is driven down. However, the user is still concerned with the
security (ok, we know it's almost impossible to tap the neighboor upstream
signal, but go figure customer's mind :-). Also, the amount of bandwidth is
limited by design. Any changes must be implemented by all elements in the
give cable/fiber segment.
In the P2P EPON proposal, each customer gets their own wavelength. You have
PON at the physical level, but a point-to-point connection at the upper
layers. I believe this is the best of both worlds, because you have high
speed, and you can provide dfferentiated services for some customers in the
segment. You're not stuck with the technology of the traditional PON
As the technology evolves, it's possible that we'll hit the technical
limitations of the first generation EPON systems - the ones that are going
to be deployed in the next months. In the cable industry, you use smaler
segments to improve efficiency. Using P2MP EPON, you can do the same, but
you can also start to deploy new wavelengths for the new services. In fact,
it is possible to envision a scenario where you end up allocating a
wavelength for every individual customer, turning your P2MP network into a
Other applications can (and should) user their own wavelengths. The best
example that comes to mind is broadcast video - it's much more efficient
and less expensive to deliver it using a separate lamda, than trying to
carry it over packets.
As it is, I would like the EFM standard to include a wavelength allocation
policy. I haven't seen this discussed in depth; some presentations touch on
this topic slightly. There is someone working specifically on this?