Hi,

This is a short yet well written document. Looks really good. Just a couple of small questions/comments:

1. It's not clear exactly what from RFC 7175 is being updated by Section 4. This is based on the last paragraph of the Intro, yet Section 5 also seems relevant to that update.
2. In the IANA COnsiderations, it would be useful to explicitly list that the "RBridge Channel Protocols" registry is part of the "Transparent Interconnection of Lots of Links (TRILL) Parameters" 

Thanks,

Carlos Pignataro.