In the previous article #003 "Are you P4 compliant ?" we exposed a setup where RARE/freeRouter was controlling BMv2 P4 dataplane called simple_switch_grpc. In this article we replace the open source BMv2 target by a commercial virtual target provided by INTEL/BAREFOOT. As a side note, we will show that this setup can be integrated with real networks. (with inherent software limitations)
Requirement
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Overview
I'm repeating the core message from #003: For those who are not familiar with data plane programming and especially with P4, "P4 is a domain-specific programming language for specifying the behaviour of the dataplanes of network-forwarding elements." (from p4.org) in short it helps you to write a "program specifying how a switch processes packets".
Article objective
In this article we'll using freeRouter setup deployed in #003 and replace bmv2/simple_switch_grpc providing freeRouter P4Lang's dataplane by INTEL BAREFOOT/bf_switchd. Actually the effective dataplane is ensured by INTEL/BAREFOOT virtual bf_switchd model running RARE P4 program called: bf_router.p4.
Diagram
[ #003 ] - Cookbook
In our example we will use the OpenNetworkLinux KVM image (ONL9) this is the recommended build from INTEL/BAREFOOT for SDE-9.2.0.
and we add a bridge network interface to or laptop RJ45 connection.
Verification
Conclusion
In this article you:
- had a demonstration of how to integrate freeRouter into a local area network (Similar to article #002)
- However instead of using pcapInt you are now using a software P4 dataplane from P4lang project: bmv2
- BMv2 simple_switch_grpc target is used an run RARE router.p4
- communication between freeRouter control plane and bmv2 is ensured by pcapInt via veth pair [ veth250 - veth251 ]
- This communication is possible via RARE forwarder.py based on GRPC P4Lang P4Runtime python binding
- In this example the BMv2 P4 switch has only 1 dataplane interface that is bound to enp0s9 VM interface exposed to the local network as a bridged interface
[ #003 ] RARE/FreeRouter-101 - key take-away
- FreeRouter is using UNIX socket in order to forward packet dedicated to control plane + dataplane communication.
This essential paradigm is used to ensure communication between freeRouter and BMv2 P4 dataplane. It is ensured by pcapInt binary from freeRouter net-tools that will bind freeRouter socket (veth251@locathost:22710) to a virtual network interface (veth250@localhost:22709) connected to CPU_PORT 64.
- freeRouter control plane and dataplane communication is enabled by RARE forwarder.py
forwarder.py is a simple python script based on GRPC P4Runtime python library.
freeRouter is doing all the control plane route computation and write/modify/remove message entry via P4Runtime so that P4 entries are created/modified/removed accordingly from P4 tables
- BMv2 target
While BMv2 target is a very good choice for packet processing algorithm validation, it is not an ideal target for production use. We will see in next articles how we can reach a higher rate throughput related required by use cases defined by network operators.