<s>
The	O
NPL	B-Protocol
network	I-Protocol
,	O
or	O
NPL	B-Protocol
Data	I-Protocol
Communications	I-Protocol
Network	I-Protocol
,	O
was	O
a	O
local	O
area	O
computer	B-Architecture
network	I-Architecture
operated	O
by	O
a	O
team	O
from	O
the	O
National	O
Physical	O
Laboratory	O
in	O
London	O
that	O
pioneered	O
the	O
concept	O
of	O
packet	B-Protocol
switching	I-Protocol
.	O
</s>
<s>
The	O
NPL	B-Protocol
network	I-Protocol
and	O
the	O
ARPANET	O
in	O
the	O
United	O
States	O
were	O
the	O
first	O
two	O
computer	B-Architecture
networks	I-Architecture
that	O
implemented	O
packet	B-Protocol
switching	I-Protocol
and	O
the	O
NPL	B-Protocol
network	I-Protocol
was	O
the	O
first	O
to	O
use	O
high-speed	O
links	O
.	O
</s>
<s>
In	O
1965	O
,	O
Donald	O
Davies	O
,	O
who	O
was	O
later	O
appointed	O
to	O
head	O
of	O
the	O
NPL	O
Division	O
of	O
Computer	O
Science	O
,	O
proposed	O
a	O
commercial	O
national	O
data	B-Architecture
network	I-Architecture
based	O
on	O
packet	B-Protocol
switching	I-Protocol
in	O
Proposal	O
for	O
the	O
Development	O
of	O
a	O
National	O
Communications	O
Service	O
for	O
On-line	O
Data	O
Processing	O
.	O
</s>
<s>
After	O
the	O
proposal	O
was	O
not	O
taken	O
up	O
nationally	O
,	O
during	O
1966	O
he	O
headed	O
a	O
team	O
which	O
produced	O
a	O
design	O
for	O
a	O
local	B-General_Concept
network	I-General_Concept
to	O
serve	O
the	O
needs	O
of	O
NPL	O
and	O
prove	O
the	O
feasibility	O
of	O
packet	B-Protocol
switching	I-Protocol
.	O
</s>
<s>
The	O
design	O
was	O
the	O
first	O
to	O
describe	O
the	O
concept	O
of	O
an	O
"	O
Interface	B-Application
computer	O
"	O
,	O
today	O
known	O
as	O
a	O
router	B-Protocol
.	O
</s>
<s>
The	O
next	O
year	O
,	O
a	O
written	O
version	O
of	O
the	O
proposal	O
entitled	O
NPL	O
Data	B-Architecture
Network	I-Architecture
was	O
presented	O
by	O
Roger	O
Scantlebury	O
at	O
the	O
Symposium	O
on	O
Operating	O
Systems	O
Principles	O
.	O
</s>
<s>
It	O
described	O
how	O
computers	O
(	O
nodes	B-Protocol
)	O
used	O
to	O
transmit	O
signals	O
(	O
packets	B-Protocol
)	O
would	O
be	O
connected	O
by	O
electrical	O
links	O
to	O
re-transmit	O
the	O
signals	O
between	O
and	O
to	O
the	O
nodes	B-Protocol
,	O
and	O
interface	B-Application
computers	O
would	O
be	O
used	O
to	O
link	O
node	O
networks	O
to	O
so-called	O
time-sharing	B-General_Concept
computers	O
and	O
other	O
users	O
.	O
</s>
<s>
The	O
interface	B-Application
computers	O
would	O
transmit	O
multiplex	B-Architecture
signals	O
between	O
networks	O
,	O
and	O
nodes	B-Protocol
would	O
switch	O
transmissions	O
while	O
connected	O
to	O
electrical	O
circuitry	O
functioning	O
at	O
a	O
rate	O
of	O
processing	O
amounting	O
to	O
mega-bits	O
.	O
</s>
<s>
The	O
NPL	B-Protocol
network	I-Protocol
initially	O
proposed	O
a	O
line	O
speed	O
of	O
768	O
kbit/s	O
.	O
</s>
<s>
Influenced	O
by	O
this	O
,	O
the	O
planned	O
line	O
speed	O
for	O
ARPANET	O
was	O
upgraded	O
from	O
2.4	O
kbit/s	O
to	O
50	O
kbit/s	O
and	O
a	O
similar	O
packet	B-Protocol
