1. Peer Selection in P2P Service Overlays using
Geographical Location Criteria
Adriano Fiorese1,2 , Paulo Sim˜es1 and Fernando Boavida1
o
1 Centre for Informatics and Systems of the University of Coimbra - CISUC
Department of Informatics Engineering - DEI
University of Coimbra - UC - Portugal
fiorese@dei.uc.pt
2 Departament of Computer Science - DCC
University of the State of Santa Catarina - UDESC
889219-710 Joinville, SC, Brazil
fiorese@joinville.udesc.br
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 1 / 14

2. Outline
1 Introduction
Background (BPSS)
2 Validation
BPSS Used Metric
Validation Aspects
Selected approach
Preliminary Results
3 Conclusions
4 Future Work
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 2 / 14

3. Introduction
Services and service components are becoming basic elements of
interaction among service providers.
Service Overlay Networks (SON) may act as an infrastructure where
services are published/offered and to which users access in order to
locate, select and use those services.
P2P technology helps to create self-organizing Service Overlay
Networks in several levels.
Therefore, services and service components are offered in a P2P SON.
In order to maximize performance, the best peer must be found in the
P2P SON, among all the potential partners that provide the desired
service.
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 3 / 14

4. Best Peer Selection Service (BPSS)
BPSS is part of an architecture for Services Management in P2P
environments called OMAN, proposed previously in Fiorese et al.,
OMAN - A Management Architecture for P2P Service Overlay
Networks, AIMS 2010.
BPSS is responsible for select the best peer for interacting with a
requesting peer, regarding a particular service and metric.
BPSS runs over a P2P SON at the same level of a second overlay-tier
called AgS responsible for speedup search operations.
SON peers can request best peer information (select BP), regarding a
particular service, from the BPSS module.
BPSS answers with the best peer regarding the agreeded metric.
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 4 / 14

5. OMAN Architecture
Application/Service
3rd Layer
QoE
Best Peer Selection Service
Autonomic
Overlay Monitoring Resilience
Configuration
Manager
2nd Layer
Support for
P2P Search Aggregation Legacy
Service Service Management
Systems
1st Layer
SON
Support for P2P Communication
provisioning
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 5 / 14

6. Best Peer Selection Service (BPSS) Framework
Aggregation links
SON peer
Physical links
Aggregation peer
Overlay links
Best Peer List of BP
Selection Service Query Aggregation Service (AgS)
(BPSS) Query
Provider/User
Se
le c B
tB P
Select BP
P
BP
Domain A Domain B Domain C
SON
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 6 / 14

7. BPSS Used Metric
Developed by Kaune et al. (2009) - Modelling the Internet delay space
based on geographical locations.
It is based on a predictive model of the Internet delay space that takes
into account the geographical location of nodes and the delay between
them.
It uses a rich set of real Internet measured data namely end-to-end
round trip time and end-to-end link jitter.
These data are mapped into a 5-dimensions Euclidean space model of
the Internet combining it with global network positioning information.
Metric
Using the coordinates of each peer in this 5-dimensions model, it is then
possible to calculate the Euclidean distance between peers, taking into
account not only network conditions but also peer location.
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 7 / 14

8. Validation Aspects
Five geographical domains comprising Portugal, Spain, France, Italy
and Germany made part of the experiments.
All the peers requesting best peers were from in the Portuguese domain.
Comparison between the best and second best peer selected.
Comparisons were made by domain.
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 8 / 14

9. Validation (selected approach)
Evaluation by simulation.
Several sizes of P2P SON were simulated, ranging from 50 to 300 P2P
SON peers, with steps of 25 peers.
Parameters:
Average of 10 repetitions of 100 best peer selection operations for each
P2P SON sizes.
Each execution simulated 50 hours of BPSS work.
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 9 / 14

10. Best Peer Selection Execution
Bars for each group correspond to Portugal, Spain, France , Italy, and Germany, respectively from the left to the right.
50
40
Number of Best peers
30
20
10
0
50 75 100 125 150 175 200 225 250 275 300
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 10 / 14

11. Averaged geographical distribution of best peer selection
35
Best Peer Distribution on Average
30
Number of Best peers
25
20
15
10
5
Portugal Spain France Italy Germany
Adriano Fiorese (UC,UDESC) Domains
ICCSA 2012 Jun 18, 2012 11 / 14

12. Summing up
Taking the sum of best peers and second-best peers by domain, SON
peers in the requester’s domain (Portugal) were selected as best peers
in 27% of the time, followed by Spain (22.5%), Italy (22%), Germany
(14.5%) and France (13%).
This means that almost half the best peer selections resulted in peers
belonging to the same geographical domain or to the neighboring
geographical domain.
Obtained results have shown that BPSS performs well and that the
overall OMAN architecture - of which the AgS service is a key
component - is very effective.
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 12 / 14

13. Future Work
Compare these results with the BPSS utilization of other selection
metrics, including related with QoS.
Use of the OMAN approach to identify ways of maximizing user QoE.
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 13 / 14

14. The End!
Thank you!
Questions/Comments/Suggestions/Discussion?
Contacts
Personal Web Page: (http://eden.dei.uc.pt/˜fiorese)
Laboratory of Communications and Telematics at UC
(http://www.cisuc.uc.pt/lct/)
(fiorese@dei.uc.pt)
GRADIS - Group of Network and Distributed Applications at UDESC
(http://www2.joinville.udesc.br/˜gradis/)
(fiorese@joinville.udesc.br)
Adriano Fiorese (UC,UDESC) ICCSA 2012 Jun 18, 2012 14 / 14