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The peer-to-peer paradigm gained more and more impact in the last years. The reason for P2P arising now is related to the continuous development of device capabilities in the last years, like CPU power, storage space and bandwidth. However, the demand for services and resources is permanently increasing, although the peers have a variety of other resources themselves. In this paper we present the idea of a P2P system acting as a service provider using the resources of participating peers and stating guarantees on the quality of the service it provides. In order to fulfill these service level agreements, the peers confederate to a distributed supervisor of peer resources (P2PCLOUD), monitoring the network, predicting trends on resource availabilities and deciding on resource allocation strategies. This paper discusses the challenges and a solution draft of the concept of P2PCLOUD.
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KOM - Multimedia Communications LabProf. Dr.-Ing. Ralf Steinmetz (Director)
Dept. of Electrical Engineering and Information TechnologyDept. of Computer Science (adjunct Professor)
TUD – Technische Universität Darmstadt Merckstr. 25, D-64283 Darmstadt, Germany
Tel.+49 6151 166150, Fax. +49 6151 166152 www.KOM.tu-darmstadt.de
© author(s) of these slides 2008 including research results of the research network KOM and TU Darmstadt otherwise as specified at the respective slide
httc – Hessian Telemedia Technology
Competence-Center e.V - www.httc.de
Dipl.-Math., Dipl.-Inform. Kalman Graffi
[email protected] Tel.+49 6151 164959
10. April 2023
From Cells to Organisms: Long-Term Guarantees on Service
Provisioning in Peer-to-Peer NetworksKalman Graffi, Aleksandra Kovacevic,
Nicolas Liebau, Ralf Steinmetz
DISPRO
KOM – Multimedia Communications Lab 2
The Peer-to-Peer Paradigm
Peer-to-Peer Systems: Users of a system provide the infrastructure of the system Service is provided from users/peers to users/peers Peer-to-Peer overlays:
virtual networks, providing new functionality E.g. Distributed Hash Tables, Keyword-based Search
Evolution of applications File sharing:
No Quality of Service (QoS) requirements Voice over IP
Real-time requirements Video-on-demand
Real-time and bandwidth requirements More resource sharing? (not just files)
Towards dynamic P2P-based grid functionalities?
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See: Kalman Graffi, et al. “Peer-to-Peer Forschung - Überblick und Herausforderungen” In: it - Information Technology (Methods and Applications of Informatics and Information Technology), vol. 46, no. 5, p. 272-279, July 2007
KOM – Multimedia Communications Lab 3
Service Level Agreements in P2P Systems
One-to-one relationship: Consumer and provider matching easy to optimize Both have to be online, transaction is interrupted if one leaves Example: BitTorrent
Both peers are consumer and provider of chunks Same resource, both online
Potentials and limitations: Any kind of resource can be efficiently allocated Only online peers can be considered No guarantees on service provision Peers have to organize backup solutions
What if they are offline?(e.g. reliable storage service)
DHT
Stores pointers on resource
providers
Peers interested in the resource ask
for providing peersProvider
dispatching with focus on
load balancing
See: Kalman Graffi, et al. “Load Balancing for Multimedia Streaming in Heterogeneous Peer-to-Peer Systems”.In: 18th Int. Workshop on Network and Operating Systems Support for Digital Audio and Video (NOSSDAV '08), ACM SIGMM, May 2008.
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Long-Term Service Guarantees?
Distributed computations: Seti@home: Just one centralized job provider Condor: dispatching of individual simulation jobs, no churn P2P based simulations: Many job providers, churn
Online time: Long term observations, who controls migration? In Skype: deliver a file to a buddy if he comes online
Storage space: To keep data objects available for a specific time with a given probability
Bandwidth: To quickly distribute/stream large data objects
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One-to-Many Relationship Resource Trading Characteristics
Application Areas: Distributed computing, backup service, worldwide testbed
Services requested, that cannot be fulfilled by single peers One provider is not enough efforts / contribution has to be combined
Heterogeneous resources in focus: “Trade” computational power against storage space? E.g. comp. power, storage space, bandwidth, online time, human presence … How to find specific resource provider, which looks especially for what I offer?
Long-term service provisioning guarantees desired Even if service requester goes offline Who is in charge of organizing the service provisioning?
Need for system-wide management enabling SLAs:DIstributed Supervisor of Peer ResOurces (DISPRO)
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Essential Building Blocks for a DISPRO
Distributed Supervisor of Peer Resources (Quorum) A cooperative of peers providing the function of service management
Resource monitoring An information management approach gathering information about the system
Prediction on resource trends Models and mechanisms that predict the current (and future) system state
Service-level agreement negotiation Based on the resource predictions, suitable “costs” can be calculated Costs describe resource contributions needed in the future for the system
Service-level agreement enforcement Accounting of service transactions and reputation maintenance of peers
Security: authenticity and reliable decision making
DISPROQuorum
SLAAccounti
ng
Security
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Example: Distributed Resource Exchange
Demand/provision of: storage space, comp. power, online time, …
Idea: Exchange resources using a Distributed Supervisor of Peer Resources
Gather informationabout the system:Who offers & con-sumes what?Statistics?
Build DISPROquorum
Request service,e.g. storage space
Calculate usage trendsand resource availabilityin the future based on gatheredinformation
Name price,e.g. comp.
power
Request service,e.g. comp. power
Name price,e.g. bandwidth
DISPROQuorum
Accounting of transactions and reputation maintenance of peers.
Detect and reallocate
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Tasks of the DISPRO
Service Provisioningand Accounting
Monitor tasks in charge for Reallocate tasks if peers fail
Account transactions Maintain peer reputation, consider it in future decisions
Analytical Models
Interpret system statistics Identify current and future system state
SLA negotiation: Identify resources that will be needed in the future: declare them as price for future transactions
Information Management System
Gather system statistics on the distributed system: Several metrics and parameters per module Average values, standard deviations, confidence intervals
Several (non-) functional requirements for information architecture Supports capacity-based peer search
SLA
Description Language enables porting of jobs need for specified resources P2P Systems
DISPROQuorum
DISPROQuorum
Security and Reputation monitor and consider be-havior of peers secure de-cision making
SLA
Security
KOM – Multimedia Communications Lab 9
Integration in P2P Systems
Components of the DISPRO Information Management System
Generates system statistics Enables capacity-based peer search
Statistics are analyzed distributed DISPRO quorum negotiates for SLAs,
it commands peers what to provide
Internet
DHT overlay .
Metrics and parameters
Peer capacity
Result: n peer IDs
Query for n peers with list of capacity req.
uses
Information Management
SystemOver-overlay for sys-tem statistics & cap.- based peer search
Peer view:
Peers
αβλ
μ
Information Management
System
Analysis, modeling and interpretation
Using information to determine
costs
VariousP2P
functionalmodules
uses
DISPRO .Quorum
Data Analyzing
Generatedsystemstatistics
Identify missing re-sources in the sys.Calculate price forresource requests
Resources to be provided
Ask for long-term SLA
Accounting
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Conclusions
System-wide management enabling Service Level Agreements:
DIstributed Supervisor of Peer ResOurces (DISPRO) Enables long-term SLAs on combined resources provided by various peers Provides a new application of the P2P paradigm:
Distributed resource exchange
Main building blocks: Information management system:
Provides system statistics and capacity-based peer search Distributed analysis component:
Determines (future) system state based on statistics, determines prices DISPRO quorum:
Built of peers, negotiates SLAs, migrates jobs, enforces resource provision SLA description language, security and accounting
For more details: please read the paper
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Further Questions ?
