Zakura released the experimental P2Pv2, and the testnet is now running in dual stack

Zakura has announced an experimental network layer P2Pv2 for Zcash nodes, intended to replace the old protocol inherited from Bitcoin. This layer combines high-throughput networking, resource control, and a consensus engine tested for properties, allowing developers to add services without permission. Zakura states that approximately 50,000 transactions per second require each full node to continuously receive about 100MB/s of block data, while the 25-second block of NU7 can carry a maximum of 2MB, with existing network throughput differing by more than a thousand times from this rate. Tachyon can reduce the proof after entering the block, but the network still needs to propagate a large number of individual transactions.

P2Pv2 replaces the protocol stack from about a decade ago with protocols that can be optimized for latency, throughput, or robustness, allowing a secure connection to carry multiple independent services. The transport layer uses its own zakura-quic, based on quinn-proto, utilizing QUIC and TLS 1.3, and authenticating peers with Ed25519 node identity. Related changes remove the dependency on Iroh, allowing nodes to configure socket buffers, flow control windows, timers, and connection admission before the TLS handshake. The new transport directly connects to peer addresses without using relays, external address lookups, automatic port mapping, or QUIC NAT traversal. Nodes sign identities, addresses, protocol scopes, and service IDs, allowing clients to find peers based on specific services.

The independent component zakura-header-chain verifies block headers and retains competing branches in a directed acyclic graph, selecting the best qualified chain. Block synchronization schedules requests based on the delivery rates measured by each peer, and a verified commitment tree is used to skip the reconstruction of Sapling, Orchard, and Ironwood trees for each block. Currently, the Mainnet still defaults to the old P2P stack, while the Testnet and Regtest run dual stacks by default, with the native protocol version being p2p-v2/3. Zakura notes that P2Pv2 still has known denial-of-service risks and has not yet become a hardened trust boundary; production hardening, resource control, and block relay protocols are still in progress.