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Airlines are running out of 4-digit flight numbers

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Re: Airlines are running out of 4-digit flight numbers

#411

Post by Thedarkb »

dotancohen wrote: post #359
ArchOversight wrote: post #335

Earlier quoted context omitted.

By that same token the general public is also not using IPv4. The general public doesn't care, so long as TikTok and Facebook appear on their mobile devices.

When you are driving are you using a throttle body?

When I drive my work van I use a throttle body, when I drive my car I use a carburettor. From my point of view as a user, I'm just driving a vehicle. The point is that users see a holistic system and neither know nor care about the underlying implementation details.

Re: Airlines are running out of 4-digit flight numbers

#412

Post by andrewstuart2 »

trueismywork wrote: post #406
tivert wrote: post #389

Earlier quoted context omitted.

>> I'm certain each flight has its own completely unique ID buried somewhere in a database > There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. Great, step one cleared. Now have all the legacy systems everywhere that use 4-digit flight numbers been updated or replaced?

4-digit flight numbers are for humans, not computers

Humans write the code that makes those computers do things, though. And humans don't always read the standards, docs, or manuals before doing so.

Re: Airlines are running out of 4-digit flight numbers

#413

Post by taneliv »

tivert wrote: post #389
delta_p_delta_x wrote: post #292

Earlier quoted context omitted.

> I'm certain each flight has its own completely unique ID buried somewhere in a database There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. [1]: https://docs.fixm.aero/#/general-guidance/flight_identificat...

>> I'm certain each flight has its own completely unique ID buried somewhere in a database > There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. Great, step one cleared. Now have all the legacy systems everywhere that use 4-digit flight numbers been updated or replaced?

Like the mechanical displays at various airports across the world pictured in the article?

Overall seems like a project of huge size and somewhat unknown reach. Not my domain, but I would imagine all kinds of ground support systems to have the four letter flight numbers baked deep into their assumptions. And not only direct support like fuel, cleaning, work shift scheduling, but also logistics systems for cargo, military systems, myriad of ticketing systems etc.

Re: Airlines are running out of 4-digit flight numbers

#414

Post by everforward »

rvnx wrote: post #333
SonOfLilit wrote: post #312

Earlier quoted context omitted.

I'm guessing everyone downvotes you for the very strange implication that most software stores IP addresses in ASCII. All networking APIs I'm aware of expect IPv4 addresses as a DWORD.

This is the point, instead of rewriting a full stack, I would rather change the prototype of these APIs. To store 999.999.999.999, then you are totally fine with a 64-bits INT (QWORD), and there is no struggle to backward-compatibility store a 32-bits INT (DWORD) into it. It's more of a matter of doing #ifdef IPV4_EXTENDED #define DWORD QWORD #endif and add an extra IP field inside the IP header packet itself that sa…

> In practice, client apps, at the time you open a new socket, if your lib says it wants an INT32 or an INT64 it doesn't matter for the developer of that app, since type is automatically casted.

A lot of networking gear is far closer to an ASIC than a general-purpose CPU, so you can't "just change it to int64". They were built to process 32-bit addresses, and are unlikely to be able to swap to 64-bit without enormous performance penalties.

E.g. routing tables would balloon in size, which in practice means that you can store far fewer routes. Ignoring changes in the size of the netmask, it's 4x the size to store 64-bit address pairs, so your route tables are a quarter the size they used to be.

The hardware refresh requirements are a big part of the reason why IPv6 rollout is so slow, and your proposal doesn't avoid that. Getting the software side of things to play nice has always been the easy part of this, even in IPv6.

> It could even be possible to give compatibility to very old software that we lost source-code from by overriding the network layer with LD_LIBRARY_PRELOAD or equivalent, and patch these softwares by manually NOP the right JGE instruction (the asm code for " >= " ) that checks if we are over 255.

In IPv6 land, you just encapsulate IPv4 in IPv6 [1]. It's a lot cleaner than jankily trying to override instructions, especially when the relevant code may run on your NIC rather than your CPU and require kernel firmware patches (or, god forbid, custom NIC firmware) to implement.

1: https://en.wikipedia.org/wiki/6to4

Re: Airlines are running out of 4-digit flight numbers

#415

Post by zeeZ »

trueismywork wrote: post #406
tivert wrote: post #389

Earlier quoted context omitted.

>> I'm certain each flight has its own completely unique ID buried somewhere in a database > There is. It's called the Globally Unique Flight Identifier (GUFI), and it's essentially a UUIDv4[1]. Great, step one cleared. Now have all the legacy systems everywhere that use 4-digit flight numbers been updated or replaced?

