<s>
Named	B-Protocol
Data	I-Protocol
Networking	I-Protocol
(	O
NDN	O
)	O
(	O
related	O
to	O
content-centric	B-Protocol
networking	I-Protocol
(	O
CCN	O
)	O
,	O
content-based	O
networking	O
,	O
data-oriented	O
networking	O
or	O
information-centric	B-Protocol
networking	I-Protocol
(	O
ICN	O
)	O
)	O
is	O
a	O
proposed	O
Future	B-Architecture
Internet	I-Architecture
architecture	O
inspired	O
by	O
years	O
of	O
empirical	O
research	O
into	O
network	O
usage	O
and	O
a	O
growing	O
awareness	O
of	O
unsolved	O
problems	O
in	O
contemporary	O
internet	O
architectures	O
like	O
IP	B-Protocol
.	O
</s>
<s>
NDN	O
has	O
its	O
roots	O
in	O
an	O
earlier	O
project	O
,	O
Content-Centric	B-Protocol
Networking	I-Protocol
(	O
CCN	O
)	O
,	O
which	O
Van	O
Jacobson	O
first	O
publicly	O
presented	O
in	O
2006	O
.	O
</s>
<s>
The	O
NDN	O
project	O
is	O
investigating	O
Jacobson	O
's	O
proposed	O
evolution	O
from	O
today	O
's	O
host-centric	O
network	O
architecture	O
IP	B-Protocol
to	O
a	O
data-centric	O
network	O
architecture	O
(	O
NDN	O
)	O
.	O
</s>
<s>
Its	O
premise	O
is	O
that	O
the	O
Internet	O
is	O
primarily	O
used	O
as	O
an	O
information	O
distribution	O
network	O
,	O
which	O
is	O
not	O
a	O
good	O
match	O
for	O
IP	B-Protocol
,	O
and	O
that	O
the	O
future	B-Architecture
Internet	I-Architecture
's	O
"	O
thin	O
waist	O
"	O
should	O
be	O
based	O
on	O
named	O
data	O
rather	O
than	O
numerically	O
addressed	O
hosts	O
.	O
</s>
<s>
Today	O
's	O
Internet	O
's	O
hourglass	O
architecture	O
centers	O
on	O
a	O
universal	O
network	O
layer	O
,	O
IP	B-Protocol
,	O
which	O
implements	O
the	O
minimal	O
functionality	O
necessary	O
for	O
global	O
inter-connectivity	O
.	O
</s>
<s>
However	O
,	O
IP	B-Protocol
was	O
designed	O
to	O
create	O
a	O
communication	O
network	O
,	O
where	O
packets	O
named	O
only	O
communication	O
endpoints	O
.	O
</s>
<s>
Sustained	O
growth	O
in	O
e-commerce	O
,	O
digital	O
media	O
,	O
social	O
networking	O
,	O
and	O
smartphone	B-Application
applications	I-Application
has	O
led	O
to	O
dominant	O
use	O
of	O
the	O
Internet	O
as	O
a	O
distribution	O
network	O
.	O
</s>
<s>
Distribution	O
networks	O
are	O
more	O
general	O
than	O
communication	O
networks	O
,	O
and	O
solving	O
distribution	O
problems	O
via	O
a	O
point-to-point	B-Architecture
communication	I-Architecture
protocol	O
is	O
complex	O
and	O
error-prone	O
.	O
</s>
<s>
The	O
Named	B-Protocol
Data	I-Protocol
Networking	I-Protocol
(	O
NDN	O
)	O
project	O
proposed	O
an	O
evolution	O
of	O
the	O
IP	B-Protocol
architecture	O
that	O
generalizes	O
the	O
role	O
of	O
this	O
thin	O
waist	O
,	O
such	O
that	O
packets	O
can	O
name	O
objects	O
other	O
than	O
communication	O
endpoints	O
.	O
</s>
<s>
In	O
2009	O
,	O
PARC	O
announced	O
their	O
content-centric	O
architecture	O
