What does it take to actually bring a zk-enabled, post-quantum Ethereum network to life? In this episode (5/6 of the Lean Ethereum series), Raúl and Will from the @ethereumfndn shift focus from primitives to system integration: networking, coordination, and client interoperability. The discussion centers on how post-quantum signatures and zk-based aggregation impact the networking layer and end-to-end protocol design. They cover: – Why post-quantum signatures introduce non-trivial constraints due to size, requiring redesign of propagation, aggregation, and bandwidth utilization – The role of DevNets as iterative integration environments: from basic interoperability → signature generation → aggregation → recursive composition – Networking constraints under EIP-7870: bounded bandwidth, latency sensitivity, and the need to optimize for “goodput” rather than raw throughput – Transition from bursty gossip-based propagation to continuous pipelined data flow, where signatures are incrementally aggregated across network topologies – Trade-offs in topology design: subnets, hierarchical aggregation, redundancy, and adversarial considerations (e.g. avoiding identifiable aggregation points) – ETH P2P as a purpose-built networking stack, replacing generic libp2p components with mechanisms such as erasure-coded broadcast and structured routing – Coordination across layers: cryptography, client implementation, networking, and metrics, with shared observability to evaluate latency, duplication, and finality convergence Watch the full episode