FLOW, the Firewall Latency Optimisation Workshop, took place on the 29th of January at the BT Tower. The presentation exposes the true landscape of latency, looking specifically at the main causes and how they affect actual trading flows for different asset classes. Neglecting latency means giving arbitrage opportunity to the competition, this can result in expensive costs for your business. NET2S have conducted much research in this area, culminating in the publication of our recent paper "The Latency Challenge - Strategies for using Latency as a Competitive Advantage". In this document, firewalls were identified as one of the key causes of latency.