ccna 200 301 booksmart cast and crew

ccna 200 301 booksmart cast and crew.Sliding window and flow control No sliding window or any flow control mechanismUsing the analogy of a phone call can help you better understand how TCP works. Most people know that before you can speak to someone over the phone, you have to establish a connection with that person - wherever they are. This is like the virtual circuit of the TCP protocol. If you tell him something important during the conversation, you might ask, "Did you know that?" or "Did you get it?" These questions are like TCP acknowledgement mechanisms, where you get an acknowledgement message. Sometimes (especially when talking on a cell phone) people ask "Are you still there? "Before hanging up, people say "goodbye" or something similar. TCP also performs a similar function.Now let's look at UDP. Using UDP is like sending a postcard. You don't need to contact the person before sending the postcard. You just write your message, the address to send it to, and send it. This is similar to the connectionless nature of UDP. Since the contents of a postcard are generally not life or death, you also don't need to get confirmation that the other person has received it. Again, UDP has no acknowledgement mechanism.Look at another diagram, shown in Figure 4.6 (in the next subsection), which shows TCP, UDP, and the applications associated with them.Port NumbersTCP and UDP must use port numbers to communicate with the upper layers, because port numbers serve to keep track of the different sessions traversing the network at the same time. Source port numbers are randomly assigned by the source host and are greater than or equal to 1024. Numbers 1023 and below are defined in RFC 3232 (or directly at www.iana.org), a document that defines so-called well-known port numbers.Those virtual circuits that do not use well-known port numbers are given a random number from a specific range. These port numbers specify the source and destination applications or processes in the TCP data segment.Figure 4.6 illustrates the port numbers used by TCP and UDP.Figure 4.6 Port Numbers for TCP and UDP The different port numbers are used as shown below. Numbers with capsules below 1024 are well-known port numbers and are defined in RFC 3232... Numbers 1024 and above are used by upper-layer applications to establish sessions with other hosts; TCP and UDP use thesenumbers as source and destination addresses in data segmentation. Next, let's look at the TCP session output from the network analyzer.