1.1.7 Networking

The following notable networking features are implemented in Unbreakable Enterprise Kernel Release 5:

  • TCP-BBR available.  UEK R5 makes available TCP-BBR, a feature that can be used to achieve higher bandwidth and lower latency for internet traffic to offer significant performance improvements for internet based applications. BBR (Bottleneck Bandwidth and Round-Trip Time) is a scheduling algorithm that helps to control the transmit rate of the TCP protocol to reduce buffering by monitoring round trip times against bandwidth bottlenecks to reduce TCP congestion. The TCP-BBR algorithm is not enabled by default in UEK R5 and the default TCP congestion control algorithm is set to cubic.

  • net.ipv4.tcp_tw_recycle removed.  The tcp_tw_recycle option, for IPv4 connections, is removed from UEK R5. This option was removed from the upstream Linux kernel in version 4.12. The option caused issued for load-balanced connections or connections that made use of network address translation. After the randomization of TCP timestamp offsets, the option created issues with all TCP connections and became non-functional. Its removal is equivalent to setting net.ipv4.tcp_tw_recycle to 0, which was the default configuration on previous kernel generations.