Chuck, should read 130mi/msec I guess. Which would end up with ~7msec per 1000miles. Arnold ----- Original Message ----- From: "Charles Scott" <cscott@gaslightmedia.com> To: "Matthew F. Ringel" <ringel@akamai.com> Cc: <nanog@merit.edu> Sent: Saturday, February 17, 2001 3:33 PM Subject: Re: T3 Latency
Matthew: Appears to be a typo in your final number of 130 mi/sec, but I get where you're going with this. I'm just having a problem trying to figure out how I end up with a couple thousand fiber miles from Northern Michigan to Chicago. Should be interesting to sort this one out.
Thanks,
Chuck
On Sat, 17 Feb 2001, Matthew F. Ringel wrote:
The rule of thumb I use is that the speed of light in fiber-optic cable
is
roughly 2x10^8 m/sec.
2x10^8 m/sec = 200,000,000 m/sec = 200,000 km/sec = 200 km/msec =~ 130 mi/sec
I once worked with a customer whose first hop out was ~30ms, regardless of the load on the line (a t3, iirc). Sure enough, he was on a very large SONET ring that travelled the north-south length of the US roughly twice before his traffic went elsewhere.
......Matthew