litchralee
Almost. By virtue of being a smaller antenna, the 30 cm panel does not focus its energy as tightly as a larger (eg 60 cm) antenna. Likewise, a smaller antenna does not pick up (ie receive) as much energy as a larger antenna does. Thus, by using a 30 cm panel, less of the high energy from the opposite radio will reach the receiver, and that keeps the receiver from being damaged.
In RF engineering, there is a careful balance between output power, antenna size/shape, environmental conditions, and desired link quality. Whoever built the radio link originally did not apparently perform the necessary calculation. I’m not an RF engineer, but for spanning a mere 50 meters, this 20 cm antenna with built-in radio should be more than sufficient for a basic link.
Normally, increased RF power is helpful to overcome interference or noise. Just like how normally, an automobile or airplane will be easier to operate if it has a bigger engine with more power.
At some point, though, the extra RF or engine power is no longer beneficial but also isn’t harmful. And if you go significantly beyond that, then you end up in a region where the extra power is downright harmful and is actively working against you.
Consider an automobile driving in a rainstorm. Having more power is bad, because the tires can lose grip more easily, leading to a crash. In an airplane that has gotten into a stall, applying power is the wrong solution and just aggravates the stall, which is not good.
Here, adding more RF power is just cooking the other receiver like it’s a Thanksgiving turkey. The extra power is no longer helpful for making communications, and may be physically damaging the receiver.
Although copyright and patents (and trademarks) are lumped together as “intellectual property”, there’s almost nothing which is broadly applicable to them all, and they might as well be considered separately. The only things I can think of – and I’m not a lawyer of any kind – are that: 1) IP protection is mentioned vaguely in the US Constitution, and 2) they all behave as property, in that they can be traded/reassigned. That’s it.
With that out of the way, it’s important to keep in mind that patent rights are probably the strongest in the family of IP, since there’s no equivalent “fair use” (US) or “fair dealing” (UK) allowance that copyright has. A patent is almost like owning an idea, whereas copyright is akin to owning a certain rendition plus a derivative right.
Disney has leaned on copyright to carve for themselves an exclusive market of Disney characters, while also occasionally renewing their older characters (aka derivatives), so that’s why they lobby for longer copyright terms.
Whereas there isn’t really a singular behemoth company whose bread-and-butter business is to churn out patents. Inventing stuff is hard, and so the lack of such a major player means a lack of lobbying to extend patent terms.
To be clear, there are companies who rely almost entirely on patent law for their existence, just like Disney relies on copyright law. But type foundries (companies that make fonts) are just plainly different than Disney. Typefaces (aka fonts) as a design can be granted patents, and then the font files can be granted copyright. But this is a special case, I think.
The point is: no one’s really clamoring for longer parents, and most people would regard a longer exclusive term on “ideas” to be very problematic. Esp if it meant pharmaceutical companies could engage in even more price-gouging, for example.
The original tech installed a 60cm panel for a rf link which is no more than 50M.
In case anyone else has this minor confusion, this is a radio link between two buildings which are 50 meters apart. And a square, directional flat-panel antenna that is 60 centimeters on a side is grossly overkill for the short distance involved.
To be clear, the legs would support the topper when it’s positioned over the tub, and also support the topper when it’s beside the tub? If that’s the case, do the legs really need to fold away? Would fixed legs be acceptable? Or is there a requirement that the legs be foldable to provide clearance over the edge of the tub?
If you hold a patent, then you have an exclusive right to that invention for a fixed period, which would be 20 years from the filing date in the USA. That would mean Ford could not claim the same or a derivative invention, at least not for the parts which overlap with your patent. So yes, you could sit on your patent and do nothing until it expires, with some caveats.
But as a practical matter, the necessary background research, the application itself, and the defense of a patent just to sit on it would be very expensive, with no apparent revenue stream to pay for it. I haven’t looked up what sort of patent Ford obtained (or maybe they’ve merely started the application) but patents are very long and technical, requiring whole teams of lawyers to draft properly.
