Improved synchronization behavior in highly cascaded networks

The boundary blocks (BC) defined in both versions of the IEEE1588 standard respectively draft standard evidence two problems when used in cascaded networks. Namely, there is strong nonlinear decreasing synchronization accuracy and rising resynchronization time after network reconfiguration. To eliminate these effects the concept of transparent clocks (TC) has been introduced in the IEEE 1588 standard version 2. The use of optimized control loops shows a clearly improved reconfiguration behavior and linear decreasing synchronization accuracy over a wide range of cascades. The paper furthermore will present related measurement results of highly (30) cascaded IEEE 1588 enabled switches. The results of the optimized control loops are compared with similar configurations based on TCs and BCs without optimization.