1. Peer to Peer networks and Performance
Hanoch Levy (hanoch at cs.tau.ac.il)
Office: Kaplun 511
Office hours: by appointment
H. Levy P2P+Performance

2. Course Information Lectures: Wed 9-12 Kaplun 319
Web site:
And follow the link: Advanced topics in Computer-Networks –
Peer-to-Peer Networks
H. Levy P2P+Performance

3. Course Objective Study P2P networks
Open the door for research in this area (Master/ Ph.D)
Cover both: Theoretical background and advanced material
H. Levy P2P+Performance

4. Course Approach
Prerequisites: Course in computer / Equivalent / teacher approval
Requirements:
Most material is New (articles)
Requires some analytic models
Approach:
Theoretical background (performance: elementary queueing theory) – frontal lectures by teacher.
Recent material: (articles) – lectures by students
H. Levy P2P+Performance

5. Course Structure and requirements
First half of semester: Teacher lectures
2nd half of semester – student lectures.
Each student gets one paper – and covers one paper in 45 minutes.
H. Levy P2P+Performance

6. Course requirements
First half (theoretical): In Class Exam (50-60% of grade)
exam time: TBD – between and in-class exam.
HW assignments
2nd Half: Give a good lecture. (40-50% of grade)
Active participation will benefit a bonus
Overflow students (if any): lecture replaced by special assignment by lecturer.
H. Levy P2P+Performance

7. Course Information Supporting Books (theoretical part)
Queueing Theory, L. Kleinrock, Vol I, Wiley (hard copy)
Online books:
Web site: (search “queueing hlynka)
Introduction to Queueing Theory (2nd edition). Robert B. Cooper pp. This classic book is available on line through Robert Cooper's home page. The link to the book is: The solution manual (by Borge Tolt, 182 pages, 1981) is available online at
H. Levy P2P+Performance

8. Course Information Supporting Books (theoretical part – cont )
3. Queueing Theory. Ivo Adan and Jacques Resing pp.
4. Queues: –A Course in Queueing Theor. Moshe Haviv. October 1, New and complete.
5. more…
H. Levy P2P+Performance

9. Motivation Last 10-15 years: communications revolution
Internet + Computer communications
Is a key factor of the Information revolution
Implications
A drastic change of some aspects of life
Revolution is affected by life
Technology drives applications
Applications drive technology
H. Levy P2P+Performance

10. Motivation (cont)
Applications / technology / research  rapidly change over time
If want to stay in frontier:
=> Research material very dynamic
=> Course material very dynamic
H. Levy P2P+Performance

11. Objectives Computer Networking course: Internet infra-structure
1 Introduction and Layering
2 Physical Layer, Data Link Layer, MAC Protocols
3 Hubs, Bridges, SwitchesData Link Layer
4 Switching UnitsSTP, Switching Fabric
5 Scheduling: Buffer Management Scheduling, WFQ example
6 Network Layer: RoutingRouting
7 Reliable Data TransferIP
8 End to End ProtocolsARQ
10 Flow Control, Congestion ControlTCP flow & congestion control
11 Network SecurityNetwork Sniffing (no slides)
12 DNS, HTTPTCP (state chart)
13 DDoS
ALL – operations of network of networks.
H. Levy P2P+Performance

12. Objectives (2)
Advanced Material – network development following technology
Peer to Peer (P2P): Bittorent, Skype
Songs /movies / video-on-demand/video online
H. Levy P2P+Performance

13. Internet Physical Infrastructure
Residential access
Cable
Fiber
DSL
Wireless
Backbone ISP
ISP
The Internet is a network of networks
Each individually administrated network is called an Autonomous System (AS)
Campus access, e.g.,
Ethernet
Wireless
H. Levy P2P+Performance 13

14. Data Networks Set of interconnected nodes exchange information
sharing of the transmission circuits= "switching".
many links allow more than one path between every 2 nodes.
network must select an appropriate path for each required connection.
H. Levy P2P+Performance

15. Real Network
H. Levy P2P+Performance

16. Peer to Peer – what is it?
“Historical” Internet : send data from A to K.
Client-server model:
A = server = data source
K = client data consumer
If C wants too – get from A (unicast or broadcast)
H. Levy P2P+Performance

17. Peer to Peer – what is it A (source) sends to K.
K (client) may become now a server.
K sends to C (another client).
H. Levy P2P+Performance

18. Peer to Peer – what the diff?K A
Client (user)
Server
Private
Commercial
“Cost free”
Costs
“contributes”
Charges
Legal??
Legal obligations
H. Levy P2P+Performance

19. Peer to Peer – what the diff?K A
Huge number
Small number
Non reliable
Reliable
unplanned
planned
Huge traffic
80%!!!!
H. Levy P2P+Performance

20. Peer to Peer – How important
0% of costs
O(0)% of revenues
0% of planning
 “Nothing”
BUT: 80% of traffic
 cannot disregard…
 If you can’t beat them, join them…
H. Levy P2P+Performance

21. Peer to Peer – Historical View
Networks developed for 40+ years
Internet – started developing late 70’s early 80’s
Distributed, Semi Organized
ATM – developed throughout the 90’s
huge amount of money!!!
Very well organized network
“failed”
P2P – started in the 00’s
VERY unorganized
80% of traffic (though SMALL % of money)
H. Levy P2P+Performance

22. Theory Many network models – based on stochastic modeling
Queueing systems
Stochastic processes
P2P models – included
Objective: study basic stochastic / queueing models
Elementary Queueing theory
H. Levy P2P+Performance