2. ‘vsperf’ Traffic Gen Guide

2.1. Overview

VSPERF supports the following traffic generators:

  • Dummy (DEFAULT): Allows you to use your own external traffic generator.
  • IXIA (IxNet and IxOS)
  • Spirent TestCenter
  • Xena Networks
  • MoonGen

To see the list of traffic gens from the cli:

$ ./vsperf --list-trafficgens

This guide provides the details of how to install and configure the various traffic generators.

2.2. Background Information

The traffic default configuration can be found in tools/pkt_gen/trafficgen/trafficgenhelper.py, and is configured as follows:

    'l2': {
        'framesize': 64,
        'srcmac': '00:00:00:00:00:00',
        'dstmac': '00:00:00:00:00:00',
    'l3': {
        'proto': 'tcp',
        'srcip': '',
        'dstip': '',
    'l4': {
        'srcport': 3000,
        'dstport': 3001,
    'vlan': {
        'enabled': False,
        'id': 0,
        'priority': 0,
        'cfi': 0,

The framesize parameter can be overridden from the configuration files by adding the following to your custom configuration file 10_custom.conf:


OR from the commandline:

$ ./vsperf --test-params "pkt_sizes=x,y" $TESTNAME

You can also modify the traffic transmission duration and the number of tests run by the traffic generator by extending the example commandline above to:

$ ./vsperf --test-params "pkt_sizes=x,y;duration=10;rfc2544_tests=1" $TESTNAME

2.3. Dummy Setup

To select the Dummy generator please add the following to your custom configuration file 10_custom.conf.


OR run vsperf with the --trafficgen argument

$ ./vsperf --trafficgen Dummy $TESTNAME

Where $TESTNAME is the name of the vsperf test you would like to run. This will setup the vSwitch and the VNF (if one is part of your test) print the traffic configuration and prompt you to transmit traffic when the setup is complete.

Please send 'continuous' traffic with the following stream config:
30mS, 90mpps, multistream False
and the following flow config:
    "flow_type": "port",
    "l3": {
        "srcip": "",
        "proto": "tcp",
        "dstip": ""
    "traffic_type": "continuous",
    "multistream": 0,
    "bidir": "True",
    "vlan": {
        "cfi": 0,
        "priority": 0,
        "id": 0,
        "enabled": false
    "frame_rate": 90,
    "l2": {
        "dstport": 3001,
        "srcport": 3000,
        "dstmac": "00:00:00:00:00:00",
        "srcmac": "00:00:00:00:00:00",
        "framesize": 64
What was the result for 'frames tx'?

When your traffic gen has completed traffic transmission and provided the results please input these at the vsperf prompt. vsperf will try to verify the input:

Is '$input_value' correct?

Please answer with y OR n.

VPSERF will ask you for:
  • Result for ‘frames tx’
  • Result for ‘frames rx’
  • Result for ‘min latency’
  • Result for ‘max latency’
  • Result for ‘avg latency’

Finally vsperf will print out the results for your test and generate the appropriate logs and csv files.

2.4. IXIA Setup

2.4.1. On the CentOS 7 system

You need to install IxNetworkTclClient$(VER_NUM)Linux.bin.tgz.

2.4.2. On the IXIA client software system

Find the IxNetwork TCL server app (start -> All Programs -> IXIA -> IxNetwork -> IxNetwork_$(VER_NUM) -> IxNetwork TCL Server)

Right click on IxNetwork TCL Server, select properties - Under shortcut tab in the Target dialogue box make sure there is the argument “-tclport xxxx” where xxxx is your port number (take note of this port number as you will need it for the 10_custom.conf file).


Hit Ok and start the TCL server application

2.4.3. VSPERF configuration

There are several configuration options specific to the IxNetworks traffic generator from IXIA. It is essential to set them correctly, before the VSPERF is executed for the first time.

