On Sun, Nov 10, 2019 at 05:09:10PM -0500, Matt Hoppes wrote: > Those buying transport from your DC to an IX, how are you avoiding TCP > windowing issues causing you to not be able to take advantage of your > new super fast data circuit ?
RFC1323 helped most people work out how to fix such issues. I'm not aware of any IP stacks that don't have window scaling now. War story time, skip it unless you want to hear about Internet in the "hinterlands." In the summer of 2001, there was an ISP with a presence in Roswell, NM and Lubbock, TX. They picked up Internet in Lubbock, and had a T-1 to Roswell. The folks I worked for covered most of NM. We were both in the same building in Roswell, so we sold them a 10M ethernet port and hauled them to Albuquerque via a DS-3 for a higher bandwidth path to their TX site via Internet transit (i recall we both bought from AS701 at the time). They regularly used 5M+ on the circuit, but claimed we only gave them 1M, and that their T-1 was "faster than your ethernet." They were kinda right -- the DS-3 path had 35ms+ latency. Their NT servers defaulted to a window size that limited them to about 1M if they used FTP between the servers. I suspect their complaints were really centered around cancelling the circuit, because we fixed their problem with a registry tweak to increase window size on their NT boxes. The next day the port went down/down on our router, and we never heard from them again... -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
