FAJITA Tofino Multicaster

This P4 program takes incoming packets, manipulates their source IP address and multicasts them towards the NF, in order to increase the offered load.

You need a Tofino to build and run the fajita_mcast program. The default configuration uses four multicast ports.

To build the code, use the following command:

/path/to/p4_build.sh /path/to/fajita_mcast.p4

fajita_mcast.p4 has been tested on SDE 9.8.0.

Configuration

Change Script Path

The setup.py script assumes that it is executed in /home/tofino/labs/FAJITA-Tofino-Multicast-P4 folder. You can change this folder by changing the script_path variable in setup.py (line 96):

script_path = os.path.join(os.environ['HOME'], "labs", "FAJITA-Tofino-Multicast-P4")

Change Port Numbers

To change the ports in the fajita_mcast program, you need to:

• Change the fajita_mcast.p4 defines:

const PortId_t PKTGEN_PORT = 52;

const PortId_t INPUT_PORT_1 = 188;
const PortId_t INPUT_PORT_2 = 180;
const PortId_t INPUT_PORT_3 = 172;
const PortId_t INPUT_PORT_4 = 164;

• Change the setup*.py files:

MCAST_PORTS = [188, 180, 172, 164]

• Change the run_pd_rpc/setup.py file:

PKTGEN_PORT = 52
MCAST_PORTS = [188, 180, 172, 164]

You then need to recompile the P4 program.

Change the Number of Multicast Copies

By default fajita_mcast will create four copies of each incoming packet. To change the number of copies, change the variable N_MULTICAST in run_pd_rpc/setup.py. If 0 is specified, it will fallback to one copy.

Enable/Disable Recirculation

By default, fajita_mcast has the ENABLE_RECIRCULATION set to 1 in setup.py. This value will create 2xN_MULTICAST copies of each packet, since one of the packet copies is sent to the recirculation port (by default 196 that is the recirculation port of pipe 1). The additional copy will be then multicasted again on the INPUT_PORT_* enabled for recirculation.

You can disable this behaviour by setting ENABLE_RECIRCULATION to 0.