2 ms·
I've always known that internet is oversubscribed (it's the only way to do it, really), but I'm still surprised just how far they have gone. The 1:32 split of
by crote 2y ago
I've always known that internet is oversubscribed (it's the only way to do it, really), but I'm still surprised just how far they have gone.
The 1:32 split of XGS-PON is already bad enough - especially with providers selling 8Gbit connections - but a 32Gbit uplink for 4000 customers?! If GunBlastGame 5000 releases an update, the 5 kids from the same school all starting an update when they come home is already enough to saturate the entire neighborhood's connection. I was expecting something more like 400Gbit for a city of 75.000 - less total capacity, but far harder to saturate at a local level.
I think one interesting topic missed in the article is how the GPON network is actually constructed. Some providers have the splitters placed close to the customers, while others have them placed close to the upstream connection. Having splitters close to the customer means you need far less fiber and can easily add an extra home, but the customer is always stuck with their neighbors - it's expensive to add extra capacity. Having a centralized splitter cabinet makes it way easier to patch a customer onto another splitter - or even give them a dedicated connection. On the other hand, you have to lay far more fiber as every home now needs its own connection to the cabinet, and adding a new home can become quite tricky if you haven't planned ahead.
- matt-p 2y ago4096 would be the theoretical maximum number of subscribers. Most providers will average about half of a 32 split PON actually having subscribers on. So using this case the maths now looks like 16Mb per customer in a failure scenario, 32Mb per customer in a normal scenario. The OLT can also take 100GB unlink cards and its only the cheap folks who are buying these 4x10G cards (which are about half the price).
- bee_rider 2y agoI think it is only inside the household (and maybe some additional restrictions, not sure), so not very useful, but IIRC Steam actually has some ability for users to provide downloads to each-other, peer-to-peer style. Applying that at a neighborhood level could be really nice.
- matt-p 2y agoQuite popular in the UK is the concept of A) Splitter cabinets which you get a fibre back to and then get put on one of several splitters. These cabs are completely passive and come in 48 or 96 (maximum) ports (usually fed by 12f back to the exchange). You can then patch a user onto a different splitter or even a dedicated fibre back to the exchange for P2P ethernet. B) Split at 8:1 near to the end user and then split again at the exchange, sometimes upto 8:1 again, so 1:64 on XGS-PON. The advantage of this is as a PON gets busy it's a 10 second job to change it to 2 X 4:1 splits in the exchange and so on all the way down to having upto 8 subscribers on a port. If you have a business park you can make a central decision to not further split at the exchange so they get 8:1, and you don't have to change your physical plant at all, so the field engineers build to one standard regardless of if it's domestic or business.
- toast0 2y ago> Some providers have the splitters placed close to the customers In the PON networks I've noticed, they tend to have a splitter per (serviced) pole, usually with about 4 ports. What they do in their cabinets, I don't know. If it's all undergrounded, I can't see that either. I'd guess they can swap in an 8 port splitter on a pole if needed as well. And my observed pole density seems to naturally be increased in areas of denser housing. When I lived on a postage stamp lot, we had poles every two houses or so; my parents live in suburbia with bigger lots, but poles were still about every other house. Now that I'm semi-rural, poles seem to be farther apart, but also not all poles host service connections.