The network layer, however, provides a hop-by-hop protocol and is used on the two end systems and every intermediatesystem.
但是网络层提供跳跃点到跳跃点的协议，所有端系统和中间系统都需要使用。
2
Beginners and intermediatesystem administrators will benefit most from this article; the explanations and examples assume you can handle most beginner-level system admin concepts.
初学者和中级系统管理员将从本文获益最多；解说和示例假设您可以运用大部分初学者级别的系统管理概念。
3
It's a complex system wherein data is copied to multiple intermediate devices, usually to speed up access to files when millions of people are trying to access the service at the same time.