<s>
The	O
Common	O
Object	B-General_Concept
Request	I-General_Concept
Broker	I-General_Concept
Architecture	O
(	O
CORBA	O
)	O
is	O
a	O
standard	O
defined	O
by	O
the	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
(	O
OMG	B-Architecture
)	O
designed	O
to	O
facilitate	O
the	O
communication	O
of	O
systems	O
that	O
are	O
deployed	O
on	O
diverse	O
platforms	O
.	O
</s>
<s>
CORBA	O
is	O
an	O
example	O
of	O
the	O
distributed	B-Operating_System
object	I-Operating_System
paradigm	O
.	O
</s>
<s>
CORBA	O
uses	O
an	O
interface	B-General_Concept
definition	I-General_Concept
language	I-General_Concept
(	O
IDL	O
)	O
to	O
specify	O
the	O
interfaces	O
that	O
objects	O
present	O
to	O
the	O
outer	O
world	O
.	O
</s>
<s>
CORBA	O
then	O
specifies	O
a	O
mapping	O
from	O
IDL	O
to	O
a	O
specific	O
implementation	O
language	O
like	O
C++	B-Language
or	O
Java	B-Language
.	O
</s>
<s>
Standard	O
mappings	O
exist	O
for	O
Ada	B-Language
,	O
C	B-Language
,	O
C++	B-Language
,	O
C++11	B-Language
,	O
COBOL	B-Application
,	O
Java	B-Language
,	O
Lisp	B-Language
,	O
PL/I	B-Language
,	O
Object	B-Language
Pascal	I-Language
,	O
Python	B-Language
,	O
Ruby	B-Language
and	O
Smalltalk	B-Application
.	O
</s>
<s>
Non-standard	O
mappings	O
exist	O
for	O
C#	B-Application
,	O
Erlang	B-Operating_System
,	O
Perl	B-Language
,	O
Tcl	B-Operating_System
and	O
Visual	B-Language
Basic	I-Language
implemented	O
by	O
object	B-General_Concept
request	I-General_Concept
brokers	I-General_Concept
(	O
ORBs	O
)	O
written	O
for	O
those	O
languages	O
.	O
</s>
<s>
The	O
application	O
initializes	O
the	O
ORB	O
,	O
and	O
accesses	O
an	O
internal	O
Object	O
Adapter	O
,	O
which	O
maintains	O
things	O
like	O
reference	B-General_Concept
counting	I-General_Concept
,	O
object	O
(	O
and	O
reference	O
)	O
instantiation	O
policies	O
,	O
and	O
object	O
lifetime	O
policies	O
.	O
</s>
<s>
For	O
example	O
,	O
due	O
to	O
the	O
nature	O
of	O
Java	B-Language
,	O
the	O
IDL-Java	O
mapping	O
is	O
rather	O
straightforward	O
and	O
makes	O
usage	O
of	O
CORBA	O
very	O
simple	O
in	O
a	O
Java	B-Language
application	O
.	O
</s>
<s>
This	O
is	O
also	O
true	O
of	O
the	O
IDL	O
to	O
Python	B-Language
mapping	O
.	O
</s>
<s>
The	O
C++	B-Language
mapping	O
requires	O
the	O
programmer	O
to	O
learn	O
datatypes	O
that	O
predate	O
the	O
C++	B-Language
Standard	B-Application
Template	I-Application
Library	I-Application
(	O
STL	O
)	O
.	O
</s>
<s>
By	O
contrast	O
,	O
the	O
C++11	B-Language
mapping	O
is	O
easier	O
to	O
use	O
,	O
but	O
requires	O
heavy	O
use	O
of	O
the	O
STL	O
.	O
</s>
<s>
Since	O
the	O
C	B-Language
language	I-Language
is	O
not	O
object-oriented	O
,	O
the	O
IDL	O
to	O
C	B-Language
mapping	O
requires	O
a	O
C	B-Language
programmer	O
to	O
manually	O
