Hmm. Some sods think... aha, udp, no one cares if we drop those, better never than late and all that... so those sometimes get dropped preferentially.
Some sods configure routers to hate ICMP, so ping is no longer very reliable. Recommendation, use a tool that tests what you're flying. UDP packets. ie. Use tracepath On Wed, Jan 18, 2012 at 2:37 PM, Derek Smithies <[email protected]>wrote: > Hi, > I have a linux box in a data centre, somewhere in the US.. > > This box runs a program which talks voip (lots of udp packets, a few tcp > packets) > with other boxes. > > Being performance conscious, things like packet loss are monitored, and > there are packets being dropped. > > An identical box, with the same settings for firewall etc, with the same > program, but in a totally different place, > reports no loss. > > ok. run > ping -q -A -c 200 4.2.2.2 > > and the loss rate may be anything from 0 to 8% (on some runs it is > perfect, on others it is bad) > > the data centre network operators claim it is not them, and that their > centre is fine. I don't know if the > data centre is running traffic shapers, bandwidth throttling, or what.. > > iptables -L reports no drop rules. > > Conclusion: it is not the firewall settings that is dropping packets. > Don't think it is hardware, but I did remember hearing something about > full & half duplex > However, one can use the command: > >>mii-tool eth0 > eth0: 10 Mbit, full duplex, link ok > (ethtool appears to be the newer tool, but ethtool fails on operations > I found a tool on the network called shaperprobe, that (apparently) works > out if there is any traffic shaping going on. > This tool reports no shaping.. > > Is it the hardware on the box? I don't think so. - it is a new box. Is it > my software - no - ping reports similar answers. > is the box heavily loaded - no. the load average is 0.00 > > Question: > is there a software tool to analyse network traffic and work out where > the packets are being lost (tcptrace?) and > say why they are being lost? > > Thanks in advance, > Derek. > > -- > Derek J Smithies Ph.D. > Christchurch, > New Zealand > > -- "How did you make it work??" "the usual, got everything right" > > ______________________________**_________________ > Linux-users mailing list > [email protected].**ac.nz <[email protected]> > http://lists.canterbury.ac.nz/**mailman/listinfo/linux-users<http://lists.canterbury.ac.nz/mailman/listinfo/linux-users> > -- John Carter Phone : (64)(3) 358 6639 Tait Electronics Fax : (64)(3) 359 4632 PO Box 1645 Christchurch Email : [email protected] New Zealand ======================================================================= This email, including any attachments, is only for the intended addressee. It is subject to copyright, is confidential and may be the subject of legal or other privilege, none of which is waived or lost by reason of this transmission. If the receiver is not the intended addressee, please accept our apologies, notify us by return, delete all copies and perform no other act on the email. Unfortunately, we cannot warrant that the email has not been altered or corrupted during transmission. =======================================================================
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