我们课本中学习的经典模型有几层? How many layers are there in the classical model of learning in our textbooks? fig1-21-The TCP IP reference model.png As mentioned earlier, the strength of the OSI reference model is the model itself (minus the presentation and session layers), which has proven to be exceptionally useful for discussing computer networks. In contrast, the strength of the TCP/IP reference model is the protocols, which have been widely used for many years. Since computer scientists like to have their cake and eat it, too, we will use the hybrid model of Fig. 1-23 as the framework for this book. 如前所述, OSI 参考模型的优势在于模型本身(减去表示层和会话层),它在讨论计算机网络时被证明是非常有用的。相比之下, TCP/IP 参考模型的优势在于协议,这些协议已经被广泛使用多年。由于计算机科学家也喜欢自己设计的混合模型,我们将使用图 1-23 的混合模型作为本书的框架。 fig1-23-The reference model used in this book.png