<s>
MOST	O
(	O
Media	B-Application
Oriented	I-Application
Systems	I-Application
Transport	I-Application
)	O
is	O
a	O
high-speed	O
multimedia	O
network	O
technology	O
for	O
the	O
automotive	O
industry	O
.	O
</s>
<s>
The	O
serial	O
MOST	B-Application
bus	I-Application
uses	O
a	O
daisy-chain	O
topology	O
or	O
ring	B-Architecture
topology	I-Architecture
and	O
synchronous	B-Protocol
serial	I-Protocol
communication	I-Protocol
to	O
transport	O
audio	O
,	O
video	O
,	O
voice	O
and	O
data	O
signals	O
via	O
plastic	B-Application
optical	I-Application
fiber	I-Application
(	O
POF	O
)	O
(	O
MOST25	O
,	O
MOST150	O
)	O
or	O
electrical	O
conductor	O
(	O
MOST50	O
,	O
MOST150	O
)	O
physical	B-Application
layers	I-Application
.	O
</s>
<s>
It	O
provides	O
the	O
user	O
with	O
a	O
standardized	O
interface	O
(	O
API	B-Application
)	O
to	O
access	O
device	O
functionality	O
.	O
</s>
<s>
The	O
communication	O
functionality	O
is	O
provided	O
by	O
driver	O
software	O
known	O
as	O
MOST	B-Application
Network	I-Application
Services	O
.	O
</s>
<s>
MOST	B-Application
Network	I-Application
Services	O
include	O
Basic	O
Layer	O
System	O
Services	O
(	O
Layer	O
3	O
,	O
4	O
,	O
5	O
)	O
and	O
Application	O
Socket	O
Services	O
(	O
Layer	O
6	O
)	O
.	O
</s>
<s>
They	O
process	O
the	O
MOST	O
protocol	O
between	O
a	O
MOST	B-Application
Network	I-Application
Interface	O
Controller	O
(	O
NIC	O
)	O
,	O
which	O
is	O
based	O
on	O
the	O
physical	B-Application
layer	I-Application
,	O
and	O
the	O
API	B-Application
(	O
Layer	O
7	O
)	O
.	O
</s>
<s>
A	O
MOST	B-Application
network	I-Application
is	O
able	O
to	O
manage	O
up	O
to	O
64	O
MOST	O
devices	O
in	O
a	O
ring	B-Architecture
configuration	I-Architecture
.	O
</s>
<s>
Plug	B-Device
and	I-Device
play	I-Device
functionality	O
allows	O
MOST	O
devices	O
to	O
be	O
easily	O
attached	O
and	O
removed	O
.	O
</s>
<s>
MOST	B-Application
networks	I-Application
can	O
also	O
be	O
set	O
up	O
in	O
virtual	O
star	B-Architecture
network	I-Architecture
or	O
other	O
topologies	O
.	O
</s>
<s>
Hubs	B-Protocol
or	O
switches	O
are	O
also	O
possible	O
,	O
but	O
they	O
are	O
not	O
well-established	O
in	O
the	O
automotive	O
sector	O
.	O
</s>
<s>
In	O
a	O
MOST	B-Application
network	I-Application
,	O
one	O
device	O
is	O
designated	O
the	O
timing	O
master	O
.	O
</s>
<s>
MOST25	O
provides	O
a	O
bandwidth	O
of	O
approximately	O
23megabaud	O
for	O
streaming	O
(	O
synchronous	O
)	O
as	O
well	O
as	O
package	O
(	O
asynchronous	O
)	O
data	O
transfer	O
over	O
an	O
optical	O
physical	B-Application
layer	I-Application
.	O
</s>
<s>
It	O
is	O
separated	O
into	O
60	O
physical	B-Application
channels	I-Application
.	O
</s>
<s>
MOST25	O
provides	O
many	O
services	O
and	O
methods	O
for	O
the	O
allocation	B-General_Concept
(	O
and	O
deallocation	B-General_Concept
)	O
of	O
