Examples described herein relate to a network interface device that includes circuitry to track one or more gaps in received packet sequence numbers using data and circuitry to indicate to a sender of packets non-delivered packets to identify a range of delivered packets. In some examples, the data identifies delivered packets and undelivered packets for one or more connections. In some examples, to indicate to a sender of packets non-delivered packets to identify a range of delivered packets, the circuitry is to provide negative acknowledgement sequence range indicating a start and end of non-delivered packets.