For their patent to be valid, they must not overlap with an existing claim, as well as being novel and non-obvious, among other requirements. They would only file a patent to: 1) protect themselves from competition in future, 2) expect that this patent can be monetized by directly implementing it, or licensing it out to others, or becoming a patent troll and extracting nuisance-value settlements, or 3) because they’re already so deep in the Intellectual Property land-grab that they must continue to participate by obtaining outlandish patents. The latter is a form of “publish or perish” and allows them to appear like they’re on the cutting edge of innovation.
A patent can become invalidated if it is not sufficiently defended. This means that if no one even attempts to infringe, then your patent would be fine. But if someone does, then you must file suit or negotiate a license with them, or else they can challenge the validity of your patent. If they win, you’ll lose your exclusive rights and they can implement the invention after all. This is not cheap, and Ford has deep pockets.
I’ll address your question in two parts: 1) is it redundant to store both the IP subnet and its subnet mask, and 2) why doesn’t the router store only the bits necessary to make the routing decision.
Prior to the introduction of CIDR – which came with the “slash” notation, like /8 for the 10.0.0.0 RFC1918 private IPv4 subnet range – subnets would genuinely be any bit arrangement imaginable. The most sensible would be to have contiguous MSBit-justified subnet masks, such as 255.0.0.0. But the standard did not preclude using something unconventional like 255.0.0.1.
For those confused what a 255.0.0.1 subnet mask would do – and to be clear, a lot of software might prove unable to handle this – this is describing a subnet with 2^23 addresses, where the LSBit must match the IP subnet. So if your IP subnet was 10.0.0.0, then only even numbered addresses are part of that subnet. And if the IP subnet is 10.0.0.1, then that only covers odd numbered addresses.
Yes, that means two machines with addresses 10.69.3.3 and 10.69.3.4 aren’t on the same subnet. This would not be allowed when using CIDR, as contiguous set bits are required with CIDR.
So in answer to the first question, CIDR imposed a stricter (and sensible) limit on valid IP subnet/mask combinations, so if CIDR cannot be assumed, then it would be required to store both of the IP subnet and the subnet mask, since mask bits might not be contiguous.
For all modern hardware in the last 15-20 years, CIDR subnets are basically assumed. So this is really a non-issue.
For the second question, the router does in-fact store only the necessary bits to match the routing table entry, at least for hardware appliances. Routers use what’s known as a TCAM memory for routing tables, where the bitwise AND operation can be performed, but with a twist.
Suppose we’re storing a route for 10.0.42.0/24. The subnet size indicates that the first 24 bits must match a prospective destination IP address. And the remaining 8 bits don’t matter. TCAMs can store 1’s and 0’s, but also X’s (aka “don’t cares”) which means those bits don’t have to match. So in this case, the TCAM entry will mirror the route’s first 24 bits, then populate the rest with X’s. And this will precisely match the intended route.
As a practical matter then, the TCAM must still be as wide as the longest possible route, which is 32 bits for IPv4 and 128 bits for IPv6. Yes, I suppose some savings could be made if a CIDR-only TCAM could conserve the X bits, but this makes little difference in practice and it’s generally easier to design the TCAM for max width anyway, even though non-CIDR isn’t supported on most routing hardware anymore.
To start off, I’m sorry to hear that you’re not receiving the healthcare you need. I recognize that these words on a screen aren’t going to solve any concrete problems, but in the interest of a fuller comprehension of the USA healthcare system, I will try to offer an answer/opinion to your question that goes into further depth than simply “capitalism” or “money and profit” or “greed”.
What are my qualifications? Absolutely none, whatsoever. Although I did previously write a well-received answer in this community about the USA health insurance system, which may provide some background for what follows.
In short, the USA healthcare system is a hodge-podge of disparate insurers and government entities (collectively “payers”), and doctors, hospitals, clinics, ambulances, and more government entities (collectively “providers”), overseen by separate authorities in each of the 50 US States, territories, tribes, and certain federal departments (collectively “regulators”). There is virtually no national-scale vertical integration in any sense, meaning that no single or large entity has the viewpoint necessary to thoroughly review the systemic issues in this “system”, nor is there the visionary leadership from within the system to even begin addressing its problems.