within	O
the	O
CCNx	B-Protocol
project	O
,	O
which	O
was	O
led	O
by	O
Jacobson	O
,	O
at	O
the	O
time	O
a	O
research	O
fellow	O
at	O
PARC	O
.	O
</s>
<s>
On	O
September	O
21	O
,	O
2009	O
,	O
PARC	O
published	O
the	O
specifications	O
for	O
interoperability	O
and	O
released	O
an	O
initial	O
open	O
source	O
implementation	O
(	O
under	O
GPL	B-License
)	O
of	O
the	O
Content-Centric	B-Protocol
Networking	I-Protocol
research	O
project	O
on	O
the	O
.	O
</s>
<s>
NDN	O
is	O
one	O
instance	O
of	O
a	O
more	O
general	O
network	O
research	O
direction	O
called	O
information-centric	B-Protocol
networking	I-Protocol
(	O
ICN	O
)	O
,	O
under	O
which	O
different	O
architecture	O
designs	O
have	O
emerged	O
.	O
</s>
<s>
The	O
is	O
a	O
lightweight	O
NDN	O
library	O
designed	O
for	O
IoT	B-Operating_System
networks	O
and	O
constrained	O
devices	O
.	O
</s>
<s>
Several	O
client	O
applications	O
are	O
being	O
developed	O
in	O
the	O
areas	O
of	O
real-time	O
conferencing	O
,	O
NDN	O
friendly	O
file	O
systems	O
,	O
chat	O
,	O
file	O
sharing	O
,	O
and	O
IoT	B-Operating_System
.	O
</s>
<s>
End-to-end	B-Application
principle	I-Application
:	O
Enables	O
the	O
development	O
of	O
robust	O
applications	O
in	O
the	O
face	O
of	O
network	O
failures	O
.	O
</s>
<s>
Forwarding	B-Protocol
Information	I-Protocol
Base	I-Protocol
(	O
FIB	O
)	O
:	O
a	O
routing	O
table	O
which	O
maps	O
name	O
components	O
to	O
interfaces	O
.	O
</s>
<s>
)	O
,	O
and	O
eliminates	O
the	O
need	O
for	O
any	O
notion	O
of	O
source	O
or	O
destination	O
nodes	O
in	O
data	O
delivery	O
,	O
unlike	O
in	O
IP	B-Protocol
's	O
end-to-end	O
packet	O
delivery	O
model	O
.	O
</s>
<s>
Namespace	O
management	O
is	O
not	O
part	O
of	O
the	O
NDN	O
architecture	O
,	O
just	O
as	O
address	O
space	O
management	O
is	O
not	O
part	O
of	O
the	O
IP	B-Protocol
architecture	O
.	O
</s>
<s>
NDN	O
routes	O
and	O
forwards	O
packets	O
based	O
on	O
names	O
,	O
which	O
eliminates	O
three	O
problems	O
caused	O
by	O
addresses	O
in	O
the	O
IP	B-Protocol
architecture	O
:	O
</s>
<s>
Address	B-Protocol
space	I-Protocol
exhaustion	I-Protocol
:	O
NDN	O
namespace	O
is	O
essentially	O
unbounded	O
.	O
</s>
<s>
NAT	B-Protocol
traversal	O
:	O
NDN	O
does	O
away	O
with	O
addresses	O
,	O
public	O
or	O
private	O
,	O
so	O
NAT	B-Protocol
is	O
unnecessary	O
.	O
</s>
<s>
High	O
loss	O
end	O
to	O
end	O
reliability	O
:	O
IP	B-Protocol
based	O
networks	O
require	O
lost	O
or	O
dropped	O
packets	O
to	O
be	O
retransmitted	O
by	O
the	O
sender	O
.	O
</s>
<s>
The	O
retransmitted	O
interest	O
only	O
needs	O
to	O
reach	O
a	O
forwarder	O
with	O
a	O
cached	O
copy	O
of	O
the	O
data	O
giving	O
NDN	O
based	O
networks	O
higher	O
throughput	O
than	O
IP	B-Protocol
based	O
networks	O
when	O
packet	O
loss	O
rates	O
are	O
high	O
.	O
</s>
<s>
