Zigbee协议栈是怎样分别执行协调器、路由器、终端的任务的？

 1         // Received whenever the device changes state in the network
 2         case ZDO_STATE_CHANGE://网络状态发生改变
 3           SampleApp_NwkState = (devStates_t)(MSGpkt->hdr.status);//把含有某部分网络发生改变的数值赋值给变量
 4           if ( (SampleApp_NwkState == DEV_ZB_COORD)     //这里就是困扰了我很久的问题所在，不明白为什么要用“或”
 5               || (SampleApp_NwkState == DEV_ROUTER)      //用“或”的话不是无法区分协调器、路由器、终端各自的
 6               || (SampleApp_NwkState == DEV_END_DEVICE) )//任务了吗？还用了else，就更难理解了（就我而言）。
 7           {
 8             // Start sending the periodic message in a regular interval.
 9             osal_start_timerEx( SampleApp_TaskID,
10                               SAMPLEAPP_SEND_PERIODIC_MSG_EVT,
11                               SAMPLEAPP_SEND_PERIODIC_MSG_TIMEOUT );
12           }
13           else
14           {
15             // Device is no longer in the network
16           }
17           break;

 1         // Received whenever the device changes state in the network
 2         case ZDO_STATE_CHANGE:
 3           SampleApp_NwkState = (devStates_t)(MSGpkt->hdr.status);
 4           
 5           //如果发生改变的是终端，则执行终端任务
 6           if (SampleApp_NwkState == DEV_END_DEVICE)
 7           {
 8             // Start sending the periodic message in a regular interval.//执行终端任务
 9             osal_start_timerEx( SampleApp_TaskID,
10                               SAMPLEAPP_SEND_PERIODIC_MSG_EVT,   //定时一段时间后发出消息
11                               SAMPLEAPP_SEND_PERIODIC_MSG_TIMEOUT );
12           }
13           //如果发生改变的是路由器，则执行路由器任务
14           else if(SampleApp_NwkState == DEV_ROUTER)
15           {
16             //执行路由器任务
17           }
18           //如果发生改变的是协调器，则执行协调器任务
19           else if(SampleApp_NwkState == DEV_ZB_COORD)
20           {
21             //执行协调器任务
22           }
23           else
24           {
25             //error
26           }