<s>
The	O
Recursive	B-Architecture
InterNetwork	I-Architecture
Architecture	I-Architecture
(	O
RINA	O
)	O
is	O
a	O
new	O
computer	B-Architecture
network	I-Architecture
architecture	O
proposed	O
as	O
an	O
alternative	O
to	O
the	O
architecture	O
of	O
the	O
currently	O
mainstream	O
Internet	B-Protocol
protocol	I-Protocol
suite	I-Protocol
.	O
</s>
<s>
RINA	O
's	O
fundamental	O
principles	O
are	O
that	O
computer	B-Architecture
networking	I-Architecture
is	O
just	O
Inter-Process	B-Operating_System
Communication	I-Operating_System
or	O
IPC	O
,	O
and	O
that	O
layering	O
should	O
be	O
done	O
based	O
on	O
scope/scale	O
,	O
with	O
a	O
single	O
recurring	O
set	O
of	O
protocols	O
,	O
rather	O
than	O
based	O
on	O
function	O
,	O
with	O
specialized	O
protocols	O
.	O
</s>
<s>
The	O
protocol	O
instances	O
in	O
one	O
layer	O
interface	O
with	O
the	O
protocol	O
instances	O
on	O
higher	O
and	O
lower	O
layers	O
via	O
new	O
concepts	O
and	O
entities	O
that	O
effectively	O
reify	O
networking	O
functions	O
currently	O
specific	O
to	O
protocols	O
like	O
BGP	B-Protocol
,	O
OSPF	B-Protocol
and	O
ARP	O
.	O
</s>
<s>
In	O
this	O
way	O
,	O
RINA	O
claims	O
to	O
support	O
features	O
like	O
mobility	O
,	O
multihoming	B-Protocol
and	O
quality	O
of	O
service	O
without	O
the	O
need	O
for	O
additional	O
specialized	O
protocols	O
like	O
RTP	B-Protocol
and	O
UDP	B-Protocol
,	O
as	O
well	O
as	O
to	O
allow	O
simplified	O
network	O
administration	O
without	O
the	O
need	O
for	O
concepts	O
like	O
autonomous	B-Architecture
systems	I-Architecture
and	O
NAT	B-Protocol
.	O
</s>
<s>
The	O
principles	O
behind	O
RINA	O
were	O
first	O
presented	O
by	O
John	O
Day	O
in	O
his	O
2008	O
book	O
Patterns	O
in	O
Network	B-Architecture
Architecture	I-Architecture
:	O
A	O
return	O
to	O
Fundamentals	O
.	O
</s>
<s>
This	O
work	O
is	O
a	O
start	O
afresh	O
,	O
taking	O
into	O
account	O
lessons	O
learned	O
in	O
the	O
35	O
years	O
of	O
TCP/IP	B-Protocol
’	O
s	O
existence	O
,	O
as	O
well	O
as	O
the	O
lessons	O
of	O
OSI	O
’s	O
failure	O
and	O
the	O
lessons	O
of	O
other	O
network	O
technologies	O
of	O
the	O
past	O
few	O
decades	O
,	O
such	O
as	O
CYCLADES	O
,	O
DECnet	B-Protocol
,	O
and	O
Xerox	B-Protocol
Network	I-Protocol
Systems	I-Protocol
.	O
</s>
<s>
The	O
starting	O
point	O
for	O
a	O
radically	O
new	O
and	O
different	O
network	B-Architecture
architecture	I-Architecture
like	O
RINA	O
is	O
an	O
attempt	O
to	O
solve	O
or	O
a	O
response	O
to	O
the	O
following	O
problems	O
which	O
do	O
not	O
appear	O
to	O
have	O
practical	O
or	O
compromise-free	O
solutions	O
with	O
current	O
network	B-Architecture
architectures	I-Architecture
,	O
especially	O
the	O
Internet	B-Protocol
protocol	I-Protocol
suite	I-Protocol
and	O
its	O
functional	O
layering	O
as	O
depicted	O
in	O
Figure	O
1	O
:	O
</s>
<s>
Transmission	O
complexity	O
:	O
the	O
separation	O
of	O
IP	B-Protocol
and	O
