First, the main function
1. Handling packet send requests from the transport layer
Load the packet into the IP datagram, populate the header, select the path to the destination node, and send the packet to the appropriate port.
2. Processing input Datagrams
First check the validity of the datagram and then route the selection.
3. Handling ICMP messages
Handles routing selection, flow control, and congestion control.
Second, IP protocol
1. Responsible for transmitting the data from the source to the purpose, but not responsible for ensuring the transmission reliability, flow control, reporting sequence and other host-to-host protocol.
2. Implement two basic functions: addressing and fragmentation. The data is routed to the destination address according to the destination address in the datagram header, in which case the IP is responsible for selecting the routing route, which is called the route function.
The number of bits represented by the value in parentheses
1-10 Internet Level