This is an Early Review of draft-ietf-6lo-prefix-registration-02, at the request of the WG chair, prior to the WGLC.

This document updates a number of IPv6 Neighbor Discovery and 6LoWPAN extensions RFCs to enable a node that owns or is directly connected to a prefix to register that prefix to neighbor routers. The registration indicates that the registered prefix can be reached via the advertising node without a loop. It also extends three Routing Protocols for LLNs RFCs. 

The document is Ready With (a few) Issues that can be clarified during the WGLC. As it stands, the document can go to WGLC, and these comments can be dealt with during the WGLC process. 

My comments:

1. I am not sure about this statement being in the right place in the 2.2 Requirements section

>  In addition, the terms "Extends" and "Amends" are used as per
   [I-D.kuehlewind-update-tag] section 3.

We are dealing with Requirements and referencing an I-D seems odd.

2. For clarity, please expand / explain in 2.4 the following terms: EARO, DAO, TIO, RTO

3. With all due respect to ASCII art, Figure 1 is not clear. Is there any difference between an 'o' and a 'z'?

4. There is an 'Extending 7400' section, but RFC 7400 is not included in the list on the header, or mentioned in the first paragraph. 

5. I appreciate the Backward Compatibility section, but I am wondering whether there are any compatibility issues related to scalability or provisioning that an operator or user should be aware about when deploying the newly defined extensions. Maybe there is room for an Operational Considerations section, or for a sub-section in the Backwards Compatibility section.