Peer Management Protocol

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Core Concepts

Peer Structure

peer = (addr, port)

IPv4/IPv6 address + port

management = (G, B, C)

Good, Banned, Connected sets

Set Invariants

G ∩ B = ∅
C ⊆ G
G, B ⊆ 𝒫

Penalty System

Penalty Types

NonDeliveryPenalty

Failed modifier delivery

MisbehaviorPenalty

Invalid modifier delivery

SpamPenalty

Unsolicited modifier

PermanentPenalty

Severe protocol violation

System Components

Penalty Book:

ip → (score, timestamp)

Blacklist:

ip → ban_timestamp

Safe Interval:

Cooldown between penalties

Peer Discovery

The peer discovery protocol aims to find new potential peers from various sources and add them to the set of good peers (G). Sources for discovery can include:

  • Other connected peers (exchanging peer lists).
  • Predefined bootstrap nodes.
  • Trusted central servers (less common in decentralized networks).
  • Potentially untrusted channels like DNS seeds, IRC, Twitter, etc. (requiring careful validation).

Discovery Process

The discovery process involves several stages to ensure network reliability and security:

  1. Initial Bootstrap: Nodes start with a predefined list of trusted bootstrap nodes.
  2. Peer Exchange: Connected peers exchange their peer lists to discover new nodes.
  3. Validation: New peers are validated through handshake and capability checks.
  4. Integration: Validated peers are added to the good peers set (G).

Connection Management

Effective peer management requires sophisticated connection handling to maintain network stability and performance.

Connection Limits

  • • Maximum connections per peer type
  • • Rate limiting for connection attempts
  • • Timeout handling for stale connections
  • • Automatic reconnection strategies

Health Monitoring

  • • Response time tracking
  • • Message delivery success rates
  • • Protocol compliance monitoring
  • • Automatic peer quality assessment

Security Considerations

Peer management includes several security mechanisms to protect against malicious actors and ensure network integrity.

Attack Prevention

Sybil Attacks

Prevention through peer validation, reputation systems, and connection limits per IP address.

Eclipse Attacks

Mitigation via diverse peer selection, bootstrap node protection, and connection diversity requirements.

Penalty System Details

Penalty TypeScoreAction
NonDeliveryPenalty+5Temporary restriction
MisbehaviorPenalty+10Extended timeout
SpamPenalty+15Connection limit
PermanentPenalty+100Immediate ban

Implementation Guidelines

When implementing peer management systems, consider these best practices for optimal network performance and security.

Performance Optimization

  • • Use efficient data structures for peer sets
  • • Implement connection pooling
  • • Optimize penalty book lookups
  • • Cache frequently accessed peer information

Monitoring & Logging

  • • Track peer connection statistics
  • • Monitor penalty application rates
  • • Log peer discovery events
  • • Alert on suspicious peer behavior