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‫A TCP segment consists of a segment header and a data section.

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‫The TCP header contains 10 mandatory fields and an optional extension field.

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‫The optional field is the options field, which is the last field seen on the slide.

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‫The TCP header includes a source port and destination port, each 16 bits in length.

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‫The source port is a port on the originating machine that emitted the packet.

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‫The destination port indicates the port on the target machine.

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‫The package should be delivered to.

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‫The sequence number and an acknowledgement number allows TCP to track a series of packets to make sure

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‫they arrive reliably and pretty much in order.

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‫No, absolutely in order.

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‫If a packet is lost, TCP will retransmit it if packets arrive out of order, TCP will adjust them to

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‫make sure that they are delivered to the destination services in the proper order.

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‫Data asset specifies the size of the TCP header in 32 bit words.

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‫The minimum size header is five words and the maximum is 15 word.

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‫There is also TCP control built space, also known as flags, which are incredibly important for tracking

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‫the state of a given TCP connection.

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‫As you know, we've talked about them a few minutes ago.

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‫Of course, if you didn't take a break, it was a few minutes ago.

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‫But whatever you do, just don't spill in the keyboard.

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‫Now, TCP senders use a number called window size, which is in byte by default.

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‫To regulate how much data they send to a receiver before requiring an acknowledgement in mature.

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‫So if the window size becomes too small, network data transfer will be unnecessarily slow, while if

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‫the window size becomes too large, the network link can become saturated or the receiver may not be

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‫able to process incoming data quickly enough.

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‫Also resulting in slow performance.

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‫Windowing algorithms built into the protocol dynamically calculate size values and use this field of

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‫the TCP headers to coordinate changes between senders and receivers.