P4P: Towards Cooperation between P2P and ISPs

Haiyong Xie (Yale)

Arvind Krishnamurthy (U. Washington)

Avi Silberschatz (Yale)

Y. Richard Yang (Yale)

2007-7-25

2007-7-25 P4PWG July Meeting 2

P2P Content Distribution Traffic volume: up to 60-70%

of Internet traffic is contributed by P2P applications [cachelogic]

Traffic pattern: random peering (e.g., BitTorrents) causes traffic spread across PoPs and domains

Problems Increased network resource usage

(e.g., using bandwidth of more links) Increased network operational costs Degraded performance to other applications

http://www.cachelogic.com

2007-7-25 P4PWG July Meeting 3

Bandwidth Battle between ISPs and P2P

The battle results in a lose-lose situation

ISPs try to “manage” P2P traffic

Upgrade network infrastructure Deploy P2P caching devices Terminate connectivity Rate limit P2P traffic

P2P tries to evade from being captured

Uses random ports Encrypts traffic

2007-7-25 P4PWG July Meeting 4

Where is the Fundamental Problem? Traditional ISP application feedback/control:

Routing/traffic engineering (TE) Rate control through congestion feedback (packet drops)

Ineffective for P2P due to highly dynamic, scattered traffic pattern caused

by dynamic, unguided (network-oblivious) peer selection

Objective: design a framework to enable better ISP and P2P cooperation

2007-7-25 P4PWG July Meeting 5

Design Rationale Performance improvement

for both ISPs and P2P Scalability

support a large number of P2P users and networks in dynamic settings

Privacy preservation Extensibility

Application-specific requirements Tracker-based vs. trackerless P2P systems Gossip among peers

Incremental deploymentability ISP contribution for P2P acceleration

2007-7-25 P4PWG July Meeting 6

The P4P Framework P4P: proactive provider participation for P2P; P2P for

providers; provider portal for P2P, … Two components

Control plane iTrackers: an ISP portal for P2P and content providers Three levels:

Network status: e.g., network topology ISP policy and guideline: e.g., traffic balance ratio for inter-AS peering

links, time of day preference ISP capabilities: e.g., QoS, CoS, ISP servers participation in content

distributions

Data plane [optional] Routers on data paths provide fine-grained, ISP policy-based feedbacks,

e.g., utilize TCP ECN bit or feedback fields in an overlay packet header

2007-7-25 P4PWG July Meeting 7

P4P Control Path: Obtain Network Status/Policy

An iTracker for each ISP.

1: Peer queries iTracker of local ISP to obtain network status/policy

2,3: Tracker-based: peer reports status/policy to appTracker; appTracker selects peering set considering both ISP status/policy and application requirements[4]: Trackerless: peers exchange information and make peering decisions

ISP BISP A

appTracker

a

iTracker BiTracker A

b

2

3

11[4]

2

3

2007-7-25 P4PWG July Meeting 8

P4P Control Path : Request Capability

ISP B

5: appTracker [content provider] requests ISP B’s participation in content distribution6: ISP B allocates servers to accelerate content distribution7: appTracker includes ISP B’s servers in returned peering sets to peers

ISP A

appTracker

a

iTracker BiTracker A

b

6

7

5Note: this can be extended to handle trackerless systems, as we did in the previous slide

appTracker/content provider requests ISP capabilities to accelerate content distribution.

2007-7-25 P4PWG July Meeting 9

P4P Framework: Data Path [optional]

Routers mark packets to provide faster, fine-grained feedbacks, e.g., virtual capacity to optimize multihoming cost and performance

ISP BISP A

a

b

Peers adjust traffic rates according to feedbacks

2007-7-25 P4PWG July Meeting 10

Test Plan for P4P Measurement study with Pando (in progress)

Evaluate P2P self-adaptation schemes (in progress) Generate best practices for P2P design Serve as comparison basis

iTracker (in progress) Network information (roughly completed) ISP policy and guideline (in progress) ISP capability (in progress)

Data path (in progress)

Evaluate P4P design with Pando and Verizon (in progress)

2007-7-25 P4PWG July Meeting 11

Preliminary Results Simulations

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: PoP-level AT&T and Abilene

topologies Network routing: OSPF routing

Internet experiments 53 Internet2 nodes on PlanetLab iTracker for Abilene network Use OSPF routing to re-construct traffic load on Abilene

links

2007-7-25 P4PWG July Meeting 12

Evaluation – BitTorrent on Abilene Compared to P4P, native

P2P can result in 2x download completion

time 2x higher link utilization

Native P2P can result in some peers experiencing very long download completion time

Native P2P can result in much larger variance in link utilization

2007-7-25 P4PWG July Meeting 13

Evaluation – BitTorrent on AT&T Compared to P4P, native

P2P can result in 1.6x download completion

time 3x higher link utilization

Some peers can experience very long download completion time with native P2P

Link utilization variance can be larger for native P2P

2007-7-25 P4PWG July Meeting 14

Evaluation – Liveswarms on PlanetLab Liveswarms* is a P2P-based video streaming application,

which adapts BitTorrent protocol to video streaming context Run liveswarms on 53 PlanetLab nodes for 900 seconds

P4P and native liveswarms achieve roughly the same amount of throughput

P4P reduces link load Average link load saving is

34MB Maximum average link load

saving is 60% Native liveswarms:1Mbps P4P liveswarms: 432Kbps

*Michael Piatek, Colin Dixon, Arvind Krishnamurthy, Tom Anderson. LiveSwarms: Adapting BitTorrent for end host multicast. Technical report: UW-CSE-06-11-01

2007-7-25 P4PWG July Meeting 15

Contact and Acknowledgement For further details, please refer to our technical report Yale/DCS TR-

1377 It is still a work-in-progress and changes rapidly

Questions/comments are highly welcome: Haiyong Xie (haiyong.xie@yale.edu) Y. Richard Yang (yry@cs.yale.edu)

AcknowledgementsWe would like to thank Charles Kalmanek (AT&T Labs), Marty Lafferty

(DCIA), Doug Pasko (Verizon), Laird Popkin (Pando), Keith Ross (Polytechnic), Ke Xu (Tsinghua Univ.) for suggestions, discussions and feedback.