Por qué una sola sonda no basta.

Put one probe on a service and watch it. One day the numbers go bad, latency climbs, loss appears. Something is wrong. But what? The service? The path to it? The probe’s own connection? With a single vantage point you cannot separate these. You have detected a problem with your measurement as much as a problem with the service. This is why Parallax measures from two independent places at once, probes in London and Paris, on separate networks and paths. When both see the same degradation at the same moment, it is the service. When only one sees it, it is local to that path, and the service is fine. The disagreement is the diagnosis. Two vantage points also close the oldest dispute in SLA monitoring: “your monitoring is wrong.” It is far harder to argue with two independent observers on different networks reporting the same thing, time-stamped, than with a single sensor that might simply be having a bad day. One probe tells you something happened. Dual-vantage tells you what, and lets you prove it.