On Tue, Apr 29, 2014, at 20:21, James Bensley wrote: > So to calculate the delay I can say (c in meters per second); > > (c*0.6) * (31000*1.4) = > (300,000,000m/s*0.6) * (180000000m) = > 0.00024111111 seconds, or 0.24ms.
RTT = d1 + d2 + 2 * (ds + l / v) Where: d1, d2 = delays due to equipment (you can consider it zero, but be ready to have bad surprises) ds = serialisation delay. For 10Gbps and reasonably sized packets, you can consider it zero or close to. l = fiber length (happened to have 2 x "radial distance" in London) v = c / 1.62 (for fiber) 2 - because you mentioned RTT, not one-way. Your result is pretty realistic for one-way. The formula.... much less so (the math too). > Before this project could have even come to light if someone had said > to me "Can you provide a link between these two PoPs that will have a > latency lower than 2ms?" - Assuming all the above accurately relates > to the real fibre properties I could say "Yes!" (subject to surveys, Beware of the customer :)
