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why ftp use random multi-ports to transfer data.

why ftp use random multi-ports to transfer data.# EmergingNetworking - 热门网络技术

r*y2006-12-05 08:12

1 楼

for efficency?
thanks.

L*t2006-12-05 08:12

2 楼

For concurrency on the server side.

【在 r******y 的大作中提到】

: for efficency?
: thanks.

r*y2006-12-05 08:12

3 楼

using one (logic) port can't transfer several files at same time?
I guess server side may have several physics ports. so that
can transfer data at same time.
also don't know if mulitip processes can improve IO efficency.

【在 L******t 的大作中提到】

: For concurrency on the server side.

L*t2006-12-05 08:12

4 楼

It depends on server implementation as well. But generally a FTP server has
a set of open ports for file transmission. If it uses one dynamic port to
transfer multiple files to one client, it's not fair to other clients. One
port can only transfer one file at a time.
IO efficiency may not necessarily be higher from multi-tasking.

【在 r******y 的大作中提到】

: using one (logic) port can't transfer several files at same time?
: I guess server side may have several physics ports. so that
: can transfer data at same time.
: also don't know if mulitip processes can improve IO efficency.