ns-3.27 was released on 12 October 2017 and features the following significant changes.
- Carrier Aggregation support was added to the LTE module.
- Native TCP models have been extended to include SACK and LEDBAT models.
- The Wi-Fi module was extended for partial 802.11ax High Efficiency (HE) support, and a new Robust Rate Adaptation Algorithm (RRPAA) rate control has been added.
- The traffic-control module has been reworked, with new support for gathering detailed statistics about the operations of a queue disc, a new multi-queue aware queue disc modelled after the mq qdisc in Linux, and the ability to explicitly trace queue sojourn time.
Finally, the release includes numerous bug fixes and small improvements, listed in the RELEASE_NOTES.