<s>
Fuzzball	B-Protocol
routers	I-Protocol
were	O
the	O
first	O
modern	O
routers	B-Protocol
on	O
the	O
Internet	O
.	O
</s>
<s>
They	O
were	O
DEC	B-Device
PDP-11	I-Device
computers	O
(	O
usually	O
LSI-11	O
personal	O
workstations	O
)	O
loaded	O
with	O
the	O
Fuzzball	O
software	O
written	O
by	O
David	O
L	O
.	O
Mills	O
(	O
of	O
the	O
University	O
of	O
Delaware	O
)	O
.	O
</s>
<s>
Six	O
Fuzzball	B-Protocol
routers	I-Protocol
provided	O
the	O
routing	O
backbone	O
of	O
the	O
first	O
56	O
kbit/s	O
NSFNET	O
,	O
allowing	O
the	O
testing	O
of	O
many	O
of	O
the	O
Internet	O
's	O
first	O
protocols	O
.	O
</s>
<s>
It	O
allowed	O
the	O
development	O
of	O
the	O
first	O
TCP/IP	O
routing	O
protocols	O
,	O
and	O
the	O
Network	B-Protocol
Time	I-Protocol
Protocol	I-Protocol
.	O
</s>
<s>
They	O
were	O
the	O
first	O
routers	B-Protocol
to	O
implement	O
key	O
refinements	O
to	O
TCP/IP	O
such	O
as	O
variable-length	O
subnet	B-Protocol
masks	I-Protocol
.	O
</s>
