Muni fiber: L1 or L2?

Jean-Francois Mezei jfmezei_nanog at
Thu Jan 31 23:58:01 UTC 2013

On 13-01-31 17:04, Scott Helms wrote:

> switch you can VLAN.  One fiber goes to the splitter on the provider side
> and then from there it splits into 8/16/32/64 connections that go to
> customers.  You can't exchange one of the customer side ports to make
> another provider interface. 

Actually you can.

Say you have 3 ISPs service a neighbouhood. 3 separate OLTs. Each with 1
line going to the "connect to customers room".

So in that room, you have say 100 fibres serving 100 homes. You have the
3 lines that come from the 3 OLTs, and splitter 1, splitter 2, splitter
3 attached to each of those lines from OLTs.

If I am home #57 and I want to be with ISP#2, then they will patch fibre
strand #57 into splitter #2.

You could theoretically have the splitters at the neighbouhood too. 3
splitters in the box, and when a customer subiscribes, its link is
attached to whcihever splitter is associated with the ISP.


This means that each ISP need to have an OLT in the MMR premises, buy
their own 32 way splitter etc.  An ISP will be losing mega money at
first because the initial investment will be grossly underused.

If you have a single FTTH plant with single OLT that is shared, then new
ISPs can easily add one or 2 customers in a neighbouhood using existing
infrastructure ad contributing their fair share of the cost of the
shared OLT.

And this makes it much easier  for a small ISP to serve a larger region
(and hence raise chances of growing and gaining enough customers to be

Canada went through this "facilities based" debate in 2009-2010 and the
CRTC's decision was quite clear. Their mandate was to go facilities
based (where small ISPs would put their own equipment in CO and in
neighbouhoods), but the process clearly showed it was not a viable
solution to enable small ISPs to grow sufficiently to provide real
competition to the incumbents. So the CRTC rules that incumbents had to
continue to share not only the very last mile, but also aggregation
networks to enable a viable competitive environment that spanned the
incumbent's whoe territory instead of small pockets where there might be
competition (small pockets being down to single multi dwelling units for

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