The Packet Processing Graph
At the core of the FD.io VPP design is the Packet Processing Graph
This makes the software:
Pluggable, easy to understand & extend
Mature graph node architecture
Full control to reorganize the pipeline
Fast, plugins are equal citizens
The FD.io VPP packet processing pipeline is decomposed into a ‘packet processing graph’. This modular approach means that anyone can ‘plugin’ new graph nodes. This makes VPP easily extensible and means that plugins can be customized for specific purposes. VPP is also configurable through it's Low-Level API.
At runtime, the FD.io VPP platform assembles a vector of packets from RX rings, typically up to 256 packets in a single vector. The packet processing graph is then applied, node by node (including plugins) to the entire packet vector. The received packets typically traverse the packet processing graph nodes in the vector, when the network processing represented by each graph node is applied to each packet in turn. Graph nodes are small and modular, and loosely coupled. This makes it easy to introduce new graph nodes and rewire existing graph nodes.
Plugins are shared libraries and are loaded at runtime by VPP. VPP find plugins by searching the plugin path for libraries, and then dynamically loads each one in turn on startup. A plugin can introduce new graph nodes or rearrange the packet processing graph. You can build a plugin completely independently of the FD.io VPP source tree, which means you can treat it as an independent component.
For more on the network stack press next.