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Networks

Version 16.1 by Zenna Elfen on 2025/11/24 11:58
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This page contains an overview of all P4P Networks in this wiki and their building blocks.

You can also add a P4P Network or have a look at the P4P Applications.

Building Blocks of P4P Networks

To fully assemble a P4P network one needs a few different building blocks, below is an overview of 15 of those building blocks. Lost in translation? Take a look at the terminology.

1. Data Synchronization

 Synchronization answers how updates flow between peers and how they determine what data to exchange. This layer is about diffing, reconciliation, order, causality tracking, and efficient exchange, not persistence or user-facing collaboration semantics.

  • How do peers detect differences and synchronize state?
  • Examples: Range-Based Set Reconciliation, RIBLT, Gossip-based sync, State-based vs op-based sync, Lamport/Vector/HLC clocks, Braid Protocol

2. Collaborative Data Structures & Conflict Resolution

 This layer defines how shared data evolves when multiple peers edit concurrently. It focuses on conflict-free merging, causality, and consistency of meaning, not transport or storage. CRDTs ensure deterministic convergence, while event-sourced or stream-driven models maintain a history of all changes and derive consistent state from it.

  • How do peers collaboratively change shared data and merge conflicts?
  • Examples: CRDTs (Yjs, Automerge), OT, Event Sourcing, Stream Processing, Version Vectors, Peritext

3. Data Storage & Replication

 This layer focuses on durability, consistency, and redundancy. It handles write-paths, crash-resilience, and replication semantics across nodes. It is the “database/storage engine” layer where data lives and survives over time, independent of sync or merging logic.

  • How is data persisted locally and replicated between peers?
  • Examples: SQLite, IndexedDB, LMDB, Hypercore (append-only logs), WALs, Merkle-DAGs (IPFS/IPLD), Blob/media storage

4. Peer & Content Discovery

 Discovery occurs in two phases:
 1. Peer Discovery → finding _any_ nodes
 2. Topic Discovery → finding _relevant_ nodes or resources
 These mechanisms enable decentralized bootstrapping and interest-based overlays.

  • How do peers find each other, and how do they discover content in the network?
  • Examples: DHTs (Kademlia, Pastry), mDNS, DNS-SD, Bluetooth scanning, QR bootstrapping, static peer lists, Interest-based routing, PubSub discovery (libp2p), Rendezvous protocols

5. Identity & Trust

 Identity systems ensure reliable mapping between peers and cryptographic keys.  They underpin authorization, federated trust, and secure overlays.

  • How peers identify themselves, authenticate, and establish trustworthy relationships?
  • Examples: PKI, Distributed Identities (DIDs), Web-of-Trust, TOFU (SSH-style), Verifiable Credentials (VCs), Peer key fingerprints (libp2p PeerIDs), Key transparency logs

6. Transport Layer

 This layer provides logical connections and flow control. QUIC and WebRTC bring modern congestion control and encryption defaults; Interpeer explores transport beyond IP assumptions.

  • How do peers establish end-to-end byte streams and reliable delivery?
  • Examples: TCP, UDP, QUIC, SCTP, WebRTC DataChannels, Interpeer transport stack

7. Underlying Transport (Physical/Link Layer)

 Highly relevant for offline-first / edge networks, device-to-device communication, and mesh networks and relates to the hardware which facilitates connections.

  • How does data move across the medium?
  • Examples: Ethernet, Wi-Fi Direct / Wi-Fi Aware (post-AWDL), Bluetooth Mesh, LoRa, NFC, Cellular, CSMA/CA, TDMA, FHSS

8. Session & Connection Management

 Manages connection lifecycle, including authentication handshakes, reconnection after drops, and session continuation—especially important in lossy or mobile networks.

  • How are connections initiated, authenticated, resumed, and kept alive?
  • Examples: TLS handshake semantics, Noise IK/XX patterns, session tokens, keep-alive heartbeats, reconnection strategies, session resumption tickets

9. Content Addressing

 Content addressing ensures immutability, verifiability, and deduplication. Identity of data = cryptographic hash, enabling offline-first and tamper-evident systems.

  • How is data addressed and verified by content, not location?
  • Examples: IPFS CIDs, BitTorrent infohashes, Git hashes, SHA-256 addressing, Named Data Networking (NDN)

10. P2P Connectivity

 Connectivity ensures peers bypass NATs/firewalls to reach each other.  

  • How can two peers connect directly across networks, firewalls, and NATs?
  • Examples: IPv6 direct, NAT Traversal, STUN, TURN, ICE (used in WebRTC), UDP hole punching, UPnP

11. Session & Connection Management

 Manages connection lifecycle, including authentication handshakes, reconnection after drops, and session continuation.

  • How are connections initiated, authenticated, resumed, and kept alive?
  • Examples: TLS handshake semantics, Noise IK/XX patterns, session tokens, keep-alive heartbeats, reconnection strategies, session resumption tickets

12. Message Format & Serialization

 Serialization ensures portable data representation, forward-compatible schemas, and efficient messaging. IPLD provides content-addressed structuring for P2P graph data.

  • How is data encoded, structured, and made interoperable between peers?
  • Examples: CBOR, Protocol Buffers, Cap’n Proto, JSON, ASN.1, IPLD schemas, Flatbuffers

13. File / Blob Synchronization

 Bulk data syncing has different trade-offs than small collaborative state (chunking, deduplication, partial transfer, resume logic). Critical for media and archival P2P use-cases.

How are large objects transferred and deduplicated efficiently across peers?
Examples: BitTorrent chunking, IPFS block-store, NDN segments, rsync-style delta sync, ZFS send-receive, streaming blob transfers

14. Local Storage & Processing Primitives

 Provides durable on-device state and local computation (event sourcing, materialization, compaction). Enables offline-first writes and deterministic replay.

  • How do nodes persist, index, and process data locally—without external servers?
  • Examples: RocksDB, LevelDB, SQLite, LMDB, local WALs/append-only logs, embedded stream processors (NATS Core JetStream mode, Actyx-like edge runtimes), Kafka-like libraries

15. Crash Resilience & Abortability

 Ensures P2P apps don’t corrupt state on crashes. Tied to local storage & stream-processing, and critical in offline-first and distributed update pipelines. Abortability is the updated term for Atomicity as part of the ACID abbreviation. 

  • How do nodes recover and maintain correctness under failure?
  • Examples: WALs, idempotent ops, partial log replay, transactional journaling, write fences

Distributed Network Types

Flowchart depicting typologies of distributed networks, such as Friend-2-Friend, Grassroots Networks, Federated Networks, Local-First, P2P and P4P Networks

Flowchart depicting distributed network variants, under development. Building on work from Z. Elfen, 2024: https://doi.org/10.17613/naj7d-6g984

Overview of P4P Networks

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