physical	B-Application
channels	I-Application
.	O
</s>
<s>
MOST25	O
supports	O
up	O
to	O
15	O
uncompressed	O
stereo	O
audio	O
channels	O
with	O
CD-quality	O
sound	O
or	O
up	O
to	O
15MPEG-1	O
channels	O
for	O
audio/video	O
transfer	O
,	O
each	O
of	O
which	O
uses	O
four	O
bytes	O
(	O
four	O
physical	B-Application
channels	I-Application
)	O
.	O
</s>
<s>
Although	O
MOST50	O
is	O
specified	O
to	O
support	O
both	O
optical	O
and	O
electrical	O
physical	B-Application
layers	I-Application
,	O
the	O
available	O
MOST50	O
Intelligent	O
Network	O
Interface	O
Controllers	O
(	O
INICs	O
)	O
only	O
support	O
electrical	O
data	O
transfer	O
via	O
a	O
three	O
copper	O
conductor	O
configuration	O
;	O
consisting	O
of	O
an	O
Unshielded	O
Twisted	O
Pair	O
(	O
UTP	O
)	O
set	O
and	O
a	O
single	O
additional	O
control	O
line	O
.	O
</s>
<s>
MOST150	O
was	O
introduced	O
in	O
October	O
2007	O
and	O
provides	O
a	O
physical	B-Application
layer	I-Application
to	O
implement	O
Ethernet	O
in	O
automobiles	O
.	O
</s>
<s>
It	O
uses	O
plastic	B-Application
optical	I-Application
fibers	I-Application
(	O
POF	O
)	O
with	O
a	O
core	O
diameter	O
of	O
1mm	O
as	O
transmission	O
medium	O
,	O
in	O
combination	O
with	O
light	O
emitting	O
diodes	O
(	O
LEDs	O
)	O
in	O
the	O
red	O
wavelength	O
range	O
as	O
transmitters	O
.	O
</s>
<s>
MOST25	O
only	O
uses	O
an	O
optical	O
physical	B-Application
layer	I-Application
.	O
</s>
<s>
MOST50	O
and	O
MOST150	O
support	O
both	O
optical	O
and	O
electrical	O
physical	B-Application
layers	I-Application
.	O
</s>
<s>
The	O
MOST	O
Cooperation	O
has	O
published	O
specifications	O
for	O
the	O
MOST	B-Application
Bus	I-Application
for	O
a	O
number	O
of	O
years	O
.	O
</s>
<s>
At	O
this	O
time	O
MOST	O
chip	O
solutions	O
are	O
available	O
from	O
SMSC	O
,	O
Analog	O
Devices	O
and	O
some	O
FPGA	B-Architecture
core	O
companies	O
.	O
</s>
<s>
IEEE	O
1355	O
has	O
a	O
slice	O
(	O
combination	O
of	O
network	O
medium	O
and	O
speed	O
)	O
TS-FO-02	O
,	O
for	O
polymer	B-Application
optical	I-Application
fiber	I-Application
operating	O
at	O
200	O
megabits/second	O
.	O
</s>
<s>
However	O
Cat	B-Protocol
5	I-Protocol
cable	I-Protocol
may	O
be	O
too	O
expensive	O
for	O
automotive	O
applications	O
.	O
</s>
<s>
Also	O
,	O
standard	O
cat-5	B-Protocol
plugs	O
do	O
not	O
resist	O
vibration	O
.	O
</s>
<s>
CAN	O
(	O
Controller	B-Protocol
Area	I-Protocol
Network	I-Protocol
)	O
,	O
LIN	O
(	O
Local	O
Interconnect	O
Network	O
)	O
and	O
other	O
automotive	O
OBD	O
standards	O
are	O
not	O
suitable	O
because	O
they	O
are	O
too	O
slow	O
to	O
carry	O
video	O
.	O
</s>
<s>
FlexRay	B-Protocol
,	O
also	O
an	O
automotive	O
bus	O
standard	O
,	O
though	O
faster	O
than	O
CAN	O
,	O
is	O
intended	O
for	O
timing	O
critical	O
applications	O
such	O
as	O
drive	O
by	O
wire	O
rather	O
than	O
media	O
.	O
</s>
