In this paper, we concentrate on the comparison of different switching policies, as well as their corresponding spatially-spectrally flexible super-channel transmission technologies, in static SDM-EONs. These switching policies are different due to their different spatial switching granularities and/or whether the space lane change (SLC) is supported. According to our simulation results, the switching policy with a finer switching granularity can achieve better network performance in terms of required frequency slices in the networks but meanwhile results in higher device cost. Moreover, we find that the application of SLC can only provide negligible improvements (0.1% ~ 3.1%) on network performance. SLC is encouraged only when the spectrum resource is highly valued by network operators compared to the additional device cost it brings. Moreover, in some previous works, the application of SLC can achieve a 7% ~ 14% improvement on the network throughput in dynamic network scenarios, especially when a finer spatial switching granularity is applied. Consequently, the results in this paper suggest that such an improvement is likely to be achieved by the means of network planning, such as the design of an efficient algorithm considering spectrum defragmentation, because if the re-routing/re-assignment of spectrum is allowed, the dynamic scenario can be treated as a sequence of static scenarios that change with time.

在本文中，我们集中在静态SDM-EON中比较不同的交换策略及其相应的空间光谱灵活的超信道传输技术。这些切换策略因其不同的空间切换粒度和/或是否支持空间车道更改（SLC）而有所不同。根据我们的仿真结果，具有更精细交换粒度的交换策略可以根据网络中所需的频率切片实现更好的网络性能，但同时导致更高的设备成本。此外，我们发现SLC的应用只能在网络性能上提供微不足道的改进（0.1％〜3.1％）。仅当网络运营商高度重视频谱资源与其带来的额外设备成本相比时，才鼓励使用SLC。此外，在以前的一些工作中，SLC的应用可以在动态网络情况下将网络吞吐量提高7％〜14％，特别是在应用更精细的空间切换粒度时。因此，本文的结果表明，通过网络规划，例如考虑频谱碎片整理的有效算法的设计，可能会实现这种改进，因为如果允许频谱的重新路由/重新分配，则可以将动态方案视为一系列随时间变化的静态方案。