Subject: [Dime] Diameter PMIPv6

From: Marco Liebsch <[email-masked]>
Date: Wed, 27 May 2009 17:58:51 +0200

Hi Jouni, all,

please find a few thoughts about the current version of 
draft-ietf-dime-pmip6-02
attached. And sorry for the huge delay in providing comments. Hope the 
comments
style is clear. Anyway, proposed changes are optional :-) Hope it helps.

Best regards,
marco

Editorial for clarification:
============================

1. Introduction

"..Dynamic assignment and downloading of PMIPv6 policy profile
 information is a desirable feature to ease the deployment and network
 maintenance of larger PMIPv6 deployments. "

> you probably mean "..maintenance of larger PMIPv6 domains."

---

"..The Diameter server in the
 Mobility Service authorizer's (MSA) network may return these
 parameters to the Network Access Server (NAS). "

> you may add ".. to the Network Access Server (NAS) during access authentication."

--

"..Once the MN authenticates to the network the MAG sends.."

> Isn't it vice versa that the network authenticates the MN? You may change to
"..Once the network has authenticated the MN, the MAG sends.." or
"..Once the MN has identified to the network and the network has authenticated
the MN..."

--

"..The NAS functionality of the MAG may be co-located or an integral
part of the MAG.."

> I'd consider the NAS and the MAG as functional entities, which may be
colocated on an access router. So, the proposed alternative may be
"..The NAS functionality may be colocated with the MAG function on the
network's access router.."

--

3. Solution Overview

"..This document defines Diameter based AAA interactions between the
MAG and the HAAA, and between the LMA and the HAAA."

> Hmm, since the extension is generic for any interface between a Diameter Client and
Diameter Server, I'd consider such operation also useful with a AAA in the visited network.
So, why limiting this to the HAAA? I'd suggest to write simply AAA.
Loading profile info is anyway transparent, as the AAAvisited contacts
the AAAhome.

--

4.2 PMIP6-IPv4-Home-Address AVP

> Would it make sense to include a BNF of this AVP as well?
Or provide a reference here to the document where the
type Address is defined.

--

Section 5.1

> Some text as you have it at the beginning of Section 5.1 I'd
propose to have much earlier to understand what the document is about,
which problem it addresses and which protocol extensions it proposes
to solve the problem.

General comments:
================

As the spec does not define a new application for PMIPv6 anymore, can the text
or even the title reflect that it's in fact a Generic Extension to Diameter
Applications for Proxy MIPv6? So far it says it's Diameter Support for
Proxy Mobile IPv6.

I'd be more precise and clear in 1. Introduction and the beginning of
3. Solution Overview about what the specification does. Well, the intro
says what PMIPv6 demands and what NAS does. Then it says that the spec
defines the Diameter support for PMIPv6 (to do what?) and that the NAS
may be colocated with the MAG.. The Intro looks very unsystematic to me.
All this is ok if you (as reader) know the details of why and how you're
doing this. I'd recommend that in the Intro you're precise with describing
the problem, the existing protocols you can re-use and extend and with what
you specify in this document to solve the problem. Then it should be ok for
most readers to understand the rest.

One feature of the LMA-AAA interface should be HNP delegation, where the
LMA can request an HNP for the MN from the AAA during mobility session
authorization. As far as I remember, this was in some time ago (? maybe not..).
Would be good to have this feature mentioned in the spec, e.g. Section 1 and
Secion 5.2.