As a trading firm that cares about low latency networking, Optiver has been working a lot with switches that can do cut through processing. On larger packets the difference between processing a packet in cut through vs store and forward mode can be more than a microsecond difference. Since a single microsecond can make or break a trade, we lean towards cut through processing naturally.

However, loads have been increasing on our networks. Congestion and temporary buffering can quickly eliminate a one microsecond advantage. Hence, it would be interesting to reevaluate our bias towards cut through processing.

We will take two leading switch brands and see how their switches handle store and forward and cut through processing. For example, what will happen when two flows collide? Are packets buffered at ingress or egress?

We will explore the typical use cases for both mechanisms and see where in our network we should ideally use what packet processing mechanism.