On Thu, Sep 30, 2010 at 10:16 AM, Jon Elson <el...@pico-systems.com> wrote: > Igor Chudov wrote: >> On Wed, Sep 29, 2010 at 8:12 PM, Jon Elson <el...@pico-systems.com> wrote: >> >>> Igor Chudov wrote: >>> >>>> Things may have somewhat improved. >>>> >>>> I checked on my unsophisticated home network. Ping time (roundtrip), >>>> involving three switches (one in my basement office, then the main >>>> switch at the main interconnect in the utility room, then the switch >>>> in the family room), and two linux boxes, is 0.21-0.34 milliseconds. >>>> >>>> >>> My understanding of ping is that it does NOT report the total round trip >>> time through >>> all nodes and switches, just the last hop. I think you need traceroute >>> to see the delay >>> at each hop. Still, 300 uS is not such a great time if you need 3 >>> messages to propagate >>> within one millisecond. >>> >> >> Jon, this is not the case. >> >> ``Round-trip times and packet loss statistics are computed.'' >> > Well, comparing results from distant nodes on the WAN seems to refute > this, unless > you have a ping option not present on my system. > I use Charter cable modem, and their backbone is a GHASTLY mess. I have a > paid secondary DNS provider with a good T3 connection. When I ping them, I > get ~60ms, which is awful. But, when I traceroute them, I get 30 hops, many > of them INDIVIDUALLY in the 60 ms range. So, the total round-trip message > has to be several hundred ms. > > Despite your quoted sentence from the ping man page, I do not believe > this information > is correct, due to the difference between ping and traceroute results. > Compare them yourself and > see if you get quite different results. Try pinging your name server or > other reliable > host on your WAN to put enough hops in it to make a difference. > Unfortunately, the > ISPs are hiding info to keep people from seeing what hideous service > they are getting, > so traceroute usually gives very incomplete info, now.
Jon, I think that traceroute too reports cumulative results. i > > Jon > > ------------------------------------------------------------------------------ > Start uncovering the many advantages of virtual appliances > and start using them to simplify application deployment and > accelerate your shift to cloud computing. > http://p.sf.net/sfu/novell-sfdev2dev > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
