type alias Ipv4Refined Refined IPv4 datagram — payload narrows by shape (TCP / UDP / ICMP / IGMP / ESP / raw bytes) and the host's protocol field is the on-wire discriminator. Definition Ipv4TcpPacket | Ipv4UdpPacket | Ipv4IcmpPacket | Ipv4IgmpPacket | Ipv4EspPacket | Ipv4Packet