North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: ATM (was Re: too many routes)
Nathan Stratton wrote: > > On Thu, 11 Sep 1997, Vadim Antonov wrote: > > > Quote from Jim Steinhardt's <[email protected]> > > personal message: > > > > >>a) light is slower in dense media > > > > > The index of refraction of glass is 1.5 vs 1.0 for > > > a vacuum. Hence, the speed of light in glass is 2 * 10 **8 m/s. > > > > That gives 60 ms RTT on 4000 mile line. > > > > Case closed. > > Yep, but you also need to add a few ms for electronics in that 4000 mile > line. My original point. (Concerning latency) > We tend to see around 64 - 65 ms delay between our DCA and PAL > routers. > > rt1.DCA.netrail.net# ping rt1.PAL > ICMP ECHO rt1.PAL.netrail.net (205.215.45.33): 56 data bytes > 64 bytes from 205.215.45.33: icmp_seq=0 ttl=255 time=65.764 ms > 64 bytes from 205.215.45.33: icmp_seq=1 ttl=255 time=64.851 ms > 64 bytes from 205.215.45.33: icmp_seq=2 ttl=255 time=65.053 ms > 64 bytes from 205.215.45.33: icmp_seq=3 ttl=255 time=64.994 ms > ^C How may hops is that ping ? I am curious, this is interesting. (Even if I did get mail bombed by responses...... ;) You realize we need to be comparing a *series* of routers, vs a *series* of ATM switches. (this is the real world, and we are modelling delivery to anywhere, not just 1 hop across the continent.) It would be interesting to see someone set up a performance test. Latency/Variability with no hops, Latency/Variability with 1 router vs 1 switch Latency/Variability with 2 routers vs 2 switches Up to about 10. I wonder what that curve would look like ? Media would have to be consistent in size (ie DS3, all the way through) Interesting , no ? > --- rt1.PAL.netrail.net ICMP ECHO statistics --- > 4 packets transmitted, 4 packets received, 0% packet loss > round-trip min/avg/max = 64.851/65.160/65.764 ms > rt1.DCA.netrail.net# > > Nathan Stratton President, CTO, NetRail,Inc. > ------------------------------------------------------------------------ > Phone (888)NetRail NetRail, Inc. > Fax (404)522-1939 230 Peachtree Suite 500 > WWW http://www.netrail.net/ Atlanta, GA 30303 > ------------------------------------------------------------------------ > "No king is saved by the size of his army; no warrior escapes by his > great strength. - Psalm 33:16 Richard
|