# Kernel UDP buffer tuning for Ouster + CycloneDDS on Ubuntu 22.04 + ROS 2 Humble.
#
# Place this file at /etc/sysctl.d/10-cyclone-max.conf and reload with:
#     sudo sysctl -p /etc/sysctl.d/10-cyclone-max.conf
#
# These settings persist across reboots (loaded by systemd at boot time).
#
# See: https://github.com/BENKRID-abdenour/Ouster_Driver_CycloneDDS_Ubuntu_22.04_ROS2_Humble

# Maximum receive buffer size (2 GB) requested by CycloneDDS from the kernel.
net.core.rmem_max=2147483647

# Default receive buffer size for new UDP sockets.
net.core.rmem_default=2147483647

# Maximum time (in seconds) a partial IP fragment is kept in the reassembly
# queue. Default is 30 s; reducing to 3 s avoids accumulation under bursty load.
net.ipv4.ipfrag_time=3

# Maximum memory used for IP fragment reassembly (128 MB).
# Critical for fragmented point clouds emitted by dense LiDARs such as OS0-128.
net.ipv4.ipfrag_high_thresh=134217728