<s>
On	O
a	O
local	B-General_Concept
area	I-General_Concept
network	I-General_Concept
,	O
token	B-Protocol
passing	I-Protocol
is	O
a	O
channel	O
access	O
method	O
where	O
a	O
packet	O
called	O
a	O
token	O
is	O
passed	O
between	O
nodes	O
to	O
authorize	O
that	O
node	O
to	O
communicate	O
.	O
</s>
<s>
In	O
contrast	O
to	O
polling	B-General_Concept
access	O
methods	O
,	O
there	O
is	O
no	O
pre-defined	O
"	O
master	O
"	O
node	O
.	O
</s>
<s>
The	O
most	O
well-known	O
examples	O
are	O
IBM	B-Device
Token	I-Device
Ring	I-Device
and	O
ARCNET	B-Protocol
,	O
but	O
there	O
were	O
a	O
range	O
of	O
others	O
,	O
including	O
FDDI	B-Protocol
(	O
Fiber	B-Protocol
Distributed	I-Protocol
Data	I-Protocol
Interface	I-Protocol
)	O
,	O
which	O
was	O
popular	O
in	O
the	O
early	O
to	O
mid	O
1990s	O
.	O
</s>
<s>
Token	B-Protocol
passing	I-Protocol
schemes	O
degrade	O
deterministically	O
under	O
load	O
,	O
which	O
is	O
a	O
key	O
reason	O
why	O
they	O
were	O
popular	O
for	O
industrial	O
control	O
LANs	B-General_Concept
such	O
as	O
MAP	B-General_Concept
,	O
(	O
Manufacturing	B-General_Concept
Automation	I-General_Concept
Protocol	I-General_Concept
)	O
.	O
</s>
<s>
Some	O
types	O
of	O
token	B-Protocol
passing	I-Protocol
schemes	O
do	O
not	O
need	O
to	O
explicitly	O
send	O
a	O
token	O
between	O
systems	O
because	O
the	O
process	O
of	O
"	O
passing	O
the	O
token	O
"	O
is	O
implicit	O
.	O
</s>
<s>
An	O
example	O
is	O
the	O
channel	O
access	O
method	O
used	O
during	O
"	O
Contention	O
Free	O
Time	O
Slots	O
"	O
in	O
the	O
ITU-T	B-General_Concept
G.hn	I-General_Concept
standard	O
for	O
high-speed	O
local	B-General_Concept
area	I-General_Concept
networking	I-General_Concept
using	O
existing	O
home	O
wires	O
(	O
power	O
lines	O
,	O
phone	O
lines	O
and	O
coaxial	O
cable	O
)	O
.	O
</s>
