P4P

The P4P Framework

P4P allows providers (ISPs) to provide hints about their network and their preferences to applications. The framework was initially designed for P2P applications (the largest bandwidth users on today's Internet), but P4P is a framework for cooperative traffic control between applications and network providers. Through this control, application users can see increased performance while network providers can reduce costs improve network efficiency.

P4P is applicable to both Tracker-based and Client-based systems. These diagrams illustrate the overall information flow for P4P applied to peer selection at both Application Trackers (if one is present) and the clients themselves.

Reducing Application Inefficiencies

The Old Days: The Internet Without P4P

Users: Many currently-deployed P2P applications locate other users randomly to share pieces of the file being downloaded and try discover "fast" peers to improve download speed. This process may be time consuming and provide poor download speeds if good peers are not found.
Service Providers: Providers are facing growing bandwidth demands from their customers while simultaneously providing other services (voice, TV) over the same infrastructure. Lack of control over this growing bandwidth has forced ISPs to adopt differeng usage or charging policies.

What's Coming: The Internet With P4P

Users: P2P applications can utilize P4P to locate better peers more quickly. The P4P information contains hints from service providers, and these hints can be combined with other information available to the P2P application (current upload/download rates, probed information) to locate better peers. Our field tests have shown that these additional hints can greatly benefit application performance.
Service Providers: The information provided to applications can influence their network usage. Since P2P applications account for a large portion of the bandwidth, these hints can help reduce operational costs and improve user satisfaction. For example, traffic may be kept local to an ISP and high-cost or heavily-loaded links can be avoided.

But ...

Will my ISP discover more about P2P usage?

No. The P4P protocol does not expose any application-specific information to ISPs than they already have today. The P2P application requests information from service providers using generic identifiers that do not uniquely identify individual clients. P2P applications utilizing encryption work equally well with P4P.

Can P4P hurt application performance?

While it is possible that the information provided by an ISP may cause applications to not perform as well, the application is free to ignore the information. P4P does not dictate when or how this information is used - it simply makes it available. One feature of the P4P framework, however, is that both applications and service providers have strong incentives to participate.

Will users discover my proprietary network information?

The P4P protocol uses a flexible interface that allows service providers to tune the granularity of the information exposed to to applications. Additionally, the information is provided in a way that hides the internal network topology and uses "anonymized" identifiers.