Or, perhaps a more simplified and easily remembered figure... RTT on a straight line run from sfo to dc would be ~63ms. (Seems to be roughly 100 to 120 for most real circuits.) We all know, however, that telcos rarely use straight lines. Still, I would not expect more than 6 to 7ms. Perhaps your telcos equipment, through some fluke, has you operating on the backup path? On Sat, Feb 17, 2001 at 09:33:02AM -0500, Charles Scott wrote:
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
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