Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:Throughput-sensitive flows were represented by TCP flows carrying a delay hint of 80 ms. Delay-sensitive flows were represented by TFRC [3] flows carrying a delay hint of 32 ms.
 Analyzing throughput and delay alone is not sufficient as application performance realistically involves tradeoffs between throughput and delay.
Category: