<s>
CobraNet	B-Protocol
is	O
a	O
combination	O
of	O
software	O
,	O
hardware	O
,	O
and	O
network	O
protocols	O
designed	O
to	O
deliver	O
uncompressed	O
,	O
multi-channel	O
,	O
low-latency	O
digital	B-General_Concept
audio	O
over	O
a	O
standard	O
Ethernet	O
network	O
.	O
</s>
<s>
Developed	O
in	O
the	O
1990s	O
,	O
CobraNet	B-Protocol
is	O
widely	O
regarded	O
as	O
the	O
first	O
commercially	O
successful	O
audio-over-Ethernet	B-Protocol
implementation	O
.	O
</s>
<s>
CobraNet	B-Protocol
was	O
designed	O
for	O
and	O
is	O
primarily	O
used	O
in	O
large	O
commercial	O
audio	O
installations	O
such	O
as	O
convention	O
centers	O
,	O
stadiums	O
,	O
airports	O
,	O
theme	O
parks	O
,	O
and	O
concert	O
halls	O
.	O
</s>
<s>
CobraNet	B-Protocol
is	O
an	O
alternative	O
to	O
analog	O
audio	O
,	O
which	O
suffers	O
from	O
signal	O
degradation	O
over	O
long	O
cable	O
runs	O
due	O
to	O
electromagnetic	O
interference	O
,	O
high-frequency	O
attenuation	O
,	O
and	O
voltage	O
drop	O
.	O
</s>
<s>
Additionally	O
,	O
the	O
use	O
of	O
digital	B-General_Concept
multiplexing	B-Architecture
allows	O
audio	O
to	O
be	O
transmitted	O
using	O
less	O
cabling	O
than	O
analog	O
audio	O
.	O
</s>
<s>
CobraNet	B-Protocol
was	O
developed	O
in	O
1996	O
by	O
Boulder	O
,	O
Colorado-based	O
Peak	O
Audio	O
.	O
</s>
<s>
The	O
first	O
permanent	O
installation	O
of	O
CobraNet	B-Protocol
in	O
this	O
early	O
form	O
was	O
to	O
provide	O
background	O
music	O
throughout	O
Disney	O
's	O
Animal	O
Kingdom	O
theme	O
park	O
.	O
</s>
<s>
The	O
first	O
commercial	O
use	O
of	O
CobraNet	B-Protocol
was	O
during	O
the	O
halftime	O
show	O
at	O
Super	O
Bowl	O
XXXI	O
in	O
1997	O
.	O
</s>
<s>
CobraNet	B-Protocol
was	O
first	O
introduced	O
as	O
an	O
interoperable	O
standard	O
in	O
collaboration	O
with	O
manufacturer	O
QSC	O
Audio	O
Products	O
.	O
</s>
<s>
At	O
this	O
point	O
CobraNet	B-Protocol
had	O
graduated	O
to	O
fast	B-Protocol
Ethernet	I-Protocol
and	O
used	O
a	O
unique	O
collision	O
avoidance	O
technique	O
to	O
carry	O
up	O
to	O
64	O
channels	O
per	O
Ethernet	B-Protocol
collision	I-Protocol
domain	I-Protocol
.	O
</s>
<s>
CobraNet	B-Protocol
was	O
subsequently	O
enhanced	O
to	O
support	O
and	O
eventually	O
require	O
a	O
switched	B-Protocol
Ethernet	I-Protocol
network	O
.	O
</s>
<s>
An	O
SNMP	B-Protocol
agent	O
was	O
added	O
for	O
remote	O
control	O
and	O
monitoring	O
.	O
</s>
<s>
Leveraging	O
Cirrus	O
DSP	B-Architecture
technology	O
,	O
a	O
low-cost	O
SoC	B-Architecture
implementation	O
of	O
CobraNet	B-Protocol
was	O
developed	O
and	O
marketed	O
.	O
</s>
<s>
Using	O
CobraNet	B-Protocol
