The magic of the existing hourglass model, and the entire premise of the end-to-end principle [1], is that you can build all those features on top of the infrastructure provided by IP. IP as the skinny neck allows service providers to focus on delivering one thing very well, and enables anyone who wants to use that infrastructure to build anything they can think of on top of it.
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.
This could be true in the general case, but in my specific case I was provided with the username/password combination that I fed into the PPPoE configuration page of my router.
Again, I'm not certain of the entire stack beyond my house, but the device they brought for installation was sealed in the box that said "Media Converter" (not "ONT") on the box. It could still be the case that they somehow set it up remotely, or it could be that no setup was needed. For all I know, I tested my connection with PPPoE.
They are provisioned remotely over network from controller run by ISP, which sets up appropriate timeslots (xPON is a time-division multiplexed network in practice, though DWDM - wavelength modulation - is also used).
Internet -> ISP network -> PPPoE -> OLT (head unit) -> passive fiber network (and/or DWDM) -> passive splitter close to home (often in inside appartment buildings) -> ONT -> ethernet to your router for PPPoE -> your systems
Can you please expand on how much of that chain can be qualified as "Ethernet" (or "TCP/IP") and how much is "neither at all", and how different that is from e.g. a classic "DSL with ATM" chain?
From OLT to ONT, and everything in between, is handled by non-ethernet/non-IP protocols over which you can tunnel whatever higher level protocol you want.
Technically that can continue to whatever hosts PPPoE gateway. Ultimately, OLT is "root node", and ONTs are "leaf nodes" of a passive optical network tree. What is distributed over it is less of interest to it. But that's why you often have ONTs called "media converters" - though they aren't exactly that. A typical ONT also includes xPON MAC component as well as all management functions necessary to login into xPON network, establish session, etc. and demux transported protocol to whatever is delivered on the other side (nearly always ethernet)
Honestly it might be helpful for these guys to have a story about their situation in a relatively large publication. Just send it to people each time it happens. Works without pictures I guess
I'm guessing the maximum possible throughput of the cables themselves is significantly larger than the actual throughput or even the maximum throughput of the whole system taking into account the equipment on each it.
So I have a pi hole for my home network, and a wireguard connection back to it when I'm out and about. I run ublock on everything, block all the javascript, all the stuff.
But I do it because ads are annoying -- I don't like how they look and I don't like how they slow down every experience. I...don't really care about the tracking aspect? As far as I can tell, nothing bad happens to people because some faceless entity is tracking all your browser history.
Is there some secret malice that I'm not aware of that I should be more concerned about? Near as I can tell all this vast tracking infrastructure is really only there to more precisely target me with ads and doesn't really do anything else.
As far as privacy goes, I'm much more weirded out by the fact that my property tax records are public. Or that cell providers have the ability to fairly accurately track my location if they want to. Facebook seems pretty benign compared against that.
The argument goes, that if they can target you for ads they can also correlate this with political beliefs, your ethnicity, your financial situation and so one.
If you want a credit and you are friends with people who don't pay back their debts you are also a risk for the bank and get a higher rate.
If you want an insurance and you are a extrem cyclists you won't get one.
If you open a shopping side and they know you can afford it, they mark up the price. (Udemy is ridiculously doing this)
Yes, this is death by a thousand paper cuts.
What could the Chinese Government do with the data? Lower or rise your social credit score? Stop you from visiting China. Throw you in Jail for watching Winnie Poo?
All the other tech giants were in the US and so we didn’t have to worried about this. At least if you weren't a terrorist or behaved like one. Now China has a totally different agenda.
Is it okay to be LGBTQ in China? What happeneds if you watch a TikTok with this theme?
Yes, I am very aware of all the potential dangers, which contributes to my blocking everything in the first place. I am curious if, in the United States, there are any realized dangers to these privacy violations.
The Udemy thing is interesting, but it's also (as far as I can tell) just doing stuff with first party cookies and region lookups. Nothing at all the level of sophistication that is being observed from Meta or Tiktok.
I'd love to hear stories of people who got screwed because of facebook or Google's broad web of surveillance, but as near as I can tell, nobody is actually being harmed.
Google and Facebook coin it as violation of their terms. Just watch HN and you will get the next story every other month.
But the most chilling quote is "we kill people based on metadata":
As NSA General Counsel Stewart Baker has said, “metadata absolutely tells you everything about somebody’s life. If you have enough metadata, you don’t really need content.” When I quoted Baker at a recent debate at Johns Hopkins University, my opponent, General Michael Hayden, former director of the NSA and the CIA, called Baker’s comment “absolutely correct,” and raised him one, asserting, “We kill people based on metadata.”