TCP	B-Protocol
results	O
in	O
inefficiency	O
,	O
with	O
the	O
MTU	B-Protocol
discovery	I-Protocol
performed	O
to	O
prevent	O
IP	B-Protocol
fragmentation	I-Protocol
being	O
the	O
clearest	O
symptom	O
.	O
</s>
<s>
Performance	O
:	O
TCP	B-Protocol
itself	O
carries	O
rather	O
high	O
overhead	O
with	O
its	O
handshake	O
,	O
which	O
also	O
causes	O
vulnerabilities	O
such	O
as	O
SYN	O
floods	O
.	O
</s>
<s>
Also	O
,	O
TCP	B-Protocol
relies	O
on	O
packet	O
dropping	O
to	O
throttle	O
itself	O
and	O
avoid	O
congestion	O
,	O
meaning	O
its	O
congestion	O
control	O
is	O
purely	O
reactive	O
,	O
not	O
proactive	O
or	O
preventive	O
.	O
</s>
<s>
Multihoming	B-Protocol
:	O
the	O
IP	B-Protocol
address	I-Protocol
and	O
port	B-Protocol
number	I-Protocol
are	O
too	O
low-level	O
to	O
identify	O
an	O
application	O
in	O
two	O
different	O
networks	O
.	O
</s>
<s>
DNS	B-Application
does	O
n't	O
solve	O
this	O
because	O
hostnames	B-Protocol
must	O
resolve	O
to	O
a	O
single	O
IP	B-Protocol
address	I-Protocol
and	O
port	B-Protocol
number	I-Protocol
combination	O
,	O
making	O
them	O
aliases	O
instead	O
of	O
identities	O
.	O
</s>
<s>
Neither	O
does	O
LISP	B-Protocol
,	O
because	O
i	O
)	O
it	O
still	O
uses	O
the	O
locator	O
,	O
which	O
is	O
an	O
IP	B-Protocol
address	I-Protocol
,	O
for	O
routing	O
,	O
and	O
ii	O
)	O
it	O
is	O
based	O
on	O
a	O
false	O
distinction	O
,	O
in	O
that	O
all	O
entities	O
in	O
a	O
scope	O
are	O
located	O
by	O
their	O
identifiers	O
to	O
begin	O
with	O
;	O
in	O
addition	O
,	O
it	O
also	O
introduces	O
scalability	O
problems	O
of	O
its	O
own	O
.	O
</s>
<s>
Mobility	O
:	O
the	O
IP	B-Protocol
address	I-Protocol
and	O
port	B-Protocol
number	I-Protocol
are	O
also	O
too	O
low-level	O
to	O
identify	O
an	O
application	O
as	O
it	O
moves	O
between	O
networks	O
,	O
resulting	O
in	O
complications	O
for	O
mobile	O
devices	O
such	O
as	O
smartphones	O
.	O
</s>
<s>
Though	O
a	O
solution	O
,	O
Mobile	B-Protocol
IP	I-Protocol
in	O
reality	O
shifts	O
the	O
problem	O
entirely	O
to	O
the	O
Care-of	B-Protocol
address	I-Protocol
and	O
introduces	O
an	O
IP	B-Protocol
tunnel	O
,	O
with	O
attendant	O
complexity	O
.	O
</s>
<s>
Management	O
:	O
the	O
same	O
low-level	O
nature	O
of	O
the	O
IP	B-Protocol
address	I-Protocol
encourages	O
multiple	O
addresses	O
or	O
even	O
address	O
ranges	O
to	O
be	O
allocated	O
to	O
single	O
hosts	O
,	O
putting	O
pressure	O
on	O
allocation	O
and	O
accelerating	O
exhaustion	O
.	O
</s>
<s>
NAT	B-Protocol
only	O
delays	O
address	O
exhaustion	O
and	O
potentially	O
introduces	O
even	O
more	O
problems	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
,	O
functional	O
layering	O
of	O
the	O
Internet	B-Protocol
protocol	I-Protocol
suite	I-Protocol
's	O
architecture	O
leaves	O
room	O
for	O
only	O
two	O
scopes	O
,	O
complicating	O
subdivision	O
of	O
administration	O
of	O
the	O
Internet	O
and	O
requiring	O
the	O
