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The "glass fiber modem" is an inherent part of the GPON network. These are complicated. The "P" stands for "passive". Yours and and up to 127 other houses ar
by MarkusWandel 9mo ago
The "glass fiber modem" is an inherent part of the GPON network. These are complicated. The "P" stands for "passive". Yours and and up to 127 other houses are all on the same "light domain" i.e. the downstream is passively split, and the upstream is passively combined, in optical boxes that don't even have electrical parts.
This needs crazy accurate timing for the upstream. The head end needs to know the exact delay to your particular box to give it a "grant" to transmit at exactly the right time so transmit bandwidth is not wasted by idle time or multiple boxes transmitting at the same time and corrupting each other.
You don't want brand X modems with dodgy configurations in this. Of course as a consumer you'd want "as little modem as possible" i.e. just give me an ethernet port running DHCP or PPPOE and let me do the rest.
- stephen_g 9mo agoThey are complicated, but standardised and commoditised. Ubiquiti, for example, sells an ONT (fibre modem) in a SFP form factor for US$39 [1], or a little standalone unit with an Ethernet port for US$49 [2]. 1. https://store.ui.com/us/en/category/fiber-gpon/products/uf-instant https://store.ui.com/us/en/category/fiber-gpon/products/uf-i... 2. https://store.ui.com/us/en/category/fiber-gpon/products/wave-fiber-onu https://store.ui.com/us/en/category/fiber-gpon/products/wave...
- direwolf20 9mo agoFor comparison: you can bring your own DOCSIS modem to a cable network, even though all the houses on the street are connected to the same cable and you could jam it, or send a voltage spike to break everyone's modem.
- perching_aix 9mo agoNot very familiar with DOCSIS and cable; the story I'm getting from my nearest friendly LLM is that while you could bring your cable modem, it'd have to be a pre-approved model, and that the firmware and configuration would be under ISP control, unlike with DSL modems. Is that wrong?
- namibj 9mo agoIn Germany it's wrong.
- perching_aix 9mo agoHow does it work in Germany?
- holowoodman 9mo agoYou may either rent/buy a device from your ISP, or you may bring your own, at your discretion. ISPs are required to accept all devices, of course if your device kills the network segment, they will kill your connectivity. But they can't refuse to let you connect.
- direwolf20 9mo agoWhat happens if your device connects 1000 volts to the cable and fries everyone else's device and the head-end?
- holowoodman 9mo agoYou get taken to court and sentenced to pay the damages? Same thing that happens with the TV cable that runs through the whole street. Or the cars parked openly along the road. If you damage it, you pay for it.
- AndreasTheDead 9mo agoYour by law allowed to chose your own hardware.
- perching_aix 9mo agoAnd do they exert any control over the software and configuration on it? That was kinda the crux of it after all.
- fL0per 9mo agoHere in Spain it was common to get one of these to replace the ISP ONT: https://eu.store.ui.com/eu/en/category/fiber-gpon/products/ufiber-loco https://eu.store.ui.com/eu/en/category/fiber-gpon/products/u... Not that I had the need or anything, but it's similarly priced to the example in 2. Seems to me like maybe they're phasing it out soon?
- bobmcnamara 9mo agoI cloned mine into an SFP+ for a handful of microseconds of latency improvement.
- Fnoord 9mo agoLess W usage as well.