<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <HTML> <HEAD> <META NAME="GENERATOR" CONTENT="SGML-Tools 1.0.9"> <TITLE>Compressed TCP/IP-Sessions using SSH-like tools: Thoughts about performance.</TITLE> <LINK HREF="Compressed-TCP-5.html" REL=next> <LINK HREF="Compressed-TCP-3.html" REL=previous> <LINK HREF="Compressed-TCP.html#toc4" REL=contents> </HEAD> <BODY> <A HREF="Compressed-TCP-5.html">Next</A> <A HREF="Compressed-TCP-3.html">Previous</A> <A HREF="Compressed-TCP.html#toc4">Contents</A> <HR> <H2><A NAME="s4">4. Thoughts about performance.</A> </H2> <P>Of course compression/encryption takes CPU time. It turned out that an old Pentium-133 is able to encrypt and compress about 1GB/hour -- that's quite a lot. If you compile SSH with the option "--with-none" you can tell SSH to use no encryption. That saves a little performance. Here is a comprise between several download methods (during the test, a noncompressed 6MB-file was transfered from a 133MHz-Pentium-1 to a 233MHz Pentium2 laptop over a 10MBit ethernet without other load). <P> <PRE> +-------------------+--------+----------+-----------+----------------------+ | | FTP |encrypted |compressed |compressed & encrypted| +-------------------+--------+----------+-----------+----------------------+ +-------------------+--------+----------+-----------+----------------------+ | Elapsed Time | |7.6s | 26s | 9s | 23s | +-------------------+--------+----------+-----------+----------------------+ | Throughput | 790K/s | 232K/s | 320K/s | 264K/s | +-------------------+--------+----------+-----------+----------------------+ |Compression Factor | 1 | 1 | 3.8 | 3.8 | +-------------------+--------+----------+-----------+----------------------+ </PRE> <HR> <A HREF="Compressed-TCP-5.html">Next</A> <A HREF="Compressed-TCP-3.html">Previous</A> <A HREF="Compressed-TCP.html#toc4">Contents</A> </BODY> </HTML>