format	O
adopted	O
.	O
</s>
<s>
The	O
first	O
theoretical	O
foundation	O
of	O
packet	B-Protocol
switching	I-Protocol
was	O
the	O
work	O
of	O
Paul	O
Baran	O
,	O
in	O
which	O
data	O
was	O
transmitted	O
in	O
small	O
chunks	O
and	O
routed	O
independently	O
by	O
a	O
method	O
similar	O
to	O
store-and-forward	B-Protocol
techniques	O
between	O
intermediate	O
networking	O
nodes	B-Protocol
.	O
</s>
<s>
Davies	O
independently	O
arrived	O
at	O
the	O
same	O
model	O
in	O
1965	O
and	O
named	O
it	O
packet	B-Protocol
switching	I-Protocol
.	O
</s>
<s>
He	O
chose	O
the	O
term	O
"	O
packet	B-Protocol
"	O
after	O
consulting	O
with	O
an	O
NPL	O
linguist	O
because	O
it	O
was	O
capable	O
of	O
being	O
translated	O
into	O
languages	O
other	O
than	O
English	O
without	O
compromise	O
.	O
</s>
<s>
Davies	O
gave	O
the	O
first	O
public	O
presentation	O
of	O
packet	B-Protocol
switching	I-Protocol
on	O
5	O
August	O
1968	O
.	O
</s>
<s>
The	O
NPL	O
team	O
used	O
their	O
packet	B-Protocol
switching	I-Protocol
concept	O
to	O
produce	O
an	O
experimental	O
network	O
using	O
a	O
Honeywell	B-Device
516	I-Device
node	O
.	O
</s>
<s>
Coincidentally	O
,	O
this	O
was	O
the	O
same	O
computer	O
chosen	O
by	O
the	O
ARPANET	O
to	O
serve	O
as	O
Interface	B-Protocol
Message	I-Protocol
Processors	I-Protocol
.	O
</s>
<s>
Elements	O
of	O
the	O
first	O
version	O
of	O
the	O
network	O
,	O
Mark	O
I	O
NPL	B-Protocol
Network	I-Protocol
,	O
became	O
operational	O
during	O
1969	O
then	O
fully	O
operational	O
in	O
January	O
1970	O
.	O
</s>
<s>
The	O
local	O
area	O
NPL	B-Protocol
network	I-Protocol
and	O
the	O
wide	O
area	O
ARPANET	O
in	O
the	O
United	O
States	O
were	O
the	O
first	O
two	O
computer	B-Architecture
networks	I-Architecture
that	O
implemented	O
packet	B-Protocol
switching	I-Protocol
.	O
</s>
<s>
The	O
network	O
later	O
used	O
high-speed	O
T1	O
links	O
(	O
1.544	O
Mbit/s	O
line	O
rate	O
)	O
,	O
the	O
first	O
computer	B-Architecture
network	I-Architecture
to	O
do	O
so	O
.	O
</s>
<s>
The	O
NPL	O
team	O
also	O
carried	O
out	O
simulation	O
work	O
on	O
the	O
performance	O
of	O
packet	B-Protocol
networks	I-Protocol
,	O
including	O
datagram	B-Protocol
networks	O
.	O
</s>
<s>
The	O
NPL	B-Protocol
network	I-Protocol
was	O
later	O
interconnected	O
with	O
other	O
networks	O
,	O
including	O
CYCLADES	O
and	O
the	O
European	O
Informatics	O
Network	O
(	O
EIN	O
)	O
in	O
1976	O
.	O
</s>
<s>
One	O
of	O
the	O
first	O
uses	O
of	O
the	O
term	O
"	O
protocol	O
"	O
in	O
a	O
data	O
commutations	O
context	O
occurs	O
in	O
a	O
memorandum	O
entitled	O
A	O
Protocol	O
for	O
Use	O
in	O
the	O
NPL	B-Protocol
Data	I-Protocol
Communications	I-Protocol
Network	I-Protocol
written	O
by	O
Roger	O
Scantlebury	O
and	O
Keith	O
Bartlett	O
in	O
April	O
1967	O
.	O
</s>
<s>
A	O
further	O
publication	O
by	O
Bartlett	O
in	O
1968	O
introduced	O
the	O
concept	O
of	O
an	O
"	O
alternating	B-Protocol
bit	I-Protocol
protocol	I-Protocol
"	O
(	O
later	O
used	O
by	O
the	O
ARPANET	O
and	O
the	O
EIN	O