It is my opinion that by bolting-on short-term solutions without a solid long-term basis, the nation was slowly led to the present dysfunction, akin to boiling a frog. And this need not be through malice or incompetence, since it can be shown that even the most well-intentioned entities in this sordid and intricate pantomime cannot overcome the pressures which this system creates. Even when there are apparent winners like filthy-rich plastic surgeons or research hospitals brimming with talented expert doctors of their specialty, know that the toll they paid was heavy and worse than it had to be.
That’s not to say you should have pity on all such players in this machine. Rather, I wish to point to what I’ll call “procedural ossification”, as my field of computer science has a term known as “protocol ossification” that originally borrowed the term from orthopedia, or the study of bone deformities. How very fitting for this discussion.
I define procedural ossification as the loss of flexibility in some existing process, such that rather than performing the process in pursuit of a larger goal, the process itself becomes the goal, a mindless, rote machine where the crank is turned and the results come out, even though this wasn’t what was idealized. To some, this will harken to bureaucracy in government, where pushing papers and forms may seem more important that actually solving real, pressing issues.
I posit to you that the USA healthcare system suffers from procedural ossification, as many/most of the players have no choice but to participate as cogs in the machine, and that we’ve now entirely missed the intended goal of providing for the health of people. To be an altruistic player is to be penalized by the crushing weight of practicalities.
What do I base this on? If we look at a simple doctor’s office, maybe somewhere in middle America, we might find the staff composed of a lead doctor – it’s her private practice, after all – some Registered Nurses, administrative staff, a technician, and an office manager. Each of these people have particular tasks to make just this single doctor’s office work. Whether it’s supervising the medical operations (the doctor) or operating/maintaining the X-ray machine (technician) or cutting the checks to pay the building rent (office manager), you do need all these roles to make a functioning, small doctor’s office.
How is this organization funded? In my prior comment about USA health insurance, there was a slide which showed the convoluted money flows from payers to providers, which I’ve included below. What’s missing from this picture is how even with huge injections of money, bad process will lead to bad outcomes.
In an ideal doctor’s office, every patient that walks in would be treated so that their health issues are managed properly, whether that’s fully curing the condition or controlling it to not get any worse. Payment would be conditioned upon the treatment being successful and within standard variances for the cost of such treatment, such as covering all tests to rule out contributing factors, repeat visits to reassess the patient’s condition, and outside collaboration with other doctors to devise a thorough plan.
That’s the ideal, and what we have in the USA is an ossified version of that, horribly contorted and in need of help. Everything done in a doctor’s office is tracked with a “CPT/HCPCS code”, which identifies the type of service rendered. That, in and of itself, could be compatible with the ideal doctor’s office, but the reality is that the codes control payment as hard rules, not considering “reasonable variances” that may have arisen. When you have whole professions dedicated to properly “coding” procedures so an insurer or Medicare will pay reimbursement, that’s when we’ve entirely lost the point and grossly departed from the ideal. The payment tail wags the doctor dog.
To be clear, the coding system is well intentioned. It’s just that its use has been institutionalized into only ever paying out if and only if a specific service was rendered, with zero consideration for whether this actually advanced the patient’s treatment. The coding system provides a wealth of directly-comparable statistical data, if we wanted to use that data to help reform the system. But that hasn’t substantially happened, and when you have fee-for-service (FFS) as the base assumption, of course patient care drops down the priority list. Truly, the acronym is very fitting.
Even if the lead doctor at this hypothetical office wanted to place patient health at the absolute forefront of her practice, she will be without the necessary tools to properly diagnose and treat the patient, if she cannot immediately or later obtain reimbursement for the necessary services rendered. She and her practice would have to absorb costs that a “conforming” doctor’s office would have, and that puts her at a further disadvantage. She may even run out of money and have to close.
The only major profession that I’m immediately aware of which undertakes unknown costs with regularity, in the hopes of a later full-and-worthwhile reimbursement, is the legal profession. There, it is the norm for personal injury lawyers to take cases on contingency, meaning that the lawyer will eat all the costs if the lawsuit does not ultimately prevail. But if the lawyer succeeds, then they earn a fixed percentage of the settlement or court judgement, typically 15-22%, to compensate for the risk of taking the case on contingency.
