<s>
Avionics	B-Protocol
Full-Duplex	I-Protocol
Switched	I-Protocol
Ethernet	I-Protocol
(	O
AFDX	B-Protocol
)	O
,	O
also	O
ARINC	B-Protocol
664	I-Protocol
,	O
is	O
a	O
data	O
network	B-Application
,	O
patented	O
by	O
international	O
aircraft	O
manufacturer	O
Airbus	O
,	O
for	O
safety-critical	O
applications	O
that	O
utilizes	O
dedicated	O
bandwidth	O
while	O
providing	O
deterministic	O
quality	O
of	O
service	O
(	O
QoS	O
)	O
.	O
</s>
<s>
AFDX	B-Protocol
is	O
a	O
worldwide	O
registered	O
trademark	O
by	O
Airbus	O
.	O
</s>
<s>
The	O
AFDX	B-Protocol
data	O
network	B-Application
is	O
based	O
on	O
Ethernet	O
technology	O
using	O
commercial	O
off-the-shelf	O
(	O
COTS	O
)	O
components	O
.	O
</s>
<s>
The	O
AFDX	B-Protocol
data	O
network	B-Application
is	O
a	O
specific	O
implementation	O
of	O
ARINC	O
Specification	O
664	O
Part	O
7	O
,	O
a	O
profiled	O
version	O
of	O
an	O
IEEE	O
802.3	O
network	B-Application
per	O
parts	O
1	O
&	O
2	O
,	O
which	O
defines	O
how	O
commercial	O
off-the-shelf	O
networking	O
components	O
will	O
be	O
used	O
for	O
future	O
generation	O
Aircraft	O
Data	O
Networks	O
(	O
ADN	O
)	O
.	O
</s>
<s>
The	O
six	O
primary	O
aspects	O
of	O
an	O
AFDX	B-Protocol
data	O
network	B-Application
include	O
full	O
duplex	O
,	O
redundancy	O
,	O
determinism	O
,	O
high	O
speed	O
performance	O
,	O
switched	B-Protocol
and	O
profiled	O
network	B-Application
.	O
</s>
<s>
Another	O
standard	O
,	O
ARINC	B-Architecture
629	I-Architecture
,	O
introduced	O
by	O
Boeing	O
for	O
the	O
777	O
provided	O
increased	O
data	O
speeds	O
of	O
up	O
to	O
2	O
Mbit/s	O
and	O
allowing	O
a	O
maximum	O
of	O
120	O
data	O
terminals	O
.	O
</s>
<s>
This	O
ADN	O
operates	O
without	O
the	O
use	O
of	O
a	O
bus	O
controller	O
thereby	O
increasing	O
the	O
reliability	O
of	O
the	O
network	B-Application
architecture	O
.	O
</s>
<s>
Because	O
of	O
this	O
,	O
other	O
manufacturers	O
did	O
not	O
openly	O
accept	O
the	O
ARINC	B-Architecture
629	I-Architecture
standard	O
.	O
</s>
<s>
AFDX	B-Protocol
was	O
designed	O
as	O
the	O
next-generation	O
aircraft	O
data	O
network	B-Application
.	O
</s>
<s>
AFDX	B-Protocol
is	O
one	O
implementation	O
of	O
deterministic	O
Ethernet	O
defined	O
by	O
ARINC	O
Specification	O
664	O
Part	O
7	O
.	O
</s>
<s>
AFDX	B-Protocol
was	O
developed	O
by	O
Airbus	O
Industries	O
for	O
the	O
A380	O
,	O
initially	O
to	O
address	O
real-time	O
issues	O
for	O
flight-by-wire	O
system	O
development	O
.	O
</s>
<s>
Building	O
on	O
the	O
experience	O
from	O
the	O
A380	O
,	O
the	O
Airbus	O
A350	O
also	O
uses	O
an	O
AFDX	B-Protocol
network	B-Application
,	O
with	O
avionics	O
and	O
systems	O
supplied	O
by	O
Rockwell	O
Collins	O
.	O
</s>
<s>
Airbus	O
and	O
its	O
EADS	O
parent	O
company	O
have	O
made	O
AFDX	B-Protocol
licenses	O
available	O
through	O
the	O
EADS	O
Technology	O
Licensing	O
initiative	O
,	O
including	O
agreements	O
with	O
Selex	O
ES	O
and	O
Vector	O
Informatik	O
