+ --vdev net_af_xdp,iface=ens786f1
+
+Limitations
+-----------
+
+- **MTU**
+
+ The MTU of the AF_XDP PMD is limited due to the XDP requirement of one packet
+ per page. In the PMD we report the maximum MTU for zero copy to be equal
+ to the page size less the frame overhead introduced by AF_XDP (XDP HR = 256)
+ and DPDK (frame headroom = 320). With a 4K page size this works out at 3520.
+ However in practice this value may be even smaller, due to differences between
+ the supported RX buffer sizes of the underlying kernel netdev driver.
+
+ For example, the largest RX buffer size supported by the underlying kernel driver
+ which is less than the page size (4096B) may be 3072B. In this case, the maximum
+ MTU value will be at most 3072, but likely even smaller than this, once relevant
+ headers are accounted for eg. Ethernet and VLAN.
+
+ To determine the actual maximum MTU value of the interface you are using with the
+ AF_XDP PMD, consult the documentation for the kernel driver.
+
+ Note: The AF_XDP PMD will fail to initialise if an MTU which violates the driver's
+ conditions as above is set prior to launching the application.
+
+- **Shared UMEM**
+
+ The sharing of UMEM is only supported for AF_XDP sockets with unique contexts.
+ The context refers to the netdev,qid tuple.
+
+ The following combination will fail:
+
+ .. code-block:: console
+
+ --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+ --vdev net_af_xdp1,iface=ens786f1,shared_umem=1 \
+
+ Either of the following however is permitted since either the netdev or qid differs
+ between the two vdevs:
+
+ .. code-block:: console
+
+ --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+ --vdev net_af_xdp1,iface=ens786f1,start_queue=1,shared_umem=1 \
+
+ .. code-block:: console
+
+ --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+ --vdev net_af_xdp1,iface=ens786f2,shared_umem=1 \
\ No newline at end of file