I am the assigned Gen-ART reviewer for this draft. For background on Gen-ART, please see the FAQ at < http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. Please resolve these comments along with any other Last Call comments you may receive. Document:  draft-ietf-netext-access-network-option-10.txt Reviewer: Alexey Melnikov Review Date: 5 May 2012 IETF LC End Date: 9 May 2012 IESG Telechat date: Unknown Summary: This draft is ready as a Proposed Standard Major issues: none Minor issues: Minor:  [ANI] and [TS23003] seem to be Normative (as per their use in 3.1.1) Nits/editorials: 1.  Introduction    This document defines a new mobility option, the Access Network    Identifier (ANI) option and its sub-options for Proxy Mobile IPv6,    that can be used by the mobile access gateway to signal the access    network information to the local mobility anchor.  The specific    details on how the local mobility anchor uses this information are    out-of-scope for this document.  These mobility options are optional    and are not mandatory for the Proxy Mobile IPv6 protocol. Nit: Last sentence: "optional" and "not mandatory" are the same thing on my book. Strictly speaking PEN numbers are not limited to 4 bytes. However you have a registry for types of identifiers, so a new value can be allocated for bigger-than-4-bytes PENs.