A mutual relationship between autonomous systems that enables the exchange of routing information using the Border Gateway Protocol.

BGP Peering

BGP (Border Gateway Protocol) peering is a fundamental mechanism that enables the interconnection of different networks across the internet through established relationships between Autonomous System operators. These relationships form the backbone of global internet routing and connectivity.

Core Concepts

Peering Requirements

Both parties must have a unique ASN (Autonomous System Number)
Agreement on technical parameters like:
- BGP protocol version
- IP addressing schemes
- Route filtering policies
- Quality of Service expectations

Types of Peering Relationships

Direct Peering
- Physical connection between two networks
- Often implemented at Internet Exchange Points
- Lower latency and better control
Transit Peering
- One AS pays another for broader internet access
- Common between smaller ISPs and Tier 1 Network providers
- Hierarchical relationship rather than equal partnership

Technical Implementation

Session Establishment

TCP connection on port 179
BGP session initialization
Exchange of routing table information
Continuous keep-alive messages

Best Practices

Implement strong network security measures
Use MD5 authentication
Apply proper route filtering policies
Monitor session health with network monitoring tools

Business Considerations

Benefits

Reduced transit costs
Improved network performance
Greater routing control
Enhanced redundancy

Challenges

Resource requirements
Technical expertise needed
Ongoing maintenance
Political and business negotiations

Operational Management

Regular maintenance tasks include:

Route optimization updates and verification
Performance monitoring
Security audits
Policy updates
Traffic engineering adjustments

Future Trends

The evolution of BGP peering continues with:

IPv6
RPKI
Software Defined Networking integration
Cloud Computing interconnection requirements

Proper BGP peering management is crucial for maintaining a robust and efficient internet infrastructure, requiring both technical expertise and business acumen to implement successfully.