<s>
A	O
Service	B-Protocol
Access	I-Protocol
Point	I-Protocol
(	O
SAP	O
)	O
is	O
an	O
identifying	O
label	O
for	O
network	O
endpoints	O
used	O
in	O
Open	O
Systems	O
Interconnection	O
(	O
OSI	O
)	O
networking	O
.	O
</s>
<s>
As	O
an	O
example	O
,	O
PD-SAP	O
or	O
PLME-SAP	O
in	O
IEEE	O
802.15.4	O
can	O
be	O
mentioned	O
,	O
where	O
the	O
medium	B-Protocol
access	I-Protocol
control	I-Protocol
(	O
MAC	O
)	O
layer	O
requests	O
certain	O
services	O
from	O
the	O
physical	B-Application
layer	I-Application
.	O
</s>
<s>
Service	B-Protocol
access	I-Protocol
points	I-Protocol
are	O
also	O
used	O
in	O
IEEE	O
802.2	O
Logical	O
Link	O
Control	O
in	O
Ethernet	O
and	O
similar	O
data	B-Protocol
link	I-Protocol
layer	I-Protocol
protocols	O
.	O
</s>
<s>
When	O
using	O
the	O
OSI	O
Network	O
system	O
(	O
CONS	B-Protocol
or	O
CLNS	B-Protocol
)	O
,	O
the	O
base	O
for	O
constructing	O
an	O
address	O
for	O
a	O
network	O
element	O
is	O
an	O
NSAP	B-Protocol
address	I-Protocol
,	O
similar	O
in	O
concept	O
to	O
an	O
IP	B-Protocol
address	I-Protocol
.	O
</s>
<s>
OSI	O
protocols	O
as	O
well	O
as	O
Asynchronous	O
Transfer	O
Mode	O
(	O
ATM	O
)	O
can	O
use	O
Transport	O
(	O
TSAP	B-Protocol
)	O
,	O
Session	O
(	O
SSAP	O
)	O
or	O
Presentation	O
(	O
PSAP	O
)	O
Service	B-Protocol
Access	I-Protocol
Points	I-Protocol
to	O
specify	O
a	O
destination	O
address	O
for	O
a	O
connection	O
.	O
</s>
<s>
These	O
SAPs	O
consist	O
of	O
NSAP	B-Protocol
addresses	O
combined	O
with	O
optional	O
transport	O
,	O
session	O
and	O
presentation	O
selectors	O
,	O
which	O
can	O
differentiate	O
at	O
any	O
of	O
the	O
three	O
layers	O
between	O
multiple	O
services	O
at	O
that	O
layer	O
provided	O
by	O
a	O
network	O
element	O
.	O
</s>
