Miscellaneous ideas
- Different types of hierarchy: topological, routing, traffic management, organizational.
Separating data and control: Per-packet actions are part of critical data path -- fewer control actions => greater forwarding speed.
- Greater separation of data and control => need to install more state in the network.
- Eg: separate CCIS channel in telephony.
- Eg: separate routing protocols in Internet.
Extensibility: hooks for future growth. Eg: version field, reserved fields.