|
North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Is latency equivalent to RTT?
On Wed, 14 May 2003 [email protected] wrote: > > Has it become common usage to define latency in an IP network as the round > trip time in that network? > > I've always considered latency to be a one-way measure of delay and RTT to > be the sum of the latencies in both directions. When I tried to find > something to back up this view, I discovered that a number of companies > define latency as equivalent to RTT in their SLAs. > > Assuming that one has measuring devices in every PoP, do you think it is > harder to measure a full matrix of one way latency compared to measuring a > full matrix of RTT? The problem is buying and installing the equipment, even if you buy an off the shelf product like RIPE NCC's TTM :-). Once installed, these products will just provide you with the numbers. > Does it even make sense to measure a full matrix of RTT when the > measurement of A to B to A should be equivalent to the measurement of B > to A to B? If you are sure that the path taken for A-B-A is equal to B-A-B, then no, measuring only A-B-A is sufficient. Henk ------------------------------------------------------------------------------ Henk Uijterwaal Email: [email protected] RIPE Network Coordination Centre WWW: http://www.ripe.net/home/henk P.O.Box 10096 Singel 258 Phone: +31.20.5354414 1001 EB Amsterdam 1016 AB Amsterdam Fax: +31.20.5354445 The Netherlands The Netherlands Mobile: +31.6.55861746 ------------------------------------------------------------------------------ That problem that we weren't having yesterday, is it better? (Big ISP NOC)
|