Muni fiber: L1 or L2?

Mon Feb 4 23:31:41 UTC 2013

On Feb 4, 2013, at 13:04 , Scott Helms <khelms at zcorum.com> wrote:

> Owen,
> 
> I'm trimming this for my own sanity if I snip out something important please let me know.
> 
> 
> 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.
> 
> OK good, now we're speaking on the same topic :)
>  
> 
>> 
>>> 
>>> 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 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.
>> 
>> 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.
> 
> That's where we disagree. The benefit is that:
> 
> 	1.	It doesn't lock the entire area into a single current technology.
> Neither does a ring architecture.
>  

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.

>  
> 	3.	Subscribers who want individualized services from different vendors have a choice.
> 
> Subscribers don't care if the hand off is at layer 1 or layer 2 so this is moot as well.  

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).

>  
> 	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.
> 
> 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. 

What I'm proposing is a hub and spoke architecture. It's just a much larger hub with much longer spokes.

>  
> 
>>  
>> 
>>>  
>>> 
>>> 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.
>> 
>> 
>> 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.
>> 
>> 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)? 
> 
> 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.
> 
> 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.
> 
> 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.
> 

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.
>>>> 
>>> 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.
>> 
>> 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.
>> 
>> Nope, no reason at all if you don't care about covering your costs. 
> 
> I just explained where the expected costs get covered, so you're going to have to explain that statement.
> 
> 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.

> 
> 
>> 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.
>> 
>> 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.  
> 
> More yes, much more, I'm not so convinced.
> 
> 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
> 