4-digit flight numbers are for humans, not computers

But humans, who interface with computers, are known to cause trouble.

Re: Airlines are running out of 4-digit flight numbers

#416

Post by everforward »

FeepingCreature wrote: post #234
nottorp wrote: post #196

Earlier quoted context omitted.

> IPv6 is seen and used directly by professionals, not the general public Yes, that's the problem. It's unusable on your fucking home network. Please, don't post again the 10 "concise" 50+ page documents that you "just" need to read to set up ipv6...

I don't really understand. My router gives me an IPv6 address...

Do your devices behind the router get IPv6 addresses, or just the router itself?

I wouldn't be super surprised to see routers getting IPv6 addresses and doing a 6in4 NAT, so devices behind the router get IPv4 addresses.

I would be surprised and impressed if your devices were actually getting public IPv6 addresses.

IPv6 can be kind of unwieldy, but the bigger issue to me is that old and/or very cheap clients (like bargain-bin AliExpress IoT stuff) may not support IPv6 at all.

I believe you can run DHCP for both and let the client pick one, but then you're into running dual-stack routers, and I would be very surprised if ISPs had any interest in supporting them for home use.

I may well be wrong, though. I haven't looked into it in a few years, because my ISP doesn't support it.

Re: Airlines are running out of 4-digit flight numbers

#417

Post by immibis »

kelnos wrote: post #384
immibis wrote: post #344

Earlier quoted context omitted.

They basically did. All the other changes are minor cleanups like getting rid of fields nobody uses, and realigning header bytes. Except SLAAC, but that wasn't part of the original design anyway. That was an accident when some major vendor implemented SLAAC before it implemented DHCPv6. The plan was to keep DHCP.

The idea that IPv6 is basically just "IPv4 with more address bits" is so wildly incorrect I'm not even sure where to start.

You could start with one of the ways it isn't, apart from minor cleanups, and apart from SLAAC because it was already mentioned.

Re: Airlines are running out of 4-digit flight numbers

#418

Post by dotancohen »

Thedarkb wrote: post #411
dotancohen wrote: post #359

Earlier quoted context omitted.

When you are driving are you using a throttle body?

When I drive my work van I use a throttle body, when I drive my car I use a carburettor. From my point of view as a user, I'm just driving a vehicle. The point is that users see a holistic system and neither know nor care about the underlying implementation details.

  > The point is that users see a holistic system and neither know nor care about the underlying implementation details.
Yes, this is my point too. End users are not "using IPv6" even if that protocol is in use to transfer their data.

Re: Airlines are running out of 4-digit flight numbers

#419

Post by lazide »

lisper wrote: post #363
ryukoposting wrote: post #259

Earlier quoted context omitted.

I'm certain each flight has its own completely unique ID buried somewhere in a database. But, shorter codes can be spoken into a radio faster and with lower probability of misinterpretation - both critical features for air traffic control. Those shorter codes will necessarily be reused, it's just a question of the time interval between re-uses of any particular code. I faintly recall seeing two Southwest flights from…

> Flight 1555 from ORD to BWI departs at 4PM today, and flight 1555 from ORD to BWI departs at 4:20PM tomorrow. Why do you find that remarkable? That's just the same flight departing at slightly different times on two different days.

Flight # of Theseus?

Re: Airlines are running out of 4-digit flight numbers

#420

Post by aworks »

thaumasiotes wrote: post #115
poikroequ wrote: post #22

Earlier quoted context omitted.

I'm pretty sure they want to keep flight numbers short because that's how passengers identify their flight. As a passenger, you wouldn't want to be reading signs with 40 digit flight numbers. Attention passengers, flight 3467548742468759027225995322800483168368 to Dallas is now boarding.

> I'm pretty sure they want to keep flight numbers short because that's how passengers identify their flight. That wouldn't describe any passenger I've ever known, including myself. We identify our flight by destination and departure time. Airport boards are conveniently sorted by departure time. In case of a tie, I'd fall back to airline, also indicated separately on the board, but a tie over destination and departu…

In the 1980s, I once boarded a Republic flight from Detroit to Houston. Unfortunately, the flight I paid for from Detroit to Houston was a different (and direct) one.

In Detroit, there was confusion on the plane as someone else had the same seat assignment but they found me another seat. They finally figured out I was on the wrong plane when we landed in Memphis. I was bounced off a full flight and had to wait 8 hours for the next plane to Houston.

Only one of the flight attendants seemed to pay attention to the flight number on my boarding pass.

I was also on a flight once to San Jose, California that had a passenger who was supposed to go to San Jose, Costa Rica.

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