Muni fiber: L1 or L2?

Tue Feb 5 16:30:30 UTC 2013

----- Original Message -----
> From: "Scott Helms" <khelms at zcorum.com>

> > Yes it does... It locks you into whatever is supported on the ring.
> 
> I don't know how I can explain this more plainly, I can (more accurately
> have) taken a fiber build that was created as a ring & spoke SONET system
> and with the same fiber plant overlaid that with GigE and ATM (further back
> in time) to backhaul for PON, DSL, VOIP, and direct Active Ethernet.

"Overlaid"?  Could you clarify that?

Owen's assertion (and mine) is that a loop architecture *requires* active
equipment, suited to the phy layer protocol, at each node.  And while those
loop fibers are running SONET, they can't be running anything else at the
same time.

> There is nothing about a hub & spoke architecture is this harmful or even
> suboptimal for doing Gig-E directly to end users today. 

You propose to run a ring *for each subscriber*?  Or put active gear in
the field to mux the subscriber AE loops into a SONET ring?

Or some other approach I don't know it possible?

>                                                         This wasn't always
> true because we've only had 40G and 100G Ethernet for carrier networks for
> a few years. In the past we were limited by how big of an etherchannel
> network we could use for the ring. I'd also point out that the
> ring architecture is optimal for redundancy since you have fewer fiber
> bundles to get cut in the field and any cut to your ring gets routed around
> the ring by ERPS (http://en.wikipedia.org/wiki/ERPS) in less than 50
> milliseconds.

I infer from that continuation of your thought that you mean the second:
active optical muxes out in the plant.

I'm sure I've made clear why that design limits me in ways I don't want
to be limited when building a fiber plant for a 50 year lifetime, but let's
address your responses below.

> > Lower the price per instance and you very likely find new demands.
> >
> 
> The vast majority of business don't WANT that kind of connectivity.

The vast majority of businesses don't want it at the price they have to
pay for it now -- or more to the point, the consultants who do their IT
don't.

You have no real way, I should think, to extrapolate whether that will
continue as prices drop, especially if sharply.

> How many MPLS connections get purchased by SMBs? That's the same kind of
> connectivity at layer 3 and that's a market that is almost entirely
> used by large corportations.

Sure; most small businesses don't need that.

But there are some that do, and there are some that it doesn't matter
*where they are at*.  "Fiber on your wall with no upfront engineering
charge" is a pretty strong call, in some markets, and I won't have to
do most of the publicity myself; it'll make the news.

> > But the vendors do and it makes a huge difference to the barrier to entry
> > price for competing
> > vendors offering different services. (I'm talking about more than
> > just IP at this point).
> 
> What vendors? ISPs don't.

And your assertion here is based on what?  How many places have ISPs
had a *choice* as to whether to take a L1 optical or L2 aggregated handoff?

> > What I'm proposing is a hub and spoke architecture. It's just a much
> > larger hub with much longer spokes.
> 
> That's called home running, but as I've said that's ok in some
> scenarios, its just that in most cases there is no benefit.

Today.  Neither you nor I know how that will change in 20, 30, or 50
years.  But that's the horizon I'm planning not to block.

> > You're assuming the current business model of incumbent-provider owned
> > fiber. In a case where you have service providers not allowed to own fiber
> > and a fiber provider not allowed to provide services, the incentives all
> > work towards cooperation and the conflicts of interest between them are
> > eliminated. I understand what you're saying about field technicians and
> > their motivations, but, again those are based largely on the current
> > business models and compensation schemes. In the proposed arena, there's no
> > reason management at the service provider and management at the fiber
> > provider cannot work together to address these issues. Further, the
> > technician that blames the fiber plant for everything rather than
> > cooperating to resolve said issues together will inherently have his
> > installations take longer than the ones that cooperate, so he is actually
> > already automatically incentivized in the correct direction.

This is my goal.

> > Admittedly,
> > without some education, that may not be intuitively obvious to him,
> > but I find that education is usually possible when attempted.
> 
> You need to understand that I've built the exact network your describing
> several times and in all those case this was for a muni network in a
> relatively small town (<25,000 residents). I also know who the installers
> are in that sized community (as a group, not personally) and even if
> you get the best ISP partners on the planet they're going to have normal
> installers doing much of the work.

When you say "normal installers", do you mean "employees of the ISP", 
"employees of the muni", or "subcontractors of one of those two"?

And why is that pertinent?

Your assertion seems to be that it will be necessary to have "abnormal" 
installers in the field in order for them not to dump problem tickets
off to the muni and fail to help meaningfully in fixing them.

First, I think this unlikely since, in most cases, we'll have 3pr available
at each address.  If we think there's a problem with the pair, we can 
"cut to clear" *temporarily*, and if the second pair is ok, then the sub
is back online while we test the first pair and clear the problem.

(GTE's failure, for all that I give them shit about CtC is that they never
*worked* the dead pairs; as long as you do, it's not a problem.)

Second, since we'll be terminating all 3 pairs to a jackbox, the
installation contractor will be able to perform and document whatever
acceptance testing we instruct them to.  Sure, that will cost some
more money, but again, if your capital plant is tested good when installed,
this reduces markedly the opex maintenance cost over time.  Where that
breakeven point will be depends on what they want to charge me to do the
testing, just as it does with Cat6.

[ Scott: ]
> >> Sure it does, even in greenfield and whats more it costs more over the
> >> long term UNLESS you know where every home and business will be located 10
> >> years from now.

A luxury I do have, since my city is nearly 100.0% built; it's certainly
100% platted.

[ Owen: ]
> >> More yes, much more, I'm not so convinced.

And Owen isn't the only one who thinks that, and I think I know Rob 
Seastrom well enough from the list to think he wouldn't concur unless he
had some data from which to work.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra at baylink.com
Designer                     The Things I Think                       RFC 2100
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