That seems more of a Trickster Mod specific tweak.
It is more of a network speed tweak which you can read here: http://en.m.wikipedia.org/wiki/TCP_c...ance_algorithm
In simple words, you have to understand what Network Congestion is, and how queues affect how much data is being transmitted. When too much data is being carried in a link or a node, the quality of service would deteriorate. To do Congestion control, it affects how much data is being transmitted through each node systematically. This is rather complicated to explain using simple terms as this is a mathematical formula which processes how much data is being transmitted.
Cubic is used by many default linux kernels. Like CPU governors, these are data transmission governors, and it is best if you use the one better for your TCP/IP connection (Carrier or Wifi)