Mobile Adventure
Joint work with Zoran Despotovic, Maximilian Michel, Jörg Widmer, Qing Wei (DoCoMo EU-Labs), Norihiro Ishikawa, Takeshi Kato, Tomoyoki Osano (NTT DoCoMo) Jörg Eberspächer, Stefan Zöls and Quirin Hofstätter (TU Munich), Jae Woo Lee, Henning Schulzrinne (Columbia Univ.), Wojciech Galuba, K. Aberer (EPFL) funded by NTT DoCoMo
Operator-driven Peer-to-Peer Service Platform for Mobile Environments Wolfgang Kellerer DoCoMo Euro-Labs, Germany DoCoMo Communications Europe GmbH Landsberger Str. 312 80687 Munich Germany
Copyright © 2007 by DoCoMo Communications Laboratories Europe GmbH All rights reserved
Mobile Adventure
Motivation • Peer-to-Peer (P2P) systems and applications ...
... challenging traditional fixed and mobile operators • Is this lost ground or can we make use of P2P technologies in a favorable way? • Does P2P open a new opportunity for service provisioning? A new service platform paradigm? • Are current technologies applicable for mobile environments? © 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Outline • Operator driven P2P service platform – Benefits – Mobile environments? – Requirements
• Platform architecture • Development of individual components – Core P2P services – Application specific P2P services
• Testbed and P2P applications
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
P2P - potential benefits • Infrastructure cost saving – through relying on existing infrastructure (e.g., the equipment of users) – with high availability and scalability • Example: Subscriber management (VoP2P)
• New business opportunities and extended service portfolio – Extension of the service coverage to ubiquitous environments (independent overlay) • Example: Controlling home appliances – Services provided by users • Example: Blogging, info sharing – Spontaneous emergence of a service overlay © 2007 by DoCoMo • Example: Community services Communications Laboratories Europe GmbH
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Mobile Adventure Objective: Operator-driven P2P service platform
• Develop building blocks for an operatorgrade service platform based on P2P technology for low cost and rapid service provisioning Operator controlled P2P service platform
n ity y lit atio un rity i b t m cu lia p u om e e Se C R R
Home network
P2P application specific services
P2P core services
Internet
Cellular network © 2007 by DoCoMo Communications Laboratories Europe GmbH
• and for any kind of user access incl. mobile 5
Mobile Adventure
P2P - definitions • Peer-to-Peer (P2P) networks are – self-organizing, distributed systems – realized as application layer overlay networks – objective: lookup and sharing of resources
• Mobile Peer-to-Peer systems involve mobile communication systems (at least one hop wireless):
GSM, GPRS, 3G, HSDPA, Bluetooth, phone, laptop, PDA, and also DSL, PC,...
ÎMobile P2P (here) = P2P in heterogeneous environments • BUT: P2P was not designed for heterogeneity © 2007 by DoCoMo Communications Laboratories Europe GmbH
[Kellerer, etal. in Steinmetz, Wehrle (Hrsg.), LNCS 3485 ]
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Mobile Adventure
P2P platform requirements (1) Mobility, heterogeneity Æ • Reduce the P2P lookup traffic overhead as much as possible, in order to overcome low transmission data rates of mobile devices • Address high churn rates (causing maintenance traffic) due to frequent joins and leaves of nodes • Considering limited resources of mobile devices addressing the heterogeneity of nodes and their distinct device capabilities
© 2007 by DoCoMo Communications Laboratories Europe GmbH
[Kellerer, A.D. Joseph, Dagstuhl 2006]
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Mobile Adventure
P2P platform requirements (2) Operator driven Æ • Guarantee reliability – E.g., "99.999%" availability
• Support system management/controllability – Monitoring the network operation and collecting (assessing) all relevant parameters: Network size, session times, etc. – Tune appropriate parameters to provide satisfactory application operation
• Provide trust and incentive models to support users’ willingness to comply to protocol • Security, interoperability, access control, … © 2007 by DoCoMo Communications Laboratories Europe GmbH
[Kellerer, etal., IEEE SPMS/SAINT 2007]8
Mobile Adventure
P2P service platform architecture Applications
Application Specific P2P Services
/ n n ch atio o r i r ea lic er IP) at S v la ity p m S o t ic ty u r p c c un P o ng e A i m e f c 2 j ni h a i (P r b e u n In ari o o m V m O ns V P Dy m m Sh Co Se P2 Co Data management • Complex queries • Information Retrieval
