On Wed, Sep 26, 2001 at 07:50:32PM +0200, Viktor Rosenfeld wrote: > I suspect that the problem lies with scp. On my local network I > experience transfer rates of less than 200kB/s with scp because the > server is an old Pentium 133 with not enough horse power.
Well, yes... scp is an encrypted protocol. Encryption takes time to perform. > With plain > old rcp I get up to 6MB/s on a 100MB (half duplex?) link. A data transfer rate of 6MByte/sec on a 100Mbit/sec link sounds pretty reasonable. 6MByte = 48MBit, plus you've got packet headers eating bandwidth, the possibility of collisions[1] and dropped packets, and good old-fashioned latency to take their bites out of your nominal 100Mb/s rate. BTW, duplex doesn't figure very prominently here. Full duplex would just allow you to independently send 100Mb/s and receive 100Mb/s, but would not allow sending at 200Mb/s. It would help in this case by reducing the chance of collisions, but headers, dropped packets, and latency would be unaffected by it. [1] In typical usage, ethernet's not good for much more than 60-75% of its nominal bandwidth due to collisions, but I would expect to see more than that out of a point-to-point link or a segment that's otherwise idle. -- When we reduce our own liberties to stop terrorism, the terrorists have already won. - reverius
