[160374] in North American Network Operators' Group
Re: Muni fiber: L1 or L2?
daemon@ATHENA.MIT.EDU (Owen DeLong)
Mon Feb 4 18:36:58 2013
From: Owen DeLong <owen@delong.com>
In-Reply-To: <CAMrdfRyMJ-ivrd44f7bAmamFssnL-LvvwK8bvX0EoCu4rcEYGw@mail.gmail.com>
Date: Mon, 4 Feb 2013 15:31:41 -0800
To: Scott Helms <khelms@zcorum.com>
Cc: NANOG <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Feb 4, 2013, at 13:04 , Scott Helms <khelms@zcorum.com> wrote:
> Owen,
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> I'm trimming this for my own sanity if I snip out something important =
please let me know.
>=20
>=20
> So long as you recognize that it's on a pair-by-pair basis end-to-end =
and not expecting any mixing/sharing/etc. by the L1 infrastructure =
provider, yes.
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> OK good, now we're speaking on the same topic :)
> =20
>=20
>>=20
>>>=20
>>> 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.
>>>=20
>>>=20
>>> This completely depends on the area and the goals of the network. =
In most cases for muni networks back hauling everything is more =
expensive.
>>=20
>> I agree it's more expensive. The question is whether it's enough more =
expensive to make it infeasible. You still haven't come anywhere near =
addressing that question.
>>=20
>> I've said repeatedly that this a network by network analysis. I've =
never said its infeasible, but that it is more expensive both initially =
and long term in MOST installs. That by itself is generally enough to =
invalidate the design since in almost all cases there's no benefit to =
home running all the connections. It doesn't make the connection faster =
nor do ISPs (as a group) care about a layer 1 versus layer 2 hand off.
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> That's where we disagree. The benefit is that:
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> 1. It doesn't lock the entire area into a single current =
technology.
> Neither does a ring architecture.
> =20
Yes it does... It locks you into whatever is supported on the ring.
> 2. It allows for individual subscribers (probably mostly =
businesses, but I have had a few occasions
> where this would have been useful as an individual) to =
get dark XC to other locations.
> Neither does a ring architecture, you do have fewer long runs, but in =
any build you're going to end up with spare pairs to use for this and in =
my experience the number of businesses who want this in given area are =
very small. I can't think of a network where this is more than 1% of =
the business connections.
That's because today, it's expensive and the price is usually way way =
way above cost-recovery (or, it's cost
recovery of the build cost / n where n is a very small number of =
fibers).
Lower the price per instance and you very likely find new demands.
> =20
> 3. Subscribers who want individualized services from =
different vendors have a choice.
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> Subscribers don't care if the hand off is at layer 1 or layer 2 so =
this is moot as well. =20
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).
> =20
> 4. Providers have to compete on a leveled playing field and =
there is thus incentive to innovate
> even if the innovation moves away from PON.
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> Again, this is a completely moot point. There is nothing in a ring or =
hub & spoke architecture that makes open access more difficult EXCEPT if =
you want to share lots of L1 connections.=20
What I'm proposing is a hub and spoke architecture. It's just a much =
larger hub with much longer spokes.
> =20
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>> =20
>>=20
>>> =20
>>>=20
>>> I'm not sure why you think it would be hard to delineate the =
responsibilities=85 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.
>>>=20
>>> There is equipment available that can test that fairly easily.
>>>=20
>>> 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.
>>=20
>>=20
>> I've talked to a few people doing exactly that. Yes, you need =
different test sets depending on which L2 gear is involved, but, in =
virtually ever case, there is a piece of test gear that can be used to =
test a loop independent of the configuration of the L2 gear in question.
>>=20
>> Yes, there is a meter for all the different kinds of technologies =
that you might want to support. For example a DOCSIS 3.0 DSAM from JDSU =
will run you around $8000.00 A PON meter with long range lasers (more =
than 10 miles) from JDSU or Trilithic will cost you nearly $10,000. =
Exactly how many of those kinds of meters do you want to have to buy? =
How many of your staff are you going to train on them (they do require =
training and knowledge to use)?=20
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> For my proposed methods of build-out, no need for the long range =
lasers. As I said, everything should be within 8km of the MMR.
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> As I suggested, the simpler approach is to require the complaining L2 =
provider to cooperate in the diagnostic process and provide access to =
the applicable meters if necessary. The standard offered absent =
assistance from the L2 provider is OTDR success.
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> Medium range lasers (anything that's running on single mode fiber) =
versus long range don't drive the cost. OTDR is not and cannot test for =
any phase modulated system and that includes every form of PON, Active =
Ethernet, and RFoG. You _might_ be able to use one to test RS-232 over =
fiber depending on the vendor. This is where you're really not getting =
it. As the owner of the physical medium you WILL be the blame of every =
problem until you prove differently. Every end user install that goes =
poorly, every time there is a connection drop, and every time some end =
user of $L1 partner calls them complaining the city will get the blame.
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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. Admittedly, without some education, that may not be =
intuitively obvious to him, but I find that education is usually =
possible when attempted.
>> For providers getting L1 service, it wouldn't be too hard to make =
this testing / providing necessary test equipment part of their =
contract.
>>>> 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.
>>>>=20
>>> 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).
>>>=20
>>>=20
>>> 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.
>>=20
>> If it's $700 per home passed to build out home-run fibers (which =
seems to be a reasonable approximation from earlier discussions), then =
there's no reason you can't sell $40/month service over that where the =
L1 component is a $10/month ($7 for capital recovery, $3 for operations =
and support) pricing component.
>>=20
>> Nope, no reason at all if you don't care about covering your costs.=20=
>=20
> I just explained where the expected costs get covered, so you're going =
to have to explain that statement.
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> No, you listed some more than optimistic numbers and passed that off =
as evidence. If you seriously think that the fiber connection is only =
worth $10 per month then you're off by ~100%.
Even if it's $20/month and you charge $50/month for L3 service and =
you're still in good shape. However, the real world numbers presented so =
far show costs closer to $10/month, so I'm not sure where your data is =
coming from.
>=20
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>> However, the point is that building the infrastructure in that manner =
doesn't cost much more than building out traditional PON infrastructure =
(if you're doing it from greenfield) and it can support either =
technology.
>>=20
>> 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. =20
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> More yes, much more, I'm not so convinced.
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> You think the fiber connectivity is only worth $10 too....
$20/subscriber/month still strikes me as being within the realm of "not =
much more". So, based on your statement above...
Owen
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