Dear MPI Forum, With this proposal we want to address the current problem of not using hardware and application topology information for communication performance optimization. Therefore we propose some new API functions to the existing MPI Topology interface. Details of the problem can be found in issue #120 and related material therein: https://github.com/mpi-forum/mpi-issues/issues/120 The proposed changes in the standard are part of pull request #98: https://github.com/mpi-forum/mpi-standard/pull/98 An annotated pdf showing the changes in the document is available under https://github.com/mpi-forum/mpi-issues/files/2875356/mpi32-report-topol-201... Best regards Christoph Niethammer and Rolf Rabenseifner -- Christoph Niethammer High Performance Computing Center Stuttgart (HLRS) Nobelstrasse 19 70569 Stuttgart Tel: ++49(0)711-685-87203 email: [email protected] http://www.hlrs.de/people/niethammer