 Internet service providers, often Tier 1 networks, participate in Internet backbone traffic by privately negotiated interconnection agreements, primarily governed by the principle of settlement-free peering.The Internet, and consequently its backbone networks, do not rely on central control or coordinating facilities, nor do they implement any global network policies.The resilience of the Internet results from its principal architectural features, most notably the idea of placing as few network state and control functions as possible in the network elements and instead relying on the endpoints of communication to handle most of the processing to ensure data integrity, reliability, and authentication.