Abstract

This document updates the Static Context Header Compression (SCHC) and fragmentation protocol (RFC 8724) and the corresponding YANG module (RFC 9363). It defines a SCHC Compound Acknowledgement (ACK) message format and procedure, which are intended to reduce the number of response transmissions (i.e., SCHC ACKs) in the ACK-on-Error Mode, by accumulating bitmaps of several windows in a single SCHC message (i.e., the SCHC Compound ACK). Both the message format and procedure are generic, so they can be used, for instance, by any of the four Low-Power Wide Area Network (LPWAN) technologies defined in RFC 8376, which are Sigfox, Long Range Wide Area Network (LoRaWAN), Narrowband Internet of Things (NB-IoT), and IEEE 802.15.4w.