> For the complete documentation index, see [llms.txt](https://polarischain-1.gitbook.io/polarischain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://polarischain-1.gitbook.io/polarischain/8.-network-layer-and-protocol-operations/8.1-p2p-communication-architecture.md).

# 8.1 - P2P Communication Architecture

Validators communicate via persistent TCP connections, forming a fully connected mesh where each node maintains direct links to all committee participants. Messages are serialized using compact binary encoding, compressed with **LZ4** for bandwidth efficiency, and framed with a 4-byte big-endian length prefix (maximum frame size: 16 MB). Protocol version negotiation (current: v7) ensures backward compatibility during rolling deployments.

**Authenticated Message Envelopes**

All inter-validator traffic is cryptographically authenticated via **Dilithium2-signed envelopes**. Each outgoing message is wrapped in a structured envelope containing:

* Sender authority index
* Per-connection monotonic sequence number
* Serialized payload
* Dilithium2 signature over the complete envelope

Receiving nodes validate the signature against the sender’s committee-published public key before processing. A sliding-window replay tracker accepts strictly newer messages and bounded out-of-order sequences, while rejecting duplicates and stale payloads. The sequence number is cryptographically bound into the signature, preventing cross-connection replay attacks.


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