Download P4P : Provider Portal for (P2P) Applications Haiyong Xie, et al

Provider Portal
for (P2P) Applications
P4P :
Haiyong Xie,
Y. Richard Yan,
Arvind Krishnamurthy, Yanbin Liu, Avi Silberschatz,
SIGCOMM’08
2008. 09. 04.
Jinyoung Han
([email protected])
Outline
 Motivation
 P4P
 Evaluations
 Summary
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P2P Bandwidth Usage
 Up to 70% of Internet traffic is contributed by
P2P applications
 However, the emerging P2P applications expose
significant new challenges to Internet traffic
control
Internet Protocol Breakdown 1993 - 2006
Ipoque Study 2007
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P2P Problem: Network Inefficiency
 Network-oblivious P2P applications may not be
network efficient

Intra-domain
 Verizon


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average P2P bit traverses 1000 miles
average P2P bit traverses 5.5 metro-hops
Inter-domain
 Karagiannis et al. BitTorrent on a university network
(2005)

50%-90% of existing local pieces in active users are
downloaded externally
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Attempts to Address P2P Problems
 ISP approaches


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
Increase capacity
Rate-limit P2P traffic
Deploy P2P caching devices
Etc..
 P2P approaches


Locality aware P2P
Etc..
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P2P Problem : Inefficient interactions
 ISP optimizer interacts poorly with adaptive P2P

ISP

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Adaptive P2P

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Traffic engineering to change routing to shift traffic away from hi
ghly utilized links
Adapt their traffic to changes in the network
Resulting in potential oscillations in traffic patterns and suboptimal routing decisions
 Traditional Internet architectural feedback to
applications is limited
 Emerging P2P applications can have tremendous
flexibility in shaping how data is communicated

The network needs to provide more information and feedback
to most effectively utilize this flexibility for improving network
efficiency
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P4P
 Let’s design a framework to enable better
providers and applications cooperation!
 P4P: Provider portal for (P2P) applications

a provider can be
 a traditional ISP (e.g., AT&T, Verizon) or
 a content distribution provider (e.g., Akamai), or
 a caching provider (e.g., PeerApp)
 Open standard

any ISP, provider, application can easily implement it
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P4P Missions
 ISP perspective:

guide applications to achieve more efficient network usage,
e.g.,

avoid undesirable (expensive/limited capacity) links to more
desirable (inexpensive/available capacity) links
 Resource providers (e.g., caching, CDN, ISP)
perspective:

provide applications with on-demand resources/quality
 P2P perspective:


better performance for users
decreased incentive for ISPs to “manage” applications
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P4P Architecture
 P4P potential entities



iTracker: individual network providers
Peer: P2P clients
appTracker: P2P
 Each network provider maintains an iTracker
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P4P iTracker
 iTracker



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a portal for each network resource provider
Allows P4P to divide traffic control responsibilities between ap
plications and network providers
Makes P4P incrementally deployable and extensible
iTracker of a provider can be identified in various ways


e.g., through DNS query
iTracker can be run by trusted third parties
 Examples of iTracker interfaces

Policy interface

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Provider capabilities interface

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Allows applications to obtain the usage polices of a network
Allows peers to request network providers’ capabilities
P4P-distnace (Virtual cost) interface

Allows others to query costs and distances between peers
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P4P distance
 P4P-distance reflect the network’s status and
preferences regarding application traffic
 P4P-distance should be..

Simple, intuitive, …
 An ISP can assign P4P-distance in a wide
variety of ways


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OSPF weights and BGP preferences
Considering financial costs or approaching congestion
ETC..
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The P4P-distance Interface:
two views
 Networks’ view seen by an iTracker


the higher the price, the more “cost” to the ISP if an
application uses the link
Reflects both network status and policy, e.g.,


higher prices on links with highest util. or higher than a
threshold
OSPF weights
 Applications’ view seen by applications

Applications adjust traffic patterns to place less load on
more expensive P2P node pairs
 Both ISP and Application can use this interface
in a variety of ways
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An example of P4P information flows
appTracker
2
iTracker
 Information flow:
1. peer queries appTracker
2/3. appTracker asks
iTracker for virtual cost
(occasionally)
4. appTracker selects and
returns a set of active
peers, according to both
application requirements
and iTracker information
3
1
4
peer
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Evaluation Methodology
 Network Topologies


Internet experiments on Abilene and ISP-B
Simulations on PoP(Point of Presence)-level topologies of
Abilene and major tier-1 ISPs
 Applications

BitTorrent, Livewarms (streaming) and Pando (commercial)
 Performance Metrics

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Completion time
P2P bandwidth-distance product (BDP)
P2P traffic on top of the most utilized link
Charging volume
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Evaluation for Intra-domain
 Simulation using Bit Torrent on ISP-A
 P4P achieves rate between latency-based localized and
native
 The utilization of P4P is less than one-half of localized,
which achieves lower than native
Completion time
Bottleneck link utilization
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Evaluation for Inter-domain
 Experiments using BitTorrent on Abilene
 P4P achieves similar application performance with
localized; but P4P has a shorter tail.
 For the charging volume of the second link: native is 4x of
P4P; delay-localized is 2x of P4P
Completion time
Charging volumes
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Evaluation – Field Tests
 Field Tests on ISP-B against Native (Pando)
 P4P achieves approximately 5 times in unit BDP

ISP Perspective
 P4P improves average completion time by 23%.

P2P Perspective
Completion time
Average Unit BDP
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Summary
 P4P: provider portal for (P2P) applications


Simple and flexible framework
Explicit cooperation between P2P and network providers
 P4P can be a promising approach to improve
both application performance and provider
efficiency
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References
 Open P4P,

http://www.openp4p.net/
 Yale P4P,

http://cs-www.cs.yale.edu/homes/yong/p4p.html
 P4P Working group,

http://www.dcia.info/activities/p4pwg/membership.html
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Discussions
 What are the incentives for P2P to participate in
P4P?


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Better network efficiency
P2P by playing nice could avoid being blocked by ISPs
P4P leaves much flexibility for P2P
Benefits the overall society
 Why cannot P2P achieves the benefits of P4P by
itself?


Probing the network to reverse engineer information such as
topology and status is difficult
Cost and policy is difficult to reverse engineer
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Discussions
 Does P4P violate network neutrality?

ISPs and P2P applications mutually agree to participate in
P4P
 How can it be feasible for P4P to orchestrate all
these networks?

iTracker interfaces are light-weight and do not handle perclient application
 Do the locality-aware P4P techniques reduce
robustness?

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P4P does not limit the mechanisms for improving robustness
If iTrackers are down, P2P applications can still make default
application decisions
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