and	O
fast	B-Protocol
Ethernet	I-Protocol
,	O
64	O
channels	O
of	O
uncompressed	O
digital	B-General_Concept
audio	O
are	O
carried	O
through	O
a	O
single	O
category	B-Protocol
5	I-Protocol
cable	I-Protocol
.	O
</s>
<s>
Using	O
gigabit	O
or	O
fiber	B-Architecture
optic	I-Architecture
Ethernet	O
variants	O
,	O
the	O
cost	O
of	O
cabling	O
per	O
audio	O
channel	O
is	O
reduced	O
further	O
compared	O
to	O
the	O
fast	B-Protocol
Ethernet	I-Protocol
implementation	O
.	O
</s>
<s>
CobraNet	B-Protocol
data	O
can	O
coexist	O
with	O
data	O
traffic	O
over	O
existing	O
Ethernet	O
networks	O
so	O
a	O
single	O
network	O
infrastructure	O
can	O
serve	O
audio	O
distribution	O
and	O
other	O
networking	O
needs	O
.	O
</s>
<s>
Audio	O
is	O
transmitted	O
in	O
digital	B-General_Concept
form	O
,	O
and	O
provides	O
reduced	O
susceptibility	O
to	O
electromagnetic	O
interference	O
,	O
crosstalk	O
,	O
coloration	O
,	O
and	O
attenuation	O
owing	O
to	O
cable	O
impedance	O
.	O
</s>
<s>
Use	O
of	O
Ethernet	O
by	O
CobraNet	B-Protocol
offers	O
many	O
high	O
availability	O
features	O
such	O
as	O
Spanning	B-Protocol
Tree	I-Protocol
Protocol	I-Protocol
,	O
link	B-Architecture
aggregation	I-Architecture
,	O
and	O
network	O
management	O
.	O
</s>
<s>
For	O
critical	O
applications	O
,	O
CobraNet	B-Protocol
devices	O
can	O
be	O
wired	O
with	O
redundant	O
connections	O
to	O
the	O
network	O
.	O
</s>
<s>
In	O
this	O
configuration	O
,	O
if	O
one	O
CobraNet	B-Protocol
device	O
,	O
cable	O
,	O
or	O
Ethernet	B-Protocol
switch	I-Protocol
fails	O
,	O
the	O
other	O
takes	O
over	O
almost	O
immediately	O
.	O
</s>
<s>
Delays	O
over	O
the	O
CobraNet	B-Protocol
transmission	O
medium	O
itself	O
are	O
at	O
least	O
milliseconds	O
per	O
network	O
traversal	O
.	O
</s>
<s>
For	O
some	O
applications	O
,	O
these	O
delays	O
can	O
be	O
unacceptable	O
–	O
especially	O
when	O
combined	O
with	O
further	O
delays	O
resulting	O
from	O
propagation	O
time	O
,	O
digital	B-General_Concept
signal	I-General_Concept
processing	I-General_Concept
and	O
the	O
conversions	O
between	O
analog	O
and	O
digital	B-General_Concept
.	O
</s>
<s>
Licensing	O
the	O
technology	O
or	O
purchasing	O
the	O
required	O
CobraNet	B-Protocol
interfaces	O
,	O
which	O
encode	O
and	O
decode	O
the	O
CobraNet	B-Protocol
signal	O
,	O
can	O
be	O
expensive	O
.	O
</s>
<s>
CobraNet	B-Protocol
is	O
transmitted	O
using	O
standard	O
Ethernet	O
packets	O
.	O
</s>
<s>
Instead	O
of	O
using	O
TCP/IP	B-Protocol
packets	O
,	O
CobraNet	B-Protocol
transfers	O
data	O
using	O
data	B-Protocol
link	I-Protocol
layer	I-Protocol
packets	O
,	O
which	O