artificial	O
notion	O
of	O
autonomous	B-Architecture
systems	I-Architecture
.	O
</s>
<s>
OSPF	B-Protocol
and	O
IS-IS	B-Protocol
have	O
relatively	O
few	O
problems	O
,	O
but	O
do	O
not	O
scale	O
well	O
,	O
forcing	O
usage	O
of	O
BGP	B-Protocol
for	O
larger	O
networks	O
and	O
inter-domain	O
routing	O
.	O
</s>
<s>
Security	O
:	O
the	O
nature	O
of	O
the	O
IP	B-Protocol
address	I-Protocol
space	O
itself	O
results	O
in	O
frail	O
security	O
,	O
since	O
there	O
is	O
no	O
true	O
configurable	O
policy	O
for	O
adding	O
or	O
removing	O
IP	B-Protocol
addresses	I-Protocol
other	O
than	O
physically	O
preventing	O
attachment	O
.	O
</s>
<s>
TLS	B-Protocol
and	O
IPSec	B-Protocol
provide	O
solutions	O
,	O
but	O
with	O
accompanying	O
complexity	O
.	O
</s>
<s>
Firewalls	B-Application
and	O
blacklists	O
are	O
vulnerable	O
to	O
overwhelming	O
,	O
ergo	O
not	O
scalable	O
.	O
</s>
<s>
Though	O
these	O
problems	O
are	O
far	O
more	O
acutely	O
visible	O
today	O
,	O
there	O
have	O
been	O
precedents	O
and	O
cases	O
almost	O
right	O
from	O
the	O
beginning	O
of	O
the	O
ARPANET	O
,	O
the	O
environment	O
in	O
which	O
the	O
Internet	B-Protocol
protocol	I-Protocol
suite	I-Protocol
was	O
designed	O
:	O
</s>
<s>
In	O
1972	O
,	O
Tinker	O
Air	O
Force	O
Base	O
wanted	O
connections	O
to	O
two	O
different	O
IMPs	B-Protocol
for	O
redundancy	O
.	O
</s>
<s>
ARPANET	O
designers	O
realized	O
that	O
they	O
could	O
n't	O
support	O
this	O
feature	O
because	O
host	O
addresses	O
were	O
the	O
addresses	O
of	O
the	O
IMP	O
port	B-Protocol
number	I-Protocol
the	O
host	O
was	O
connected	O
to	O
(	O
borrowing	O
from	O
telephony	O
)	O
.	O
</s>
<s>
Initial	O
TCP	B-Protocol
versions	O
performed	O
the	O
error	O
and	O
flow	O
control	O
(	O
current	O
TCP	B-Protocol
)	O
and	O
relaying	O
and	O
multiplexing	O
(	O
IP	B-Protocol
)	O
functions	O
in	O
the	O
same	O
protocol	O
.	O
</s>
<s>
In	O
1978	O
TCP	B-Protocol
was	O
split	O
from	O
IP	B-Protocol
even	O
though	O
the	O
two	O
layers	O
had	O
the	O
same	O
scope	O
.	O
</s>
<s>
By	O
1987	O
,	O
the	O
networking	O
community	O
was	O
well	O
aware	O
of	O
IP	B-Protocol
fragmentation	I-Protocol
's	O
problems	O
,	O
to	O
the	O
point	O
of	O
considering	O
it	O
harmful	O
.	O
</s>
<s>
However	O
,	O
it	O
was	O
not	O
understood	O
as	O
a	O
symptom	O
that	O
TCP	B-Protocol
and	O
IP	B-Protocol
were	O
interdependent	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
TCP	B-Protocol
uses	O
both	O
explicit	O
handshaking	O
as	O
well	O
as	O
more	O
limited	O
timer-based	O
management	O
of	O
the	O
connection	O
's	O
state	O
.	O
</s>
<s>
Early	O
in	O
1972	O
the	O
International	B-Protocol
Networking	I-Protocol
Working	I-Protocol
Group	I-Protocol
(	O
INWG	O
)	O
was	O
created	O
to	O
bring	O
together	O
the	O
nascent	O
network	O
research	O
community	O
.	O
</s>
<s>
When	O
TCP/IP	B-Protocol
was	O
introduced	O
it	O
ran	O
at	O
the	O
internetwork	B-Protocol
