<s>
Data-Link	B-Protocol
Switching	I-Protocol
(	O
DLSw	B-Protocol
)	O
is	O
a	O
tunneling	B-Protocol
protocol	I-Protocol
designed	O
to	O
tunnel	O
unroutable	O
,	O
non-IP	O
based	O
protocols	O
such	O
as	O
IBM	B-Architecture
Systems	I-Architecture
Network	I-Architecture
Architecture	I-Architecture
(	O
SNA	O
)	O
and	O
NBF	B-Protocol
over	O
an	O
IP	O
network	O
.	O
</s>
<s>
DLSw	B-Protocol
was	O
initially	O
documented	O
in	O
IETF	O
RFC	O
1434	O
in	O
1993	O
.	O
</s>
<s>
DLSw	B-Protocol
version	O
2	O
was	O
presented	O
in	O
1997	O
in	O
IETF	O
RFC	O
2166	O
as	O
an	O
improvement	O
to	O
RFC	O
1795	O
.	O
</s>
<s>
Cisco	O
Systems	O
has	O
its	O
own	O
proprietary	O
extensions	O
to	O
DLSw	B-Protocol
in	O
DLSw+	O
.	O
</s>
<s>
According	O
to	O
Cisco	O
,	O
DLSw+	O
is	O
100%	O
IETF	O
RFC	O
1795	O
compliant	O
but	O
includes	O
some	O
proprietary	O
extensions	O
that	O
can	O
be	O
used	O
when	O
both	O
devices	O
are	O
Cisco	O
.	O
</s>
<s>
Some	O
organisations	O
are	O
starting	O
to	O
replace	O
DLSw	B-Protocol
tunneling	O
with	O
the	O
more	O
modern	O
Enterprise	O
Extender	O
(	O
EE	O
)	O
protocol	O
which	O
is	O
a	O
feature	O
of	O
IBM	O
APPN	O
on	O
z/OS	O
systems	O
.	O
</s>
<s>
Enterprise	O
Extender	O
uses	O
UDP	O
traffic	O
at	O
the	O
transport	B-Architecture
layer	I-Architecture
rather	O
than	O
the	O
network	B-Application
layer	I-Application
.	O
</s>
