Hacker News Reader

Comment by NooneAtAll3 | Hacker News Reader

> Internet routing can't handle mobility - at all.

so all the fairy tales about IP invented for nuclear war was a lie? the moment military started moving around, IP became useless?

View on HN

The source and destination addresses don't change. If a bomb takes out a router in-between (the military scenario DARPA had in mind), it is NOT IP (L3) or TCP (L4) that handles it. Rather it is a dynamic routing protocol that informs all affected routers of the changed route. Since the early days of the Internet, that's been the job of routing protocols.

For smaller internets, protocols such as RIP (limited to 16 hops) broadcast routing information from each still-working router to other routers. Each router built a picture of the internet (simplifying a bit here, RIP and similar protocols used "distance vector" routing, but other more advanced routing protocols did have each a picture of the internet). So when a packet arrived at its router, that router can forward the pack towards the destination. Such protocols are "interior" routing protocols, used within an ISP's network.

The Internet is too big for such automatic routing and uses an "exterior" routing protocol called BGP. This protocol routes packets from one ISP to the next, using route and connectivity information input by humans. (Again I'm simplifying a bit.)

Wifi uses entirely different protocols to route packets between cells.

Fun fact: wifi is not an acronym for anything, the inventors simply liked how it sounded.

> Fun fact: wifi is not an acronym for anything, the inventors simply liked how it sounded.

Most certainly it's a reference to "Sci-Fi" or "Hi-Fi".

I always thought Wi-Fi meant wireless fidelity? (Or wireless fiction since in the end, everything is wired).

It doesn't, but the phrase was used in the early days.

https://boingboing.net/2005/11/08/wifi-isnt-short-for.html

t was made to sound like Hi-Fi, which stands for high fidelity, and Wireless, but "wireless fidelity" is a meaningless phrase and not what it was intended to directly mean.

Moving running computers around and maintaining connection would have required large trucks and very long cables at the time the internet was invented.

the mobility in context of article means "changing IP within same TCP connection".

IP + some dynamic routing handles the situation of "the connection site got nuked and we need to route around it", it's just not in the protocol, it's additional layer on top of it

But there's now multipath TCP handover? Weird behaviour to want different network interfaces on different network share the same IP, and pass it along like a volleyball?

Wi-Fi and ethernet also have different IPs. And what if you also add Wi-Fi peer-to-peer (Airdrop-ish), Wi-Fi Tunneled Direct Link Setup (literally Chromecast)?

If a vendor implemented simultaneous Dual Band (DBDC) Wi-Fi, that means it can connect to both 2.4ghz and 5ghz at the same time, each with their own mac & ip, because you're trying to connect to the same network on a different band. Or route packages from a 'wan' Wi-Fi to a 'lan' Wi-Fi (share internet on (BSS) infrastructure Wi-Fi A to a new (IBSS) ad-hoc Wi-Fi network B with your smartphone as the gateway on Android.

There's also 802.11 the IEEE 802.11 standard to add wireless access in vehicular environments (WAVE) and EV chargers or IP over the CCS protocol, etc. If all cars need to be 'connected' and 'have a unique address' NAT / CGNAT also isn't cutting it.

There's also IoT. Thread is ipv6 because it's the alternative to routing whatever between wan / lan / zigbee / Z-Wave / etc with a specific gateway at a remote point in the mesh network.

And how about the new DHCP / DNS specs for ipv6, you can now share encrypted DNS servers, DHCP client-ID, unique OUID, etc etc.

It's an infuriating post really. As if IP was only designed for a small scale VPN / overlay network service such as Tailscale.

> But there's now multipath TCP handover? Weird behaviour to want different network interfaces on different network share the same IP, and pass it along like a volleyball?

Mobile IP actually wanted to do this, it just never took off (not the least because both endpoints need to understand it to get route optimization). I think some Windows versions actually had partial Mobile IPv6 support.

Mobile IPv6 is a thing. I could compile it into the kernel on my mobile machines, main reason to not do it is that I'm currently using a phone as a WiFi hotspot and it doesn't have Mobile IPv6 support.

Mobile IPv6 support is theoretically possible. Practically, like so many cool things you could do with your network, ISPs won't have it. The best you can do is hide it from your ISP by using some tunnel, but then you might as well just use a VPN.

Reply on news.ycombinator.com