)	O
and	O
described	O
the	O
need	O
for	O
three	O
levels	O
of	O
data	O
transmission	O
(	O
roughly	O
corresponding	O
to	O
the	O
lower	O
levels	O
of	O
the	O
seven-layer	O
OSI	O
model	O
that	O
emerged	O
a	O
decade	O
later	O
)	O
.	O
</s>
<s>
The	O
NPL	B-Protocol
network	I-Protocol
was	O
a	O
testbed	O
for	O
internetworking	B-Architecture
research	O
throughout	O
the	O
1970s	O
.	O
</s>
<s>
Davies	O
,	O
Scantlebury	O
and	O
Barber	O
were	O
active	O
members	O
of	O
the	O
International	B-Protocol
Networking	I-Protocol
Working	I-Protocol
Group	I-Protocol
(	O
INWG	O
)	O
formed	O
in	O
1972	O
.	O
</s>
<s>
Vint	O
Cerf	O
and	O
Bob	O
Kahn	O
acknowledged	O
Davies	O
and	O
Scantlebury	O
in	O
their	O
1974	O
paper	O
"	O
A	O
Protocol	O
for	O
Packet	B-Protocol
Network	I-Protocol
Intercommunication	O
"	O
.	O
</s>
<s>
NPL	O
research	O
investigated	O
the	O
"	O
basic	O
dilemma	O
"	O
involved	O
in	O
internetworking	B-Architecture
;	O
that	O
is	O
,	O
a	O
common	O
host	O
protocol	O
would	O
require	O
restructuring	O
existing	O
networks	O
if	O
they	O
were	O
not	O
designed	O
to	O
use	O
the	O
same	O
protocol	O
.	O
</s>
<s>
NPL	O
connected	O
with	O
the	O
European	O
Informatics	O
Network	O
by	O
translating	O
between	O
two	O
different	O
host	O
protocols	O
while	O
the	O
NPL	O
connection	O
to	O
the	O
Post	O
Office	O
Experimental	O
Packet	B-Protocol
Switched	I-Protocol
Service	O
used	O
a	O
common	O
host	O
protocol	O
in	O
both	O
networks	O
.	O
</s>
<s>
Davies	O
and	O
Barber	O
published	O
"	O
Communication	O
networks	O
for	O
computers	O
"	O
in	O
1973	O
and	O
"	O
Computer	B-Architecture
networks	I-Architecture
and	O
their	O
protocols	O
"	O
in	O
1979	O
.	O
</s>
<s>
They	O
spoke	O
at	O
the	O
Data	O
Communications	O
Symposium	O
in	O
1975	O
about	O
the	O
"	O
battle	O
for	O
access	O
standards	O
"	O
between	O
datagrams	B-Protocol
and	O
virtual	B-Protocol
circuits	I-Protocol
,	O
with	O
Barber	O
saying	O
the	O
"	O
lack	O
of	O
standard	O
access	O
interfaces	B-Application
for	O
emerging	O
public	O
packet-switched	B-Protocol
communication	O
networks	O
is	O
creating	O
'	O
some	O
kind	O
of	O
monster	O
 '	O
for	O
users	O
"	O
.	O
</s>
<s>
For	O
a	O
long	O
period	O
of	O
time	O
,	O
the	O
network	O
engineering	O
community	O
was	O
polarized	O
over	O
the	O
implementation	O
of	O
competing	O
protocol	O
suites	O
,	O
commonly	O
known	O
as	O
the	O
Protocol	B-Protocol
Wars	I-Protocol
.	O
</s>
<s>
It	O
was	O
unclear	O
which	O
type	O
of	O
protocol	O
would	O
result	O
in	O
the	O
best	O
and	O
most	O
robust	O
computer	B-Architecture
networks	I-Architecture
.	O
</s>
<s>
Davies	O
 '	O
research	O
at	O
NPL	O
later	O
focused	O
on	O
data	O
security	O
for	O
computer	B-Architecture
networks	I-Architecture
.	O
</s>
<s>
NPL	O
sponsors	O
a	O
gallery	O
,	O
opened	O
in	O
2009	O
,	O
about	O
the	O
development	O
of	O
packet	B-Protocol
switching	I-Protocol
and	O
"	O
Technology	O
of	O
the	O
Internet	O
"	O
at	O
The	O
National	O
Museum	O
of	O
Computing	O
at	O
Bletchley	O
Park	O
.	O
</s>