layer	I-Protocol
on	O
top	O
of	O
the	O
Host-IMP	B-Protocol
Protocol	I-Protocol
,	O
when	O
running	O
over	O
the	O
ARPANET	O
.	O
</s>
<s>
But	O
when	O
NCP	B-Protocol
was	O
shut	O
down	O
,	O
TCP/IP	B-Protocol
took	O
the	O
network	O
role	O
and	O
the	O
internetwork	B-Protocol
layer	I-Protocol
was	O
lost	O
.	O
</s>
<s>
This	O
explains	O
the	O
need	O
for	O
autonomous	B-Architecture
systems	I-Architecture
and	O
NAT	B-Protocol
today	O
,	O
to	O
partition	O
and	O
reuse	O
ranges	O
of	O
the	O
IP	B-Protocol
address	I-Protocol
space	O
to	O
facilitate	O
administration	O
.	O
</s>
<s>
The	O
need	O
for	O
an	O
address	O
higher-level	O
than	O
the	O
IP	B-Protocol
address	I-Protocol
was	O
well	O
understood	O
since	O
the	O
mid-1970s	O
.	O
</s>
<s>
However	O
,	O
application	O
names	O
were	O
not	O
introduced	O
and	O
DNS	B-Application
was	O
designed	O
and	O
deployed	O
,	O
continuing	O
to	O
use	O
well-known	O
ports	O
to	O
identify	O
applications	O
.	O
</s>
<s>
The	O
advent	O
of	O
the	O
web	O
and	O
HTTP	B-Protocol
created	O
a	O
need	O
for	O
application	O
names	O
,	O
leading	O
to	O
URLs	O
.	O
</s>
<s>
URLs	O
,	O
however	O
,	O
tie	O
each	O
application	O
instance	O
to	O
a	O
physical	O
interface	O
of	O
a	O
computer	O
and	O
a	O
specific	O
transport	O
connection	O
,	O
since	O
the	O
URL	O
contains	O
the	O
DNS	B-Application
name	O
of	O
an	O
IP	B-Protocol
interface	O
and	O
TCP	B-Protocol
port	I-Protocol
number	O
,	O
spilling	O
the	O
multihoming	B-Protocol
and	O
mobility	O
problems	O
to	O
applications	O
.	O
</s>
<s>
What	O
is	O
worse	O
,	O
the	O
adopted	O
congestion	O
control	O
-	O
the	O
Ethernet	O
congestion	O
avoidance	O
scheme	O
,	O
with	O
a	O
few	O
modifications	O
-	O
was	O
put	O
in	O
TCP	B-Protocol
.	O
</s>
<s>
In	O
1988	O
IAB	O
recommended	O
using	O
SNMP	B-Protocol
as	O
the	O
initial	O
network	O
management	O
protocol	O
for	O
the	O
Internet	O
to	O
later	O
transition	O
to	O
the	O
object-oriented	O
approach	O
of	O
CMIP	O
.	O
</s>
<s>
SNMP	B-Protocol
was	O
a	O
step	O
backwards	O
in	O
network	O
management	O
,	O
justified	O
as	O
a	O
temporary	O
measure	O
while	O
the	O
required	O
more	O
sophisticated	O
approaches	O
were	O
implemented	O
,	O
but	O
the	O
transition	O
never	O
happened	O
.	O
</s>
<s>
In	O
1992	O
the	O
IAB	O
produced	O
a	O
series	O
of	O
recommendations	O
to	O
resolve	O
the	O
scaling	O
problems	O
of	O
the	O
IPv4-based	O
Internet	O
:	O
address	O
space	O
consumption	O
and	O
routing	O
information	O
explosion	O
.	O
</s>
<s>
Three	O
options	O
were	O
proposed	O
:	O
introduce	O
CIDR	B-Protocol
to	O
mitigate	O
the	O
problem	O
;	O
design	O
the	O
next	O
version	O
of	O
IP	B-Protocol
(	O
IPv7	O
)	O
based	O
on	O
CLNP	B-Protocol
;	O
or	O
continue	O
the	O
research	O
into	O
naming	O
,	O
addressing	O
and	O
routing	O
.	O
</s>
<s>
CLNP	B-Protocol
was	O
an	O
OSI-based	O
protocol	O
that	O
addressed	O
nodes	O
instead	O
of	O
interfaces	O
,	O
