Friendship is used by Low Power nodes to limit the amount of time that they need to listen. If a node cannot receive continuously, then it is possible that it will not receive mesh messages that it should be processing. This includes security updates required for maintaining the security of the network as well as the normal mesh messages.
低功耗节点使用友谊来限制他们需要监听的时间。如果一个节点不能连续接收，那么它可能不会接收它应该处理的网格消息。这包括维护网络安全和正常的mesh消息所需的安全更新。
If the Low Power node does not receive such messages, then it may not operate as desired and it may also fail to keep up-to-date with the latest security state of the network and eventually drop off the network if this security is changed without its knowledge.
如果低功耗节点没有接收到这样的消息，那么它可能无法按预期操作，也可能无法及时了解网络的最新安全状态，如果在不知情的情况下更改了这种安全状态，最终会退出网络。
Friendship is a special relationship between a Low Power node and one neighboring Friend node. These nodes must be within a single hop of each other and in the same subnet.
友谊是一个低功耗节点和一个相邻的朋友节点之间的特殊关系。这些节点必须在彼此的单跳范围内，并且在相同的子网中。
Friendship is first established and initiated by the Low Power node; once established, the Friend node performs a number of actions that help reduce the power consumption on the Low Power node. The Friend node maintains a Friend Queue for the Low Power node, which stores all incoming messages addressed to the Low Power node. The Friend node delivers those messages to the Low Power node when requested by the Low Power node. Also, the Friend node delivers security updates to the Low Power node.
友谊首先由低功率节点建立和启动;朋友节点一旦建立起来，朋友节点就会执行许多动作来帮助低功耗节点降低功耗。朋友节点为低功耗节点维护一个朋友队列，该队列存储所有发送到低功耗节点的传入消息。当低功率节点请求时，朋友节点将这些消息传递给低功率节点。此外，朋友节点向低功耗节点提供安全更新。
When friendship is established between a Low Power node and one Friend node, the two nodes are considered to be “friends”.
当一个低功率节点和一个朋友节点之间建立友谊时，这两个节点被认为是“朋友”。
A Friend node may be friends with multiple Low Power nodes. A Low Power node can only be friends with a single Friend node.
一个朋友节点可以是多个低功耗节点的朋友。低功耗节点只能与单个朋友节点成为朋友。
An example topology of a mesh network illustrating Friend nodes and Low Power nodes is shown and described in Section 2.3.12.
在2.3.12节中给出了一个MESH网络拓扑结构的例子，它演示了友节点和低功耗节点。