emulate	O
object-oriented	O
features	O
.	O
</s>
<s>
In	O
order	O
to	O
build	O
a	O
system	O
that	O
uses	O
or	O
implements	O
a	O
CORBA-based	O
distributed	B-Operating_System
object	I-Operating_System
interface	O
,	O
a	O
developer	O
must	O
either	O
obtain	O
or	O
write	O
the	O
IDL	O
code	O
that	O
defines	O
the	O
object-oriented	O
interface	O
to	O
the	O
logic	O
the	O
system	O
will	O
use	O
or	O
implement	O
.	O
</s>
<s>
For	O
example	O
:	O
Normally	O
the	O
server	O
side	O
has	O
the	O
Portable	B-Protocol
Object	I-Protocol
Adapter	I-Protocol
(	O
POA	O
)	O
that	O
redirects	O
calls	O
either	O
to	O
the	O
local	O
servants	B-Protocol
or	O
(	O
to	O
balance	O
the	O
load	O
)	O
to	O
the	O
other	O
servers	O
.	O
</s>
<s>
The	O
CORBA	O
specification	O
(	O
and	O
thus	O
this	O
figure	O
)	O
leaves	O
various	O
aspects	O
of	O
distributed	B-Architecture
system	I-Architecture
to	O
the	O
application	O
to	O
define	O
including	O
object	O
lifetimes	O
(	O
although	O
reference	B-General_Concept
counting	I-General_Concept
semantics	O
are	O
available	O
to	O
applications	O
)	O
,	O
redundancy/fail	O
-over	O
,	O
memory	O
management	O
,	O
dynamic	O
load	O
balancing	O
,	O
and	O
application-oriented	O
models	O
such	O
as	O
the	O
separation	O
between	O
display/data/control	O
semantics	O
(	O
e.g.	O
</s>
<s>
In	O
addition	O
to	O
providing	O
users	O
with	O
a	O
language	O
and	O
a	O
platform-neutral	O
remote	B-Operating_System
procedure	I-Operating_System
call	I-Operating_System
(	O
RPC	O
)	O
specification	O
,	O
CORBA	O
defines	O
commonly	O
needed	O
services	O
such	O
as	O
transactions	O
and	O
security	O
,	O
events	O
,	O
time	O
,	O
and	O
other	O
domain-specific	O
interface	O
models	O
.	O
</s>
<s>
A	O
servant	B-Protocol
is	O
the	O
invocation	O
target	O
containing	O
methods	O
for	O
handling	O
the	O
remote	B-Operating_System
method	I-Operating_System
invocations	I-Operating_System
.	O
</s>
<s>
In	O
the	O
newer	O
CORBA	O
versions	O
,	O
the	O
remote	O
object	O
(	O
on	O
the	O
server	O
side	O
)	O
is	O
split	O
into	O
the	O
object	O
(	O
that	O
is	O
exposed	O
to	O
remote	B-Operating_System
invocations	I-Operating_System
)	O
and	O
servant	B-Protocol
(	O
to	O
which	O
the	O
former	O
part	O
forwards	B-Application
the	O
method	O
calls	O
)	O
.	O
</s>
<s>
It	O
can	O
be	O
one	O
servant	B-Protocol
per	O
remote	O
object	O
,	O
or	O
the	O
same	O
servant	B-Protocol
can	O
support	O
several	O
(	O
possibly	O
all	O
)	O
objects	O
,	O
associated	O
with	O
the	O
given	O
Portable	B-Protocol
Object	I-Protocol
Adapter	I-Protocol
.	O
</s>
<s>
The	O
servant	B-Protocol
for	O
each	O
object	O
can	O
be	O
set	O
or	O
found	O
"	O
once	O
and	O
forever	O
"	O
(	O
servant	B-Protocol
activation	O
)	O
or	O
dynamically	O
chosen	O
each	O
time	O
the	O
