The Linux Programming Interface

Sockets: Fundamentals of TCP/IP Networks 1183

Figure 58-3: Layered communication via the TCP/IP protocols

Figure 58-4: Encapsulation within the TCP/IP protocol layers

TCP protocol

(transfers TCP segments)

Data link protocol

(transfers data frames)

IP protocol

(transfers IP datagrams)

Application

TCP

IP

Data link

Application

TCP

IP

Data link

Application-defined protocol

(transfers application data)

Network medium

TCP

segment

IP

datagram

Application

data

Source + destination

port #, sequence #,

acknowledgement #,

flags, checksum, etc.

TCP header TCP data

Source +

destination IP

address, header

checksum, etc.

IP header IP data

Application-defined

content