Detailed description of options follows:

  • TRAFFICGEN_IXNET_MACHINE - IP address of server, where IxNetwork TCL Server is running
  • TRAFFICGEN_IXNET_PORT - PORT, where IxNetwork TCL Server is accepting connections from TCL clients
  • TRAFFICGEN_IXNET_USER - username, which will be used during communication with IxNetwork TCL Server and IXIA chassis
  • TRAFFICGEN_IXIA_HOST - IP address of IXIA traffic generator chassis
  • TRAFFICGEN_IXIA_CARD - identification of card with dedicated ports at IXIA chassis
  • TRAFFICGEN_IXIA_PORT1 - identification of the first dedicated port at TRAFFICGEN_IXIA_CARD at IXIA chassis; VSPERF uses two separated ports for traffic generation. In case of unidirectional traffic, it is essential to correctly connect 1st IXIA port to the 1st NIC at DUT, i.e. to the first PCI handle from WHITELIST_NICS list. Otherwise traffic may not be able to pass through the vSwitch.
  • TRAFFICGEN_IXIA_PORT2 - identification of the second dedicated port at TRAFFICGEN_IXIA_CARD at IXIA chassis; VSPERF uses two separated ports for traffic generation. In case of unidirectional traffic, it is essential to correctly connect 2nd IXIA port to the 2nd NIC at DUT, i.e. to the second PCI handle from WHITELIST_NICS list. Otherwise traffic may not be able to pass through the vSwitch.
  • TRAFFICGEN_IXNET_LIB_PATH - path to the DUT specific installation of IxNetwork TCL API
  • TRAFFICGEN_IXNET_TCL_SCRIPT - name of the TCL script, which VSPERF will use for communication with IXIA TCL server
  • TRAFFICGEN_IXNET_TESTER_RESULT_DIR - folder accessible from IxNetwork TCL server, where test results are stored, e.g. c:/ixia_results; see test-results-share
  • TRAFFICGEN_IXNET_DUT_RESULT_DIR - directory accessible from the DUT, where test results from IxNetwork TCL server are stored, e.g. /mnt/ixia_results; see test-results-share

2.4.4. Test results share

VSPERF is not able to retrieve test results via TCL API directly. Instead, all test results are stored at IxNetwork TCL server. Results are stored at folder defined by TRAFFICGEN_IXNET_TESTER_RESULT_DIR configuration parameter. Content of this folder must be shared (e.g. via samba protocol) between TCL Server and DUT, where VSPERF is executed. VSPERF expects, that test results will be available at directory configured by TRAFFICGEN_IXNET_DUT_RESULT_DIR configuration parameter.

Example of sharing configuration:

  • Create a new folder at IxNetwork TCL server machine, e.g. c:\ixia_results

  • Modify sharing options of ixia_results folder to share it with everybody

  • Create a new directory at DUT, where shared directory with results will be mounted, e.g. /mnt/ixia_results

  • Update your custom VSPERF configuration file as follows:

    TRAFFICGEN_IXNET_DUT_RESULT_DIR = '/mnt/ixia_results'

    Note: It is essential to use slashes ‘/’ also in path configured by TRAFFICGEN_IXNET_TESTER_RESULT_DIR parameter.

  • Install cifs-utils package.

    e.g. at rpm based Linux distribution:

    yum install cifs-utils
  • Mount shared directory, so VSPERF can access test results.

    e.g. by adding new record into /etc/fstab

    mount -t cifs //_TCL_SERVER_IP_OR_FQDN_/ixia_results /mnt/ixia_results
          -o file_mode=0777,dir_mode=0777,nounix

It is recommended to verify, that any new file inserted into c:/ixia_results folder is visible at DUT inside /mnt/ixia_results directory.

2.5. Spirent Setup

Spirent installation files and instructions are available on the Spirent support website at:


Select a version of Spirent TestCenter software to utilize. This example will use Spirent TestCenter v4.57 as an example. Substitute the appropriate version in place of ‘v4.57’ in the examples, below.

2.5.1. On the CentOS 7 System

Download and install the following:

Spirent TestCenter Application, v4.57 for 64-bit Linux Client

2.5.2. Spirent Virtual Deployment Service (VDS)

Spirent VDS is required for both TestCenter hardware and virtual chassis in the vsperf environment. For installation, select the version that matches the Spirent TestCenter Application version. For v4.57, the matching VDS version is 1.0.55. Download either the ova (VMware) or qcow2 (QEMU) image and create a VM with it. Initialize the VM according to Spirent installation instructions.

