[dpdk-users] Weird phenomenon involving KNI

DoHyung Kim dohyung.kim at fluidic.io
Mon Dec 31 10:42:40 CET 2018

I'm on the latest revision of 17.11 w/ a 2-port Intel X540 NIC. And having
some trouble. one of the 2 ports is bound to a uio_pci_generic, and a KNI
interface is up and assigned the MAC address of the port and an IP address,
while the other port is kept intact bound to the kernel.

Initially the 2 ports are known by their own IP addresses. But a few dozen
seconds later, the latter port begins to report via ARP it has the IP
address originally assigned to the KNI interface. So my DPDK app doesn't
receive any of packets sent to the IP address assigned to the KNI interface.

If I set the latter port down w/ ifdown and start my DPDK app, then my app
receives packets as intended. But when I set the normal port up again, then
it doesn't receive any packet since, this time, the KNI announces via ARP
it has the IP address of the other port too.

I searched for solution in DPDK mailing lists for this problem, but instead
found a few posts mentioning KNI will be replaced w/ something else. But it
seems that it's still gaining functionalities over the releases. So I'm

Please inform me of any clue for solving the problem described above. Or
should I fallback to something more stable like TAP driver?

Thanks in advance.

DoHyung Kim
Fluidic Inc.

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