Enforcing collaboration among Peers • Incentives • Reputation management
Digital Rights Management DRM
Community support services Location-based services
Core P2P Services
Information lookup considering - mobile environment - churn - heterogeneity - mobility (ad hoc) - network topology
Controllability & manageability Reliability
Dynamic adaptation
Security Information distribution
Access control
Interworking Bootstrapping
© 2007 by DoCoMo Communications Laboratories Europe GmbH
[Kellerer, etal., IEEE SPMS/SAINT 2007]9
Mobile Adventure
Core P2P Services • Efficient lookup in heterogeneous (mobile) environments: Chordella hierachical P2P Overlay • Controllability • Bootstrapping
Core P2P Services
Information lookup considering - mobile environment - churn - heterogeneity - mobility (ad hoc) - network topology
Controllability & manageability Reliability
Dynamic adaptation
Security Information distribution
Access control
Interworking Bootstrapping
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Hierarchical P2P • Objective: efficient lookup of resources in heterogeneous networks and through diverse devices
• Basic concept: structured P2P Æ reduced lookup traffic • Heterogeneity: hierarchical architecture
© 2007 by DoCoMo Communications Laboratories Europe GmbH
[Kellerer, etal., Elsevier AEÜ 2006]
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Mobile Adventure
Our solution: Chordella L L
L
• Hierarchical P2P Overlay – Superpeers
L
S L
S S
L L
L
Chord Ring
S
L
– Leafpeers L
S L
S L L
• Structured P2P (we use Chord) • Routing of all lookup requests
L
Chordella
L
• Devices with limuted resources interfacinf to a superpeer • No routing • [Ganesan, ICDS04]: hierarchical Chord adapting to network topology • [Garces-Erice, Biersack, Euro-Par03]: reducing the lookup path length
S: Superpeer L: Leafpeer
• Chordella: Total cost optimized design
© 2007 by DoCoMo Communications Laboratories Europe GmbH
[Zöls, Kellerer, Despotovic, IEEE P2P 2006]
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Mobile Adventure
Evaluation
Number of messages ~ Cost
5 peer classes with different data rates, stability, shared objects,... Æ Improved cost compared to Chord ÆVariation with the number of superpeers Chord Chordella Chordella Chordella Chordella
– – – –
2% 5% 10% 20%
Ration of superpeers among total number of peers Number of peers
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure Looking for optimal design Cost-based analysis of Chordella L L L L
S
L L
S L L L
S
Chord Ring
S
S L
S L
L
L
L L
Determine the optimal superpeer ratio • Total cost: (Cost= number of messages) CT = {LookupS, LookupL, Ping, Stabilize, Fixfingers, Republish} as a function of timers, number of peers, objects,... • Cost per superpeer: CSi = {LookupSi, PingSi, StabilizeSi, FixfingersSi, RepublishSi} • Definition: Highest Load Factor (HLF): max{CSi}/Limit{CSi}
Suchrate
1 / 60s
UMTS
1 / 30s
GPRS
1 / 30s
Objekte
500
100
50
Upstream [kbit/s]
256
92
50
0,5
300% DSL
UMTS B
0,4
DSL
GPRS
UMTS
GPRS
200%
A
HLF
DSL
Total Network Costs [Gbit/s]
Example:
0,3
A 100% B
0,2
0% 1
Number of Superpeers
90000
1
2007 by DoCoMo90000 Number of©Superpeers Communications Laboratories Europe GmbH
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Mobile Adventure Configuration of hierarchical P2P: Determine the optimal ratio α # superpeers α= • α : Super Peer Ratio # peers • αOPT : optimal ratio Superpeer ratio α with minimum cost, while no superpeer is overloaded (HLF ≤ 100%)
αOPT = argmin CT(α) α ∈ [αmin;1]
© 2007 by DoCoMo Communications Laboratories Europe GmbH
αmin = min (α ∈ (0;1] | max (HLFSi(α)) ≤ 100%)
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Mobile Adventure
Controllable P2P system • Monitor the state of the network and take appropriate actions to prevent undesirable changes by tuning appropriate parameters • Distributed feedback control loop mechanism Uncontrollable parameters
Initial configuration
Corrections
Core of distributed system
Observed output
Adjustment measures Adjustment triggers
Analysis
• Example: optimal selection of the superpeers ratio
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Bootstrapping • Services in networks convened for short time periods and then disbanded again – large-scale events, disaster recovery, during meetings …
