Which version of DOCSIS allows for an increased upstream frequency of up to 85 MHz?

The version of DOCSIS that allows for an increased upstream frequency of up to 85 MHz is DOCSIS 3.0. This version introduced significant enhancements over its predecessors, particularly in terms of upstream capacity. While earlier versions, such as DOCSIS 1.0 and 2.0, supported upstream channels with a range up to 30 MHz, DOCSIS 3.0 expanded that capability, making it possible to utilize higher frequencies for upstream data.

DOCSIS 3.0 also introduced the concept of channel bonding, which combined multiple channels to increase potential bandwidth, further improving the performance of broadband services. Thus, the ability to support higher upstream frequencies was a key advancement, allowing for better upload speeds which are increasingly important in today’s internet usage scenarios.

In contrast, while DOCSIS 3.1 brought improvements such as higher overall capacity and enhanced spectrum efficiency, it does not primarily focus on just the upstream frequency increase but rather on overall advanced capabilities. Therefore, recognizing DOCSIS 3.0's specific feature of supporting upstream frequencies up to 85 MHz highlights its importance in the evolution of broadband technology.