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Version 55.1 by Zenna Elfen on 2026/01/05 20:27

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5 = Building Blocks of P4P Networks =
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Zenna Elfen 51.1 7 Making a P4P network is a bit different than traditional communication networks, namely because we side-step the traditional confinement of the internet layers and connect in a variety of means, from bluetooth to sneakernet and beyond. This is of course very nice in a variety of circumstances and to read more about the principles and capabilities of P4P networks, see the about page.
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Zenna Elfen 55.1 9 To fully assemble a P4P network one needs a few different building blocks, below is an overview of 15 of those building blocks. This outline of 15 building blocks has been collaboratively developed. If you see something missing or would like to give feedback, please reach out to Zenna. Now, let's dive into the building-blocks which make P4P protocols. 
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Zenna Elfen 52.1 20 == 15 Building Blocks of P4P Networks ==
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Zenna Elfen 15.1 23 ==== **1. Data Synchronization** ====
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Zenna Elfen 13.1 25 > 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.
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Zenna Elfen 15.1 27 * //How do peers detect differences and synchronize state?//
28 * Examples: Range-Based Set Reconciliation, RIBLT, Gossip-based sync, State-based vs op-based sync, Lamport/Vector/HLC clocks, Braid Protocol
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Zenna Elfen 15.1 32 ==== **2. Collaborative Data Structures & Conflict Resolution** ====
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Zenna Elfen 13.1 34 > 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.
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Zenna Elfen 15.1 36 * //How do peers collaboratively change shared data and merge conflicts?//
37 * Examples: CRDTs (Yjs, Automerge), OT, Event Sourcing, Stream Processing, Version Vectors, Peritext
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Zenna Elfen 15.1 41 ==== **3. Data Storage & Replication** ====
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43 > 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.
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Zenna Elfen 15.1 45 * //How is data persisted locally and replicated between peers?//
46 * Examples: SQLite, IndexedDB, LMDB, Hypercore (append-only logs), WALs, Merkle-DAGs (IPFS/IPLD), Blob/media storage
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Zenna Elfen 15.1 50 ==== **4. Peer & Content Discovery** ====
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Zenna Elfen 13.1 52 > Discovery occurs in two phases:
53 > 1. **Peer Discovery** → finding _any_ nodes
54 > 2. **Topic Discovery** → finding _relevant_ nodes or resources
55 > These mechanisms enable decentralized bootstrapping and interest-based overlays.
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Zenna Elfen 15.1 57 * //How do peers find each other, and how do they discover content in the network?//
58 * Examples: DHTs (Kademlia, Pastry), mDNS, DNS-SD, Bluetooth scanning, QR bootstrapping, static peer lists, Interest-based routing, PubSub discovery (libp2p), Rendezvous protocols
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Zenna Elfen 15.1 62 ==== **5. Identity & Trust** ====
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64 > Identity systems ensure reliable mapping between peers and cryptographic keys. They underpin authorization, federated trust, and secure overlays.
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Zenna Elfen 15.1 66 * //How peers identify themselves, authenticate, and establish trustworthy relationships?//
67 * Examples: PKI, Distributed Identities (DIDs), Web-of-Trust, TOFU (SSH-style), Verifiable Credentials (VCs), Peer key fingerprints (libp2p PeerIDs), Key transparency logs
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Zenna Elfen 15.1 71 ==== **6. Transport Layer** ====
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Zenna Elfen 15.1 73 > This layer provides logical connections and flow control. QUIC and WebRTC bring modern congestion control and encryption defaults; Interpeer explores transport beyond IP assumptions.
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Zenna Elfen 16.1 75 * //How do peers establish end-to-end byte streams and reliable delivery?//
Zenna Elfen 15.1 76 * Examples: TCP, UDP, QUIC, SCTP, WebRTC DataChannels, Interpeer transport stack
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Zenna Elfen 15.1 80 ==== **7. Underlying Transport (Physical/Link Layer)** ====
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82 > Highly relevant for **offline-first / edge networks**, device-to-device communication, and mesh networks and relates to the hardware which facilitates connections.
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Zenna Elfen 16.1 84 * //How does data move across the medium?//
Zenna Elfen 15.1 85 * Examples: Ethernet, Wi-Fi Direct / Wi-Fi Aware (post-AWDL), Bluetooth Mesh, LoRa, NFC, Cellular, CSMA/CA, TDMA, FHSS
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Zenna Elfen 15.1 89 ==== **8. Session & Connection Management** ====
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91 > Manages **connection lifecycle**, including authentication handshakes, reconnection after drops, and session continuation—especially important in lossy or mobile networks.
