[FRIAM] The Last Mile, again

[Steven A Smith]

>  
>
> Thanks So much.  Can you explain the following  passage in greater
> detail?  What do you mean by “over-subscription”. 
>
If I actually got my 10Mbps down and 5Mbps up from my provider
consistently and I had say 4 devices running in my house, potentially
all trying to use *all* 10/5, then within my household I would be
"oversubscribed" by 4X.   Of course, I know that it is unlikely for all
4 devices to be trying to push/pull that hard at the same time,
continuously so for all practical purposes, my 10/5 is available to all
4 devices under most "normal" circumstances.

I don't know who (if anyone) regulates oversubscription of bandwidth, in
this modern wild west it is probably just market forces.
>
> That seems to be what they are promising.  See my answer to Gary, just
> sent.  The said that they had contracted for a 1 gig pipe and that
> that would take care of anything subscribers could throw at them.  I
> didn’t make any sense to me, but perhaps I just misunderstood.  If I
> understood the units, 40 users could exhaust I G if they all got on at
> the same time.
>
Yes, I misregistered the units by 10x.  IF 40 users all started pushing
(or pulling) as hard as the link would let them (25/3) at the same time,
continuously, then you would begin to see degradation (probably sooner
for lots of reasons), but the fact is, very few people have the need to
use the network that heavily except in bursts and rarely is there a
service on the other end willing to meet them halfway and push/pull that
much data.   If they are planning on supporting 100 users, then they are
at a 2.5X oversubscription rate, but from anecdotal evidence, THAT is
very reasonable.  
>
>   I assume we are talking about Mega/Giga per second here.  So to
> carry out the promise as I heard it, they would have to have a 1 gig
> pipe for every 40 users and they are talking about 100-200 users to
> begin with.  So, is that what you mean by “over-subscription”:  the
> number of paid subscribers who would be left out if everybody tried to
> get on simultaneously at full speed? 
>
Yes, that is a correct understanding, but as I indicated above, it is
unlikely that anyone, much less everyone can push/pull that hard except
very intermittently.
>
> What questions should I be asking them?
>
I think they are making all of the right promises and suggesting all the
right things...  the real proof will be in their execution.   You aren't
in a good position to be second guessing too much about their technical
design, but what their redundancy/backup plans are may define how long
they stay down if a backhoe, for example, cuts their main line... or if
lightning fries a rack of gear, etc.    They probably will tell you
reassuring things in any case, so the bigger question is whether you
trust them.  

One thing that might be *real* problems are "line of sight" from your
location to one of their towers... if you can *see* one or more of the
hilltops where they have towers, you are in pretty good shape unless you
are seeing it through your bare trees (or right past the edge) or your
neighbor puts up a big barn in the way.

Another is whether they have the install capacity to stand up 100 or
more customers quickly... one install team might be able to do several a
day (without problems) but with delays and weekends, that might mean
some customers won't see service for a couple of months.



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