[dpdk-users] Too much data being sent with small packet and IXGBE

terry.montague.1980 at btinternet.com terry.montague.1980 at btinternet.com
Mon Sep 10 20:51:09 CEST 2018

Hi there,
I'm trying to send a single IGMP control packet out of an Intel X550 to its connected router.
I've looked at the packet in wireshark and its absolutely fine, the ethernet header, the ip header, the ipchecksum offload and the IGMP payload & checksum - there's nothing wrong with it.
It is 46 bytes formatted and the pkt and data lengths of the allocated buffer are all set to 46 bytes. Its a 46 byte packet - end of!
However....  what comes out of the interface is 60 bytes of data - the 46 bytes I want to send + 14 bytes of zeros.
The 14 bytes is curiously equivalent to the size of an ethernet header, but I just cannot see how it is just being added on to the end of the packet data.
Has anyone else observed this effect , or indeed know what's causing it ?
Many thanks

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