Though they actually exist only as simulations in software, they can be thought of as physical layers of nodes.

尽管它们实际上只作为软件中的模拟而存在，但它们可以被视为节点的物理层。

MAC addresses, collision detection, exponential backoff and similar low level protocols that mediate access to the physical layer are part of the Data Link Layer.

MAC 地址、冲突检测、指数退避和调解对物理层的访问的类似低级协议是数据链路层的一部分。