nanog mailing list archives
Re: Traceroute versus other performance measurement
From: "Daniel Senie" <dts () senie com>
Date: Wed, 29 Nov 2000 11:52:29 -0500
Programs such as pathchar can AT MOST tell you about latency, not about bandwidth. Any cases where links are in parallel (e.g. multilink PPP of multiple ISDN or T1 lines, or trunked Ethernet links) will typically NOT show up in the calculations, since all packets from the test tool will travel only one of the possible links in these cases. (Yes, multilink PPP permits splitting packets across links, which would make it possible to see the added bandwidth, but I haven't seen an implementation actually do this). This compounds other issues with trying to determine path characteristics with such tools, most especially (and as others mentioned) asymmetric paths. ----- Original Message ----- From: Ping Pan <pingpan () cs columbia edu> To: Paul Bradford <paul () adelphia net> Cc: <nanog () merit edu> Sent: Wednesday, November 29, 2000 11:09 AM Subject: Re: Traceroute versus other performance measurement
Have you tried pathchar? It's pretty much the same as traceroute, but it is to estimate e2e bandwidth. When it first came out, I tried it. It didn't give good results. I heard it had been enhanced since. Go to ftp://ftp.ee.lbl.gov/pathchar/ - Ping On Wed, 29 Nov 2000, Paul Bradford wrote:I have been reading NANOG posts for probably 2 years now.. this is my
1st post.
I need help with a reality/sanity check. Traceroute is a good tool for checking for routing type problems (loops). Does anyone feel it's a
good tool
to use for testing "bandwidth".... My obvious answer is it isn't a good
tool
for that.... One problem I see is that the way traceroute works, if a transport mixes media between say Ethernet to LANE and back to Ethernet
you
give room for Destination unreachable responses from a trace route
because you
have to to packet switching medias with a fast cell switched media in between.... packets less than 64k (like traceroute info) are easily lost
in the
conversion from ethernet to LANE. Does this sound right? Thanks, Paul A. Bradford
Current thread:
- Traceroute versus other performance measurement Paul Bradford (Nov 29)
- Re: Traceroute versus other performance measurement Ping Pan (Nov 29)
- Re: Traceroute versus other performance measurement grisha (Nov 29)
- Re: Traceroute versus other performance measurement Daniel Senie (Nov 29)
- Re: Traceroute versus other performance measurement Bruce A. Mah (Nov 29)
- Re: Traceroute versus other performance measurement Valdis . Kletnieks (Nov 29)
- Re: Traceroute versus other performance measurement Quark Physics (Nov 29)
- Re: Traceroute versus other performance measurement Andrew Brown (Nov 29)
- <Possible follow-ups>
- RE: Traceroute versus other performance measurement Mark Borchers (Nov 29)
- Re: Traceroute versus other performance measurement Marshall Eubanks (Nov 29)
- Re: Traceroute versus other performance measurement smd (Nov 29)
- Re: Traceroute versus other performance measurement Daniel Senie (Nov 29)
- Re: Traceroute versus other performance measurement Joel Jaeggli (Nov 29)
- Re: Traceroute versus other performance measurement Daniel Senie (Nov 29)
- Re: Traceroute versus other performance measurement smd (Nov 29)
(Thread continues...)
- Re: Traceroute versus other performance measurement Ping Pan (Nov 29)