On Tue, 25 May 2004, Amir Hardon wrote: > I started downloading the floppy image from the mirror that replied to my ping > the fastest, but the download speed was very low...
this is because 'ping' checks latency, not bandwidth. > I tried to send bigger pings (of 1000 bytes) and still found no relation > between the ping reply time and the actuall download speed... TCP packets get larger then this - a ping of 1400+ bytes would be more appropriate, however.... > Why is this? is the only way to find the fastest host is to start downloading > and check the actual download speed? Isaw some windows programs that looks > for the fastest mirror before downloading (I think one of them is Getright), > how does they do it? any router along the way (as well as the original server) can decide to: 1. define different QoS characteristics for different services (e.g. give ping's ICMP echo/echo-reply a high priority, so no matter how link is by http traffic, ping will get a fast response). 2. throttle connections - e.g. using 'thttpd' (tiny/trivial/throttling http daemon) - which can define how much bandwidth each TCP connection will have. in a perfect world, pinging would have been enough. in our internet, only downloading could tell you something, and even that's not enough - they might favor short downloads over long ones (i.e. the connection starts fast, but after a given ammount of data was downloaded, the connection's speed is lowered, in favor of newer and shorter connections). -- guy "For world domination - press 1, or dial 0, and please hold, for the creator." -- nob o. dy ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
