flowlabel_state_ranges

file: /proc/sys/net/ipv6/flowlabel_state_ranges
variable: net.ipv6.flowlabel_state_ranges
Official reference

Split the flow label number space into two ranges. 0-0x7FFFF is reserved for the IPv6 flow manager facility, 0x80000-0xFFFFF is reserved for stateless flow labels as described in RFC6437. TRUE: enabled FALSE: disabled Default: true

source