On Mon, Jun 17, 2013 at 10:45 AM, <Valdis.Kletnieks@xxxxxx> wrote: > On Mon, 17 Jun 2013 10:03:02 -0400, Greg Freemyer said: > >> The solution from the very start of tcp/ip in the late 70's was to >> have a sliding window of un-ack'ed data. The normal default is 4 x >> MSS (iirc). That means the sender can send 4 large packets worth of >> data without getting a single ACK. (The default can be overridden up >> to 64K bytes max (iirc).) > > Up to 64K if you don't support RFC1323 window scaling, which pretty much > everybody does, because even at 10mbit speed, 64K only allows a 6.4ms RTT > before a full window prevents you from using more bandwidth (in other > words, if your RTT is over 6.4ms, your performance starts dropping). And > if you're at 100mbit or gigabit or higher, the allowable RTT drops even more. > > With RFC1323 window scaling, the windows can get to multiple megabytes > in size - enough to do line-rate 40 gbit/sec cross country. And even faster: > > http://www.extremetech.com/extreme/141651-caltech-and-uvic-set-339gbps-internet-speed-record > Thanks It's been 10 years since I did a deep dive into TCP/IP sliding windows and it was for a 19.2KB satellite based network, so window scaling was not used. Greg _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
