On Tue, Aug 5, 2014 at 9:26 PM, William Herrin <bill@herrin.us> wrote:
Hi Eugeniu,
The word you're searching for is "microduct."
That's it, I wasn't sure about it.
I'm a big fan of Microduct. There's even some wicked cool equipment which will force the core out of in-place coax plant, converting it to microduct suitable for a fiber installation. But here are some of the places you may run in to trouble using it for a municipal fiber installation:
1. 10 miles of fiber optic cable is expensive (from a consumer perspective) even when you're able to float it through a series of ducts instead of having to trench. Who covers the cost? If the service provider amortizes it for the consumer (instead of the municipal infrastructure provider) then you're right back to the consumer lock-in that damages competition.
For business connections, the customer pays the cost from the nearest PoP to its premises as a one time installation fee and then the yearly cost of "renting" is spread out over 12 months. This is what one of my ISPs told me. But the price is pretty much negligible to rent this compared to what you pay for the actual "Internet" connection. For residential areas I'm not sure, but being predominantly apartment blocks, I think the ISP takes the "hit" as at least my bills haven't gone up.
2. While microduct supports 12 or 24 fibers in a single duct, it does not support adding or removing fibers from a duct. To install a different quantity, you have to remove all the existing fiber and then blow a completely new set of fibers. Obviously service provider A is not motivated to install extra fibers that service provider B can subsequently sell you service on. Only a bare infrastructure provider would have that motivation.
Each ISP has a microduct. I've seen "output/breakout" boxes in the street with several microducts labeled with different ISP names, so no worries here. I'm not sure how many are installed by default, but probably it depends on the area, maybe 12 in residential areas and 24 in crowded areas. I really don't know. Also, one ISP can have (I think) as many microducts as they can buy.
3. Structure is good. It facilitates reuse. If you permit the fiber to be run between arbitrary points you end up with the same cruft as an office without structured cabling. Even if you use microduct, future-proofing requires central cross-connect points where folks patch.
There are a lot of manholes for this stuff, some bigger and some a little bit smaller. I've never been into one to see how they are organized. Yes, you can get a lot of cruft, but installing OMMRs in the middle of the street tends to be expensive (even if you can somehow burry a room underneath the street to house them) so I guess the current method works best given the conditions.
4. I'm not sure how far you can float fiber down a microduct but I'm pretty sure you don't do it miles at a stretch. So, if you build your system with microduct and fiber-blown-later, you'll have a *lot* of points where the ducts have to be joined.
I also have no idea about the length, but it seems to be working so far. Also, splicing fibers is done so fast by qualified technicians that it doesn't add a significant amount of time to get a circuit ready - I think it's around 5 minutes for a pair of fibres. Eugeniu