Network Slicing in SDN

Next Generation Networks, A.Y. 2025/2026 Mirko Lana, Mattia Zagatti

An SDN network slicing controller built on Kathara and os-ken. It reserves bandwidth on a multi-link topology, preempts lower-priority flows when capacity is tight, and reroutes around failures, all driven through an interactive web dashboard.

Architecture

graph TB
  subgraph "Control Plane"
    C[controller.py]
    R[routing.py]
    A[admission.py]
    S[state.py]
  end

  subgraph "Data Plane"
    T[topology.py]
    K[Kathara Lab]
  end

  subgraph "User Interface"
    D[dashboard.py]
    CLI[client.py]
  end

  CLI --> C
  D --> S
  C --> A
  C --> R
  C --> S
  C --> T
  T --> K

• state.py tracks flows and residual capacity. Only mutator.
• routing.py widest-path and shortest-path algorithms.
• admission.py decides admit, reject, or preempt. Never mutates state.
• controller.py translates decisions into OpenFlow flow mods.
• dashboard.py live web UI on port 8080.

Features

• Widest-path routing: selects the path with highest bottleneck residual capacity.
• Priority-based preemption: higher-priority flows can reclaim capacity from lower-priority ones.
• TTL-based resource release: flows expire automatically.
• Reactive rerouting: reroutes victims after link failure or preemption.
• Interactive dashboard: real-time network view at http://127.0.0.1:8080.
• iperf3 validation: throughput measurements with and without admission control.

Quick Start

# requires Python 3.11 (pyenv or Homebrew)
./setup.sh

# start controller + deploy lab
.venv/bin/python -m netslice.topology start

# open dashboard
open http://127.0.0.1:8080

# stop everything
.venv/bin/python -m netslice.topology stop

Client CLI

.venv/bin/python -m netslice.client add h1 h4 5 --priority 2
.venv/bin/python -m netslice.client flows
.venv/bin/python -m netslice.client links
.venv/bin/python -m netslice.client remove f3

Demos

# run all five
.venv/bin/python -m netslice.demo

# run specific demo
.venv/bin/python -m netslice.demo 3

# list available demos
.venv/bin/python -m netslice.demo list

#	Demo	What it shows
1	Admission control	admit/reject based on residual capacity
2	Widest path	path selection with max-bottleneck
3	Preemption	low-priority flow replaced by high-priority
4	TTL expiry	automatic resource release
5	Rerouting	victim flows rerouted after failure

Tech Stack

Component	Technology
Network emulator	Kathara 3.8.3
Controller	os-ken 4.2.1 (OpenFlow 1.3)
Language	Python 3.11
Traffic gen	iperf3
Topology shaping	tc (traffic control)