1. P4P: ISPs and P2P
Laird Popkin, Pando Networks
Doug Pasko, Verizon

2. The Fundamental Problem?
Traditional ISP feedback/controls to application traffic:
Routing
Rate control through congestion feedback (packet drops)
These are ineffective for P2P
Due to highly dynamic, scattered traffic pattern caused by dynamic, unguided (network-oblivious) peer selection
Need a mechanism for ISPs to communicate with P2P about network structure and policies
ISPs do not disclose their network information for various concerns
P2P does not have sufficient information to determine network-aware peering relationships
P2P can infer some network information; however, a lot of important information cannot be inferred

3. P4P: Partnership among ISPs and P2P Networks
The slides are based on our technical report Yale DCS/TR1377.
This is a joint work with Arvind Krishnamurthy and Yang Richard Yang.

4. P4P Working Group Members
P4P Working Group: Co-Chaired by Pando and Verizon, based on research from Yale, hosted by Distributed Computing Industry Association.
Core Group
Observers
AT&T
BitTorrent
Cisco Systems
Grid Networks
Joost
LimeWire
Manatt
Abacast
Cablevision
CacheLogic
Cox Communications
Comcast
MPAA
NBC Universal
Oversi
PeerApp
Time Warner Cable
Turner Broadcasting
Pando Networks
RawFlow
Telefonica Group
VeriSign
Verizon
Washington University
Yale University

5. Goals Design a framework to enable better ISP and P2P coordination
Guided P2P connections should yield benefits:
Improve throughput to P2P users
Allow ISPs to manage link utilization
Reduces number of links transited by content
Push traffic from undesirable (expensive/limited capacity) links to more desirable (inexpensive/available capacity) links
The motivation for involving ISPs in this process :
ISPs are best positioned with respect to gathering information regarding the state of the network and the needs of
P2P systems. By letting ISPs make recommendations and letting the peer-to- peer systems use these as hints
in their peering process, we hope to design a system that is efficient and incurs low operational costs

6. ISP Benefits Industry Solution
Create cooperative win-win solutions to an industry issue
Solve the problem before we have to cope with the problem
Carrier Grade P2P
Opportunity for new services
What if the fastest path from A to B is P2P?

7. P2P Benefits P2P Applications benefit from:
Faster downloads for users.
Decrease incentives for ISPs to manage P2P traffic.
Easy to implement
Open standard, so one solution for all ISPs.

8. P4P Enables Efficient Delivery
Traditional CDN
P2P
P2P with P4P
Internet Transit
Regional Routers
Edge Network
More Viewers =
Worse performance
Higher cost
More Viewers =
Better performance
Lower cost
Network Aware P2P will reduce costs, improve performance

9. P4P Framework – Goals Performance improvement for both ISPs and P2Ps
Scalability
Support a large number of P2P users and networks in dynamic settings
Privacy preservation
Flexibility: apply to many P2P architectures
Application-specific requirements
Tracker-based and trackerless P2P systems
“Gossip” among peers
Ease of implementation (“low hanging fruit”)
Open standard: any ISP, P2P can easily implement it

10. P4P: Architecture 2 3 1 4 ISP A peer pTracker iTracker
Use BitTorrent in a single ISP as an example
pTracker runs P2P system
iTracker makes suggestions for peering relationships
Information flow:
peer queries pTracker
pTracker asks iTracker for guidance (occasionally)
iTracker returns high-level peering suggestions
pTracker selects and returns a set of active peers, according to the suggestions
iTracker can be run by trusted third parties, P2P network, or ISPs.
pTracker
iTracker 2
ISP A 3 1 4
peer

11. Optimizing P2P Peering Formulate as a joint optimization problem
ISPs’ objective: minimize network utilization by P2P
P2Ps’ objective: maximize throughput
Joint Objective: Protect and Improve customer experience

12. Evaluation – Simulations
Simulation Methodology
Discrete-event simulation
a module for modeling BitTorrent protocol
a module for modeling underlying network topology and data transfer dynamics using TCP rate equation
Network topology provided by AT&T, Telefonica, and Verizon.

13. Telefonica Simulation
Results: Good for ISPs
Telefonica Simulation
Verizon Simulation
P4P yields a dramatic drop in data delivery average “hop count”, which equates to lower cost to ISPs.

14. Telefonica Simulation
Results: Good for P2Ps
Telefonica Simulation
Verizon Simulation
P4P yields a dramatic improvement in data delivery speed, which results in faster downloads for users.

15. Interested? P4PWG is free to join.
Monthly phone calls CES, Tuesday at 8:00am)
Working Group mission:
Evaluate the P4P design through large-scale experiments
Formalize and promote adoption of P4P protocols
Serve as a forum for ISPs and P2P networks
For more info, Marty Lafferty: or or