snappi-trex 0.0.71

The T-Rex Open Traffic Generator Python Package

Snappi-Trex

Snappi-Trex is a Snappi plugin that allows executing scripts written using Snappi with Cisco's T-Rex Traffic Generator

Installing Snappi-Trex

First, make sure that Snappi is installed.

pip3 install snappi

Now, install the snappi_trex extension.

pip3 install snappi_trex

Installing and Running T-Rex

For a quick tutorial on T-Rex installation, running, and basic usage, check out my T-Rex Tutorial

Start Scripting

import snappi


def hello_snappi():
    """
    This script does following:
    - Send 1000 packets back and forth between the two ports at a rate of
      1000 packets per second.
    """
    # create a new API instance where host points to controller
    api = snappi.api(host='https://localhost', ext='trex')
    
    # and an empty traffic configuration to be pushed to controller later on
    cfg = api.config()

    # add two ports where location points to traffic-engine (aka ports)
    p1, p2 = (
        cfg.ports
        .port(name='p1', location='localhost:5555')
        .port(name='p2', location='localhost:5556')
    )

    # add layer 1 property to configure same speed on both ports
    ly = cfg.layer1.layer1(name='ly')[-1]
    ly.port_names = [p1.name, p2.name]
    ly.speed = ly.SPEED_1_GBPS

    # enable packet capture on both ports
    cp = cfg.captures.capture(name='cp')[-1]
    cp.port_names = [p1.name, p2.name]

    # add two traffic flows
    f1, f2 = cfg.flows.flow(name='flow p1->p2').flow(name='flow p2->p1')
    # and assign source and destination ports for each
    f1.tx_rx.port.tx_name, f1.tx_rx.port.rx_name = p1.name, p2.name
    f2.tx_rx.port.tx_name, f2.tx_rx.port.rx_name = p2.name, p1.name

    # configure packet size, rate and duration for both flows
    f1.size.fixed = 128
    f2.size.fixed = 256
    for f in cfg.flows:
        # send 1000 packets and stop
        f.duration.fixed_packets.packets = 1000
        # send 1000 packets per second
        f.rate.pps = 1000

    # configure packet with Ethernet, IPv4 and UDP headers for both flows
    eth1, ip1, udp1 = f1.packet.ethernet().ipv4().udp()
    eth2, ip2, udp2 = f2.packet.ethernet().ipv4().udp()

    # set source and destination MAC addresses
    eth2.src.value, eth2.dst.value = '00:AA:00:00:00:AA', '00:AA:00:00:04:00'
    eth1.src.increment.start = '10:AA:00:00:04:00'
    eth1.src.increment.step = 2
    eth1.src.increment.count = 1000
    eth2.src.values = ['33:33:33:11:11:11', '22:22:22:22:22:22']
    eth1.dst.decrement.start = '10:AA:00:00:04:00'
    eth1.dst.decrement.step = 4
    eth1.dst.decrement.count = 1000

    # set source and destination IPv4 addresses
    ip2.src.value, ip2.dst.value = '10.0.0.2', '10.0.0.1'

    ip1.src.increment.start = '11.0.0.1'
    ip1.src.increment.step = 2
    ip1.src.increment.count = 1000
    ip1.dst.decrement.start = '12.0.0.0'
    ip1.dst.decrement.step = 4
    ip1.dst.decrement.count = 1000

    # set incrementing port numbers as source UDP ports
    udp1.src_port.value = 5000
    udp2.src_port.decrement.start = 5000
    udp2.src_port.decrement.step = 1
    udp2.src_port.decrement.count = 1000

    # assign list of port numbers as destination UDP ports
    udp1.dst_port.values = [8000, 8004, 8049, 9001]
    udp2.dst_port.decrement.start = 5000
    udp2.dst_port.decrement.step = 1
    udp2.dst_port.decrement.count = 1000


    print('Pushing traffic configuration ...')
    api.set_config(cfg)

    print('Starting transmit on all configured flows ...')
    ts = api.transmit_state()
    ts.state = ts.START
    api.set_transmit_state(ts)


if __name__ == '__main__':
    hello_snappi()