solving	O
the	O
old	O
multihoming	B-Protocol
problem	O
dating	O
back	O
to	O
the	O
ARPANET	O
,	O
and	O
allowing	O
for	O
better	O
routing	O
information	O
aggregation	O
.	O
</s>
<s>
CIDR	B-Protocol
was	O
introduced	O
,	O
but	O
the	O
IETF	O
did	O
n't	O
accept	O
an	O
IPv7	O
based	O
on	O
CLNP	B-Protocol
.	O
</s>
<s>
IAB	O
reconsidered	O
its	O
decision	O
and	O
the	O
IPng	B-Protocol
process	O
started	O
,	O
culminating	O
with	O
IPv6	B-Protocol
.	O
</s>
<s>
One	O
of	O
the	O
rules	O
for	O
IPng	B-Protocol
was	O
not	O
to	O
change	O
the	O
semantics	O
of	O
the	O
IP	B-Protocol
address	I-Protocol
,	O
which	O
continues	O
to	O
name	O
the	O
interface	O
,	O
perpetuating	O
the	O
multihoming	B-Protocol
problem	O
.	O
</s>
<s>
RINA	O
is	O
the	O
result	O
of	O
an	O
effort	O
to	O
work	O
out	O
general	O
principles	O
in	O
computer	B-Architecture
networking	I-Architecture
that	O
apply	O
in	O
all	O
situations	O
.	O
</s>
<s>
As	O
explained	O
above	O
,	O
the	O
IP	B-Protocol
address	I-Protocol
is	O
too	O
low-level	O
an	O
identifier	O
on	O
which	O
to	O
base	O
multihoming	B-Protocol
and	O
mobility	O
efficiently	O
,	O
as	O
well	O
as	O
requiring	O
routing	O
tables	O
to	O
be	O
bigger	O
than	O
necessary	O
.	O
</s>
<s>
Moreover	O
,	O
the	O
last	O
step	O
can	O
be	O
performed	O
more	O
frequently	O
to	O
exploit	O
multihoming	B-Protocol
for	O
load	O
balancing	O
.	O
</s>
<s>
With	O
this	O
naming	O
structure	O
,	O
mobility	O
and	O
multihoming	B-Protocol
are	O
inherently	O
supported	O
if	O
the	O
names	O
have	O
carefully	O
chosen	O
properties	O
:	O
</s>
<s>
The	O
Internet	B-Protocol
protocol	I-Protocol
suite	I-Protocol
also	O
generally	O
dictates	O
that	O
protocols	O
be	O
designed	O
in	O
isolation	O
,	O
without	O
regard	O
to	O
whether	O
aspects	O
have	O
been	O
duplicated	O
in	O
other	O
protocols	O
and	O
,	O
therefore	O
,	O
whether	O
these	O
can	O
be	O
made	O
into	O
a	O
policy	O
.	O
</s>
<s>
The	O
same	O
research	O
also	O
notes	O
that	O
TCP	B-Protocol
already	O
uses	O
these	O
timers	O
in	O
its	O
operation	O
,	O
making	O
Delta-T	O
comparatively	O
simpler	O
.	O
</s>
<s>
Among	O
other	O
things	O
,	O
the	O
security	O
policy	O
can	O
also	O
specify	O
an	O
authentication	O
mechanism	O
;	O
this	O
obsoletes	O
firewalls	B-Application
and	O
blacklists	O
because	O
a	O
DAP	O
or	O
IPCP	O
that	O
ca	O
n't	O
join	O
a	O
DAF	O
or	O
DIF	O
ca	O
n't	O
transmit	O
or	O
receive	O
.	O
</s>
<s>
In	O
addition	O
to	O
this	O
,	O
BU	O
has	O
incorporated	O
RINA	O
concepts	O
and	O
theory	O
in	O
their	O
computer	B-Architecture
networking	I-Architecture
courses	O
.	O
</s>
<s>
The	O
main	O
goal	O
of	O
IRINA	O
is	O
to	O
study	O
the	O
use	O
of	O
the	O
Recursive	B-Architecture
InterNetwork	I-Architecture
Architecture	I-Architecture
(	O
RINA	O
)	O
as	O
the	O
foundation	O
of	O
the	O
next	O
generation	O
NREN	O
and	O
GÉANT	O
network	B-Architecture
architectures	I-Architecture
.	O
</s>
