Choose Layer when:
- You need maximum throughput and minimum latency
- All backend servers can handle any request type
- You don't need content-based routing decisions
Choose Layer when:
- Different URLs need different server pools
- You need SSL termination at the load balancer
- You want to inject headers or modify requests
- You need sticky sessions based on cookies
Many architectures use both: Layer at the edge for raw speed, Layer behind it for smart routing.