4.1 introduction 4.2 virtual circuit and datagram networks 4.3 what’s inside a router 4.4 IP: Internet Protocol ▪ datagram format ▪ IPv4 addressing ▪ ICMP ▪ IPv6 4.5 routing algorithms ▪ link state ▪ distance vector ▪ hierarchical routing 4.6 routing in the Internet ▪ RIP ▪ OSPF ▪ BGP 4.7 broadcast and multicast routing