Skype system

Comment:

Why the SuperNode in a Skype network can boost the speed of the system?

Follow-up:

Sorry for causing this confusion!

In fact, each SuperNode is mainly responsible for routing calls for other users. In the routing mechanism, sometimes a SuperNode needs to serve as an agent on behalf of another Skype user who is behind a firewall or an NAT router (very commonly used at home or in an organization). Thus, each SuperNode is really helping to enhance the “reachability” of the Skype network, rather than the speed of the system.

Comment:

How can the Skype system enable “computer-to-telephone” calls?

Follow-up:

Good question.

Specifically, there are some Skype servers (not shown in the diagram in the presentation slide) that have connections to some PSTN (Public Switched Telephone Network) gateways. Thus, through such servers we can route our VoIP (voice over IP) calls to reach a landline telephone or a cell phone. As this directly consumes resources in the Skype network (owned and operated by the Skype company), the caller and the callee both need to pay some money to make this happen.