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Re: [802.21] Comments on 21-06-0698-01-0000_IP_configuration_methods_IE.doc



Hi Daniel,

Please see my comments below.

On Sat, Aug 05, 2006 at 10:11:04AM +0900, Soohong Daniel Park wrote:
> Good discussion and effort Yoshi,
> 
> For further details, we may have to clarify each facility like below:
> 
> - IP Address Configuration Method IE
> - DHCP Server Address IE
> - HA/FA Address IE
> 
> Let me answer on the first IE among IP_Configuration_Methods_IE.
> 
> As I explained in SD, the existing flag of PoA Capability IE is not
> sufficient since there is no any explicit information in order to
> prepare what kind of IP address configuration will happen while
> attaching a new PoA. For example, even the mobile station has a PoA
> Capability IE=IPv6, the mobile station based on the existing IP
> stack/RFC will trigger Router Solicitation message (after listening
> Router Advertisement for a while) in every time regardless of DHCPv6
> availability (It means there is no RS/RA capability). That causes lots
> of delays for the IP configuration when in motion. Simple extension of
> 21 IE can resolve these problems in mobile environment. If the mobile
> station has a PoA Capability IE=IPv6 & DHCPv6, then the mobile station
> will trigger DHCPv6 Solicit message immediately instead of RA or RS
> message for its own IP configuration method. I guess it's clear
> concept. Isn't it ?

First, it is not clear whether it is allowed to run DHCPv6 before
running router discovery.

Second, if it is allowed to run DHCPv6 before running router
discovery, then it should be possible to run DHCPv6 and router
discovery in parallel regardless of the use of proposed IE or even
regardless of the use of 802.21.  The only benefit to use the proposed
IE would be to avoid running DHCPv6 when DHCPv6 is not used at all for
configuring IP address and other information, but I think DHCPv6 is
used in most deployment at least for configuring other information.
So the benefit of the IP_Configuration_Methods_IE is still not clear
to me.

Regards,
Yoshihiro Ohba


> 
> On 8/5/06, Yoshihiro Ohba <yohba@tari.toshiba.com> wrote:
> >I had a discussion on the contribution with Bernard Aboba.
> >
> >Clarification on the benefit of the proposal is needed.  If the goal
> >is to allow the mobile station to choose between points of attachment,
> >then existing PoA Capability IE (carring flags for IPv4 support, IPv6
> >support, etc.) may be sufficient.  Detailed IP configuration
> >information can be determined using standard IP protocols after
> >handover.
> >
> >Best regards,
> >Yoshihiro Ohba
> >
> 
> 
> -- 
> 
> 
> Daniel (Soohong Daniel Park)
> Mobile Convergence Laboratory, SAMSUNG Electronics.
>