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Zenna Elfen 16.1 93 * //How are connections initiated, authenticated, resumed, and kept alive?//
Zenna Elfen 15.1 94 * Examples: TLS handshake semantics, Noise IK/XX patterns, session tokens, keep-alive heartbeats, reconnection strategies, session resumption tickets
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Zenna Elfen 15.1 98 ==== **9. Content Addressing** ====
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100 > Content addressing ensures **immutability, verifiability, and deduplication**. Identity of data = cryptographic hash, enabling offline-first and tamper-evident systems.
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Zenna Elfen 16.1 102 * //How is data addressed and verified by content, not location?//
Zenna Elfen 15.1 103 * Examples: IPFS CIDs, BitTorrent infohashes, Git hashes, SHA-256 addressing, Named Data Networking (NDN)
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Zenna Elfen 15.1 107 ==== **10. P2P Connectivity** ====
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Zenna Elfen 16.1 109 > Connectivity ensures peers bypass NATs/firewalls to reach each other. 
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Zenna Elfen 16.1 111 * //How can two peers connect directly across networks, firewalls, and NATs?//
Zenna Elfen 15.1 112 * Examples: IPv6 direct, NAT Traversal, STUN, TURN, ICE (used in WebRTC), UDP hole punching, UPnP
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Zenna Elfen 15.1 116 ==== **11. Session & Connection Management** ====
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118 > Manages **connection lifecycle**, including authentication handshakes, reconnection after drops, and session continuation.
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Zenna Elfen 16.1 120 * //How are connections initiated, authenticated, resumed, and kept alive?//
Zenna Elfen 15.1 121 * Examples: TLS handshake semantics, Noise IK/XX patterns, session tokens, keep-alive heartbeats, reconnection strategies, session resumption tickets
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Zenna Elfen 15.1 125 ==== **12. Message Format & Serialization** ====
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127 > Serialization ensures **portable data representation**, forward-compatible schemas, and efficient messaging. IPLD provides content-addressed structuring for P2P graph data.
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Zenna Elfen 16.1 129 * //How is data encoded, structured, and made interoperable between peers?//
Zenna Elfen 15.1 130 * Examples: CBOR, Protocol Buffers, Cap’n Proto, JSON, ASN.1, IPLD schemas, Flatbuffers
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Zenna Elfen 15.1 134 ==== **13. File / Blob Synchronization** ====
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136 > 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.
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Zenna Elfen 16.1 138 //How are large objects transferred and deduplicated efficiently across peers?//
Zenna Elfen 15.1 139 Examples: BitTorrent chunking, IPFS block-store, NDN segments, rsync-style delta sync, ZFS send-receive, streaming blob transfers
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Zenna Elfen 15.1 142 ==== **14. Local Storage & Processing Primitives** ====
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144 > Provides durable on-device state and local computation (event sourcing, materialization, compaction). Enables offline-first writes and deterministic replay.
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Zenna Elfen 16.1 146 * //How do nodes persist, index, and process data locally—without external servers?//
Zenna Elfen 15.1 147 * Examples: RocksDB, LevelDB, SQLite, LMDB, local WALs/append-only logs, embedded stream processors (NATS Core JetStream mode, Actyx-like edge runtimes), Kafka-like libraries
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Zenna Elfen 15.1 151 ==== **15. Crash Resilience & Abortability** ====
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153 > 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.
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Zenna Elfen 16.1 155 * //How do nodes recover and maintain correctness under failure?//
Zenna Elfen 15.1 156 * Examples: WALs, idempotent ops, partial log replay, transactional journaling, write fences
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168 {{box title=" **Contents**"}}
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Zenna Elfen 48.1 176 == Distributed Network Types ==
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179 [[Flowchart depicting distributed network variants, under development. Building on work from Z. Elfen, 2024: ~[~[https:~~~~/~~~~/doi.org/10.17613/naj7d-6g984~>~>https://doi.org/10.17613/naj7d-6g984~]~]>>image:P4P_Typology.png||alt="Flowchart depicting typologies of distributed networks, such as Friend-2-Friend, Grassroots Networks, Federated Networks, Local-First, P2P and P4P Networks" data-xwiki-image-style-alignment="center" height="649" width="639"]]
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Zenna Elfen 35.1 183 == Overview of P4P Networks ==
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185 {{include reference="Projects.WebHome"/}}
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