Satoru Matsushima wrote, on 08/01/2011 10:41 PM:
> Thanks, a clarification has made to clear a confusion of restricted port
> set/ranges and NAT session table limitation. Even if a CPE is allocated 256
> ports, NAT session can be made over 900G sessions in theory. ('2^32'<Full
> 32bits v4 address> - '2^29'<class-D/E> - '2^7'<0/8,127/8>) * 2^8<256 ports>.

This is only true for endpoint-dependent NATs, which are forbidden by the BEHAVE
RFCs (4787 and 5382). According to these RFCs, NATs MUST have
endpoint-independent mapping behaviour. This means that each NAT session will
consume one external port.

Simon
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