Dear Remi-san,

Thank you for your comments. Please see inline below.

* On Mon, 31 Oct 2011 10:25:03 +0100
* Remi Despres <[email protected]> wrote:

> Hi Masataka-san,
> 
> 1.
> Thank you for sharing your interesting experience with the JPIX trial service 
> based on 464XLAT.
> Could you, for clarification, describe in more details formats of XLAT 
> prefixes in this trial? 

IPv6 address for translation have IPv4 address embedded in the
low-order 32 bits of the IPv6 address, as you well know.
http://tools.ietf.org/html/draft-mawatari-softwire-464xlat-02#section-6.1

I might not understand what you want to know.
I described 464XLAT address translation chart here.

                                        source IPv4 address
                                        +-----------------------------+
                                        | IPv4 [global] (32bit)       |
                                        | [assigned to IPv4 pool@PLAT]|
                             +--------+ +-----------------------------+
                             |  IPv4  | destination IPv4 address
                             | server | +-----------------------------+
                             +--------+ | IPv4 [global] (32bit)       |
                                 ^      + [assigned to IPv4 server]   |
                                 |      +-----------------------------+
                             +--------+
                             |  PLAT  | Stateful XLATE (v4:v6=1:n)
                             +--------+
                                 ^
                                 |
source IPv6 address         (IPv6 cloud)
 +--------------------------------------+-----------------------------+
 |  XLAT prefix for src (96bit)         | IPv4 [private] (32bit)      |
 |  [assigned to each consumer of ISP]  | [assigned to IPv4 client]   |
 +--------------------------------------+-----------------------------+
destination IPv6 address
 +--------------------------------------+-----------------------------+
 |  XLAT prefix for dst (96bit)         | IPv4 [global] (32bit)       |
 |  [assigned to PLAT]                  | [assiend to IPv4 server]    |
 +--------------------------------------+-----------------------------+
                            (IPv6 cloud)
                                 ^
                                 |
                             +--------+
                             |  CLAT  | Stateless XLATE (v4:v6=1:1)
                             +--------+
                                 ^      source IPv4 address
                                 |      +-----------------------------+
                             +--------+ | IPv4 [private] (32bit)      |
                             |  IPv4  | | [assigned to IPv4 client]   |
                             | client | +-----------------------------+
                             +--------+ destination IPv4 address
                                        +-----------------------------+
                                        | IPv4 [global] (32bit)       |
                                        + [assigned to IPv4 server]   |
                                        +-----------------------------+


additional reference (sorry, a bit outdated)
http://www.apricot.net/apricot2011/media/Masataka_Mawatari_IPv6v4_Exchange_Service_for_sharing_IPv4_address.pdf


> 2.
> Objectives of 464XLAT and 4rd-U look very similar (ref 
> draft-despres-softwire-4rd-u-01).
> 
> Indeed:
> - Both use "DHCPv6 prefix delegation or another method" to inform CLAT/CEs of 
> their IPv6 prefixes.
> - Both "can implement traffic engineering based on IPv4 source address and 
> IPv4 destination address" (a feature that, as noted in your draft, is missing 
> in encapsulation).
> 
> OTOH, unless I miss something, 464XLAT doesn't provide incoming connectivity 
> of CLATs in case of shared IPv4 addresses (while 4rd-U does provide it to 
> CEs). In this respect 4rd-U seems functionally more complete.
> 
> Thoughts?
> 
> 
> Regards,
> RD


Kind Regards,
Masataka MAWATARI


-- 
Japan Internet Exchange
MAWATARI Masataka <[email protected]>
tel:+81-3-3243-9579

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