I was asked to review this document on behalf of the ops directorate. This document describes a new protocol to do PIM DR load balancing. In general, I think this document is ready. I appreciate both the backwards compat and operator considerations sections. In fact, as I read through this, I kept thinking, "I hope they talk about legacy vs. new routers on the same shared LAN". One thing that might be good to add is a callout to vendors/implementors that they are explicit in which GDR for which group/source. Thinking with a troubleshooting mind, this changes the paradigm in forwarding and knowing how that behaves will be critical. I also found three really small nits: Section 5.2.1: s/ordinal number of router X/ordinal number of Router X/ === Section 5.4: s/permissable/permissible/ === Section 5.8: s/take part in an load-balancing/take part in load-balancing/