North American Network Operators Group

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Re: pon's and ethernet to the home

  • From: Rubens Kuhl Jr.
  • Date: Tue Dec 09 17:01:50 2003

> As far as I have understood, the idea is to use the fiber as it was
> coax, doing some kind of FDM (frequency division multiplexing) with
> the lambdas (somehow the same). This would give us the capability

In the optics field it is usually called WDM (Wavelenght Division

> to move at leat n x 10mbps ethernet on the same fiber using diferent
> lambdas for each customer, until power budget goes down.

Nope; PON works by sharing the same channel among the users. There is a WDM
use of the fiber only because the uplink and downlink use different
wavelenghts, but the downlink is shared with TDM (Time Division
Multiplexing) and the uplink with TDMA (TDM/Multiple Access).

> If the idea is correct, this would mean "next jump" on bandwidth.
> Who would be making this "ethernet/lambda multiplexors" right
> now? Is it feasible to do it today? or should we wait a little more?

PONs are feasible today; the CO equipment is called OLT (Optical Line
Terminator), and the CPE is a ONT/ONU (Optical Network Terminator/Unit). The
only external device is a passive star coupler.
Check out, and

> I mean, there are solutions using packet over sonet or alike, but
> pure ethernet?

PON has three flavors: APON/BPON, EPON (IEEE 802.3ah) and GPON. APON uses
ATM framing, EPON uses Ethernet framing and GPON uses GFP (Generic Framing
Protocol). GFP can also be used on top of SONET to make Ethernet-over-SONET,