Interface Settings

Global settings

In the Interface settings tab of Global settings, you choose the interface type for monitoring ports.

• MTU greater than 3000 bytes without IP configuration support (DPDK): Allows an MTU greater than 3000 bytes and uses the DPDK user space packet path for the highest capture throughput. Because the kernel stack is bypassed, monitoring ports do not support IP configuration in this mode and are not visible to standard system tools (ip, ethtool, and so on). Choose this when your monitored links use jumbo frames, or when you prioritize maximum throughput.
• MTU up to 3000 bytes with IP configuration support (XDP): Allows IP configuration on monitoring ports and uses the in-kernel XDP fast path. MTU is limited to 3000 bytes; packets longer than 3000 bytes are discarded on receipt. Choose this when you need IP connectivity on the monitoring port (for example, to route encapsulated traffic).

Click Save to apply changes.

Monitoring port settings

In the Interface settings tab of a monitoring port, you can configure the interface, link, and IP settings. Not all configuration options described in this guide are available on all Flowmon appliances.

Only hardware appliances can change link settings. Virtual appliances inherit link settings from the hypervisor. Enable Autonegotiation to let the interface set the speed and duplex automatically.

Depending on the probe appliance type and license type, you may be able to set the MTU (Maximum Transmission Unit) value for the monitoring port.

• Virtual probe appliances support MTU configuration.
• Hardware probe appliances without a PRO license support MTU configuration. By default, the MTU is set to 3000 bytes so that XDP technology can be used for fast packet capture. Increasing the MTU above 3000 bytes results in switching to standard kernel packet capture, which will likely reduce the maximum capture throughput.
• Hardware probe appliances with a PRO license always have the MTU set to the maximum value supported by the network interface card.

The Interface Index value is retrieved by the Collector from the Probe through SNMP and is used in the profile channel filter to select flow data from the specific source interface. Changing this to an incorrect value may disrupt flow data collection. We recommend changing this value during the redeployment of a Probe to set the index value as it was before the redeployment.

Use the Traffic type optimization slider to optimize for Maximum throughput or Burst resistance. This is a trade-off; increasing burst resistance decreases maximum throughput, and the opposite is also true. It is highly sensitive to the type and character of the monitored traffic and should be set per port. The default value is suitable for most appliances and monitored networks. Do not change this setting unless you experience packet loss, and consult Support at the Flowmon Support and Learning Hub.

Monitoring ports support static IPv4 and IPv6 address configuration. Click the slider to enable or disable IPv4 or IPv6 configuration. Click New static route to open a dialog that lets you add an IPv4 or IPv6 static route.

Click Save to apply changes.