== Chapter 4.1 ==

Definitions: 
   * InternetWork or InterNet
   * MPLS MultiProtocolLabelSwitching
   * InternetServiceModel is the key to handling heterogeneity.
   * IPv4 Protocol InternetProtocolV4

== Chapter 4.2 ==

   * ForwardingVsRouting p271 Peterson and Davie
   * InteriorGatewayProtocol (IGPs)