2. PHILOSOPHY

• 2.1 Elements of the Internetwork System
• 2.2 Model of Operation
• 2.3 The Host Environment
• 2.4 Interfaces
• 2.5 Relation to Other Protocols
• 2.6 Reliable Communication
• 2.7 Connection Establishment and Clearing
• 2.8 Data Communication
• 2.9 Precedence and Security
• 2.10 Robustness Principle