<s>
IBM	B-Architecture
Advanced	I-Architecture
Peer-to-Peer	I-Architecture
Networking	I-Architecture
(	O
APPN	B-Architecture
)	O
is	O
an	O
extension	O
to	O
the	O
Systems	B-Architecture
Network	I-Architecture
Architecture	I-Architecture
(	O
SNA	O
)	O
"	O
that	O
allows	O
large	O
and	O
small	O
computers	O
to	O
communicate	O
as	O
peers	O
across	O
local	O
and	O
wide-area	O
networks.	O
"	O
</s>
<s>
The	O
goals	O
of	O
APPN	B-Architecture
were	O
:	O
</s>
<s>
APPN	B-Architecture
was	O
defined	O
around	O
1986	O
,	O
and	O
was	O
meant	O
to	O
complement	O
IBM	O
's	O
Systems	B-Architecture
Network	I-Architecture
Architecture	I-Architecture
.	O
</s>
<s>
APPN	B-Architecture
was	O
originally	O
meant	O
to	O
be	O
a	O
"	O
DECNET	B-Protocol
killer	O
"	O
,	O
but	O
DEC	O
actually	O
died	O
before	O
APPN	B-Architecture
was	O
completed	O
.	O
</s>
<s>
APPN	B-Architecture
has	O
been	O
largely	O
superseded	O
by	O
TCP/IP	B-Protocol
(	O
Internet	O
)	O
.	O
</s>
<s>
APPN	B-Architecture
evolved	O
to	O
include	O
a	O
more	O
efficient	O
data	O
routing	O
layer	O
which	O
was	O
called	O
High	O
Performance	O
Routing	O
(	O
HPR	O
)	O
.	O
</s>
<s>
APPN	B-Architecture
should	O
not	O
be	O
confused	O
with	O
the	O
similarly	O
named	O
APPC	B-Protocol
(	O
Advanced	B-Protocol
Program-to-Program	I-Protocol
Communication	I-Protocol
)	O
.	O
</s>
<s>
APPN	B-Architecture
manages	O
communication	O
between	O
machines	O
,	O
including	O
routing	O
,	O
and	O
operates	O
at	O
the	O
transport	O
and	O
network	O
layers	O
.	O
</s>
<s>
By	O
contrast	O
,	O
APPC	B-Protocol
manages	O
communication	O
between	O
programs	O
,	O
operating	O
at	O
the	O
application	O
and	O
presentation	O
layers	O
.	O
</s>
<s>
APPN	B-Architecture
has	O
nothing	O
to	O
do	O
with	O
peer-to-peer	O
file	O
sharing	O
software	O
such	O
as	O
Bittorrent	B-Protocol
or	O
emule	B-Protocol
.	O
</s>
<s>
The	O
designation	O
peer-to-peer	O
in	O
the	O
case	O
of	O
APPN	B-Architecture
refers	O
to	O
its	O
independence	O
from	O
a	O
central	O
point	O
of	O
control	O
,	O
similar	O
to	O
the	O
way	O
that	O
a	O
FireWire	B-Protocol
PC	O
connection	O
allows	O
a	O
video	O
camera	O
to	O
talk	O
directly	O
to	O
a	O
disk	O
drive	O
on	O
the	O
FireWire	B-Protocol
network	O
.	O
</s>
<s>
An	O
APPN	B-Architecture
network	O
can	O
be	O
composed	O
of	O
up	O
to	O
five	O
types	O
of	O
nodes	O
:	O
</s>
<s>
Network	O
Node	O
(	O
NN	O
)	O
APPN	B-Architecture
router	O
End	O
Node	O
(	O
EN	O
)	O
application	O
host	O
Low	O
Entry	O
Node	O
(	O
LEN	O
)	O
original	O
peer	O
node	O
that	O
"	O
allowed	O
communication	O
between	O
two	O
nodes	O
with	O
the	O
intervention	O
of	O
VTAM.	O
"	O
</s>
<s>
Composite	O
Network	O
Node	O
(	O
CNN	O
)	O
VTAM/NCP	O
node	O
Branch	O
Network	O
Node	O
(	O
BrNN	O
)	O
"	O
appears	O
as	O
an	O
EN	O
to	O
an	O
upstream	O
NN	O
while	O
it	O
provides	O
NN	O
services	O
for	O
downstream	O
ENs	O
and	O
LENs.	O
"	O
</s>
<s>
In	O
VTAM	B-Application
,	O
APPN	B-Architecture
nodes	O
are	O
defined	O
as	O
PU	O
2.1	O
.	O
</s>
<s>
APPN	B-Architecture
is	O
supported	O
on	O
a	O
variety	O
of	O
IBM	O
and	O
non-IBM	O
"	O
intelligent	O
"	O
devices	O
and	O
software	O
.	O
</s>
<s>
It	O
is	O
available	O
on	O
mainframes	O
,	O
AS/400	O
,	O
System/36	O
,	O
OS/2	B-Application
via	O
Communications	O
Server	O
,	O
Cisco	O
equipment	O
,	O
and	O
Microsoft	O
Host	O
Integration	O
Services	O
(	O
HIS	O
)	O
for	O
Windows	O
.	O
</s>
