Keyun Cheng

Reading Notes: SDN Textbook

Title: Software-Defined-Networks: A Systems Approach (Chapter 3)

Book (SDN): Link

Summary

SDN’s basic architecture and open-source software-stack

Details

• Architecture
  • Network OS (network-wide) <-> switch OS (per switch)
    • virtual switch on the host machine. e.g. Open vSwitch (OVS)
    • SmartNIC assists (or replaces) vSwitch for computations
  • use gRPC as the transport protocol from Network OS to Switch OS
• Hardware
  • Switch: Tofino/Tomahawk
• Switch OS
  • Run API calls issued to the switch from Network OS
  • Example: Stratum (Google), also called as Thin Switch OS
• Network OS
  • Configuring and controlling a network of switches
  • Runs off-switch as a logically centralized SDN controller; maintaining a global view of the topology and the state of the network; reflecting the status to Control Apps through the Network APIs
  • Example: Open Network OS (ONOS)
• Leaf-spine Fabric
  • Focus on ONOS-hosted SDN Control Apps. e.g. SD-Fabric
    • SD-Fabric is a suite of Control Apps on Network OS (not a single App)
  • SD-Fabric is also deployed for SD-RAN for cellular networks