Now you may be wondering, what happens if two different clients establish a Telnet session to a server, and each of these clients choose the same source port number x? How will the server be able to demultiplex the segments when the two sessions have exactly the same port number pair? The answer to this question is that server also uses the IP addresses in the IP datagrams carrying these segments. (We will discuss IP datagrams and addressing in detail in Chapter 4.) The situation is illustrated in Figure 3.2-3, in which host A initiates two Telnet sessions to host C, and host A initiates one Telnet session to host C. Hosts A, B and C each have their own unique IP address; host A has IP address A, host B has IP address B, and host C has IP address C. Host A assigns two different source port (SP) numbers (x and y) to the two Telnet connections emanating from host A. But because host B is choosing source port numbers independently from A, it can also assign SP=x to its Telnet connection. Nevertheless, host C is still able to demultiplex the two connections since the two connections have different source IP addresses. In summary, we see that when a destination host receives data from the network layer, the triplet [source IP address, source port number, destination port number] is used to forward the data to the appropriate process.