Selects which metric style (narrow, wide, or both) this router actually considers when performing its own SPF (shortest path) calculation at this level, defaulting to narrow, independent of which style it generates in its own LSPs (isisSysLevelMetricStyle). An admin sets this to match the metric style actually populated in the network's LSPs, to ensure the router's path computation uses meaningful metric values rather than ignoring the style other routers are using.