Keyun Cheng

Reading Notes: SDN Textbook

Title: Software-Defined-Networks: A Systems Approach (Chapter 4)

Book (SDN): Link

Summary

Introduction to bare-metal switches. I don’t read the low-level technical details.

Details

• Network Processing Unit (NPU)
  • A specialized processor for packet processing
  • Forwarding pipeline + SRAM packet buffers
• Programmable pipeline of packet processing
  • Programmable parser/deparser with P4
  • P4 compiler will allocate the resources to realize the pipeline
• Examples of P4 architecture programs
  • V1Model
  • Tofino
• P4 language
  • Close to C; designed for low-level system codes
  • Headers and metadata, parser, ingress processing, egress processing, deparser (opposite to parser)
• Fixed-function pipelines still dominate the markets
  • Example: OpenFlow-Data Plane Abstraction (OF-DPA)
  • Low-level chip interfaces maybe proprietary (e.g. Broadcom SDK)
• Switch Abstraction Interface (SAI)
  • vendor-defined and communinity-defined logical fixed-function pipelines
  • All vendors can agree on
  • The future trend