d the PTP message must wait. While it is in a queue waiting, the time data it represents (or carries) is aging and becoming stale. It should also be noted that this effect shrinks as the interface speeds increase, since a large packet takes much less time to pass out of a faster interface. The means that any queued packets will not have to wait as long to clear out the frame in front of them, reducing the PDV impact. To see more details of how the effects of queuing at an interface can be mitigated in unaware nodes, especially in low-latency situations, refer to Chapter 11. However, for network elements, the best way to limit the effects of dynamic asymmetry is to use a well-designed PTP-aware clock, as it has been designed to either reduce dynamic asymmetry (boundary clock) or measure it (transparent clock). This is the main reason why a BC will only timestamp a PTP message as it is in the process of transmission, to minimize the aging while wait- ing in an output queue. For the transport systems in the network, the only mitigation strategy for asymmetry is to avoid, limit, and reduce it before it reaches a level that causes problems. The main idea, then, is to filter out as much of it as possible and budget for the amount that cannot be removed through filtering. Because dynamic asymmetry changes rapidly, a low-pass filter will safely remove the high-fre- quency noise (the rapid changes). Where it becomes difficult to filter is for very low frequency ef- fects, such as the daily peaks and troughs in traffic caused by human daily cycles. So, the engineer accepts that some dynamic asymmetry will appear and manages it to be below a certain limit. Most end-to-end budgets allow for an amount of dynamic asymmetry in the network elements and network transport, SO the idea is to manage the conditions to stay within those bound- aries. See the previous section "Parameters for Timing Performance" and the later section "Budget- ing End-to-End Time Error". Correction and Calibration The clear strategy for mitigating any st