libp2p
Origin:
composes: an existing, widely-used networking library Solidus adopts as-is. Solidus status:shipped, carries all peer-to-peer traffic on the live public testnet today.
libp2p is a toolkit of networking building blocks for peer-to-peer systems, how nodes find each other, how they open secure connections, and how they broadcast or route messages, all without a central server. Rather than one monolithic protocol, it's a set of composable pieces: a gossip-based publish/subscribe system (gossipsub) for broadcasting messages efficiently across a large mesh of peers, a distributed hash table (Kademlia) for peer discovery, and various transport and connection-security modules. Any project can pick the pieces it needs.
Where it comes from
libp2p started as the networking layer extracted from IPFS and has since been maintained as its own project by Protocol Labs and an open community, independent of any single blockchain. It's now widely reused: Ethereum's post-Merge consensus clients (Prysm, Lighthouse, Teku and others) run on libp2p, as does Filecoin and Polkadot's networking layer. Solidus is one more adopter among many: it did not write a competing stack.
What Solidus uses it for
Every peer-to-peer message on the Solidus testnet, new blocks, new transactions, consensus votes, peer discovery, travels over libp2p. Different message types use different libp2p modules deliberately: block and transaction propagation uses gossipsub (efficient for messages that genuinely need to reach everyone); consensus votes and timeout messages travel point-to-point via request-response (a validator collecting votes for a quorum certificate only needs replies from its own committee, so broadcasting to the whole network would be wasted bandwidth); and new nodes find peers first through a small set of hardcoded bootstrap addresses, then through libp2p's Kademlia distributed hash table for everything after.
Check it yourself
The public solidusnetwork/protocol repository's networking crate depends on libp2p directly, and its transport/message-routing configuration is visible in source, no running node required to check it.
Related terms: HotStuff · Committee Election · Finality
Where it comes from
Someone else specified this. Solidus assembles it.
libp2p is a modular peer-to-peer networking stack originally extracted from IPFS and maintained by Protocol Labs together with an open community of contributors. It also underpins Ethereum's consensus-layer clients, Filecoin, and Polkadot, among others. Solidus did not write its own networking stack: it uses libp2p as-is for transport, and layers its own consensus messages (block/transaction gossip, votes, timeout certificates) on top of libp2p's existing modules.
How to check this
Running in production today.
The public solidusnetwork/protocol repository's networking crate depends on and configures libp2p directly. A stranger can inspect the dependency and the transport wiring without running a node.