Re: Muni fiber: L1 or L2?

[Scott Helms <khelms () zcorum com>]

On Sun, Feb 3, 2013 at 2:53 PM, Owen DeLong <owen () delong com> wrote:

> On Feb 2, 2013, at 5:06 PM, Scott Helms <khelms () zcorum com> wrote:
>
> Owen,
> I think the confusion I have is that you seem to want to create solutions
> for problems that have already been solved.   There is no cost effective
> method of sharing a network at layer 1 since DWDM is expensive and requires
> compatible gear on both sides and no one has enough fiber (nor is cheap
> enough in brand new builds) to simply home run every home and maintain
> that.  ISPs that would want to use the shared network in general (>95% in
> my experience) don't want to maintain the access gear and since there is no
> clear way to delineate responsibilities when there is an issue its hard.
>
> ??
>
> Who said anything about sharing the network at L1?

You did.

> Is it more expensive to home-run every home than to put splitters in the
> neighborhood? Yes. Is it enough more expensive that the tradeoffs cannot be
> overcome? I remain unconvinced.


This completely depends on the area and the goals of the network.  In most
cases for muni networks back hauling everything is more expensive.


> I'm not sure why you think it would be hard to delineate the
> responsibilities… You've got a fiber path maintained by the municipality
> with active equipment maintained by the ISP at each end. If the light
> coming out of the equipment at one end doesn't come out of the fiber at the
> other end, you have a problem in the municipality's domain. If the light
> makes it through in tact, you have a problem in the ISP's domain.
>
> There is equipment available that can test that fairly easily.

OK, this one made my wife get scared I laughed so hard.  You clearly have
never tried to do this or had to work with different operators in the same
physical network.  Please, go talk to someone whose worked in the field of
a FTTx network and describe this scenario to them.  Its clear you don't
want to hear it from me via email so please go do some research.



> The long and short of it is lots of people have tried to L1 sharing and
> its not economical and nothing I've seen here or elsewhere changes that.
>  The thing you have to remember is that muni networks have to be cost
> effective and that's not just the capital costs.  The operational cost in
> the long term is much greater than the cost of initial gear and fiber
> install.
>
> We can agree to disagree. A muni network needs to be able to recover its
> costs. The costs of building out and maintaining home-run
> fiber are not necessarily that much greater than the costs of building out
> and maintaining fiber at the neighborhood. One option, for
> example, would be to have neighborhood B-Boxes where the fiber can either
> be fed into provider-specific splitters (same economy
> as existing PON deployments) or cross-connected to fiber on the F1 cable
> going back to the MMR (home-run).
We can agree all we want, that doesn't change history.  Handing out
connections at layer 1 is both more expensive and less efficient.  Its also
extremely wasteful (which is why its more expensive) since your lowest unit
you can sell is a fiber strand whether the end customer wants a 3 mbps
connection or a gig its the same to the city.  I'm not saying you shouldn't
sell dark fiber, I'm saying that in 99% of the cities you can't build a
business model around doing just that unless your city doesn't want to
break even on the build and maintenance.



> The only additional cost in this system over traditional PON is the larger
> number of fibers required in the F1 cable.
PON networks aren't deployed this way and if you're going to backhaul all
of the connections to a central point you wouldn't run PON.   PON is worse
in every performance related way to PON and the only reasons operators
deploy it today is because its less expensive.  Its less expensive because
you don't have to backhaul all of the connections or have active components
at the neighborhood level.




> Owen
>
>
> On Feb 2, 2013 4:54 PM, "Owen DeLong" <owen () delong com> wrote:
>
> > It seems that you are (deliberately or otherwise) seriously misconstruing
> > what I am saying.
> >
> > I'm saying that if you build an L1 dark fiber system as we have
> > described, the purchasers can use it to deploy Ethernet, PON, or any other
> > technology.
> >
> > I'm not saying it's how I would build out a PON only system. That was
> > never the goal.
> >
> > The goal is to provide a municipal L1 service that can be used by ANY
> > provider for ANY service, or as close to that as possible.
> >
> > To make the offering more attractive to low-budget providers, the system
> > may also incorporate some L2 services.
> >
> > Owen
> >
> > On Feb 2, 2013, at 1:31 PM, Scott Helms <khelms () zcorum com> wrote:
> >
> > Owen,
> >
> > Cross connecting at layer 1 is what I'm saying isn't feasible.  If you
> > want to simply hand them a fiber then sell dark fiber or DWDM ports but
> > trying to create an architecture around PON or other splitters won't work
> > because PON splitters aren't compatible with other protocols.
> >
> >
> > On Sat, Feb 2, 2013 at 4:26 PM, Owen DeLong <owen () delong com> wrote:
> >
> > > On Feb 2, 2013, at 12:07 PM, Scott Helms <khelms () zcorum com> wrote:
> > >
> > > Owen,
> > >
> > > A layer 1 architecture isn't going to be an economical option for the
> > > foreseeable future so opining on its value is a waste of time...its simple
> > > not feasible now or even 5 years from now because of costs.  The optimal
> > > open access network (with current or near future technology) is well known.
> > >  Its called Ethernet and the methods to do triple play and open access are
> > > well documented not to mention already in wide spread use. Trying to
> > > enforce a layer 1 approach would be more expensive than the attempts to
> > > make this work with Packet Over SONET or even ATM.
> > >
> > > What is about a normal Ethernet deployment that you see as a negative?
> > >  What problem are you tying to solve?
> > >
> > >
> > > Ethernet works just fine in the L1 solution I've proposed, so I'm not
> > > sure why you say it isn't economically viable to do so.
> > >
> > > Owen
> > >
> > >
> > > On Sat, Feb 2, 2013 at 1:04 PM, Owen DeLong <owen () delong com> wrote:
> > >
> > > > On Feb 2, 2013, at 2:19 AM, Eugen Leitl <eugen () leitl org> wrote:
> > > >
> > > > > On Fri, Feb 01, 2013 at 04:43:56PM -0800, Leo Bicknell wrote:
> > > > >
> > > > > > The only place PON made any sense to me was extreme rural areas.
> > > > > > If you could go 20km to a splitter and then hit 32 homes ~1km away
> > > > > > (52km fiber pair length total), that was a win.  If the homes are
> > > > > > 2km from the CO, 32 pair (64km fiber pair length total) of home
> > > > > > runs was cheaper than the savings on fiber, and then the cost of
> > > > > > GPON splitters and equipment.  I'm trying to figure out if my
> > > > assessment
> > > > > > is correct or not...
> > > > >
> > > > > Is there any specific reason why muni networks don't use 1-10 GBit
> > > > > fiber mesh, using L3 switches in DSLAMs on every street corner?
> > > >
> > > > Well, one reason is that, IMHO, the goal here is to provide a flexible
> > > > L1 platform that will allow multiple competing providers a low barrier
> > > > to entry to provide a multitude of competitive services.
> > > >
> > > > Owen
> > >
> > >
> > > --
> > > Scott Helms
> > > Vice President of Technology
> > > ZCorum
> > > (678) 507-5000
> > > --------------------------------
> > > http://twitter.com/kscotthelms
> > > --------------------------------
> >
> >
> > --
> > Scott Helms
> > Vice President of Technology
> > ZCorum
> > (678) 507-5000
> > --------------------------------
> > http://twitter.com/kscotthelms
> > --------------------------------


-- 
Scott Helms
Vice President of Technology
ZCorum
(678) 507-5000
--------------------------------
http://twitter.com/kscotthelms
--------------------------------