On Wed, Oct 26, 2016 at 5:36 PM, Mikael Abrahamsson <swmike@swm.pp.se> wrote:

On Wed, 26 Oct 2016, Jan Ceuleers wrote:

What I mean is that the OLT optics become very expensive if you need to
support as many lambdas as you have customers. You'd furthermore need an
OLT port for much fewer customers (e.g. 1 port per 64 or 128 customers)
than the thousands you can support on a (shared) GPON port on a single
lambda.

That only works if your customers don't use their Internet access very much. If they do, you're in trouble and have to rebuild.

Yes, and the question then becomes: How much is "very much"? This can of course be analyzed mathematically, which e.g. Google have done here:

http://research.google.com/pubs/pub44935.html

In my market, we're now in the access speeds where 100/10 is on the lower end of access, and it's not uncommon for people to have 250, 500 or 1000 downstream. If they then actually start using their bw then you'd have to rebuild to either go higher speed for some CPE (complicated and expensive), or rebuild to have smaller splitter domains.

The standard answer from PON proponents (I'm not one) is to upgrade equipment, from GPON to XG-PON or NG-PON2. But upgrading hardware as bandwidth demand increases is necessary whatever the technology - what's important is the scalability of the solution.