• CDN
• congestion avoidance
• P2P optimization
• SIP overload control

The way users utilize the Internet has drastically changed in the last decade. Some
years ago, the average user used to identify the Internet with the web browsing application.
Nowadays there are multiple applications available for the users; the way
people do shopping, mantain social relationships, do research and get entertainment
has dramatically changed given the new bouquet of applications available on the
Internet.
Historically, the Internet has a best-effort nature that does not match the requirements
of amny of these emerging applications. Real-time, delay-sensitive applications
need a more reliable infrastructure. For this reason, new communication
models have been developed and new issues arose. In general, we can identify
these communication models as Distributed Systems. In this thesis, we investigate
the new issues that arose from different new applications (i.e. VoIP, delay-sensitive
content delivery and live streaming) and the related communication infrastructure
(client/server, Content Delivery Network, Peer to Peer).
For each application/infrastructure we describe the issues, we define a goal and then
we describe the solution to fulfill such goal. To do so, we present three use-cases and
go into details for each of them; at the end we conclude with some general findings
obtained from the specific solutions applied to each of the investigated scenario.