travel	O
quickly	O
through	O
hubs	B-Protocol
,	O
bridges	B-Protocol
and	O
switches	B-Protocol
,	O
and	O
are	O
not	O
as	O
susceptible	O
to	O
the	O
latency	O
and	O
QoS	O
problems	O
commonly	O
found	O
in	O
streaming	O
protocols	O
using	O
a	O
higher	O
transport	B-Architecture
layer	I-Architecture
.	O
</s>
<s>
However	O
,	O
since	O
CobraNet	B-Protocol
does	O
not	O
use	O
IP	B-Protocol
protocol	I-Protocol
,	O
its	O
packets	O
cannot	O
travel	O
through	O
routers	B-Protocol
,	O
and	O
therefore	O
it	O
is	O
limited	O
to	O
use	O
on	O
a	O
LAN	B-General_Concept
;	O
CobraNet	B-Protocol
cannot	O
be	O
used	O
over	O
the	O
Internet	O
.	O
</s>
<s>
The	O
network	O
over	O
which	O
CobraNet	B-Protocol
is	O
transmitted	O
must	O
be	O
able	O
to	O
operate	O
at	O
a	O
minimum	O
of	O
.	O
</s>
<s>
All	O
CobraNet	B-Protocol
packets	O
are	O
identified	O
with	O
a	O
unique	O
Ethernet	B-Protocol
protocol	I-Protocol
identifier	I-Protocol
(	O
0x8819	O
)	O
assigned	O
to	O
Cirrus	O
Logic	O
.	O
</s>
<s>
CobraNet	B-Protocol
is	O
not	O
designed	O
to	O
work	O
over	O
wireless	O
networks	O
.	O
</s>
<s>
However	O
,	O
wireless	O
communication	O
of	O
CobraNet	B-Protocol
data	O
can	O
be	O
accomplished	O
reliably	O
using	O
lasers	O
.	O
</s>
<s>
CobraNet	B-Protocol
data	O
is	O
organized	O
into	O
channels	O
and	O
bundles	O
.	O
</s>
<s>
A	O
typical	O
CobraNet	B-Protocol
signal	O
can	O
contain	O
up	O
to	O
4bundles	O
of	O
audio	O
traveling	O
in	O
each	O
direction	O
,	O
for	O
a	O
total	O
of	O
8bundles	O
per	O
device	O
.	O
</s>
<s>
CobraNet	B-Protocol
is	O
somewhat	O
scalable	O
,	O
in	O
that	O
channel	O
capacity	O
increases	O
when	O
16-bit	O
audio	O
is	O
used	O
,	O
and	O
channel	O
capacity	O
decreases	O
when	O
24-bit	O
audio	O
is	O
used	O
.	O
</s>
<s>
The	O
number	O
of	O
channels	O
allowed	O
per	O
bundle	O
is	O
limited	O
by	O
the	O
1,500	O
-byte	O
Ethernet	O
MTU	B-Protocol
.	O
</s>
<s>
Multicast	O
bundles	O
are	O
sent	O
from	O
one	O
CobraNet	B-Protocol
device	O
to	O
all	O
other	O
CobraNet	B-Protocol
devices	O
in	O
the	O
network	O
using	O
Ethernet	O
multicast	O
addressing	O
.	O
</s>
<s>
Each	O
CobraNet	B-Protocol
device	O
individually	O
determines	O
if	O
it	O
will	O
use	O
the	O
bundle	O
or	O
discard	O
it	O
.	O
</s>
<s>
Unicast	O
bundles	O
are	O
sent	O
from	O
one	O
CobraNet	B-Protocol
device	O
to	O
any	O
other	O
device	O
or	O
devices	O
configured	O
to	O
receive	O
the	O
bundle	O
number	O
.	O
</s>
<s>
Unicast	O
bundles	O
are	O
much	O
more	O
efficient	O
because	O
network	B-Protocol
switches	I-Protocol
route	O
them	O
only	O
to	O
devices	O
which	O
actually	O
want	O
to	O
receive	O
