We don’t perform any NAT operation. Let's first discuss the encapsulation:
In SD-WAN there is an IP tunneling of some sort (there are several options but
not relevant here). So we have an inner payload which can be v4 or v6 and goes
end to end, the inner payload is encapsulated in an outer IP tunnel.
So what happens is the following. I make abstraction of inner payload
SD-WAN CPE2 (v4)
SD-WAN CPE1 (v4) <----------- v4 ---------> GW <-----------------v6
------------- > SD-WAN CPE3(v6).
Upstream traffic from SD-WAN CPE1
src-ip v4: A1, dst-IP v4 B1 ---------------> mapping < src-Ip v6: C1, dst-ip v6
D1 ----->
Upstream traffic from SD-WAN CPE2
src-ip v4: A2, dst-IP v4 B1 ---------------> mapping < src-Ip v6: C1, dst-ip v6
D1 ----->
So irrespective of which src-CPE 1 or 2 is sending to the v6 SD-WAN CPE3 will
use the same src/dst v6 address
With NAT64 even stateless the src-IP or src-port will be different to ensure
you can map the reverse.
This is also used to map private IPv4 to public Ipv4, etc and many other
operations.
On 06/11/2018, 14:53, "Gert Doering" <g...@space.net> wrote:
Hi,
On Tue, Nov 06, 2018 at 01:06:52AM +0000, Henderickx, Wim (Nokia -
BE/Antwerp) wrote:
> Even a NAT64 is not needed. What we do now is we go to a GW (lets call it
like this for now) and the GW rewrites the outer header of the tunnel srcIP and
dstIP from v4 to v6 or vice versa. It is kind of decap/encap operation on the
outer header as if you terminate the tunnel and reinitiate the tunnel. No NAT64
required.
>
So how exactly is this different from a NAT64?
"You take off the IPv4 header, put on an IPv6 header, and remember where
the response packets needs to be sent to"
If you preconfigure the mapping, it's still a NAT64 :-)
Gert Doering
-- NetMaster
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have you enabled IPv6 on something today...?
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