method	O
on	O
that	O
object	O
is	O
invoked	O
(	O
servant	B-Protocol
location	O
)	O
.	O
</s>
<s>
Both	O
servant	B-Protocol
locator	O
and	O
servant	B-Protocol
activator	O
can	O
forward	O
the	O
calls	O
to	O
another	O
server	O
.	O
</s>
<s>
In	O
the	O
object-oriented	O
languages	O
,	O
both	O
remote	O
object	O
and	O
its	O
servant	B-Protocol
are	O
objects	O
from	O
the	O
viewpoint	O
of	O
the	O
object-oriented	O
programming	O
.	O
</s>
<s>
Incarnation	O
is	O
the	O
act	O
of	O
associating	O
a	O
servant	B-Protocol
with	O
a	O
CORBA	O
object	O
so	O
that	O
it	O
may	O
service	O
requests	O
.	O
</s>
<s>
Incarnation	O
provides	O
a	O
concrete	O
servant	B-Protocol
form	O
for	O
the	O
virtual	O
CORBA	O
object	O
.	O
</s>
<s>
Activation	O
and	O
deactivation	O
refer	O
only	O
to	O
CORBA	O
objects	O
,	O
while	O
the	O
terms	O
incarnation	O
and	O
etherealization	O
refer	O
to	O
servants	B-Protocol
.	O
</s>
<s>
However	O
,	O
the	O
lifetimes	O
of	O
objects	O
and	O
servants	B-Protocol
are	O
independent	O
.	O
</s>
<s>
You	O
always	O
incarnate	O
a	O
servant	B-Protocol
before	O
calling	O
activate_object( )	O
,	O
but	O
the	O
reverse	O
is	O
also	O
possible	O
,	O
create_reference( )	O
activates	O
an	O
object	O
without	O
incarnating	O
a	O
servant	B-Protocol
,	O
and	O
servant	B-Protocol
incarnation	O
is	O
later	O
done	O
on	O
demand	O
with	O
a	O
Servant	B-Protocol
Manager	O
.	O
</s>
<s>
The	O
(	O
POA	O
)	O
is	O
the	O
CORBA	O
object	O
responsible	O
for	O
splitting	O
the	O
server	O
side	O
remote	B-Operating_System
invocation	I-Operating_System
handler	O
into	O
the	O
remote	O
object	O
and	O
its	O
servant	B-Protocol
.	O
</s>
<s>
The	O
object	O
is	O
exposed	O
for	O
the	O
remote	B-Operating_System
invocations	I-Operating_System
,	O
while	O
the	O
servant	B-Protocol
contains	O
the	O
methods	O
that	O
are	O
actually	O
handling	O
the	O
requests	O
.	O
</s>
<s>
The	O
servant	B-Protocol
for	O
each	O
object	O
can	O
be	O
chosen	O
either	O
statically	O
(	O
once	O
)	O
or	O
dynamically	O
(	O
for	O
each	O
remote	B-Operating_System
invocation	I-Operating_System
)	O
,	O
in	O
both	O
cases	O
allowing	O
the	O
call	O
forwarding	B-Application
to	O
another	O
server	O
.	O
</s>
<s>
The	O
branches	O
of	O
this	O
tree	O
can	O
be	O
independently	O
activated/deactivated	O
,	O
have	O
the	O
different	O
code	O
for	O
the	O
servant	B-Protocol
location	O
or	O
activation	O
and	O
the	O
different	O
request	O
handling	O
policies	O
.	O
</s>
<s>
The	O
following	O
describes	O
some	O
of	O
the	O
most	O
significant	O
ways	O
that	O
CORBA	O
can	O
be	O
used	O
to	O
facilitate	O
communication	O
among	O
distributed	B-Operating_System
objects	I-Operating_System
.	O
</s>
<s>
This	O
reference	O
is	O
either	O
acquired	O
through	O
a	O
stringified	O
Uniform	O
