| 摘要 |
The notion of a “PTP aware” path is one current proposed approach to reduce asymmetry effects. In a fully PTP aware path there is the notion of on-path support mechanisms such as boundary clocks and transparent clocks at every switching or routing node. However, on-path support methods only address time-transfer errors introduced inside network elements and any asymmetry in the transmission medium, such as, for example, the fiber strands for the two directions of transmission, cannot be compensated for by on-path support mechanisms. Furthermore, in a real operational network, which may traverse different operational domains administered by different entities, full on-path support is a difficult challenge. In certain managed network scenarios full on-path support can be contemplated. Nevertheless, the universal asymmetry compensation method described herein mitigates the asymmetry in a network path, without requiring on-path support mechanisms such as transparent clocks and boundary clocks. |
