The size and complexity of emerging low-earth orbit (LEO) satellite communications (Satcom) constellations introduce challenges for network traffic engineering. As low latency Satcom connectivity LEO constellations with inter-satellite link (ISL) technology take off, improvements in cost and performance are key to increasing market share. Delivering the best service to customers in this increasingly competitive marketplace is driving operators to consider new technologies to scale-up capacity whilst improving service performance and controlling expenditure. The vision at the heart of all mega-constellation systems is a Very Wide Area Network (VWAN) with low latency that can compete with land-based fibre systems. One area where ISL-enabled mega-constellation systems show promise is delivering lower latency and higher throughput communications over long distances with fewer satellite network gateways, which in turn drives the total cost of ownership of the system down substantially.