Muni Fiber and Politics

Scott Helms khelms at
Tue Jul 22 19:00:09 UTC 2014


PON versus Active Ethernet versus $topology_of_the_day makes no real
difference.  If you buy low port density shelves then your cost per port
will be higher.

BCP38 (and BCP64) have nothing to do with who is doing layer 2 since
neither of those technologies pay any attention to the layer 2 network
anyway.  I'd be curious to see your reasoning as to why it needs to be done
between layer 2 and layer 3 given that all of the access gear, including
the Ethernet equipment, has layer 2 enforcement of layer 3 information like
DHCP and static assignments of IP addresses.

"It's cleaner just to do L1 and aggregate thousands or tens of thousands of
residential properties in the same place."

In my experience that's simply untrue today.  Trying to put multiple
operator's layer 2 gear into the collocation space needed inevitably leads
to that space not having enough power, rack units, or cooling and that's
not considering the complaints (actual) of ISP1 accusing ISP2's tech of
intentionally "tripping" over a cable and causing an outage for them.

Keep in mind that in most places a muni network is currently feasible that
muni doesn't have a telco quality wiring center in place already and where
cities have the resources to build one the market usually doesn't need them

Scott Helms
Vice President of Technology
(678) 507-5000

On Tue, Jul 22, 2014 at 2:39 PM, Mikael Abrahamsson <swmike at>

> On Tue, 22 Jul 2014, Scott Helms wrote:
>  One of the main problems with trying to draw the line at layer 1 is that
>> its extremely inefficient in terms of the gear.  Now, this is in large part
>> a function of how gear is built and if a significant number of locales went
>> in this direction we _might_ see changes, but today each ISP would have to
>> purchase their own OLTs and that leads to many more shelves than the total
>> number of line cards would otherwise dictate. There are certainly many
>> other issues, some of which have been discussed on this list before, but
>> I've done open access networks for several cities and _today_ the cleanest
>> situations by far (that I've seen) had the city handling layer 1 and 2 with
>> the layer 2 hand off being Ethernet regardless of the access technology
>> used.
> Stop doing PON then. Use point to point fiber, you get 40-48 active
> customers per 1U. I'd imagine there might be newer platforms with even
> higher densities.
> Yes, there are many examples of L2 being used but in order to deliver
> triple play the L2 network won't be purely L2, also BCP38 needs it to start
> doing L2.5+ functions, meaning it's harder to deploy new servies such as
> IPv6 because now the local network needs to support it.
> It's cleaner just to do L1 and aggregate thousands or tens of thousands of
> residential properties in the same place.
> --
> Mikael Abrahamsson    email: swmike at

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