W4 Lecture Part I (Network Calculus)

1. Computer Networks Lecture Week 4 (Part I)

Performance Evaluation Techniques
Artem Burmyakov
February 13, 2026

2.

[Recap]
Client-Server
Peer-to-Peer
Server →
Clients
Peer
2

3.

[Recap]
Client-Server
Peer-to-Peer
Server →
Clients
Peer
Node types
- Clients (active)
- Server (centralized, passive)
Peers running both
client and server processes
3

4.

[Recap]
Client-Server
Peer-to-Peer
Server →
Clients
Peer
Node types
- Clients (active)
- Server (centralized, passive)
Efficiency for
increasing
peers’ number
Decreases
Peers running both
client and server processes
Increases
4

5.

[Recap]
Client-Server
Peer-to-Peer
Server →
Clients
Peer
Node types
- Clients (active)
- Server (centralized, passive)
Peers running both
client and server processes
Efficiency
Decreases with the number of clients
Increases with the number of peers
Robustness
A single point of failure – server
Very robust, no single point of failure
Cost
Requires a high-performing server
No significant direct expenses
Complexity
Simpler
More complex, distributed algorithms
needed
Usage
Dominant
Less used
5

6.

Comparison: Client-Server vs. Peer-to-Peer Architecture for Network Applications
Peer
Server
Clients
Peer
Most of the existing applications
BitTorrent – file-sharing
Bitcoin, Filecoin – decentralized digital currencies
Open Garden – mobile internet connection sharing
Others
Skype – probably hybrid (?)
9

7.

Networks Calculus Basics
Server
Clients
1
N
2
…
13

8.

Networks Calculus Basics
Performance Metrics
Server