Frame length value is supposed to be the following:
unsigned int frame_length; /* Original length of packet before
Note: For a layer 2 header_protocol,
length is total number of octets
of data received on the network
(excluding framing bits but
including FCS octets).
Hardware limitations may
prevent an exact reporting
of the underlying frame length,
but an agent should attempt to
be as accurate as possible. Any
octets added to the frame_length
to compensate for encapsulations
removed by the underlying hardware
must also be added to the stripped
You can see that “Frame length” is still at 146.
You’ll also notice the small payload size of 80 bytes, during this test I was uploading at 6 MB/s, but every flow received had the same payload size, so the end result was wrong. But this might be a different issue altogether.
Going back to the “Frame length = 146”, I have further experimented since then. I have tried reducing the size of the UDP datagrams to 1000 and 100, here are the PCAP results:
Frame length seems to be stuck at the value 146 whatever the length of the packet.
Here is my config:
set system flow-accounting disable-imt
set system flow-accounting buffer-size 64
set system flow-accounting enable-egress
set system flow-accounting interface eth0
set system flow-accounting sflow agent-address xxxxxx.217
set system flow-accounting sflow sampling-rate 64
set system flow-accounting sflow server xxxxxx.221