how airport works- receiving packets with airport off

Hi,
Could anyone familiar with the way Mac's Airport software actually works, particularly regarding the wi-fi 'on-off' switch. Unlike some pc's that have a hardware switch, the only way to turn off the wi-fi is though a software switch. In this case, the switch can, in theory, be worked-around (by my wits at least).

I bring this up because I was getting random spikes in CPU from the Safari web content process, despite me not interacting with my open web tabs. This isn't totally perplexing, but when I turned Airport "off", I continued to see packets received and sent. The rate after a minute or so was about 1 single packet of 302 kB sent and received simultaneously every 10-20 seconds. This is probably normal as well, but I'd like to know more about how Airport works, and how if "off" packets can be sent and received at all.

How are you collecting the packet data?

I am monitoring packets and network activity by using the Activity Monitor

Open Network Utilty - Info tab

Select each of the network interfaces in turn and see which is listed as sending/receiving data

Very interesting...well it definitely would be airport, since all the others are either not connected or disabled. But I checked anyway; no activity. The interesting thing that I don't understand is, Network Utility shows no record to the activity that Activity Monitor reports. When packets in/out increase according to AM, they do not increase according to NU. Accordingly, there are more packets reported sent/received on the AM than on NU.

Activity monitor is showing processes. What you have is applications and processes trying to use the network interface. E.g. System updates, network mounts, application updates, calendar sync, iCloud, Dropbox etc etc

Network utility is showing the actual packets passing through the interface. As you can see with wi-fi switched off no packets are moving in or out of your machine over wi-fi

Thank you, I think I understand now. So the reason why the packets in/out on AM is the same after I turn off the wi-fi is that the packets trying to be sent are just 'bounced back' (because they have no where to go). Thank you for your education!

That's pretty much it. The various applications and services don't know there's no connection so still go about their business as usual