Resource	O
Locator	O
(	O
URL	O
)	O
,	O
NameService	O
lookup	O
(	O
similar	O
to	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
(	O
DNS	B-Protocol
)	O
)	O
,	O
or	O
passed-in	O
as	O
a	O
method	O
parameter	O
during	O
a	O
call	O
.	O
</s>
<s>
The	O
CORBA	O
Interface	B-General_Concept
Definition	I-General_Concept
Language	I-General_Concept
provides	O
the	O
language	O
-	O
and	O
OS-neutral	O
inter-object	O
communication	O
definition	O
.	O
</s>
<s>
CORBA	O
Objects	O
are	O
passed	O
by	O
reference	O
,	O
while	O
data	O
(	O
integers	O
,	O
doubles	O
,	O
structs	B-Application
,	O
enums	O
,	O
etc	O
.	O
)	O
</s>
<s>
Apart	O
from	O
remote	O
objects	O
,	O
the	O
CORBA	O
and	O
RMI-IIOP	B-Language
define	O
the	O
concept	O
of	O
the	O
OBV	O
and	O
Valuetypes	O
.	O
</s>
<s>
Though	O
not	O
dependent	O
on	O
"	O
language	O
dependent	O
Enterprise	B-Language
Java	I-Language
Beans	I-Language
(	O
EJB	B-Language
)	O
"	O
,	O
it	O
is	O
a	O
more	O
general	O
form	O
of	O
EJB	B-Language
,	O
providing	O
four	O
component	O
types	O
instead	O
of	O
the	O
two	O
that	O
EJB	B-Language
defines	O
.	O
</s>
<s>
The	O
CCM	O
has	O
a	O
component	O
container	O
,	O
where	O
software	B-Architecture
components	I-Architecture
can	O
be	O
deployed	O
.	O
</s>
<s>
These	O
services	O
include	O
(	O
but	O
are	O
not	O
limited	O
to	O
)	O
notification	B-Application
,	O
authentication	O
,	O
persistence	B-Application
and	O
transaction	B-General_Concept
processing	I-General_Concept
.	O
</s>
<s>
These	O
are	O
the	O
most-used	O
services	O
any	O
distributed	B-Architecture
system	I-Architecture
requires	O
,	O
and	O
,	O
by	O
moving	O
the	O
implementation	O
of	O
these	O
services	O
from	O
the	O
software	B-Architecture
components	I-Architecture
to	O
the	O
component	O
container	O
,	O
the	O
complexity	O
of	O
the	O
components	O
is	O
dramatically	O
reduced	O
.	O
</s>
<s>
Portable	O
interceptors	O
are	O
the	O
"	O
hooks	O
"	O
,	O
used	O
by	O
CORBA	O
and	O
RMI-IIOP	B-Language
to	O
mediate	O
the	O
most	O
important	O
functions	O
of	O
the	O
CORBA	O
system	O
.	O
</s>
<s>
IOR	B-Protocol
interceptors	O
mediate	O
the	O
creation	O
of	O
the	O
new	O
references	O
to	O
the	O
remote	O
objects	O
,	O
presented	O
by	O
the	O
current	O
server	O
.	O
</s>
<s>
Client	O
interceptors	O
usually	O
mediate	O
the	O
remote	B-Operating_System
method	I-Operating_System
calls	I-Operating_System
on	O
the	O
client	O
(	O
caller	O
)	O
side	O
.	O
</s>
<s>
If	O
the	O
object	O
Servant	B-Protocol
exists	O
on	O
the	O
same	O
server	O
where	O
the	O
method	O
is	O
invoked	O
,	O
they	O
also	O
mediate	O
the	O
local	O
calls	O
.	O
</s>
<s>
Server	O
interceptors	O
mediate	O
the	O
handling	O
of	O
the	O
remote	B-Operating_System
method	I-Operating_System
calls	I-Operating_System