2.5.3. Using Spirent TestCenter Virtual (STCv)

STCv is available in both ova (VMware) and qcow2 (QEMU) formats. For VMware, download:

Spirent TestCenter Virtual Machine for VMware, v4.57 for Hypervisor - VMware ESX.ESXi

Virtual test port performance is affected by the hypervisor configuration. For best practice results in deploying STCv, the following is suggested:

  • Create a single VM with two test ports rather than two VMs with one port each
  • Set STCv in DPDK mode
  • Give STCv 2*n + 1 cores, where n = the number of ports. For vsperf, cores = 5.
  • Turning off hyperthreading and pinning these cores will improve performance
  • Give STCv 2 GB of RAM

To get the highest performance and accuracy, Spirent TestCenter hardware is recommended. vsperf can run with either stype test ports.

2.5.4. Using STC REST Client

The stcrestclient package provides the stchttp.py ReST API wrapper module. This allows simple function calls, nearly identical to those provided by StcPython.py, to be used to access TestCenter server sessions via the STC ReST API. Basic ReST functionality is provided by the resthttp module, and may be used for writing ReST clients independent of STC.

To use REST interface, follow the instructions in the Project page to install the package. Once installed, the scripts named with ‘rest’ keyword can be used. For example: testcenter-rfc2544-rest.py can be used to run RFC 2544 tests using the REST interface.

2.6. Xena Networks

2.6.1. Installation

Xena Networks traffic generator requires specific files and packages to be installed. It is assumed the user has access to the Xena2544.exe file which must be placed in VSPerf installation location under the tools/pkt_gen/xena folder. Contact Xena Networks for the latest version of this file. The user can also visit www.xenanetworks/downloads to obtain the file with a valid support contract.

Note VSPerf has been fully tested with version v2.43 of Xena2544.exe

To execute the Xena2544.exe file under Linux distributions the mono-complete package must be installed. To install this package follow the instructions below. Further information can be obtained from http://www.mono-project.com/docs/getting-started/install/linux/

rpm --import "http://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF"
yum-config-manager --add-repo http://download.mono-project.com/repo/centos/
yum -y install mono-complete

To prevent gpg errors on future yum installation of packages the mono-project repo should be disabled once installed.

yum-config-manager --disable download.mono-project.com_repo_centos_

2.6.2. Configuration

Connection information for your Xena Chassis must be supplied inside the 10_custom.conf or 03_custom.conf file. The following parameters must be set to allow for proper connections to the chassis.


2.6.3. RFC2544 Throughput Testing

Xena traffic generator testing for rfc2544 throughput can be modified for different behaviors if needed. The default options for the following are optimized for best results.


Each value modifies the behavior of rfc 2544 throughput testing. Refer to your Xena documentation to understand the behavior changes in modifying these values.

2.7. MoonGen

2.7.1. Installation

MoonGen architecture overview and general installation instructions can be found here:


  • Note: Today, MoonGen with VSPERF only supports 10Gbps line speeds.

For VSPerf use, MoonGen should be cloned from here (as opposed to the previously mentioned GitHub):

git clone https://github.com/atheurer/MoonGen

and use the opnfv-stable branch:

git checkout opnfv-stable

VSPerf uses a particular example script under the examples directory within the MoonGen project:


Follow MoonGen set up instructions here:


Note one will need to set up ssh login to not use passwords between the server running MoonGen and the device under test (running the VSPERF test infrastructure). This is because VSPERF on one server uses ‘ssh’ to configure and run MoonGen upon the other server.

One can set up this ssh access by doing the following on both servers:

ssh-keygen -b 2048 -t rsa
ssh-copy-id <other server>

2.7.2. Configuration

Connection information for your Xena Chassis must be supplied inside the 10_custom.conf or 03_custom.conf file. The following parameters must be set to allow for proper connections to the chassis.