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Figure 16.1 |
The historic ISO 7-Layer Reference Model. A layering model is a tool to help protocol designers construct a suite of protocols that solves all communication problems. |
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Figure 16.2 |
The conceptual path of data as it travels from an application on computer 1 across a network to an application on computer 2. |
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Figure 16.3 |
Examples of older protocol stacks that have been replaced by TCP/IP protocols. Although the stacks shared many general concepts, the details differed, making them incompatible. |
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Figure 16.4 |
The nested protocol headers that appear in a frame as the frame travels across a network if the full ISO stack is used. Each layer of protocol software adds a header to an outgoing frame. |
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Figure 16.5 |
The layering principle applied at each layer of the old ISO model. If protocol software on the sending computer changes the message, the change must be reversed by the corresponding protocol software on the receiver. |
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Figure 16.6 |
A 4-packet window sliding through outgoing data. The window is shown (a) when transmission begins, (b) after two packets have been acknowledged, and (c) after eight packets have been acknowledged. The sender can transmit all packets in the window. |
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Figure 16.7 |
Messages required to send a sequence of four packets using (a) stop-and-go flow control, and (b) a 4-packet sliding window. Time proceeds down the page, and each arrow shows one message sent from one computer to the other. |
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Figure 16.8 |
A graph that represents a network of six packet switches. Such networks can experience congestion. |