on	O
the	O
server	O
(	O
handler	O
)	O
side	O
.	O
</s>
<s>
Interceptors	O
can	O
also	O
throw	O
forwarding	B-Application
exceptions	O
,	O
redirecting	O
request	O
to	O
another	O
target	O
.	O
</s>
<s>
The	O
GIOP	B-Operating_System
is	O
an	O
abstract	O
protocol	O
by	O
which	O
Object	B-General_Concept
request	I-General_Concept
brokers	I-General_Concept
(	O
ORBs	O
)	O
communicate	O
.	O
</s>
<s>
Standards	O
associated	O
with	O
the	O
protocol	O
are	O
maintained	O
by	O
the	O
Object	B-Architecture
Management	I-Architecture
Group	I-Architecture
(	O
OMG	B-Architecture
)	O
.	O
</s>
<s>
The	O
GIOP	B-Operating_System
architecture	O
provides	O
several	O
concrete	O
protocols	O
,	O
including	O
:	O
</s>
<s>
Internet	O
InterORB	O
Protocol	O
(	O
IIOP	B-Operating_System
)	O
The	O
Internet	B-Operating_System
Inter-Orb	I-Operating_System
Protocol	I-Operating_System
is	O
an	O
implementation	O
of	O
the	O
GIOP	B-Operating_System
for	O
use	O
over	O
the	O
Internet	O
,	O
and	O
provides	O
a	O
mapping	O
between	O
GIOP	B-Operating_System
messages	O
and	O
the	O
TCP/IP	B-Protocol
layer	O
.	O
</s>
<s>
SSL	B-Protocol
InterORB	O
Protocol	O
(	O
SSLIOP	O
)	O
SSLIOP	O
is	O
IIOP	B-Operating_System
over	O
SSL	B-Protocol
,	O
providing	O
encryption	O
and	O
authentication	O
.	O
</s>
<s>
HyperText	O
InterORB	O
Protocol	O
(	O
HTIOP	O
)	O
HTIOP	O
is	O
IIOP	B-Operating_System
over	O
HTTP	B-Protocol
,	O
providing	O
transparent	O
proxy	O
bypassing	O
.	O
</s>
<s>
Zipped	O
IOP	O
(	O
ZIOP	O
)	O
A	O
zipped	O
version	O
of	O
GIOP	B-Operating_System
that	O
reduces	O
the	O
bandwidth	O
usage	O
.	O
</s>
<s>
Minor	O
codes	O
for	O
the	O
standard	O
exceptions	O
are	O
prefaced	O
by	O
the	O
VMCID	O
assigned	O
to	O
OMG	B-Architecture
,	O
defined	O
as	O
the	O
unsigned	O
long	O
constant	O
CORBA::OMGVMCID	O
,	O
which	O
has	O
the	O
VMCID	O
allocated	O
to	O
OMG	B-Architecture
occupying	O
the	O
high	O
order	O
20	O
bits	O
.	O
</s>
<s>
Vendors	O
may	O
request	O
allocation	O
of	O
VMCIDs	O
by	O
sending	O
email	O
to	O
tagrequest@omg.org	O
.	O
</s>
<s>
A	O
list	O
of	O
currently	O
assigned	O
VMCIDs	O
can	O
be	O
found	O
on	O
the	O
OMG	B-Architecture
website	O
at	O
:	O
</s>
<s>
The	O
VMCID	O
OMGVMCID	O
(	O
Section	O
3.17.1	O
,	O
"	O
Standard	O
Exception	O
Definitions	O
"	O
,	O
on	O
page	O
3-52	O
)	O
and	O
1	O
through	O
0xf	O
are	O
reserved	O
for	O
OMG	B-Architecture
use	O
.	O
</s>
<s>
All	O
CORBA	O
products	O
must	O
support	O
two	O
OMG-defined	O
URLs	O
:	O
""	O
and	O
""	O
.	O
</s>
<s>
The	O
purpose	O
of	O
these	O
is	O
to	O
provide	O
a	O
human	O
readable	O
and	O
editable	O
way	O
to	O
specify	O
a	O
location	O
where	O
an	O
IOR	B-Protocol
can	O
be	O
obtained	O
.	O
</s>
<s>
The	O
semantics	O
of	O
these	O
is	O
that	O
they	O
provide	O
details	O
