Configurable MTU

Getting Started with Napatech Link-Virtualization™ Software

Platform
Napatech SmartNIC
Content Type
Getting Started Guide
Capture Software Version
Link-Virtualization™ Software 4.4

How to change the MTU size

Ports are configured with 1500-byte MTU by default. The MTU size is configurable using the mtu_request attribute. The following example shows how to change the MTU size of an existing port.
ovs-vsctl set int dpdkvp0 mtu_request=9000
This sets the MTU to 9000 bytes on dpdkvp0. This means that IP Packets larger than 9000 bytes are dropped on this port. To see the MTU configuration for all ports, run the following command:
ovs-appctl dpctl/show --statistics
An output example:
...
  port 3: dpdkvp0 (dpdk: configured_rx_queues=1, configured_rxq_descriptors=2048, configured_tx_queues=1, configured_txq_descriptors=2048, lsc_interrupt_mode=false, mtu=9000, requested_rx_queues=1, requested_rxq_descriptors=2048, requested_tx_queues=)
    RX packets:51016171 errors:0 dropped:0 overruns:? frame:?
    TX packets:222058411 errors:0 dropped:0 aborted:? carrier:?
    collisions:?
    RX bytes:4640370096 (4.3 GiB)  TX bytes:90159340830 (84.0 GiB)
...
Note: The MTU refers to the length of the L3 IP packet excluding L2 headers (Ethernet header, VLAN and MPLS) and FCS. The MTU can be configured to a maximum of 9982 bytes.
Note: The MTU can be configured on virtual ports and physical ports.