Last Call Review of draft-ietf-dmm-distributed-mobility-anchoring-13
review-ietf-dmm-distributed-mobility-anchoring-13-opsdir-lc-wu-2019-10-02-00

• Status
• Email expansions
• History

• Versions
• 00

Review
review-ietf-dmm-distributed-mobility-anchoring-13-opsdir-lc-wu-2019-10-02

I have reviewed this document as part of the Operational directorate's ongoing
effort to review all IETF documents being processed by the IESG.  These
comments were written with the intent of improving the operational aspects of
the IETF drafts. Comments that are not addressed in last call may be included
in AD reviews during the IESG review.  Document editors and WG chairs should
treat these comments just like any other last call comments.

This draft discusses how distributed mobility anchoring functions work in both network based mobility solution and host based mobility solution. I think this draft lacks clarity on terminoloy definition and IP mobility support in different use cases.

Major issue:
Not found

Minor issue:
1. Good to see anchor definition in the terminology section, however when we say anchor of IP prefix, how it is related to control plane anchor and data plane anchor? It will be nice to define CPA and DPA in the terminology section as well and clarify their relationship.
2. LM and FM functions are two terms defined in terminology section, however it is not clear to me how LM and FM functions related to 3GPP mobility components? How they are related to anchor defined in this document? Clarify this in ther terminology section will be helpful. Add 3GGP reference will be good.
3.Section 4.1
 Not sure IP session continuity is needed in this nomadic case. If IP session continuity is supported, how is it different from two mobility cases? I think normadic case only supports application layer session continuity rather than IP session continuity. Would it be great to clarify the difference between IP session continuity, higher layer session continuity and  IP mobility support in the terminology section
4. Section 4.1. I see in most cases IP mobiity support is equivalent to IP session continuity support, but in this draft, I see some difference between IP mobility and IP session continuity, e.g., IP mobility may not support IP session continuity, if the answer is yes, please clarify in the terminology section and redefine IP mobility.

5. Section 4.1, Figuer 4. In figuer 4, it is not clear to me how does CN know new address of MN, i.e.,IP2? Do we need any communication between CPA and DPA or CPA in the home network and CPA in new visited network? Control plane channel or data plane channel or Do we rely on LM and FM function to make CN know new IP address of MN when MN moves to new network? Please clarify.
6. Section 4.2, Not sure the case (ii) always enable optimized routes, it seems not consistent with what was said in section 4.3 since section 4.3 supports two cases, one is keeping anchoring to IP address of flow in the home networ, the other is switch the IP prefix/address anchoring to the new network.
7. Section 4.3 Also it is not clear to me why traffic redirection mobility case described in section 4.2 and anchor relocation mobility case described in section 4.3 should be breifly discussed in section 4.2.
8. How work flow in traffic redirection mobility case in section 4.2 is different from anchor relocation mobility case described in section 4.3? Why some piece of work flow for anchor relocation should be described in figure 5.