cisco certification 2020 ccnp

cisco certification 2020 ccnp.that all data received is processed and the cache is re-released, leaving the window size unchanged. However, if for some reason the TCP receiver is unable to process the data in the cache in a timely manner, it reduces the window size and simultaneously informs the TCP sender. Take Figure1.86 as an example, theThe TCP receiver (server) notifies the TCP sender (TCP client) that the local TCP window size is 200 bytes, instead of the initial 300 bytes. Upon receiving the notification, the TCP client slows down the data transfer accordingly. The above process is dynamic, which means that the server can also increase the window size.3. The idea behind TCP socket multiplexing, a method that allows multiple applications to run on the same host and use different sockets, is to uniquely identify a transport layer connection with an IP address, a transport layer protocol and a port number. There are some "well-known" applications that use fixed port numbers (for example, the WWW uses TCP port 80). This means that the Web server keeps the socket on the local TCP80 port open, listening for access requests from various hosts. When trying to open a connection to the Web server, the host (TCP client) uses TCP port 80 as the destination port and chooses a random port number (higher than 1024) as the source port. The randomly selected port number must be higher than 1024, since any port number below 1024 is reserved for well-known applications.Table 1-24 shows some common applications and their port numbers. Table 1-24 Some Commonly Used TCP Applications and Their Corresponding Port NumbersApplication Name Port NumberFTP Data 20FTP Control 21SSH 22telnet 23