layer model的用法和样例：
例句
- This layered model facilitates a good correspondence between actual implementation and standardization.
这个分层模型使实际实施和标准易于对应。 - The section on application layer protocols has been expanded and a new section provides an introduction to network protocol analyzers.
并通过网络提供的服务讨论网络协议的分层模型和不同层之间的交互作用。