them	O
.	O
</s>
<s>
As	O
long	O
as	O
multicast	O
bundles	O
are	O
used	O
sparingly	O
,	O
it	O
is	O
virtually	O
impossible	O
to	O
exceed	O
the	O
bandwidth	O
of	O
a	O
100Mbit	O
network	O
with	O
CobraNet	B-Protocol
data	O
.	O
</s>
<s>
The	O
CobraNet	B-Protocol
network	O
is	O
synchronized	O
to	O
a	O
single	O
CobraNet	B-Protocol
device	O
known	O
as	O
the	O
conductor	O
.	O
</s>
<s>
In	O
the	O
event	O
that	O
the	O
conductor	O
fails	O
,	O
another	O
CobraNet	B-Protocol
device	O
will	O
be	O
chosen	O
to	O
become	O
the	O
conductor	O
within	O
milliseconds	O
.	O
</s>
<s>
CobraNet	B-Protocol
cannot	O
function	O
without	O
a	O
conductor	O
.	O
</s>
<s>
Four	O
main	O
types	O
of	O
packet	O
are	O
used	O
in	O
the	O
transmission	O
and	O
synchronization	O
of	O
CobraNet	B-Protocol
:	O
</s>
<s>
Beat	O
packets	O
–	O
the	O
conductor	O
outputs	O
a	O
beat	O
packet	O
to	O
all	O
other	O
CobraNet	B-Protocol
devices	O
on	O
the	O
network	O
at	O
a	O
rate	O
of	O
750packets	O
per	O
second	O
.	O
</s>
<s>
All	O
other	O
CobraNet	B-Protocol
devices	O
on	O
the	O
network	O
synchronize	O
their	O
audio	O
clock	O
and	O
their	O
data	O
transmissions	O
to	O
the	O
beat	O
packet	O
.	O
</s>
<s>
Audio	O
packets	O
–	O
also	O
known	O
as	O
isochronous	B-Device
data	O
packets	O
,	O
these	O
packets	O
are	O
sent	O
out	O
by	O
all	O
CobraNet	B-Protocol
devices	O
after	O
they	O
receive	O
a	O
beat	O
packet	O
.	O
</s>
<s>
Their	O
function	O
is	O
to	O
control	O
bandwidth	O
allocation	O
,	O
initiate	O
connections	O
between	O
CobraNet	B-Protocol
devices	O
,	O
and	O
monitor	O
the	O
status	O
of	O
CobraNet	B-Protocol
devices	O
.	O
</s>
<s>
Serial	O
bridge	O
packets	O
–	O
asynchronous	O
serial	O
data	O
may	O
be	O
sent	O
between	O
CobraNet	B-Protocol
devices	O
on	O
the	O
same	O
network	O
.	O
</s>
<s>
Additional	O
delays	O
are	O
introduced	O
through	O
analog-to-digital	O
and	O
digital-to-analog	O
conversion	O
.	O
</s>
<s>
In	O
most	O
cases	O
,	O
the	O
programmer	O
can	O
choose	O
the	O
desired	O
CobraNet	B-Protocol
latency	O
for	O
a	O
particular	O
CobraNet	B-Protocol
device	O
(	O
,	O
,	O
or	O
milliseconds	O
)	O
.	O
</s>
<s>
Reducing	O
latency	O
requires	O
more	O
processing	O
by	O
the	O
CobraNet	B-Protocol
interface	O
and	O
may	O
reduce	O
channel	O
capacity	O
.	O
</s>
<s>
Reducing	O
latency	O
places	O
additional	O
demands	O
on	O
network	O
performance	O
,	O
and	O
may	O
not	O
be	O
possible	O
in	O
some	O
network	O
configurations	O
if	O
the	O
forwarding	B-Protocol
delay	I-Protocol
is	O
too	O
high	O
.	O
</s>
<s>
So	O
,	O
while	O
eight	O
24-bit	O
,	O
96kHz	O
channels	O
can	O
be	O
sent	O
in	O
