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Mptcp: Moving laptop from GBit to wireless without applications noticing?

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Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#21
post #9

You can use WireGuard and our service hoppy.network to achieve the same thing! By having a static IP address exposed, you can switch from WiFi to ethernet or cellular without any network connections breaking. Probably not the best solution from an architectural standpoint, but certainly practical.

This is a neat project. You're up against people setting up their own WireGuard exit nodes -- are these folks just not in your target audience?

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#22

MPTCP has been on my radar for a long while and seems very cool. I will say that for seamless wireless/wired switching, Linux bonding works very well. ~15+ years ago I had my laptop set up with eth and wifi bonded, with eth as the preferred, I believe using link-beat as the method. I could be running a big copy, plug in the ethernet and the transfer rate would almost instantly shoot up, and then when done I could unp…

Yep, I used to do that when I had a thinkpad and a docking station and didn't want all my ssh sessions to drop.

Before that I was even doing awful things like forcing the same IP onto both eth and wifi :D

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#24
post #9

You can use WireGuard and our service hoppy.network to achieve the same thing! By having a static IP address exposed, you can switch from WiFi to ethernet or cellular without any network connections breaking. Probably not the best solution from an architectural standpoint, but certainly practical.

This is a neat project. You're up against people setting up their own WireGuard exit nodes -- are these folks just not in your target audience?

[dead]

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#25
post #15

Earlier quoted context omitted.

Using NAT with IPv6 sounds tragic, hopefully this isn't common.

There are reasons to do some kind of NAT across IPv6. For example, switching ISPs may throw your internal network addressing in disarray which can be either a pain or a massive problem; NPTv6 will prevent that from being too much of an issue inside the premises, which should cover 95% of the issues. The best thing is that you keep most of the advantages of IPv6 (all addresses and all ports publicly reachable, foregoi…

>switching ISPs may throw your internal network addressing in disarray which can be either a pain or a massive problem

Those are what ULA's do. A local router that provides global addresses and ULAs solves all your problems, and that's the default behaviour of OpenWRT (and probably other routers). If you want traffic to not leave your local network, listen to your ULA (fd00::whatever) and call it a day.

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#26
Surely if your application doesn't have some TCP reconnect handling its gonna have a problem eventually? Some switch fail-over scenarios i've tested will blackhole a connection which is why nearly anything serious will have some application level heartbeating to determine connection health. Can't depend on the OS for this stuff

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#27
post #9

You can use WireGuard and our service hoppy.network to achieve the same thing! By having a static IP address exposed, you can switch from WiFi to ethernet or cellular without any network connections breaking. Probably not the best solution from an architectural standpoint, but certainly practical.

A VPS is much cheaper and the user is not reqired to trust a VPN-like service not to snoop traffic.

But it still does not solve the problem of adding a lot of latency.

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#28
post #8

The net community gave up on the TCP->SCTP upgrade because of NAT (and other middle-) boxes breaking IP. It would have fixed many other things too (eg head-of-line blocking). The good side was that we kept the simplicity of TCP. I wonder what's the middlebox story of MPTCP.

Aside from terrible middleboxes, SCTP also suffered from a lack of kernel implementations on non-Linux platforms and performance issues in the existing implementation. It's still there but there hasn't been a need for a protocol to really use it. Protocols like HTTP(S) could really use the SCTP benefits but those need solid client implementations; server protocols like DNS or FTP are restricted more by their own limi…

I think one other major reason SCTP never went anywhere because performant SCTP NAPT is impossible.

With UDP, TCP and SCTP, if you need to change ports in the header, then you need to update the checksum. The traditional TCP/UDP checksum is kinda crap, but this works in its favour here, because you can just perform a corresponding and easy adjustment of the header.

SCTP protects packets with a strong CRC32C checksum. This is on the whole a good thing, but you can't do the twiddle trick with CRC32C. If you're rewriting ports, you need to recalculate the checksum over the entire packet.

This means that linerate SCTP NAT accelerators have never existed. On the whole, what SCTP NATs exist only do address translation: If two people try to establish outbound SCTP connections from the same source port, the second person's connection just gets dropped by the NAT.

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#29
post #9

You can use WireGuard and our service hoppy.network to achieve the same thing! By having a static IP address exposed, you can switch from WiFi to ethernet or cellular without any network connections breaking. Probably not the best solution from an architectural standpoint, but certainly practical.

A VPS is much cheaper and the user is not reqired to trust a VPN-like service not to snoop traffic. But it still does not solve the problem of adding a lot of latency.

If your threat model is based on your ISP not snooping on you then you need to improve your security…

Re: Mptcp: Moving laptop from GBit to wireless without applications noticing?

#30
post #9

You can use WireGuard and our service hoppy.network to achieve the same thing! By having a static IP address exposed, you can switch from WiFi to ethernet or cellular without any network connections breaking. Probably not the best solution from an architectural standpoint, but certainly practical.

This is a neat project. You're up against people setting up their own WireGuard exit nodes -- are these folks just not in your target audience?

It’s mostly people who need good IP reputation and a user friendly managed service. It’s hard to get clean IPs from massive cloud services.
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