NDN	O
can	O
use	O
conventional	O
routing	O
algorithms	O
such	O
as	O
link	B-Protocol
state	I-Protocol
and	O
distance	B-Protocol
vector	I-Protocol
.	O
</s>
<s>
Instead	O
of	O
announcing	O
IP	B-Protocol
prefixes	I-Protocol
,	O
an	O
NDN	O
router	O
announces	O
name	O
prefixes	O
that	O
cover	O
the	O
data	O
the	O
router	O
is	O
willing	O
to	O
serve	O
.	O
</s>
<s>
Conventional	O
routing	O
protocols	O
,	O
such	O
as	O
OSPF	B-Protocol
and	O
BGP	B-Protocol
,	O
can	O
be	O
adapted	O
to	O
route	O
on	O
name	O
prefixes	O
by	O
treating	O
names	O
as	O
a	O
sequence	O
of	O
opaque	O
components	O
and	O
doing	O
component-wise	O
longest	O
prefix	O
match	O
of	O
a	O
name	O
in	O
an	O
Interest	O
packet	O
against	O
the	O
FIB	B-Protocol
table	I-Protocol
.	O
</s>
<s>
This	O
per	O
hop	O
,	O
per	O
packet	O
state	O
differs	O
from	O
IP	B-Protocol
's	O
stateless	O
data	O
plane	O
.	O
</s>
<s>
Packets	O
cannot	O
loop	O
in	O
NDN	O
,	O
which	O
means	O
there	O
is	O
no	O
need	O
for	O
time-to-live	O
and	O
other	O
measures	O
implemented	O
in	O
IP	B-Protocol
and	O
related	O
protocols	O
to	O
address	O
these	O
issues	O
.	O
</s>
<s>
In	O
contrast	O
to	O
TCP/IP	O
security	O
(	O
e.g.	O
,	O
TLS	O
)	O
which	O
secures	O
communication	O
by	O
securing	O
IP-to-IP	O
channels	O
,	O
NDN	O
secures	O
the	O
data	O
itself	O
by	O
requiring	O
data	O
producers	O
to	O
cryptographically	O
sign	O
every	O
Data	O
packet	O
.	O
</s>
<s>
The	O
publisher	O
's	O
signature	O
ensures	O
the	O
integrity	O
and	O
enables	O
authentication	O
of	O
data	O
provenance	O
,	O
allowing	O
a	O
consumer	O
's	O
trust	B-General_Concept
in	O
data	O
to	O
be	O
decoupled	O
from	O
how	O
or	O
where	O
it	O
is	O
obtained	O
.	O
</s>
<s>
NDN	O
also	O
supports	O
fine-grained	O
trust	B-General_Concept
,	O
allowing	O
consumers	O
to	O
reason	O
about	O
whether	O
a	O
public	B-Application
key	I-Application
owner	O
is	O
an	O
acceptable	O
publisher	O
for	O
a	O
specific	O
piece	O
of	O
data	O
in	O
a	O
specific	O
context	O
.	O
</s>
<s>
The	O
second	O
primary	O
research	O
thrust	O
is	O
designing	O
and	O
developing	O
usable	O
mechanisms	O
to	O
manage	O
user	O
trust	B-General_Concept
.	O
</s>
<s>
There	O
has	O
been	O
research	O
into	O
3	O
different	O
types	O
of	O
trust	B-General_Concept
models	O
:	O
</s>
<s>
hierarchical	O
trust	B-General_Concept
model	O
:	O
where	O
a	O
key	O
namespace	O
authorizes	O
use	O
of	O
keys	O
.	O
</s>
<s>
A	O
data	O
packet	O
carrying	O
a	O
public	B-Application
key	I-Application
is	O
effectively	O
a	O
certificate	O
,	O
since	O
it	O
is	O
signed	O
by	O
a	O
third	O
party	O
,	O
and	O
this	O
public	B-Application
key	I-Application
is	O
used	O
to	O
sign	O
specific	O
data	O
.	O
</s>
<s>
web	O
of	O
trust	B-General_Concept
:	O
to	O
enable	O
secure	O
communication	O
without	O
requiring	O
