問題文
An operator asks why the per-priority pause mechanism is preferred over pausing the whole link when lossless behavior is required. Which reason is correct?
選択肢
- It is the only mechanism the switching silicon implements in hardware.
- It sends the pause request further upstream than a link-wide pause does, so the back-pressure reaches the source of the burst in a single step rather than propagating one hop at a time through the intervening switches.
- It pauses only the class of traffic that needs the guarantee, so the other classes on the same link keep flowing instead of being stopped along with it.
- It removes the need for the marking-based congestion signal, and a class that is never allowed to overflow does not need to notify the sender at all, so the marking thresholds can stay at defaults.