フリー問題

問題文

What is the purpose of explicit congestion notification in a lossless data center fabric?

選択肢

1. A switch that is starting to build a queue marks packets instead of discarding them, and the endpoints use that signal to reduce their sending rate before loss occurs.
2. A switch that is congested sends a message to the management system, which then instructs the scheduler to stop placing new jobs on the affected nodes until the condition clears by itself.
3. A switch that is congested holds the packet until the queue drains, which is why explicit congestion notification removes the need for any endpoint behavior.
4. A switch that is congested rewrites the destination of the packet so it takes a less loaded path through the fabric.