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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

#341

Post by RaftPeople »

snapcaster wrote: post #228
jll29 wrote: post #227

> Here’s the full answer, along with how they triage the problem – for instance by assigning the same flight number to more than one flight a day (although that means they need for it to be flights that would never both be in the air at the same time, such as where the same plane is used and can’t reasonably be substituted) This sounds like it's calling for trouble! Whenever I hear that any IDs could be "recycled", I…

>Whenever I hear that any IDs could be "recycled", I make a mental note to replace the person making such a proposal from all teams that I am involved in. Couldn't agree more, not even interested in debating it

> Couldn't agree more, not even interested in debating it

Given that the industry has rejected the natural but very expensive solution, and that airlines exist in a connected space, this information is shared with partners and external parties so they can't just change their internal systems, it doesn't seem like there are too many solutions.

One solution could be to assign multiple airline codes per airline, but I'm not sure of the downsides.

Do you have a solution you think would work?

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

#342

Post by immibis »

nottorp wrote: post #241
FeepingCreature wrote: post #234

Earlier quoted context omitted.

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

Do you understand on what basis? Do you know enough to assign addresses in a way that you, not your router, wants? Can you ssh/other forms of remote into any machine that accepts ssh on your local network using only ipv6? Can you redirect ports to specific local machines using only ipv6 (that implies they keep constant addresses)? Can you easily switch between two internet connections going through different routers…

Do you do all this stuff with IPv4? No... especially not at home.

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

#343

Post by Macha »

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…

So you need to send a message from your host 5.6.7.8 to one of these newly enabled hosts 500.600.700.800. You update the software on your host, and your target's ISP is updated, and your target updates, and we'll even hand wave and assume your ISP is updated despite apparently having enough legacy addresses to allocate you one.

The message goes out to your ISP router, who then sends it to their upstream ISP, who looks at the IP message, doesn't understand whatever header you've shoved the extended address in, and discards it. Then what's in your standard, backwards compatible 32 bit field? The start of the address? Does your packet go to some other random host on the internet? A placeholder address like all 0s? Does your message get discarded?

How do you convince that middleman to update their hardware? They have no benefit from it? This is the situation IPv6 was in for decades until their literally were not enough IPv4 addresses which finally lit a fire under companies to start enabling it.

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

#344

Post by immibis »

ReptileMan wrote: post #310
zeagle wrote: post #80

Clearly the successor solution is to use eight groups of four hexadecimal digits each, separated by colons. Then each individual seat and peanut could be addressed to it's final destination. More seriously the solution suggested of giving the 3 companies other unused prefixes like D* U* and A* to use with their codeshares and non rev flights to start seems the easiest.

Roughly 20 years ago a network engineer I worked with said - "We took a look and IPv4 had everything we want and need but the address space". Why the committees didn't just made it 128 bit and be done with it is beyond me.

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.

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

#345

Post by zwily »

madcaptenor wrote: post #311
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…

Short flights out-and-back from a hub can have the same number on the two legs. An example is AA 1992, which today departs PHL 3:06 PM, arrives ATL 5:17 PM, departs ATL 5:57 PM, arrives back at PHL 8:05 PM. (All times US Eastern.) My mother recently had an itinerary where both her flights were this flight - the PHL-ATL leg on a Sunday and the ATL-PHL leg on the following Saturday. (It looks like as of Tuesday AA 1992…

I recently flew SLC-CLT and CLT-SLC, and both flights were DL2070.

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

#346

Post by zwily »

snapcaster wrote: post #228
jll29 wrote: post #227

> Here’s the full answer, along with how they triage the problem – for instance by assigning the same flight number to more than one flight a day (although that means they need for it to be flights that would never both be in the air at the same time, such as where the same plane is used and can’t reasonably be substituted) This sounds like it's calling for trouble! Whenever I hear that any IDs could be "recycled", I…

>Whenever I hear that any IDs could be "recycled", I make a mental note to replace the person making such a proposal from all teams that I am involved in. Couldn't agree more, not even interested in debating it

Flight numbers are already recycled (sometimes on the same day). The proposal is just changing the recycling frequency.

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

#347

Post by vel0city »

immibis wrote: post #336
vel0city wrote: post #256

Earlier quoted context omitted.

IP addresses (especially IPv4) are not even supposed to be globally unique. How many 192.168.1.1 devices are out there? How many different distinct physical boxes respond to traffic going to 1.1.1.1?

They are most definitely designed to be globally unique, and we fucked it up.

If that was supposed to be the case it's been fucked up since they first gave 19.0.0.0/8 to a car company in 1988, or when IPv4 was originally designed with such a small address range.

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

#348

Post by mise_en_place »

Part of the problem is codesharing, you have to use two flight numbers for the same flight. The whole practice is confusing and I don't think it should be allowed, except in the rarest of circumstances. The seat quality is also suspect at best, when you're not directly buying from the operating carrier.

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

#349

Post by daemin »

pixl97 wrote: post #321
daemin wrote: post #207

Earlier quoted context omitted.

There was no need to have 5 digit codes or more than 0-9 for the flight numbers 20 years ago. Arguably there isn't a need now. It's 3 airlines in the entire world which have this issue because they want to have their own 4000 flights plus codeshare more than 6000 other flights from partner companies. This is a problem for people inside those 3 airlines to solve within the constraints that the current living world has…

Ever hear the saying "If you owe the bank 1 million dollars it's your problem. If you owe the bank 10 billion dollars it's their problem". You list listed off the largest airlines on the planet of which pretty much every other airline has to interoperate with. This isn't "AA just has to deal with it", it becomes "This is now everyones problem".

Yes I have heard of that saying.

What I am saying is that "the rest of the world" is bigger than AA.

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

#350

Post by madcaptenor »

zwily wrote: post #345
madcaptenor wrote: post #311

Earlier quoted context omitted.

Short flights out-and-back from a hub can have the same number on the two legs. An example is AA 1992, which today departs PHL 3:06 PM, arrives ATL 5:17 PM, departs ATL 5:57 PM, arrives back at PHL 8:05 PM. (All times US Eastern.) My mother recently had an itinerary where both her flights were this flight - the PHL-ATL leg on a Sunday and the ATL-PHL leg on the following Saturday. (It looks like as of Tuesday AA 1992…

I recently flew SLC-CLT and CLT-SLC, and both flights were DL2070.

I've also seen this on Delta on ATL-PHL. I had guessed it was limited to relatively short flights - because why waste a number on a short flight, and because there's less room for irregularity where you end up with both flights in the air at the same time - but it looks like at least SLC-CLT on Delta and DFW-SEA on American do it.
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