This read-write field selects the routing metric used for path-selection decisions specifically for QoS Class 2 traffic, independent of whatever metric governs class 1, letting different traffic classes optimize for different network characteristics. An admin might choose end-to-end-delay for class 2 if it carries interactive video that is sensitive to overall latency but less sensitive to jitter than voice would be. For example, setting lportAtmRouteMetricQoS2 to end-to-end-delay(2) ensures class-2 connections get routed via the path with the lowest total propagation and queuing delay, even if that path has higher administrative cost or slightly more jitter than an alternative.