RE: How to include APBP scenarios in the Coexistence RequirementI-D

["Dan Wing" <dwing@cisco.com>]

> Following some privatly received comments of Dan Wing, the 
> standby phase hasn't be long, and the idea to possibly give up 
> APBP stands no longer !
> 
> I just posted draft-01,  with  I believe  substantial simplifications 
> and improved applicability.
> 
> Sorry for the one more change.

Allow me to elaborate a bit on our offline discussion over the weekend.

I noticed all of the current proposals (SNAT, NAT64, NAT6, IVI,
dual-stack-lite, etc.) are quiet on a significant aspect of a requirement that
is important:  keeping existing games and existing applications working.  I am
thinking of game boxes like Microsoft's Xbox that need UPnP IGD in order to
function properly over the Internet, and applications such as Microsoft
Netmeeting (needs an H.323 ALG in the NAT), Quicktime and RealAudio streaming
(RTSP), and so on.  http://tools.ietf.org/html/rfc3027 does a good job of
explaining the specifics.

A protocol which meets the requirements of APBP would allow UPnP IGD, NAT-PMP,
and appropriate ALGs to be in the subscriber-side CPE box, and allow using
APBP to the carrier-owned NAT64/NAT44 box to obtain a real, publicly-routable
v4 transport address.  That publicly-routable v45 transport address would then
be used by the subscriber-side CPE in exactly the same way that today's
subscriber-side CPE uses its own WAN transport address for the same functions.
For UPnP IGD, the availability of APBP means a host that performs the UPnP
getPublicIPAddress() API call would get a publicly-routable v4 transport
address.  Without APBP, a host performing that same function call would not
get a v4 address at all.


Here is some beautiful ASCII art diagrams of the difference between today's
UPnP IGD (and NAT-PMP) and what I am suggesting is useful (and necessary) for
tomorrow's APBP in conjunction with UPnP IGD and NAT-PMP:


Today's UPnP IGD and NAT-PMP function at a high level:

+-----------------+
|incoming UPnP IGD|
|or NAT-PMP packet|
+----+------------+
     |
     V
+-------------+          +-----------------------+
|  need new   |-----YES->| create NAT binding    |
|NAT binding? |          |using NAT's WAN address|
+----+--------+          +---------+-------------+
     |                             |
     NO                            |
     |                             |
     V                             |
+----+---------------+             |
|respond to UPnP IGD |<------------+
|or NAT-PMP request  |
+----+---------------+


Change to UPnP IGD or NAT-PMP function inside of the subscriber NAT
(difference highlighted with "=" and capital letters):


+-----------------+
|incoming UPnP IGD|
|or NAT-PMP packet|
+----+------------+
     |
     V
+-------------+          +=========================+
|  need new   |-----YES->| SEND "APBP" MESSAGE     |
|NAT binding? |          | TOWARDS SP'S CARRIER NAT|
+----+--------+          +=========+===============+
     |                             |
     NO                            |
     |                             |
     V                             |
+----+---------------+             |
|respond to UPnP IGD |<------------+
|or NAT-PMP request  |
+----+---------------+

-d