Adrian, MAP facilitates both IPv6 deployment and IPv4 address exhaustion without involving any CGN mess in the network. This allows the home networks to stay dual-stack, use IPv6 as possible, and resort to IPv4 if IPv6 is not feasible for the intended destinations. One could promote the intent being that as more and more traffic goes over IPv6, less and less IPv4 will be needed (thereby shrinking the reliance on IPv4 ports sharing). Note that MAP Translation mode (i.e. MAP-T) does not involve any encapsulation, so, any QoS or Security or LI or DPI or Caching needing access to Layer4 info (i.e. UDP/TCP ports) would work just fine anywhere in the network. In case of MAP-E (Encapsulation mode), layer4 info (i.e. UDP/TCP ports) is not available in the network (until at boundary of the network where decapsulation is done).

* The ISP's router to which the user connects being able to route packets on routes that go beyond the IP address and into the port number field of TCP/UDP.

Nope. The routers still follow the dynamic IPv4 and IPv6 routing for packet forwarding. That is UNCHANGED. The routers (expected to the boundary routers/ASBR, not the PE routers connecting the users) must have to look at the ports for IPv4->IPv6 stateless translation. Once translated, routing lookup as usual.

* A CE router being instructed to constrain itself to using a limited set of ports on the WAN side in its NAT44 implementation.

Indeed. And it is not much different from how it works today. Almost all CPEs (I.e. Residential routers) work with limited set of ports (typically 2000) for dynamic NAT44 anyway. Of course, when MAP is enabled, the range would no longer be the default (as is the case today), rather something that is assigned using DHCP or TR069. That's in the control plane. Cheers, Rajiv -----Original Message----- From: "nanog-request@nanog.org" <nanog-request@nanog.org> Reply-To: "nanog@nanog.org" <nanog@nanog.org> Date: Tuesday, September 25, 2012 12:08 AM To: "nanog@nanog.org" <nanog@nanog.org> Subject: NANOG Digest, Vol 56, Issue 84

Date: Mon, 24 Sep 2012 22:42:46 +0100 From: Mike Jones <mike@mikejones.in> To: Adrian Bool <aid@logic.org.uk> Cc: "nanog@nanog.org" <nanog@nanog.org> Subject: Re: Throw me a IPv6 bone (sort of was IPv6 ignorance) Message-ID: <CAAAas8H8ERETrcnn0TaFD3cNToAfpdy12G6goNP5e=2cYtH1bQ@mail.gmail.com> Content-Type: text/plain; charset=UTF-8

On 24 September 2012 21:11, Adrian Bool <aid@logic.org.uk> wrote:

...

On 24 Sep 2012, at 17:57, Tore Anderson <tore.anderson@redpill-linpro.com> wrote:

...

* Tore Anderson

...

I would pay very close attention to MAP/4RD.

FYI, Mark Townsley had a great presentation about MAP at RIPE65 today, it's 35 minutes you won't regret spending:

https://ripe65.ripe.net/archives/video/5 https://ripe65.ripe.net/presentations/91-townsley-map-ripe65-ams-sept-24 -2012.pdf

Interesting video; thanks for posting the link.

This does seem a strange proposal though. My understanding from the video is that it is a technology to help not with the deployment of IPv6 but with the scarcity of IPv4 addresses. In summary; it simply allows a number of users (e.g. 1024) to share a single public IPv4 address.

My feeling is therefore, why are the IPv4 packets to/from the end user being either encapsulated or translated into IPv6 - why do they not simply remain as IPv4 packets?

If the data is kept as IPv4, this seems to come down to just two changes,

* The ISP's router to which the user connects being able to route packets on routes that go beyond the IP address and into the port number field of TCP/UDP. * A CE router being instructed to constrain itself to using a limited set of ports on the WAN side in its NAT44 implementation.

Why all the IPv6 shenanigans complicating matters?

While you could do something similar without the encapsulation this would require that every router on your network support routing on port numbers, by using IPv6 packets it can be routed around your network by existing routers. And it's not like anyone is going to be deploying such a system without also deploying IPv6, so it's not adding any additional requirements doing it that way.

- Mike

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Message: 3 Date: Mon, 24 Sep 2012 23:34:30 +0100 From: Adrian Bool <aid@logic.org.uk> To: "nanog@nanog.org" <nanog@nanog.org> Subject: Re: Throw me a IPv6 bone (sort of was IPv6 ignorance) Message-ID: <8BEEBCDA-B6FA-4407-BF95-E122B26F4916@logic.org.uk> Content-Type: text/plain; charset=us-ascii

On 24 Sep 2012, at 22:42, Mike Jones <mike@mikejones.in> wrote:

...

While you could do something similar without the encapsulation this would require that every router on your network support routing on port numbers,

Well, not really. As the video pointed out, the system was designed to leverage hierarchy to reduce routing complexity. Using the hierarchy, port number routing is only required at the level where a routes diverge on a port basis - which if you're being sensible about such a deployment would only be at the edge of the access layer.

aid