What is Sync-Speed, and why is it different than my download/upload speed?
The vast majority (possibly all) DSL lines are rated at their sync rate. Since DSL runs over atm/frame relay, it is very important that your DSL modem or router and the DSLAM (the device that takes data from your modem and transmits it onto your ISP’s networkk and vice versa) use a common frame size and frame rate. Your sync rate is only really affected by one thing: Packet loss. DSL companies in 99.9% of cases guarantee only the sync rate on residential lines. This is also why providors will never give you the maximum amount of speed you can theoretically recieve. Since there are really no factors that affect sync rate on a regular basis they can do this. The reason you never achieve your sync rate is because of latency and the internet. Once the signal is off of your local telco line, then it is affected by MANY MANY other things. There have been many good descriptions of how latency and the internet work. If you want more information, then check this out. http://www.dslreports.