pre-agreed	O
trust	B-General_Concept
anchors	O
.	O
</s>
<s>
lightweight	O
trust	B-General_Concept
for	O
IoT	B-Operating_System
:	O
The	O
NDN	O
trust	B-General_Concept
model	O
primarily	O
based	O
on	O
asymmetric	B-Application
cryptography	I-Application
,	O
which	O
is	O
infeasible	O
for	O
resource	O
constraint	O
devices	O
in	O
IoT	B-Operating_System
paradigm	O
.	O
</s>
<s>
But	O
trust	B-General_Concept
management	O
,	O
i.e.	O
,	O
how	O
to	O
determine	O
the	O
authenticity	O
of	O
a	O
given	O
key	O
for	O
a	O
particular	O
packet	O
in	O
a	O
given	O
application	O
,	O
is	O
a	O
primary	O
research	O
challenge	O
.	O
</s>
<s>
Consistent	O
with	O
an	O
experimental	O
approach	O
,	O
NDN	O
trust	B-General_Concept
management	O
research	O
is	O
driven	O
by	O
application	O
development	O
and	O
use	O
:	O
solving	O
specific	O
problems	O
first	O
and	O
then	O
identifying	O
common	O
patterns	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
security	O
needs	O
of	O
NLSR	O
required	O
development	O
of	O
a	O
simple	O
hierarchical	O
trust	B-General_Concept
model	O
,	O
with	O
keys	O
at	O
lower	O
(	O
closer	O
to	O
root	O
)	O
levels	O
,	O
being	O
used	O
to	O
sign	O
keys	O
in	O
higher	O
levels	O
in	O
which	O
keys	O
are	O
published	O
with	O
names	O
that	O
reflect	O
their	O
trust	B-General_Concept
relationship	O
.	O
</s>
<s>
In	O
this	O
trust	B-General_Concept
model	O
,	O
the	O
namespace	O
matches	O
the	O
hierarchy	O
of	O
trust	B-General_Concept
delegation	O
,	O
i.e.	O
,	O
/root/site/operator/	O
router/process	O
.	O
</s>
<s>
This	O
paradigm	O
can	O
be	O
easily	O
extended	O
to	O
Other	O
applications	O
where	O
real	O
world	O
trust	B-General_Concept
tends	O
to	O
follow	O
a	O
hierarchical	O
pattern	O
,	O
such	O
as	O
in	O
our	O
building	O
management	O
systems	O
(	O
BMS	O
)	O
.	O
</s>
<s>
Since	O
NDN	O
leaves	O
the	O
trust	B-General_Concept
model	O
under	O
the	O
control	O
of	O
each	O
application	O
,	O
more	O
flexible	O
and	O
expressive	O
trust	B-General_Concept
relations	O
,	O
may	O
also	O
be	O
expressed	O
.	O
</s>
<s>
One	O
such	O
example	O
is	O
ChronoChat	O
,	O
which	O
motivated	O
experimentation	O
with	O
a	O
web-of-trust	O
model	O
.	O
</s>
<s>
Future	O
applications	O
will	O
implement	O
a	O
cross-certifying	O
model	O
(	O
SDSI	O
)	O
[	O
13	O
,	O
3 ]	O
,	O
which	O
provides	O
more	O
redundancy	O
of	O
verification	O
,	O
allowing	O
data	O
and	O
key	O
names	O
to	O
be	O
independent	O
,	O
which	O
more	O
easily	O
accommodates	O
a	O
variety	O
of	O
real-world	O
trust	B-General_Concept
relationships	O
.	O
</s>
<s>
Owing	O
to	O
multi-source	O
,	O
multicast	O
content-delivery	O
nature	O
of	O
Named	B-Protocol
Data	I-Protocol
Networking	I-Protocol
,	O
the	O
random	O
linear	O
coding	O
can	O
improve	O
over	O
all	O
network	O
efficiency	O
.	O
</s>