one	O
bundle	O
at	O
ms	O
latency	O
,	O
due	O
to	O
processing	O
constraints	O
,	O
the	O
CobraNet	B-Protocol
device	O
may	O
only	O
be	O
able	O
to	O
send	O
and	O
receive	O
one	O
bundle	O
instead	O
of	O
the	O
usual	O
four	O
.	O
</s>
<s>
The	O
bundle	O
capacity	O
of	O
CobraNet	B-Protocol
devices	O
are	O
unique	O
to	O
the	O
particular	O
device	O
and	O
are	O
not	O
always	O
the	O
same	O
.	O
</s>
<s>
The	O
Channels	O
per	O
bundle	O
vs.	O
test	O
case	O
latencies	O
table	O
illustrates	O
the	O
bundle	O
capacity	O
for	O
a	O
Biamp	O
AudiaFLEX-CM	O
DSP	B-Architecture
device	O
.	O
</s>
<s>
CobraNet	B-Protocol
interfaces	O
come	O
in	O
several	O
varieties	O
,	O
some	O
of	O
which	O
can	O
support	O
more	O
channels	O
than	O
others	O
.	O
</s>
<s>
Additionally	O
,	O
CobraNet	B-Protocol
interfaces	O
have	O
two	O
Ethernet	O
ports	O
labelled	O
"	O
primary	O
"	O
and	O
"	O
secondary	O
"	O
.	O
</s>
<s>
Only	O
the	O
primary	O
Ethernet	O
port	O
needs	O
to	O
be	O
connected	O
,	O
but	O
if	O
both	O
ports	O
are	O
connected	O
the	O
latter	O
acts	O
as	O
a	O
fail-safe	B-General_Concept
.	O
</s>
<s>
The	O
typical	O
CobraNet	B-Protocol
interfaces	O
provided	O
by	O
Cirrus	O
Logic	O
are	O
the	O
CM-1	O
and	O
the	O
CM-2	O
:	O
</s>
<s>
CM-1	O
–	O
the	O
standard	O
CobraNet	B-Protocol
card	O
,	O
provides	O
32	O
in	O
and	O
32	O
out	O
audio	O
channels	O
.	O
</s>
<s>
Cirrus	O
Logic	O
provides	O
a	O
software	O
application	O
known	O
as	O
CobraCAD	O
,	O
which	O
assists	O
in	O
the	O
design	O
of	O
the	O
network	O
on	O
which	O
the	O
CobraNet	B-Protocol
system	O
will	O
run	O
.	O
</s>
<s>
It	O
helps	O
to	O
identify	O
if	O
there	O
are	O
too	O
many	O
routers	B-Protocol
between	O
two	O
CobraNet	B-Protocol
devices	O
,	O
if	O
a	O
certain	O
latency	O
is	O
possible	O
given	O
the	O
network	O
configuration	O
and	O
other	O
tasks	O
.	O
</s>
<s>
For	O
instance	O
,	O
a	O
simple	O
breakout	B-Protocol
box	I-Protocol
which	O
converts	O
a	O
CobraNet	B-Protocol
signal	O
to	O
eight	O
analog	O
audio	O
signals	O
would	O
require	O
little	O
or	O
no	O
configuration	O
by	O
the	O
end	O
user	O
apart	O
from	O
possibly	O
selecting	O
the	O
bundle	O
number	O
.	O
</s>
<s>
If	O
configuration	O
is	O
required	O
(	O
for	O
example	O
,	O
in	O
a	O
DSP	B-Architecture
box	O
with	O
integrated	O
CobraNet	B-Protocol
I/O	O
)	O
,	O
then	O
the	O
manufacturer	O
of	O
the	O
device	O
typically	O
supplies	O
proprietary	O
software	O
for	O
that	O
purpose	O
.	O
</s>
<s>
One	O
type	O
of	O
device	O
that	O
integrates	O
CobraNet	B-Protocol
is	O
the	O
audio	O
DSP	B-Architecture
.	O
</s>
<s>
As	O
self-powered	B-Device
speakers	I-Device
