CS143Network Simulator 

Project Presentation

Sean ChoiLiang Wang*Tiffany WangDoris Xin

* Project Manager

Overview

• Written in Python• Multi-threading and task scheduling via SimPy• Routing: 

o Two algorithms: Dijkstra, Floyd Warshall o Routing table updated at specific interval

• TCP Renoo Error Control: Go BACK N o Congestion Control: 

AIMD, Vegas 

Simulator Structure

Input

Performance of Routing Algorithms

* input6.txt

Topology of test network

Performance of Routing Algorithms

Dijkstra, updating every 20 ms

Performance of Routing Algorithms

Dijkstra, updating every 100ms

Performance of Routing Algorithms

Floyd-Warshall, updating every 20 ms

Performance of Routing Algorithms

Floyd-Warshall, updating every 100ms

Network Topology 1 

* input5.txt

VEGAS with ONE FLOWCalculations:

VEGAS with ONE FLOW

VEGAS with ONE FLOW

AIMD with ONE FLOWCalculations:

AIMD with ONE FLOW

AIMD with ONE FLOW

Calculations:

VEGAS with TWO FLOWS at the same time

VEGAS with TWO FLOWS at the same time

VEGAS with TWO FLOWS at the same time

Calculations:

AIMD with TWO FLOWS at the same time

AIMD with TWO FLOWS at the same time

AIMD with TWO FLOWS at the same time

Network Topology 2

VEGAS with THREE FLOWS

Window Size

VEGAS with THREE FLOWS

Receiving Rate

VEGAS with THREE FLOWS

RTT

AIMD with THREE FLOWS

Window Size

AIMD with THREE FLOWS

Receiving Rate

AIMD with THREE FLOWS

RTT

The effect of α on the fairness of Vegas

• Bottleneck Link capacity: 0.5

• Flow: 17 and 18

• Flow 17 state at 5ms

• Flow 18 start at 500ms

α = 0.3 = β Window Size

α = 0.3 = β Throughput

α = 0.3 β=0.5 Window Size

α = 0.3 β=0.5 Throughput

α = 0.5 = β Window Size

α = 0.5 = β Throughput

α = 0.8 = β Window Size

α = 1.1 = β Throughput

α = 0.8 β=1.0 Window Size

α = 0.8 β=1.0 Throughput

When α is larger…(α = 3)

Throughput

Questions?