<s>
The	O
Address	B-Protocol
plus	I-Protocol
Port	I-Protocol
(	O
A+P	B-Protocol
)	O
within	O
the	O
network	B-Application
layer	I-Application
communications	O
protocol	O
for	O
Internet	B-Protocol
networking	I-Protocol
is	O
an	O
experimental	O
approach	O
to	O
the	O
IPv4	B-Protocol
address	I-Protocol
shortage	I-Protocol
.	O
</s>
<s>
It	O
is	O
a	O
technique	O
for	O
sharing	O
single	O
IPv4	O
addresses	O
among	O
several	O
users	O
without	O
using	O
stateful	O
network	B-Protocol
address	I-Protocol
translation	I-Protocol
(	O
NAT	O
)	O
in	O
the	O
carrier	O
network	O
.	O
</s>
<s>
A+P	B-Protocol
uses	O
the	O
destination	O
TCP	B-Protocol
or	O
UDP	B-Protocol
port	O
in	O
addition	O
to	O
the	O
IP	O
address	O
to	O
extend	O
the	O
range	O
of	O
available	O
host	O
addresses	O
.	O
</s>
<s>
A+P	B-Protocol
is	O
a	O
stateless	B-Protocol
alternative	O
to	O
conventional	O
stateful	O
NAT	O
,	O
as	O
the	O
A+P	B-Protocol
gateway	O
does	O
not	O
need	O
to	O
keep	O
track	O
of	O
every	O
TCP	B-Protocol
or	O
UDP	B-Protocol
flow	O
.	O
</s>
<s>
However	O
,	O
it	O
does	O
require	O
A+P	B-Protocol
aware	O
software	O
at	O
the	O
end-point	O
,	O
capable	O
of	O
limiting	O
the	O
range	O
of	O
port	O
numbers	O
used	O
for	O
originating	O
connections	O
to	O
its	O
allocated	O
range	O
,	O
either	O
in	O
the	O
end	O
host	O
,	O
or	O
,	O
in	O
the	O
more	O
common	O
likely	O
scenario	O
,	O
in	O
the	O
customer	O
premises	O
equipment	O
own	O
local	O
NAT44	B-Protocol
implementation	O
.	O
</s>
