What is "Software Update" doing when it claims "Checking for new software"?

"Software Update" appears to take a long period of time. What is it doing?

Energies - > Activity Monitor returns :

• CPU use reduced (1% - 2%) by the "Software Update" procedure.
• +network website traffic incoming,

[image of Network task after beginning "Software Update" ]

[Network task after ~ 30 secs to ~ 90 secs ]

[Network task after ~ 90 secs ]

*note : images changed to remove "Data obtained : [complete ] and also Data Sent : [complete ] ". Network task videotaped after closing down all various other applications.