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Mem-PEX Gossip Swarm Discovery Protocol

Mem-PEX (Peer Exchange, core/pex, PubSub Topic: /membuss/pex/1.0.0) allows active nodes to exchange peer multiaddresses in real-time over PubSub gossip without constant DHT lookups.

1. Message Payload Schema​

{
  "peer_id": "12D3KooW...",
  "addrs": [
    "/ip4/192.168.1.10/tcp/4001",
    "/ip4/192.168.1.10/udp/4001/quic-v1"
  ],
  "timestamp": 1753801200
}

2. Sybil Defense & Subnet Limits​

PEX enforces IP bucket limits (max 3 peers per /24 IPv4 subnet) to defend against Sybil routing table poisoning.