• This is the original instrumentation option introduced for ASP.NET Core 1.x. It is the default setting for ASP.NET Core 1.x, and a configurable option for 2.x.
• Set the node property aspdotnet-core-instrumentation (string) = "Legacy" to enable this for ASP.NET Core 2.x.

The MVC Routing instrumentation functionality has been deprecated with ASP.NET Core 3.0. It provides full pipeline visibility by instrumenting from the first middleware in the pipeline. However, when attempting to do MVC naming of incoming web requests, it may cause issues. It assumes that you built the middleware pipeline in a specific way, and contains very specific middleware request delegates.

If you are using ASP.NET Core 2.x, and need full pipeline visibility with MVC naming, then this is the only available option for you.