Subject: [v6ops] Comments on 464xlat-00

From: Washam Fan <[email-masked]>
Date: Tue, 7 Feb 2012 14:01:19 +0800

Hi,

I generally support this work. But have several comments below.

1. section 7.4 mentioned DNS proxy for both IPv4 and IPv6 hosts, i
don't know why DNS proxy for IPv6 hosts is needed.

2. I think the author should elaborate on what the configuration
function is like in section 7.6

3. i don't know what is the meaning for the text under section 7.5. I
think NDP should always perform while SLAAC perform only if the prefix
equals to 64.

4. I don't know if the draft should cover the host1-CLAT1-CLAT2-host2
communication case.

Thanks,
washam

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From: MAWATARI Masataka <[email-masked]>
Date: Fri, 10 Feb 2012 13:29:44 +0900

Dear Washam-san,

Thank you for your comments and sorry for delay.

> don't know why DNS proxy for IPv6 hosts is needed.

The 464XLAT does not require DNS Proxy for both IPv4 and IPv6 hosts.
IPv6 host may directly query an IPv6 DNS server.  IPv4 host may also
directly query an IPv4 DNS server through 464XLAT translation.
DNS Proxy is useful function for IPv4 host so the host can not easily
discover an IPv4 DNS server address.

> function is like in section 7.6

I do not know where your consideraton about this configuration
function is.
Could you please specifically indicate about your consideraton?
I think we can make a appropriate document by yours.

> think NDP should always perform while SLAAC perform only if the prefix

If CLAT gets a single /64 prefix from WAN interface, it has to perform
ND for 464XLAT IPv6 addresses(It means that IPv4 host under CLAT),
and it has to perform ND-Proxy for IPv6 host under CLAT.

> 4. I don't know if the draft should cover the host1-CLAT1-CLAT2-host2

This 464XLAT architecture is hub and spoke model.

Kind Regards,
Masataka MAWATARI

* On Tue, 7 Feb 2012 14:01:19 +0800

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From: Washam Fan <[email-masked]>
Date: Fri, 10 Feb 2012 13:18:00 +0800

Hi,

> discover an IPv4 DNS server address.

Got it. But it seemed to me that such DNS Proxy is required when I
read section 7.4.

> I think we can make a appropriate document by yours.
i was referring to the configuration function which allows the PLAT
and CLAT not to include the Fragment Header.

> and it has to perform ND-Proxy for IPv6 host under CLAT.

Do you mean ND for the translated ipv6 addresses where ipv4 addresses
assigned to the hosts under CLAT are embeded? If yes, then i think you
need to clarify in this section because this section is too vague.

My point was ND can perform even the prefix != 64, cant it? And when
you say ND, are you referring to DAD or full functionality of ND?

> This 464XLAT architecture is hub and spoke model.
Would you mind clarify this scope in somewhere in the draft?

Thanks,
washam

---

From: Washam Fan <[email-masked]>
Date: Fri, 10 Feb 2012 13:21:33 +0800

Hi,

Thanks,
washam

---

From: Masanobu Kawashima <[email-masked]>
Date: Fri, 10 Feb 2012 19:02:32 +0900

Hi Washam,

Thank you for your useful comments. Please see inline.

>Got it. But it seemed to me that such DNS Proxy is required when I

I'm sorry for confusing you. I took similar question from Brian
a few weeks ago. We will add some clarifying language in the next version.
http://www.ietf.org/mail-archive/web/v6ops/current/msg11853.html

>and CLAT not to include the Fragment Header.

The function provide a configuration function to adjust minimum IPv6 MTU,
or can configure whether it include the Fragment Header.

>assigned to the hosts under CLAT are embeded?

Yes, exactly.

>If yes, then i think you need to clarify in this section because this
>section is too vague.

I agree with you. We will add some clarifying language about this in
the next version.

>you say ND, are you referring to DAD or full functionality of ND?

Would you mind clarifying what you meant by that?
If CLAT gets a single /64 prefix from WAN interface, it has to perform
full functionality of ND for 464XLAT IPv6 addresses.

>Would you mind clarify this scope in somewhere in the draft?

We will add some language in somewhere in next version. :-)

Regards,
Masanobu

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========================================
 NEC AccessTechnica, Ltd.               
 Product Development Department         
 Masanobu Kawashima                     
 [email-masked]               
 http://www.necat.co.jp/                
========================================

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From: Washam Fan <[email-masked]>
Date: Fri, 10 Feb 2012 23:22:27 +0800

Hi,

> full functionality of ND for 464XLAT IPv6 addresses.

Sorry haven't made clearer. If CLAT gets a prefix length longer or
shorter than /64, should it perform ND for the IPv6 addresses? And
another question, did you mean perform ND at the interface facing the
network under CLAT or at the WAN interface?

Thanks,
washam

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From: Masanobu Kawashima <[email-masked]>
Date: Sat, 11 Feb 2012 01:17:13 +0900

Hi Washam,

If CLAT gets a prefix longer than /64, it does not need to perform ND
for 464XLAT addresses on WAN interface because 464XLAT addresses are
assigned to LAN interface or Virtual interface in CLAT. (i.e. 464XLAT
addresses are not included in WAN Prefix.)

If CLAT gets a prefix shorter than /64, it must perform ND for 464XLAT
addresses on WAN interface because 464XLAT addresses are assigned to
WAN interface. (i.e. 464XLAT addresses are included in WAN Prefix.)

Moreover, if CLAT gets a prefix shorter than /96, it can not perform
CLAT function.

Regards,
Masanobu

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From: Cameron Byrne <[email-masked]>
Date: Fri, 10 Feb 2012 09:16:17 -0800

> Moreover, if CLAT gets a prefix shorter than /96, it can not perform

Allow me to add a use case that may make this clearer.  In the draft,
we will work on making that language clear.  This is one of the key
benefits of working group feedback.

In the ideal case, DHCP-PD will provide a dedicated /64 that can be
used for sourcing and receiving the RFC 6145 stateless translation
traffic.

In the case of a 3G phone from a 3GPP pre-release 10 network that does
not support DHCP-PD, the CLAT/Phone will receive a /64 from the
network to be used on the WAN 3G interface.  The CLAT function on the
phone will own the lower /96 of /64 and claim those addresses as its
own so that i may source and receive RFC6145 stateless translations.
It is relevant to reserve this address space for data sessions that
originate from the phone as well as the use case of the phone being
used as a wireless router with NDproxy to the 3G network.

This also applies to any landline deployment where there is either
only 1 WAN or LAN /64.  The CLAT must ensure that /96 is owned by the
CLAT for that subnet for RFC 6145 to function properly and not
conflict with the IPv6 addresses of other devices on the subnet.

CB

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From: Washam Fan <[email-masked]>
Date: Sun, 12 Feb 2012 13:33:05 +0800

Hi Masanobu,

> WAN interface. (i.e. 464XLAT addresses are included in WAN Prefix.)

But the draft says if CLAT get a prefix *equals to* /64, it MUST
perform ND. Anyway, I think more text in section is necessary.

Thanks,
washam

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From: Masanobu Kawashima <[email-masked]>
Date: Sun, 12 Feb 2012 21:52:14 +0900

Hi Washam,

Thank you for your helpful comments.
We will add some clarifying language about this in the next version.

Regards,
Masanobu