Regarding the OTN system network-level protection switching test, is the following statement wrong? ()

High-risk operations refer to all operations that may affect the stable operation of equipment, the normal operation of customer services, and the normal monitoring of network management. Which of the following are usually included? (multiple choice)

When deploying QoS, where the complex classification of data flows is usually deployed in the network

When congestion occurs, queuing strategies can be varied. If you need to take service for the messages that arrive first, you can use the () queuing strategy; if you want to ensure that the most urgent and critical services are served first, you can use the () queuing strategy; if you need to balance the delay and delay jitter of each stream, You can choose () queuing strategy; if you want to provide professional bandwidth for a specific business, you can choose () queuing strategy.

What technologies can be used to achieve congestion avoidance (multiple choice)