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

[Rémi Després <remi.despres@free.fr>]

Dan Wing  - Le 7/16/08 8:03 PM :

> 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.

Thanks, a very useful RFC.



> 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:

In the new APBP draft
(http://tools.ietf.org/html/draft-despres-v6ops-apbp-01), an APBP client 
obtains in one request a public IPv4 address and a range of ports to go 
with it.
An APBP message to the APBP server is then not necessary for each 
UPnP... packet, and independent outgoing connections will have the same 
public IPv4 source adress, IMO an important progress.

Here is a proposed revision of your ASCII art:

+-----------------+
|incoming UPnP IGD|
|or NAT-PMP packet|
+----+------------+
     |
     V
+-------------+          +===============================+
|  need new   |-----YES->|If needed, Send an APBP Request|
|NAT binding? |          |   Then create NAT binding     |
+----+--------+          |using the obtained IPv4 address|
     |                   | and a free port in its range  |
     NO                  +===============================+
     |                             |
     V                             |
+----+---------------+             |
|respond to UPnP IGD |<------------+
|or NAT-PMP request  |
+----+---------------+




Once an APBP client has obtained a range of ports with an address, it
can operate as though it would have an exclusive v4 address, except that
it has less than 64K ports to go with it, and no port in the < 1024 range.
- Of course, this is still a significant restriction but, IMU, CGNs
won't do better.
- To be reachable on a well-known port, in a site that has an IPv6
prefix and no public IPv4 address, applications should better be
reachable in IPv6.


Regards.

RD