  Packet fragmentation has mostly been addressed in the literature when
referring to splitting data that does not fit a frame. It has received
attention in the IoT community after the 6LoWPAN working group of IETF started
studying the fragmentation headers to allow IPv6 1280 B MTU to be sent over
IEEE 802.15.4 networks supporting a 127 B MTU. In this paper, and following
some of the recent directions taken by the IETF LPWAN WG, an analysis of packet
fragmentation in LPWANs has been done. We aim to identify the impact of sending
the data in smaller fragments considering the restrictions of industrial
duty-cycled networks. The analyzed parameters were the energy consumption,
throughput, goodput and end to end delay introduced by fragmentation. The
results of our analysis show that packet fragmentation can increase the
reliability of the communication in duty-cycle restricted networks. This is of
especial relevance when densifying the network. We observed relevant impact in
energy consumption and extra latency, and identified the need for
acknowledgements from the gateway/sink to exploit some of the benefits raised
by fragmentation.
