Subject: [v6ops] Review of the new version draft-sarikaya-v6ops-prefix-delegation-04

From: Qin Wu <[email-masked]>
Date: Wed, 25 May 2011 09:39:37 +0800

Hi, 
I was asked to review this new version of draft-sarikaya-v6ops-prefix-delegation.

This version looks better, but I am still not sure it clealy clarify how prefix management 
issue is addressed in the AR or homegateway for per-MN interface prefix model, in particular:

Section 1,  it seems to me the figure 1 is combination of WiMAX archteicture and 
3GPP architecutre. I am not sure I understand
the difference between access GW and access router. To my mind,  PDN-GW
 is edge router rather than access router. If I am wrong, please correct me.

Section 3.1, This draft is referencing to TS23.401, I am wondering what is missing in TS23.401
for stateless address autoconfiguration. As described in section 5.3.1.2.2 of TS23.401,
IPv6 can be allocated from external PDN,e.g., DHCP server to PDN GW and then PDN GW 
will allocate IPv6 address to UE through Router Soliciation/Router Advertisement exhange. 
Also Prefix can be released during release of the PDN connection. So I am wondering whether 
prefix mangement is a real a issue in the PDN-GW for stateless address autocofigureation case? 
What is the special issue for per-MN interface prefix model?
So it is better it clarify how it gets alignment with TS23.401, what is missing in 
TS23.401, How it overcomes the problem unsolved in TS23.401.

Section 3.2, As regarding to stateful address configuation, I don't know why TS23.401 does not cover this
case and specify something. In this draft, it assumes one specific case, i.e., DHCP client is 
collocated with DHCP server in the AR. It is okay. 
Otherwise, AR will not be responsible for prefix management. Instead, DHCP server will do. 
However is there too much value for this case, since we can not mandate DHCP 
server should be always sitting in the AR. there are other depoyment scenarios.
So it is better to explain why stateful address allocation is useful in such case.

Regards!
-Qin
----- Original Message ----- 
From: <[email-masked]>
To: <[email-masked]>
Sent: Thursday, May 19, 2011 6:00 PM
Subject: I-D Action:draft-sarikaya-v6ops-prefix-delegation-04.txt

>A New Internet-Draft is available from the on-line Internet-Drafts directories.
> 
> Title           : DHCPv6 Prefix Delegation as IPv6 Migration Tool in Mobile Networks
> Author(s)       : B. Sarikaya, et al.
> Filename        : draft-sarikaya-v6ops-prefix-delegation-04.txt
> Pages           : 14
> Date            : 2011-05-19
> 
> As interest on IPv6 deployment is increasing in cellular networks
> several migration issues are being raised and IPv6 prefix management
> is the one addressed in this document.  Based on the idea that DHCPv6
> servers can manage prefixes, we address prefix management issues such
> as the access router offloading delegation and release tasks of the
> prefixes to a DHCPv6 server using DHCPv6 PD.  The access router first
> requests a prefix for an incoming mobile node from the DHCPv6 server.
> The access router may next stateless or stateful address allocation
> to the mobile node, e.g. with a Router Advertisement or using DHCP.
> We also describe prefix management using Authentication Authorization
> and Accounting servers.
> 
> A URL for this Internet-Draft is:
> http://www.ietf.org/internet-drafts/draft-sarikaya-v6ops-prefix-delegation-04.txt
> 
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
> 
> Below is the data which will enable a MIME compliant mail reader
> implementation to automatically retrieve the ASCII version of the
> Internet-Draft.
>

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