became	O
more	O
common	O
,	O
Cobranet	B-Protocol
was	O
frequently	O
used	O
to	O
distribute	O
the	O
audio	O
signal	O
from	O
the	O
DSP	B-Architecture
.	O
</s>
<s>
These	O
devices	O
typically	O
receive	O
audio	O
from	O
CobraNet	B-Protocol
(	O
and	O
often	O
from	O
other	O
digital	B-General_Concept
or	O
analog	O
sources	O
simultaneously	O
)	O
,	O
and	O
process	O
the	O
audio	O
using	O
digital	B-General_Concept
filters	O
and	O
effects	O
(	O
for	O
example	O
,	O
volume	O
control	O
,	O
EQ	O
,	O
compression	O
,	O
delay	O
,	O
crossovers	B-Algorithm
,	O
etc	O
.	O
)	O
</s>
<s>
and	O
then	O
output	O
the	O
audio	O
via	O
CobraNet	B-Protocol
(	O
or	O
other	O
digital	B-General_Concept
or	O
analog	O
outputs	O
)	O
.	O
</s>
<s>
Some	O
DSPs	O
even	O
have	O
an	O
integral	O
telephone	O
hybrid	O
,	O
and	O
can	O
incorporate	O
CobraNet	B-Protocol
and	O
other	O
sources	O
into	O
a	O
teleconferencing	O
application	O
.	O
</s>
<s>
Amplifiers	O
with	O
integrated	O
CobraNet	B-Protocol
help	O
keep	O
the	O
signal	O
chain	O
digital	B-General_Concept
for	O
a	O
longer	O
span	O
.	O
</s>
<s>
Amplifiers	O
with	O
CobraNet	B-Protocol
inputs	O
may	O
also	O
have	O
limited	O
DSP	B-Architecture
and	O
network	O
monitoring	O
capabilities	O
.	O
</s>
<s>
Loudspeakers	O
with	O
integrated	O
CobraNet	B-Protocol
help	O
keep	O
the	O
signal	O
chain	O
digital	B-General_Concept
for	O
an	O
even	O
longer	O
span	O
.	O
</s>
<s>
However	O
,	O
a	O
powered	B-Device
speaker	I-Device
,	O
powered	O
by	O
an	O
electrical	O
cable	O
and	O
fitted	O
with	O
integrated	O
CobraNet	B-Protocol
inputs	O
,	O
eliminates	O
the	O
speaker	O
cable	O
and	O
replaces	O
it	O
with	O
a	O
network	O
cable	O
.	O
</s>
<s>
Since	O
a	O
speaker	O
will	O
only	O
use	O
one	O
audio	O
channel	O
out	O
of	O
the	O
bundle	O
,	O
many	O
speakers	O
with	O
CobraNet	B-Protocol
will	O
also	O
have	O
a	O
number	O
of	O
analog	O
outputs	O
for	O
the	O
rest	O
of	O
the	O
channels	O
in	O
the	O
bundle	O
,	O
which	O
is	O
useful	O
in	O
speaker	O
cluster	O
applications	O
.	O
</s>
<s>
Many	O
digital	B-General_Concept
mixing	O
consoles	O
are	O
available	O
with	O
optional	O
CobraNet	B-Protocol
interfaces	O
for	O
increased	O
channel	O
capacity	O
and	O
reduced	O
cabling	O
.	O
</s>
<s>
Manufacturers	O
who	O
wish	O
to	O
integrate	O
CobraNet	B-Protocol
connectivity	O
into	O
their	O
devices	O
either	O
license	O
the	O
technology	O
or	O
purchase	O
CobraNet	B-Protocol
interface	O
modules	O
or	O
chips	O
from	O
Cirrus	O
Logic	O
.	O
</s>
<s>
Many	O
audio	O
equipment	O
manufacturers	O
have	O
included	O
CobraNet	B-Protocol
in	O
their	O
products	O
.	O
</s>
