cisco certification 2.0

cisco certification 2.0.It is the basis for the functions performed by UDP and TCP. On a single host, there may be multiple applications that use both transport layer protocols (i.e., TCP and UDP) to communicate with a remote host. Take, for example, Host B in Figure 1.79, which is running both a Web server and an FTP server. Suppose that Host A wants to access both the Web service and the FTP service provided by Host B. So, it sends two TCP connection requests to Host B. The question is, how does Host B distinguish between the two TCP connection requests and deliver the packets to the correct service?The answer to that question is that Host B relies on TCP's multiplexing feature, which is based on the socket'. The concept of sound ko. A socket consists of the following 3 pieces of information.The IP address of the host. The port number. The transport layer protocol.96 Chapter 1 Network Protocols and Network Device BasicsHost A Host B10.0.1.1 10.0.2.2(10.0.2.2,TCP,21) (10.0.1.1,TCP,1026) FTP data TCP (10.0.2.2,TCP,80) (101.1.1.1,TCR1027) Web dataTCP Figure 1.79 TCP Multiplexing ExampleThe first two pieces of information are sometimes merged together, depending on the concept of socket addresses. A socket (in this case, a TCP socket) consists of the IP address and port number of a host, and the host identifies a specific TCP connection by virtue of the port number. A socket pair established between two hosts (Host A and Host B) uniquely identifies a transport layer connection.For example, for that FTP connection, the socket of host A is (10.0.1.1,1026), where 10.0.1.1 is the IP address of host A and 1026 is the TCP port number used for communication; the socket of host B is (10.0.2.2,21), where 21 is the standard port number assigned to the FTP service.