Skype uses heavy cryptographic techniques, so deep packet analysis was not possible. Some more important observations were :-
1) Skype traces contains very diverse range of TCP ports and balanced mix of TCP and UDP ports are used, so
it was not possible to distinguish Skype packets just by filtering one particular type of port.
2) There were huge number of IP addresses (close to 350) in trace collected for 5 hours duration. This could be because Skype uses peer-to-peer architecture and so data didn’t solely belong to user.
3) All the packets in Skype are encrypted so it is difficult to find packet details.
4) Due to these limitations, it was also not possible to confirm with certainty that certain captured packet belongs to Skype or not?
Because of above mentioned reasons, analysis is different from Facebook application in.