1. A Hybrid Approach to
Modeling End-to-End Delay
in P2P Networks
Philipp Berndt,
Dominic Battré,
Odej Kao
Complex and Distributed IT-Systems
<firstname.lastname@tu-berlin.de>
AVSTP2P’10, October 29th 2010, Firenze, Italy

2. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Motivation
2
Evaluation of
P2P Systems
Simulation
Network Model
End-to-End
Delays
Locality Jitter Queuing
provides
accounts for

3. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Overview
● Motivation
● Overview
● Related Work
■ Statistical Models, Global Network Positioning, Network
Simulation
● The Delfoi Model
● Evaluation
● Implementation
● Current/Future Research
● Summary & Questions
3

4. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Statistical Models
4
Locality
Queuing
Jitter

5. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Global Network Positioning
5
Locality
Queuing
Jitter?
Dabek, F.; Cox, R.; Kaashoek, F. & Morris, R. Vivaldi: A Decentralized Network Coordinate System In SIGCOMM, 2004, 15-26

6. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Network Simulators
6
Locality
Queuing
Jitter?

7. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Overview
● Motivation
● Overview
● Related Work
■ Statistical Models, Global Network Positioning, Network
Simulation
● The Delfoi Model
● Evaluation
● Implementation
● Current/Future Research
● Summary & Questions
7

8. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
The Delfoi Model:
One way end-to-end delay
8
1. 4.
2. 5.
3. 6.
 :),,,delay( 21 SlHH P
 
upH
PupH
bandwidth
lS
,
,
1
1
queuelevel 
upHwiredelay ,1
  

D
i iHiH cc1
2
,, 21
 2121 ,, ,rlnorm HHHH 
 
downH
PdownH
bandwidth
lS
,
,
2
2
queuelevel 
downHwiredelay ,2
1 2 3 4 5 6

9. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
The Delfoi Model:
Usage
9

10. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Delfoi: Evaluation
10
Locality
Queuing
Jitter

11. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Delfoi: Implementation
● Implementation split in two parts:
■ Gnplib
♦ http://sourceforge.net/projects/gnplib/
■ INET Framework fork
♦ http://github.com/pberndt/inet
● Parametrization data
■ CAIDA
■ PingER
■ speedtest.net (work in progress)
11
XML data set available from
http://peerfact.kom.e-technik.tu-darmstadt.de/

12. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Ongoing&Future Research
● Model Parametrization from world wide measurements
● DSL/Cable modem specific characteristics
● Improve Jitter model
● Background traffic generation
● Autoconfiguration
● Large scale tests
12

13. philipp.berndt@tu-berlin.de A Hybrid Approach to Modeling End-to-End Delay in P2P Networks
Summary
● Simulation is essential
● Realistic network models
● Delfoi provides:
■ World-wide latency
■ World-wide jitter
■ World-wide access network
& Local queuing characteristics
● Example Application:
■ Visualizing and Reducing Wait Delay in Periodic Butterfly
Communication
■ Demo Session at 16:00
13