How would you optimize network performance for a high-traffic web application?

Multi-level optimization: Transport: enable TCP BBR, tune kernel parameters (buffer sizes, backlog), enable TFO. Protocol: HTTP/2 or HTTP/3, connection pooling, gzip/brotli compression. Application: efficient serialization (protobuf), request batching, pagination. Caching: CDN for static, edge caching, browser caching headers. Infrastructure: keep-alive connections, connection reuse, geo-distributed deployment. Monitoring: measure P99 latency, identify bottlenecks (network vs compute). Load testing under realistic conditions. Consider: tradeoffs between latency, throughput, and cost.