Efficient Multi-WAN Transport for 5G with OTTER

In the ongoing cloudification of 5G, software network functions (NFs) are replacing fixed-function network hardware, allowing 5G network operators to leverage the benefits of cloud computing. The migration of NFs and their management to the cloud causes 5G traffic to traverse an operator's wide-area network (WAN) to the cloud WAN that hosts the datacenters (DCs) running 5G NFs and applications. However, achieving end-to-end performance for 5G traffic across two WANs is hard. Placing 5G flows across two WANs with different performance and reliability characteristics, edge and DC resource constraints, and interference from other flows is different and more challenging than single-WAN traffic engineering. We address this challenge and show that orchestrating paths across a multi-WAN overlay 1 allows us to achieve average 13% more throughput, 15% less RTT, 45% less jitter, or reduce average loss from 0.06% to under 0.001%. We implement our multi-WAN 5G flow placement in a scalable optimization prototype that allocates 26%-45% more bytes on the network than greedy baselines while also satisfying the service demands of more flows.