• Initial problem: discovery of other potential peers • Solution: z2z - Zeroconf-to-Zeroconf gateway – Based on Apple’s implementation of Zeroconf [RFC3924] – Discovers peers on the local link – z2z bridges multiple separate Zeroconf networks using OpenDHT © 2007 by DoCoMo Communications Laboratories Europe GmbH
[Lee, Schulzrinne, Kellerer, Despotovic, 2006]
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Mobile Adventure
Application specific P2P services Example: • Reputation Management Application Specific P2P Services
Data management • Complex queries • Information Retrieval
Enforcing collaboration among Peers • Incentives • Reputation management
Digital Rights Management DRM
Community support services Location-based services
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
P2P reputation management • Users can be: – Selfish – being clients but not servers • Problem of cooperation – Malicious – trying to subvert the network • P2P protocol security problem – Peers can also fail independently of user actions • Fault tolerance problem
• We handle all these problems in a single framework: – Take an existing system with recursively routed service requests and add feedback messages Æ reputation – Failures are reported to the failure predictor – The predictions of the failure predictor are used to avoid faulty routes – Reciprocation is used to punish free riders and other defectors [Aberer, Despotovic, Galuba, Kellerer, 2006]
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Simulations sample • DEFECTOR nodes: – Always provide a bad service – Do not reciprocate – Learn to choose next hops that don’t reciprocate
Services replicated to 4 nodes on average
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Applications Applications
/ n n ch atio o r i r ea lic er IP) at S v la ity p m S o t ic ty u r p c c un P o ng e A i m e f c 2 j ni h a i (P r b e u n In ari o o m V m O ns V P Dy m m Sh Co Se P2 Co P2P application specific services
P2P core services
Current implementations • Info sharing • Sensor network data management Æ person tracking • Dynamic services © 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Chordella testbed • Current layout – 6 Linux PCs and Laptops (Debian) – 6 cerfcube (Embedded Linux) – 8 Nokia Mobile Phones (Symbian Series 60) T T
S
S T T T
T T
S
S S
S T
T
T
T
VPN connection
DoCoMo site
University site © 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Mobile P2P Information Sharing • Users create content on their mobile phones (Blog, photos, v-cards, address book,…) • Users share this information without central server • Dynamic scalability to avoid uploading not demanded content and replicate demanded content • Examples – – – – –
Pictures of local attraction Info in discussion group Address book info among corporate users Lecture schedule among students on a campus Social network service: share info among community without infrastructure setup – Private diary-like web page
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Example: Information sharing
6 Index: MP2P
Routing Hop II
1
3
Info: MP2P
wn lo
5
ad
Chord Ring Routing Hop I Do
w
4
Do
7
nl oa d
2 8
MP2P Foto? © 2007 by DoCoMo Communications Laboratories Europe GmbH
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Example: P2P and sensor networks: person tracking
Mobile Adventure
Children Tracking
• Determine the location of a person • Retrieve her/his image from a camera • Retrieve the movement history
camera
Amusement park
• High dynamicity in request and update rate are not favorable for centralized or flooding based concepts
Alarm Child
HERE! Parent
• Solution: – Sensor nodes run a Chordella overlay – Mobile phones (leaf peers) act as • Clients for monitoring • Localization sources © 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure Consistent interplay of localization, sensor data management and queries
Sensor nodes: - Camers - WLAN access point - Chordella Superpeer
Mobile phone
Cellular NW
safety verification by parents
Chordella Overlay Sensor Node (Superpeer)
Sensor Node (Superpeer)
TAG
Sensor Node (Superpeer)
Sensor Node (Superpeer) TAG
Leafnode safety verification by parents
Localization via signal strength measurement and insertion to DHT
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Summary P2P Service Platform • Architecture to enable quick and easy application development • Component based architecture • Core Service: Chordella for heterogeneous environments • Operator driven – Controllability – Dynamic tuning of the components – Reputation management © 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
Thank You! Dr.-Ing.
