Quote from JackR:
Bernard:
Think of the internet as a series of different streets connecting two points. If all the traffic lights are green you get there at the speed limit. If there is an intersection that has a light that goes from green to red and back to green traffic slows. You get there, but more slowly. When a bad packet is detected it gets discarded (packets are internally serial numbered) and the router that detected the bad packet requests a retransmission of that packet from the preceding router. When it gets it successfully it forwards it on and the entire message stream, made up of a number of packets, is reassembled. This takes time. TCP/IP was designed to be robust (it was actually designed to remain functional during a nuclear attack) and to get the message through. In a properly designed network your message can be rerouted half-way through and you'd be unaware of a network problem unless you were measuring latency (or listening to music or voice).
What I did not mention in my previous reply is the influence of local loading on latency. To simplify a bit - Your PC connects to a router. That physical connection uses the ethernet protocol. If you have a number of PC's operating on your local area network the traffic will slow as there is contention for use of the network bandwidth. In a DSL connection you are essentially tied directly to your ISP's router and then into the backbone network, no local contention. In a cable connection you are tied into a neighborhood local area network. That network is tied to the ISP router. So as more of your neighbors use their internet connections your effective bandwidth goes down and your latency goes up. I haven't done any reading on the newer digital cable systems so it's possible they have changed their network architecture and this is no longer a problem.
Jack