of	O
how	O
to	O
download	O
a	O
stringified	O
IOR	B-Protocol
(	O
or	O
,	O
recursively	O
,	O
download	O
another	O
URL	O
that	O
will	O
eventually	O
provide	O
a	O
stringified	O
IOR	B-Protocol
)	O
.	O
</s>
<s>
Currently	O
there	O
are	O
many	O
languages	O
supported	O
by	O
various	O
CORBA	O
providers	O
,	O
the	O
most	O
popular	O
being	O
Java	B-Language
and	O
C++	B-Language
.	O
</s>
<s>
There	O
are	O
also	O
C++11	B-Language
,	O
C-only	O
,	O
Smalltalk	B-Application
,	O
Perl	B-Language
,	O
Ada	B-Language
,	O
Ruby	B-Language
,	O
and	O
Python	B-Language
implementations	O
,	O
just	O
to	O
mention	O
a	O
few	O
.	O
</s>
<s>
CORBA	O
is	O
available	O
in	O
Java	B-Language
(	O
OS-independent	O
)	O
,	O
as	O
well	O
as	O
natively	O
for	O
Linux/Unix	O
,	O
Windows	O
,	O
Solaris	O
,	O
OS	O
X	O
,	O
OpenVMS	O
,	O
HPUX	O
,	O
Android	O
,	O
LynxOS	O
,	O
VxWorks	O
,	O
ThreadX	O
,	O
INTEGRITY	O
,	O
and	O
others	O
.	O
</s>
<s>
When	O
integrating	O
C	B-Language
,	O
C++	B-Language
,	O
Object	B-Language
Pascal	I-Language
,	O
Java	B-Language
,	O
Fortran	O
,	O
Python	B-Language
,	O
and	O
any	O
other	O
language	O
or	O
OS	O
into	O
a	O
single	O
cohesive	O
system	O
design	O
model	O
,	O
CORBA	O
provides	O
the	O
means	O
to	O
level	O
the	O
field	O
and	O
allow	O
disparate	O
teams	O
to	O
develop	O
systems	O
and	O
unit	O
tests	O
that	O
can	O
later	O
be	O
joined	O
together	O
into	O
a	O
whole	O
system	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
design	O
of	O
a	O
multitier	B-Operating_System
architecture	I-Operating_System
is	O
made	O
simple	O
using	O
Java	B-Application
Servlets	I-Application
in	O
the	O
web	O
server	O
and	O
various	O
CORBA	O
servers	O
containing	O
the	O
business	O
logic	O
and	O
wrapping	O
the	O
database	O
accesses	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
C++	B-Language
legacy	O
code	O
can	O
talk	O
to	O
C/Fortran	O
legacy	O
code	O
and	O
Java	B-Language
database	O
code	O
,	O
and	O
can	O
provide	O
data	O
to	O
a	O
web	O
interface	O
.	O
</s>
<s>
CORBA	O
Interface	B-General_Concept
Definition	I-General_Concept
Language	I-General_Concept
provides	O
the	O
mechanism	O
to	O
ensure	O
that	O
user-code	O
conforms	O
to	O
method-names	O
,	O
return-	O
,	O
parameter-types	O
,	O
and	O
exceptions	O
.	O
</s>
<s>
ORBexpress	O
(	O
Ada	B-Language
,	O
C++	B-Language
,	O
and	O
Java	B-Language
implementation	O
)	O
and	O
OmniORB	O
(	O
open	O
source	O
C++	B-Language
and	O
Python	B-Language
implementation	O
)	O
)	O
have	O
options	O
for	O
tuning	O
the	O
threading	O
and	O
connection	O
management	O
features	O
.	O
</s>
<s>
This	O
extension	O
is	O
called	O
ZIOP	O
and	O
this	O
is	O
now	O
a	O
formal	O
OMG	B-Architecture
standard	O
.	O
</s>
<s>
CORBA	O
's	O
notion	O
of	O
location	O
transparency	O
