NS to End point - The NS does not send data it receives it. Obviously, if you perform a tickle or RTSM action, or something similar, then some small command like data will be sent.
End point to NS - This depends on what plugins are installed. The SMA's basic inventory NSE is usually over 1MB; however, the SMA compresses files that are over 200KB by default (this can be changed). Each type of inventory scan will create a different size of NSE file, and most inventory scans have a delta capability.
Task server to End point - Small action data.
End point to Task server - Results data.
Package server to Endpoint (when no patch management or software distribution is happenin) - Nothing.
Endpoint to Package server (when no patch management or software distribution is happenin) - Nothing.
NS to Package Server (when no patch management or software distribution is happenin) - Nothing.
Package Server to NS (when no patch management or software distribution is happenin) - Package status data. Size depends on how many packages the PS has, but the NSE files will be compressed as previoulsy mentioned.
NS to Task Server - Small action data.
Task Server to NS - Summary data containing endpoint result data.