Virtualized Network Topologies using P4
This repository contains the P4 implementation for the virntup (without the 4) project. You can find more information about the project there.
The P4 program in this repository allows to emulate many routers (vRouters) on a single P4 Target. Each vRouter can be assigned to each switch port and has its own routing table. The implementation is very basic as virntup is a proof of concept and is not meant for production use.
You can find the P4Runtime client which is used to configure the tables automatically here.
The P4 implementation is very straight forward. We first need to find out which vRouter should be consulted if a packet arrives on port x. Hence we apply the vRouterNumberMatching table. If we found a vRouter, we set the vRouterNumber for the current packet. If not we drop the packet.
Next we apply the ipv4NextHopLPM table, which matches on the vRouterNumber and does LPM as usual. If the table conains a matching entry, we call the ipv4Forwar action, if not, we drop the packet.
Thats it! Simple right?