SDN

Key Features

1. Network Topology Awareness: The controller requires knowledge of all host addresses in the network. Lack of this information leads to packet drops.
2. Static Network Support: The network to be managed should not involve adding or removing switches.
3. Traffic Management: Manages TCP/UDP traffic, primarily focusing on routing new incoming packets to switches.
4. Path Search: Implements a lowest-cost path search for routing packets.
5. Flow Control: Blocks flows on links with excessive active flows by setting a limit. Links between switches and hosts are exempt from this limitation.
6. Rule Management: Inactive flows are deleted from links upon rule timeout expiry, thus freeing up the link in the virtual graph.

Primary Objective

• Generates TCP/UDP connections between client and server, reaching the flow limit on a link, which is then blocked. New flows are routed via alternative paths.
• Connections between switches and hosts are excluded from these operations.

Secondary Objective

• Once flows on the primary path complete, routing rules are removed post-timeout, reactivating the link.
• Demonstrates link reactivation by generating new TCP/UDP flow.

Automated Testing

• Initial pingall for MAC address discovery and ARP table population.
• Creation of two servers (UDP h2 and TCP h3) and establishment of three connections:
  • h5 to h2 (UDP, 100 seconds)
  • h6 to h3 (TCP, 100 seconds, with ACK response flow)
  • h4 to h2 (UDP, 100 seconds)
• Observing the active flow limit on link s2-s3 and routing behavior.
• A sleep action for 20 seconds followed by a new UDP stream from h4 to h2, demonstrating reactivation of the s2-s3 link.
• Limited bandwidth for clearer InMon mininet dashboard (Sflow) graphs.

This project was a joint effort with my colleagues Manuele Montrasio and Luigi Borroni, we worked together on developing code, analyzing data, and generating visual aids to support our results.