Example 03: packet I/O

Subscribes to PacketIn messages and prints each packet's ingress port and payload. With --send-port, it sends a 60-byte Ethernet frame at startup, including both egress_port and zero _pad metadata.

Use Go 1.26 or newer and run commands from the repository root. Start BMv2 with ./scripts/run-bmv2.sh, which compiles the L2 files, then run example 02 to install the pipeline. The command below sends to port 1, so bind a host-facing interface to that port. See the fixture guide and script requirements.

For an existing target, compile the L2 files with ./scripts/compile-l2.sh and install that pair first. CPU loopback uses --send-port 255 and works through the gRPC connection.

Run

go run ./examples/03_packetio \
    --addr 127.0.0.1:9559 \
    --p4info ./examples/testdata/l2.p4info.txt \
    --send-port 1

Use Ctrl+C to exit.

Send an Ethernet frame with a destination absent from MyIngress.t_l2 to a bound data port. The example prints a PacketIn with that ingress port and the original Ethernet frame, without the control header. Frames that match the table are forwarded to their configured data port.

Example 03: packet I/O ​

Run ​

Example 03: packet I/O

Run