Creating VPP Startup Configuration

This document describes how to create the VPP startup configuration file located at /etc/vpp/contiv-vswitch.conf.

Hardware Interface Configuration

Single-NIC Configuration

You need to configure hardware interfaces for use by VPP. First, find out the PCI address of the host’s network interface. On Debian-based distributions, you can use lshw:

sudo lshw -class network -businfo
Bus info          Device      Class          Description
========================================================
pci@0000:03:00.0  ens160      network        VMXNET3 Ethernet Controller

In our case, it would be the ens3 interface with the PCI address 0000:00:03.0

Now, add or modify the VPP startup config file (/etc/vpp/contiv-vswitch.conf) to contain the proper PCI address:

unix {
    nodaemon
    cli-listen /run/vpp/cli.sock
    cli-no-pager
    coredump-size unlimited
    full-coredump
    poll-sleep-usec 100
}
nat {
    endpoint-dependent
}
dpdk {
    dev 0000:00:03.0
}
api-trace {
   on
   nitems 500
}

Multi-NIC Configuration

Similar to the single-NIC configuration, use command lshw to find the PCI addresses of all the NICs in the system, for example:

$ sudo lshw -class network -businfo
Bus info          Device      Class      Description
====================================================
pci@0000:00:03.0  ens3        network    Virtio network device
pci@0000:00:04.0  ens4        network    Virtio network device

In the example above, ens3 would be the primary interface and ens4 would be the interface that would be used by VPP. The PCI address of the ens4 interface would be 0000:00:04.0.

Make sure the selected interface is shut down, otherwise VPP will not grab it:

sudo ip link set ens4 down

Now, add or modify the VPP startup config file in /etc/vpp/contiv-vswitch.conf to contain the proper PCI address:

unix {
    nodaemon
    cli-listen /run/vpp/cli.sock
    cli-no-pager
    coredump-size unlimited
    full-coredump
    poll-sleep-usec 100
}
nat {
    endpoint-dependent
}
dpdk {
    dev 0000:00:04.0
}
api-trace {
   on
   nitems 500
}

If assigning multiple NICs to VPP you will need to include each NIC’s PCI address in the dpdk stanza in /etc/vpp/contiv-vswitch.conf.

Assigning all NICs to VPP

On a multi-NIC node, it is also possible to assign all NICs from the kernel for use by VPP. First, you need to install the STN daemon, as described [here][1], since you will want the NICs to revert to the kernel if VPP crashes.

You also need to configure the NICs in the VPP startup config file in /etc/vpp/contiv-vswitch.conf. For example, to use both the primary and secondary NIC, in a two-NIC node, your VPP startup config file would look something like this:

unix {
    nodaemon
    cli-listen /run/vpp/cli.sock
    cli-no-pager
    coredump-size unlimited
    full-coredump
    poll-sleep-usec 100
}
nat {
    endpoint-dependent
}
dpdk {
    dev 0000:00:03.0
    dev 0000:00:04.0
}
api-trace {
   on
   nitems 500
}

Installing lshw on CentOS/RedHat/Fedora

Note: On CentOS/RedHat/Fedora distributions, lshw may not be available by default, install it by

sudo yum -y install lshw

Power-saving Mode

In regular operation, VPP takes 100% of one CPU core at all times (poll loop). If high performance and low latency is not required you can “slow-down” the poll-loop and drastically reduce CPU utilization by adding the following stanza to the unix section of the VPP startup config file:

unix {
    ...
    poll-sleep-usec 100
    ...
}

The power-saving mode is especially useful in VM-based development environments running on laptops or less powerful servers.

VPP API Trace

To troubleshoot VPP configuration issues in production environments, it is strongly recommended to configure VPP API trace. This is done by adding the following stanza to the VPP startup config file:

api-trace {
    on
    nitems 500
}

You can set the size of the trace buffer with the attribute.