I'm not entirely sure what you're hinting at. Are you saying that the US military and intelligence agencies use metadata to track down and kill people that they deem as enemies? And that Meta/Google/etc. are in cahoots with them to do this?
Can you link me example of this happening? Is there credible evidence that an ordinary citizen (like myself) is in more danger from state actors because of the information harvesting that large corporations engage in? I feel like if the government wants to track down and kill me they already have my address, cell phone records, etc. No need to contact Meta or Tiktok.
If they had no need for contacting Meta and Microsoft and Google, why did they do so?
How could would this put an ordinary citizen at risk? I don't know. All the data is run through an AI and if it labels you terrorist, who is to question it?
They sure kill a lot of people in Pakistan based on this data:
Surface contact is one reason you want an ice/water slurry instead of just ice, but the real reason is that ice melting consume a lot more energy than just ice being warmed up to it's melting point.
The ice will quickly come up to it's melting (equilibrium!) point, without cooling the ice cream mixture very much. Remember, we're trying to freeze the ice cream (not just cool it down), which is proportionally just as thermodynamically expensive as melting ice. Bringing the ice up to it's melting point alone won't suck enough heat out of the ice cream mixture to freeze it.
This right here is the explanation that clicks for me. It’s not enough to say “salt makes the ice colder than 32”. Which might cause one to wrongly assume you do it so the ice cream freezes “faster.”
What you say here is the reason WHY that is needed in the first place, and you say it very clearly
Remember, we're trying to freeze the ice cream (not just cool it down), which is proportionally just as thermodynamically expensive as melting ice.
Is it just proportional, or is it actually pretty close to 1:1? That is, how accurate is the view that if you want to freeze 1L (or kg) of ice cream you need to melt 1L (or kg) of ice? Although I guess ice cream is not just frozen water, so perhaps that forms a fixed proportion. Alternatively stated, how much ice do you need to start with to freeze a given quantify of ice cream?
The ice actually comes up to the temperature of the water while it's melting. That's what the equilibrium temperature is: the temperature of the entire ice / water system until it's been converted to all liquid or all solid.
Naturally there's some small local variations, but if you let the system come up to steady state, that's what will occur.
To be fair to GP, it does take some energy to heat the ice from freezer temp to 0C (or the new, depressed freezing point), part of which will come out of the ice cream. It's just that that amount of energy is very small compared to the other energies we're interested in here (as you pointed out elsewhere).
yes - then it wont be ice any more - but while there's still ice the temp of the liquid will stay at the equilibrium point - after that it will start to warm
"then it won't be ice anymore". Not so: the freezing point is the temperature at which ice and water are in equilibrium. If you take a bowl of ice to its freezing point it will still be entirely frozen. Then if you continue adding energy, it will remain at its freezing point while progressively more of it melts, i.e. going from 100% ice to 50% ice/50% water to 100% water. All at one temperature. In other words, if you are at the freezing point, then all of the energy you add goes to melting the ice (and none of it goes to increasing the temperature), until all of the ice is gone. That is the case even if you wait to true equilibrium, e.g. for all temperature gradients to go away.
> and none of it goes to increasing the temperature
You’re clearly more knowledgeable than I am, but this strikes me as probably wrong? The temperature at the surface has raised, which is how some of the surface ice melted. The temperature on average has to raise because thermodynamics. If I understand the article, the core temperature of the remaining ice can decrease and localities can decrease with them. But the energy is increasing temperature in every other area at a higher rate, because it has to (conservation of energy) and because it has to (more ice melts than freezes).
>> If you take a bowl of ice to its freezing point it will still be entirely frozen. Then if you continue adding energy, it will remain at its freezing point while progressively more of it melts [...] if you are at the freezing point, then all of the energy you add goes to melting the ice (and none of it goes to increasing the temperature), until all of the ice is gone.
> this strikes me as probably wrong? The temperature at the surface has raised, which is how some of the surface ice melted. The temperature on average has to raise because thermodynamics.
What do yo you think is wrong in the quoted passage?
The "temperature on average" of the system described is the temperature of every part of it: the temperature where the liquid and solid phases co-exist. When you heat that system (i.e. add energy) the temperature doesn't have to increase "because of thermodynamics". The ice melts and everything remains at the same temperature. Only when the ice is gone the water starts to warm up.
And the state change occurs when the portion of solid ice becoming liquid water warms however slightly, even if there’s a cooling side effect on the remaining ice as more energy is dissipated during that warming. Or am I still misunderstanding?
[1] https://en.wikipedia.org/wiki/End-to-end_principle