Kitz Forum

Computers & Hardware => Networking => Topic started by: Weaver on July 03, 2018, 12:12:11 PM

Title: Petabit TCP
Post by: Weaver on July 03, 2018, 12:12:11 PM
I cannot imagine TCP surviving onto terabit or petabit optical links? Am I wrong?

I can see why the designers of TCP used byte numbers as their sequence numbers. But that is dangerous and so we have PAWS now.
Title: Re: Petabit TCP
Post by: CarlT on July 09, 2018, 03:12:08 PM
Unless you know of some standard that uses TCP to encapsulate the entire capacity of optical links it's fine. These links are layer 1 links that are separated out and reduced substantially in capacity before they are fed to data link interfaces let alone IP or, above that, TCP. That's ignoring that these core network links handle millions of flows, they aren't being saturated by a single enormous TCP stream for obvious reasons - to do so means it's not really a core network link as it's not aggregating anything, it's point to point with some insane network cards / shelves at the edges fed by some insane servers.

Applications requiring immense throughput don't use TCP in any event.

Going forward they can either modify existing headers or populate something into the TCP options field if they need to but this is a solution looking for a problem for the foreseeable.
Title: Re: Petabit TCP
Post by: Weaver on July 09, 2018, 05:50:02 PM
I was thinking about future very high speed optical LANs with processors wanting to sync large amounts of data from ram to ram. I wondered about TCP and other contenders in that kind of environment.
Title: Re: Petabit TCP
Post by: CarlT on July 09, 2018, 07:14:23 PM
I see. We don't use TCP for that now let alone in the future. Infiniband is big in super computing to link processors to RAM. It operates at 600Gb/s with 3Tb/s on the road map. It is actually intended for exactly the purpose you mentioned, it offers remote DMA.

https://en.wikipedia.org/wiki/InfiniBand

For access to storage/SANs Fibre Channel is a big one. FC goes up to 128Gb/s right now.