Wolfgang Kellerer Senior Manager Ubiquitous Services Platform Group Future Networking Lab DoCoMo Euro-Labs Lecturer Technische Universität München (TUM) http://www.wolfgangkellerer.de
DoCoMo Communications Laboratories Europe GmbH Landsberger Str. 312 80687 München Tel: +49-89-56824-222 Fax: +49-89-56824-300 Email:
[email protected] http://www.docomoeurolabs.de © 2007 by DoCoMo Communications Laboratories Europe GmbH
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Mobile Adventure
References •
W. Kellerer, G. Kunzmann, R. Schollmeier, S. Zöls. Structured Peer-to-Peer Systems for Telecommunications and Mobile Environments. International Journal of Electronics and Communications, Elsevier, Vol. 60, Issue 1, January 2006, pp. 25-29.
•
W. Kellerer, Z. Despotovic, M. Michel, S. Zoels, Q. Hofstaetter. Towards a Mobile Peer-to-Peer Service Platform. 3rd IEEE SPMS workshop in conjunction with IEEE SAINT 2007, Hiroshima, Japan, Jan. 15-19, 2007. S. Zoels, Z. Despotovic, W. Kellerer. Cost-Based Analysis of Hierarchical DHT Design. In proc. 6th IEEE Intl. Conference on P2P Computing (IEEE P2P 2006), Sept. 6-8, Cambridge, UK. S. Zoels, S. Schubert, W. Kellerer, Z. Despotovic. Content Availability and Signaling Overhead in DHT Systems for Mobile Environments. PODC 2006, July, 23-26, 2006, Denver, Colorado, US (Poster). K. Aberer, Z. Despotovic, W. Galuba, W. Kellerer. The Complex Facets of Reputation and Trust. Invited Paper. Intl. Conf. on Computational Intelligence, Dortmund, Germany, Sept. 18-20, 2006. S. Zöls, S. Schubert, W. Kellerer, Z. Despotovic. Hybrid DHT Design for Mobile Environments. AP2P workshop at AAMAS 2006, Hakodate, Japan, May 9-12, 2006. W. Kellerer and A.D. Joseph. Mobile Peer-to-Peer. Dagstuhl Seminar Peer-to-Peer Systems and Applications, teamwork on mobile P2P, Dagstuhl, Germany, March 26-29, 2006. S. Zöls, M. Eichhorn, A. Tarlano, W. Kellerer. Content-based Hierarchies in DHT-based Peer-to-Peer Systems. 2nd IEEE/IPSJ SAINT 2006 workshop SPMS2006, Phoenix, Arizona, USA, Jan. 23-27, 2006. W. Kellerer, R. Schollmeier. Proactive Search Routing for Mobile Peer-to-Peer Networks: Zone-based P2P. ASWN 2005, Paris, France, June 29 – July 1, 2005. S. Zöls, R. Schollmeier, Q. Hofstätter, A. Tarlano, W. Kellerer. The Impact of Content Distribution on Structured P2P Networks in Mobile Scenarios. EUNICE 2005, Colmenarejo, Spain, July 6-8, 2005. S. Zöls, R. Schollmeier, A. Tarlano, W. Kellerer. The Hybrid Chord Protocol: A Peer-to-peer Lookup Service for Context-Aware Mobile Applications. IEEE ICN, Reunion Island, April 2005. LNCS 3421. I. Gruber, R. Schollmeier, W. Kellerer. Performance Evaluation of the Mobile Peer-to-Peer Protocol. ACM/IEEE Intl. Workshop on Global Peer-to-Peer Computing, Chicago, US, April 19-22, 2004.
• • • • • • • • • •
© 2007 by DoCoMo Communications Laboratories Europe GmbH
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