You could possibly use a sniffer and then generate a data stream and then look at the difference between timestamps that the sniffer tacked on each packet.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Thompson Sent: Friday, January 18, 2008 1:28 PM To: Dave Roberts Cc: vyatta-users@mailman.vyatta.com Subject: Re: [Vyatta-users] latency tool On Jan 17, 2008, at 7:15 AM, Dave Roberts wrote: >> I am looking for a tool that is able to measure the (one-way) >> latency or delay. >>> From what i know ping or traceroute are only able to measure the >>> RTT. > > There is no widely-used, standard tool that I know of. I'm sure > there is > some code you could snarf from somewhere, though. > > I think the reason that a standard tool doesn't exist is that the > problem > of latency testing essentially degenerates to one of clock > synchronization > between the source and the destination. If you do RTT measurements, > the > transmitter and receiver are the same box, so the clocks are > automatically > synchronized. > > If you do one-way testing, you need to get clock synchronization > between > the source and dest nodes. If you need highly accurate measurements, > then > you might need something like GPS to help you synchronize (as > opposed to > NTP, which is great for basic date/time stuff, but won't help you much > with microsecond resolution timing). > > Once you have the clock synchronization issue nailed, the code to do > the > measurement is only about half a page of C on both the source and > test: > take a timestamp, transmit a UDP packet out, receive it sometime > later, > and take another timestamp. http://www.caida.org/workshops/isma/0312/slides/dveitch_bwest_probing.pdf http://www.cis.udel.edu/~mills/database/papers/history.pdf http://dast.nlanr.net/NPMT/ ... _______________________________________________ Vyatta-users mailing list Vyatta-users@mailman.vyatta.com http://mailman.vyatta.com/mailman/listinfo/vyatta-users _______________________________________________ Vyatta-users mailing list Vyatta-users@mailman.vyatta.com http://mailman.vyatta.com/mailman/listinfo/vyatta-users