has	O
been	O
criticized	O
;	O
that	O
is	O
,	O
that	O
objects	O
residing	O
in	O
the	O
same	O
address	B-General_Concept
space	I-General_Concept
and	O
accessible	O
with	O
a	O
simple	O
function	O
call	O
are	O
treated	O
the	O
same	O
as	O
objects	O
residing	O
elsewhere	O
(	O
different	O
processes	O
on	O
the	O
same	O
machine	O
,	O
or	O
different	O
machines	O
)	O
.	O
</s>
<s>
Implementations	O
were	O
further	O
hindered	O
by	O
the	O
general	O
tendency	O
of	O
the	O
standard	O
to	O
be	O
verbose	O
,	O
and	O
the	O
common	O
practice	O
of	O
compromising	O
by	O
adopting	O
the	O
sum	O
of	O
all	O
submitted	O
proposals	O
,	O
which	O
often	O
created	O
APIs	B-Application
that	O
were	O
incoherent	O
and	O
difficult	O
to	O
use	O
,	O
even	O
if	O
the	O
individual	O
proposals	O
were	O
perfectly	O
reasonable	O
.	O
</s>
<s>
The	O
SUN	O
Java	B-Language
SDK	O
comes	O
with	O
CORBA	O
built-in	O
.	O
</s>
<s>
CORBA	O
(	O
more	O
precisely	O
,	O
GIOP	B-Operating_System
)	O
is	O
not	O
tied	O
to	O
any	O
particular	O
communications	O
transport	O
.	O
</s>
<s>
A	O
specialization	O
of	O
GIOP	B-Operating_System
is	O
the	O
Internet	B-Operating_System
Inter-ORB	I-Operating_System
Protocol	I-Operating_System
or	O
IIOP	B-Operating_System
.	O
</s>
<s>
IIOP	B-Operating_System
uses	O
raw	O
TCP/IP	B-Protocol
connections	O
in	O
order	O
to	O
transmit	O
data	O
.	O
</s>
<s>
If	O
the	O
client	O
is	O
behind	O
a	O
very	O
restrictive	O
firewall	O
or	O
transparent	O
proxy	O
server	O
environment	O
that	O
only	O
allows	O
HTTP	B-Protocol
connections	O
to	O
the	O
outside	O
through	O
port	O
80	O
,	O
communication	O
may	O
be	O
impossible	O
,	O
unless	O
the	O
proxy	O
server	O
in	O
question	O
allows	O
the	O
HTTP	B-Protocol
CONNECT	I-Protocol
method	O
or	O
SOCKS	B-Application
connections	O
as	O
well	O
.	O
</s>
<s>
These	O
communicate	O
using	O
XML/SOAP	O
via	O
port	O
80	O
,	O
which	O
is	O
normally	O
left	O
open	O
or	O
filtered	O
through	O
a	O
HTTP	B-Protocol
proxy	O
inside	O
the	O
organization	O
,	O
for	O
web	O
browsing	O
via	O
HTTP	B-Protocol
.	I-Protocol
</s>
<s>
Recent	O
CORBA	O
implementations	O
,	O
though	O
,	O
support	O
SSL	B-Protocol
and	O
can	O
be	O
easily	O
configured	O
to	O
work	O
on	O
a	O
single	O
port	O
.	O
</s>
<s>
Some	O
ORBS	O
,	O
such	O
as	O
TAO	B-Protocol
,	O
omniORB	O
and	O
JacORB	O
also	O
support	O
bidirectional	O
GIOP	B-Operating_System
,	O
which	O
gives	O
CORBA	O
the	O
advantage	O
of	O
being	O
able	O
to	O
use	O
callback	O
communication	O
rather	O
than	O
the	O
polling	O
approach	O
characteristic	O
of	O
web	O
service	O
implementations	O
.	O
</s>
<s>
Also	O
,	O
most	O
modern	O
firewalls	O
support	O
GIOP	B-Operating_System
&	O
IIOP	B-Operating_System
and	O
are	O
thus	O
CORBA-friendly	O
firewalls	O
.	O
</s>
