mirror of
https://framagit.org/bortzmeyer/echoping
synced 2024-11-15 00:12:48 +00:00
119 lines
4.4 KiB
Plaintext
119 lines
4.4 KiB
Plaintext
#use wml::template Title="echoping details"
|
|
|
|
<!-- $Id$ -->
|
|
|
|
|
|
<H2>echo service</H2>
|
|
|
|
<P>echoping, with its default setting, assumes the remote host accepts
|
|
such connections. Experience show that most Internet routers or hosts
|
|
do not. Some Unices are not shipped with this service enabled and,
|
|
anyway, the administrator is always free to close it (I think they
|
|
shouldn't). echoping has therefore less chance to succeed than ping or
|
|
bing. (On a typical Unix box, "echo" service is configured in
|
|
/etc/inetd.conf but see the <A
|
|
HREF="http://www.cert.org/advisories/CA-1996-01.html">CERT
|
|
advisory</A>.)
|
|
|
|
<H2>What does it measure?</H2>
|
|
|
|
<P>echoping simply shows the elapsed time, including the time to set up the TCP
|
|
connection and to transfer the data (but excluding the time for the
|
|
- possible - DNS call). Therefore, it is unsuitable to physical
|
|
line raw throughput measures (unlike bing). On the other end, the action it
|
|
performs are close from a HTTP request and it is meaningful to use it
|
|
(carefully) to measure Web performances.
|
|
|
|
<H2>UDP and inetd</H2>
|
|
|
|
<P>With UDP servers you can have surprises: the first test is quite often
|
|
much slower since inetd has to launch the process. After that, the process
|
|
stays a while so the next texts run faster.
|
|
|
|
<H2>A nice example</H2>
|
|
|
|
<P>There are many, many traps when measuring something on the Internet. Just one
|
|
example: 'echoping -w 0 -n 4 a-sunOS-machine' and you'll see the first test
|
|
succeed in a very short time (if you are close from the machine) and all of
|
|
the others take a much longer time (one second). With '-w 1' (wait one second
|
|
between tests, the default), everything works fine: it seems the sockets on
|
|
SunOS need time to recover :-)
|
|
|
|
<H2>To measure performances on the Internet you can also see</H2>
|
|
|
|
<H3>Unix</H3>
|
|
|
|
<UL>
|
|
<LI><A
|
|
HREF="http://www.freenix.fr/freenix/logiciels/bing.html">bing</A>, a
|
|
bandwidth measurement tool
|
|
<LI>pathchar or <A
|
|
HREF="http://www.employees.org/~bmah/Software/pchar/">pchar, a bandwidth measurement tool
|
|
<LI>ping, probably available with your system
|
|
<LI>traceroute, idem (otherwise, see <A HREF="ftp://ftp.ee.lbl.gov/">LBL</A>)
|
|
<LI><A HREF="ftp://ftp.arl.mil/pub/ttcp/">ttcp</A>, the best measurement tool but it needs some control over the
|
|
two machines
|
|
<LI><A HREF="ftp://ftp.scl.ameslab.gov/pub/netpipe/">Netpipe</A>, it needs some control over the two machines
|
|
<LI><A HREF="http://www.psc.edu/~pscnoc/treno_info.html">treno</A> (evaluates available bandwidth for TCP)
|
|
<LI>spray is a tool which I dont't know very well. It is available on some
|
|
machines (Sun, OSF/1).
|
|
<LI>I've also heard of but never tried:
|
|
<UL>
|
|
<LI><A
|
|
HREF="http://www.netperf.org/netperf/NetperfPage.html">Netperf</A>, a suite of Bandwidth Measuring programs from gnn@netcom.com
|
|
These are <A HREF="ftp://ftp.netcom.com/~ftp/gnn/bwmeas-0.3.tar.Z">several
|
|
programs</A> that measure bandwidth and jitter over several kinds of
|
|
IPC links, including TCP and UDP.
|
|
</UL>
|
|
</UL>
|
|
|
|
<H3>MacOS</H3>
|
|
|
|
<UL>
|
|
<LI>TCP Watcher, a very nice "swiss-army knife" tool, to test ping, DNS, echo.
|
|
It includes an echo server. Available on <A
|
|
HREF="http://www.info-mac.org/">Info-Mac</A> in "comm/inet".
|
|
</UL>
|
|
|
|
<H3>MS-Windows</H3>
|
|
|
|
(I have little knowledge of that environment and I tested nothing.)
|
|
|
|
<UL>
|
|
<LI><A
|
|
HREF="http://www.ccs.org/winsock/xref-e.html#echo_clients">WSNUTIL</A>.
|
|
Seems to be an echo client and server.
|
|
<LI><A
|
|
HREF="http://www.winsite.com/info/pc/win95/misc/echox32.zip/">echox32</A>,
|
|
an echo server
|
|
<LI><A
|
|
HREF="http://www.winsite.com/info/pc/win3/winsock/cfing13b.zip/">cfinger</A>,
|
|
an
|
|
echo client and server
|
|
</UL>
|
|
|
|
<H3>Windows-NT</H3>
|
|
|
|
echo and other services can (apparently) be provided within
|
|
'Simple TCP/IP Services' which
|
|
can be enabled through the Network Control Panel
|
|
|
|
<H3>Web clients</H3>
|
|
|
|
You can ping or traceroute on the Web. See <A
|
|
HREF="http://www.traceroute.org/">traceroute.org</A>.
|
|
|
|
<P>Use all of them with care, the result is not obvious to interpret.
|
|
|
|
<P>If you are interested in Internet measurements, there is an <A
|
|
HREF="http://www.ietf.org/">Internet Engineering Task Force</A>
|
|
Working Group, <A
|
|
HREF="http://www.ietf.org/html.charters/ippm-charter.html">IPPM (IP
|
|
Performance Metrics)</A> which produces many fine RFC that are really
|
|
good to read. I appreciate RFC 2330 and 3148.
|
|
|
|
<P>And don't forget to read RFC 1470 ("Tools for Monitoring and Debugging
|
|
TCP/IP Internets and Interconnected Devices"), specially its "Benchmark"
|
|
section and the Richard Stevens' books (all of them), published by
|
|
Addison-Wesley.
|