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Ask HN: Why does it seem hard to buy an ONT for fiber?

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Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#31

Post by windexh8er »

PaulAJ wrote: post #15

The ONT's job is to translate from (typically) Ethernet to the optical fibre, and nothing else. In networking terms its "Level 1"; concerned only with moving bits from one end to the other. Most ISPs will provide an ONT which does that and nothing else, and then a regular router/firewall that plugs in to the ONT via Ethernet. Your security barrier is the firewall in the router, plus whatever encryption you apply to c…

One point of correction...

> In networking terms it's "Level 1"

What, I think, you mean to say is "Layer 1" of the OSI model, which is still incorrect. An active device, even when "dumb" is a "Layer 2" (Data Link) device. Ultimately a "bridge" networking device. The device is doing local media conversion which can't be accomplished by physical media interconnects alone. Even if the data link protocol is the same on both sides bridging the media types often requires a conversion. But in the case of ONT it's not going to be Ethernet on the WAN / carrier side. Not sure of the setup here but the PON is usually a very "dumb" last mile as it's often some sort of DWDM driven headend that's splitting out wavelengths for downstream consumption by the PON via the OLT and then broken out to Ethernet on the CPE, which is an ONU in this case.

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#32

Post by madjam002 »

vel0city wrote: post #14
madjam002 wrote: post #10

A good fibre ISP will have a separate ONT and router, so you can still pick your own router. The ONT should be considered part of the ISPs network and not tampered with or replaced. Fibre with an ONT (PON) is a shared medium with other customers, and trying to use your own equipment has the possibility of degrading service for other customers.

In a DOCSIS network the coax is a shared medium with other customers and at least in the US you largely could bring your own modem, within approved device lists.

Ah ok, in the UK our only widespread DOCSIS network strictly forbids 3rd party modems for the same reasons I mentioned.

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#33

Post by madjam002 »

nicolaslem wrote: post #17
madjam002 wrote: post #10

A good fibre ISP will have a separate ONT and router, so you can still pick your own router. The ONT should be considered part of the ISPs network and not tampered with or replaced. Fibre with an ONT (PON) is a shared medium with other customers, and trying to use your own equipment has the possibility of degrading service for other customers.

The same can be said of cellular networks where in most part of the world connecting your own equipment is accepted and expected.

True I guess, although one would perhaps expect a fibre network to be more reliable and stable than a cellular network.

Why would a large ISP allow customers to bring their own ONT if it means higher chance of problems on the PON? It doesn't seem worth the reputational risk. Allowing customers to bring their own router doesn't affect other customers.

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#35

Post by maratc »

"Modem" stands for "modulator-demodulator" and it is there to convert the TCP/IP traffic in your house to some sort of non-TCP/IP connection that goes to your ISP. In case of cable provider, I believe the outgoing protocol is called DOCSIS, and in case of a telephone provider it could be ADSL/VDSL etc. (Historically some also used ATM above the physical layer.) The modem is there to do that translation.

With fiber, there is TCP/IP traffic within your house and TCP/IP traffic to your ISP. There is no translation to do, so no translator device (modem) is needed. The only thing needed is a physical layer conversion, from 0s and 1s as voltage over copper, to (exactly same) 0s and 1s as light over fiber. This conversion (not "translation") could be done by a stand-alone ONT (a rather uncomplicated, or could I say "trivial" device), but there are several router boxes that have fiber connections — either built-in (on board) or as plug-in modules.

Different ISPs have different offerings, but as you might imagine not many people want to manage their own router. My ISP has provided me with a free ONT which goes into my router, to which I connect my WiFi access points, all of which I manage myself.

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#36

Post by mleo »

rr808 wrote: post #34

Even the router I still use fios Quantum because I suspect fios configures it from time to time. Am I wrong? I'd prefer to have my own but it works well enough.

On Frontier and when it was previously Verizon I have only used my own router plugged into ONT via Ethernet cable. This has been 11 years now.

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#37

Post by noodlesUK »

moronix wrote: post #4

For the most part, I believe it is all about the management and troubleshooting ability from the ISP side. You can buy ONT devices, but I think that the OLT device of the ISP must support the one you bought, which really defeats the purpose of buying it. There are even SFP modules that can work as an ONT interface. Really your best bet is to ask your ISP if they can bridge a port on the ONT so you can use your own ro…

My ISP was not willing to do this for me, but they did give me the admin password for the device so I could change the SSID on the integrated WiFi. From there I was able to configure a bridge interface. Everyone is happy with this outcome.

Most of the time in my experience you can’t BYO ONT because it needs to be authed to the network and the ISP won’t do that other than for their own hardware. On the other hand I’ve never heard of being charged rental fees for an ONT.

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#38

Post by timrice »

maratc wrote: post #35

"Modem" stands for "modulator-demodulator" and it is there to convert the TCP/IP traffic in your house to some sort of non-TCP/IP connection that goes to your ISP. In case of cable provider, I believe the outgoing protocol is called DOCSIS, and in case of a telephone provider it could be ADSL/VDSL etc. (Historically some also used ATM above the physical layer.) The modem is there to do that translation. With fiber, t…

This is not entirely true with PON (passive optical networks). The ONT is more than a media converter (optical -> copper), it facilitates the conversation with the OLT (Optical Line Terminal) further upstream. That connection is not an ethernet connection and needs specialized hardware that can communicate using the PON protocols.

The ONT is managed by the service provider and provisioned with their tooling. It typically holds the user profile of the customer, and contains information about the subscribers service level. It is not something that can reasonably be replaced by the end user with their own hardware.

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#39

Post by [deleted] »

timrice wrote: post #38
maratc wrote: post #35

"Modem" stands for "modulator-demodulator" and it is there to convert the TCP/IP traffic in your house to some sort of non-TCP/IP connection that goes to your ISP. In case of cable provider, I believe the outgoing protocol is called DOCSIS, and in case of a telephone provider it could be ADSL/VDSL etc. (Historically some also used ATM above the physical layer.) The modem is there to do that translation. With fiber, t…

This is not entirely true with PON (passive optical networks). The ONT is more than a media converter (optical -> copper), it facilitates the conversation with the OLT (Optical Line Terminal) further upstream. That connection is not an ethernet connection and needs specialized hardware that can communicate using the PON protocols. The ONT is managed by the service provider and provisioned with their tooling. It typic…

[deleted]

Re: Ask HN: Why does it seem hard to buy an ONT for fiber?

#40

Post by LelouBil »

alufers wrote: post #16

I'm not sure where you live (probably the US), but here in Europe you can easily get GPON ONTs from different manufacturers. There even are whole communities dedicated to replacing your ISP's ONT+modem combo: https://hack-gpon.org/quick-start In some countries (Germany) it's super easy, because there are laws forcing the ISPs to allow customer provided equipment, while in other countries you need to do some hackery w…

In France there's this forum

https://lafibre.info

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