What’s particularly notable is that lawyers must have a good eye to only accept cases they can reasonably win, and to decline cases which are marginal or unlikely to cover costs. This heuristic takes time to hone, but a lawyer could start by being conservative with cases accepted. The reason I mention this is because a doctor-patient relationship is not at all as transactional as a lawyer-client relationship. A doctor should not drop a patient because their health issues won’t allow the doctor to recoup costs.
The notion that an altruistic doctor’s office can exist sustainably under the FFS model would require said doctor to discard the final shred of decency that we still have in this dysfunctional system. This is wrong in a laissez-faire viewpoint, is wrong in a moral viewpoint, and is wrong in a healthcare viewpoint. Everything about this is wrong.
But the most insidious problems are those that perpetuate themselves. And because of all those aforementioned payers, providers, and regulators are merely existing and cannot themselves take the initiative to unwind this mess, it’s going to take more than a nudge from outside to make actual changes.
As I concluded my prior answer on USA health insurance, I noted that Congressional or state-level legislation would be necessary to deal with spiraling costs for healthcare. I believe the same would be required to refocus the nation’s healthcare procedures to put patient care back as the primary objective. This could come in the form of a single-payer model. Or by eschewing insurance pools outright by extending a government obligation to the health of the citizenry, commonly in the form of a universal healthcare system. Costs of the system would become a budgetary line-item so that the health department can focus its energy on care.
To be clear, the costs still have to be borne, but rather than fighting for reimbursement, it could be made into a form of mandatory spending, meaning that they are already authorized to be paid from the Treasury on an ongoing basis. For reference, the federal Medicare health insurance system (for people over 65) is already a mandatory spending obligation. So upgrading Medicare to universal old-people healthcare is not that far of a stretch,
Good luck with your endeavors! Always keep in mind that when debugging a complex problem, try isolating individual components and testing them individually. This can be as easy as swapping a web application with the Python SimpleHTTPServer to validate firewall and reverse proxy configuration.
Thank you for that detailed description. I see two things which are of concern: the first is the IPv6 network unreachable. The second is the lost IPv4 connection, as opposed to a rejection.
So staring in order, the machine on the external network that you’re running curl on, does it have a working IPv6 stack? As in, if you opened a web browser to https://test-ipv6.com/ , does it pass all or most tests? An immediate “network is unreachable” suggests that external machine doesn’t have IPv6 connectivity, which doesn’t help debug what’s going on with the services.
Also, you said that all services that aren’t on port 80 or 443 are working when viewed externally, but do you know if that was with IPv4 or IPv6? I use a browser extension called IPvFoo to display which protocol the page has loaded with, available for Chrome and Firefox. I would check that your services are working over IPv6 equally well as IPv4.
Now for the second issue. Since you said all services except those on port 80, 443 are reachable externally, that would mean the IP address – v4 or v6, whichever one worked – is reachable but specifically ports 80 and 443 did not.
On a local network, the norm (for properly administered networks) is for OS firewalls to REJECT unwanted traffic – I’m using all-caps simply because that’s what I learned from Linux IP tables. A REJECT means that the packet was discarded by the firewall, and then an ICMP notification is sent back to the original sender, indicating that the firewall didn’t want it and the sender can stop waiting for a reply.
For WANs, though, the norm is for an external-facing firewall to DROP unwanted traffic. The distinction is that DROPping is silent, whereas REJECT sends the notification. For port forwarding to work, both the firewall on your router and the firewall on your server must permit ports 80 and 443 through. It is a very rare network that blocks outbound ICMP messages from a LAN device to the Internet.
With all that said, I’m led to believe that your router’s firewall is not honoring your port-forward setting. Because if it did and your server’s firewall discarded the packet, it probably would have been a REJECT, not a silent drop. But curl showed your connection timed out, which usually means no notifications was received.
This is merely circumstantial, since there are some OS’s that will DROP even on the LAN, based on misguided and improper threat modeling. But you will want to focus on the router’s firewall, as one thing routers often do is intercept ports 80 and 443 for the router’s own web UI. Thus, you have to make sure there aren’t such hidden rules that preempt the port-forwarding table.