GmbH	O
.	O
</s>
<s>
This	O
type	O
of	O
network	B-Application
can	O
significantly	O
reduce	O
wire	O
runs	O
,	O
thus	O
the	O
weight	O
of	O
the	O
aircraft	O
.	O
</s>
<s>
In	O
addition	O
,	O
AFDX	B-Protocol
can	O
provide	O
quality	O
of	O
service	O
and	O
dual	O
link	O
redundancy	O
.	O
</s>
<s>
AFDX	B-Protocol
adopted	O
concepts	O
such	O
as	O
the	O
token	B-Algorithm
bucket	I-Algorithm
from	O
the	O
telecom	O
standards	O
,	O
Asynchronous	O
Transfer	O
Mode	O
(	O
ATM	O
)	O
,	O
to	O
fix	O
the	O
shortcomings	O
of	O
IEEE	O
802.3	O
Ethernet	O
.	O
</s>
<s>
By	O
adding	O
key	O
elements	O
from	O
ATM	O
to	O
those	O
already	O
found	O
in	O
Ethernet	O
,	O
and	O
constraining	O
the	O
specification	O
of	O
various	O
options	O
,	O
a	O
highly	O
reliable	O
full-duplex	O
deterministic	O
network	B-Application
is	O
created	O
providing	O
guaranteed	O
bandwidth	O
and	O
quality	O
of	O
service	O
(	O
QoS	O
)	O
.	O
</s>
<s>
The	O
network	B-Application
is	O
designed	O
in	O
such	O
a	O
way	O
that	O
all	O
critical	O
traffic	O
is	O
prioritized	O
using	O
QoS	O
policies	O
so	O
delivery	O
,	O
latency	O
,	O
and	O
jitter	O
are	O
all	O
guaranteed	O
to	O
be	O
within	O
set	O
parameters	O
.	O
</s>
<s>
A	O
highly	O
intelligent	O
switch	O
,	O
common	O
to	O
the	O
AFDX	B-Protocol
network	B-Application
,	O
is	O
able	O
to	O
buffer	B-General_Concept
transmission	O
and	O
reception	O
packets	B-Protocol
.	O
</s>
<s>
AFDX	B-Protocol
extends	O
standard	O
Ethernet	O
to	O
provide	O
high	O
data	O
integrity	O
and	O
deterministic	O
timing	O
.	O
</s>
<s>
Further	O
a	O
redundant	O
pair	O
of	O
networks	O
is	O
used	O
to	O
improve	O
the	O
system	O
integrity	O
(	O
although	O
a	O
virtual	O
link	O
may	O
be	O
configured	O
to	O
use	O
one	O
or	O
the	O
other	O
network	B-Application
only	O
)	O
.	O
</s>
<s>
Data	B-Protocol
link	I-Protocol
(	O
MAC	B-Protocol
and	O
virtual	O
link	O
addressing	O
concept	O
)	O
;	O
</s>
<s>
Network	B-Application
(	O
IP	B-Protocol
and	O
ICMP	B-Protocol
)	O
;	O
</s>
<s>
Application	O
(	O
network	B-Application
)	O
(	O
sampling	O
,	O
queuing	O
,	O
SAP	B-Protocol
,	O
TFTP	B-Device
and	O
SNMP	B-Protocol
)	O
.	O
</s>
<s>
The	O
main	O
elements	O
of	O
an	O
AFDX	B-Protocol
network	B-Application
are	O
:	O
</s>
<s>
The	O
central	O
feature	O
of	O
an	O
AFDX	B-Protocol
network	B-Application
are	O
its	O
virtual	O
links	O
(	O
VL	O
)	O
.	O
</s>
<s>
In	O
one	O
abstraction	O
,	O
it	O
is	O
possible	O
to	O
visualise	O
the	O
VLs	O
as	O
an	O
ARINC	O
429	O
style	O
network	B-Application
each	O
with	O
one	O
source	O
and	O
one	O
or	O
more	O
destinations	O
.	O
</s>
<s>
Unlike	O
that	O
of	O
a	O
traditional	O
Ethernet	O
switch	O
which	O
switches	O
frames	O
based	O
on	O
the	O
Ethernet	O
destination	O
or	O
MAC	B-Protocol
address	O
,	O
AFDX	B-Protocol
routes	O
packets	B-Protocol
using	O
a	O
virtual	O
link	O
ID	O
,	O
which	O
is	O
carried	O
in	O
the	O
same	O
position	O
in	O
an	O
AFDX	B-Protocol
frame	O
as	O
the	O
MAC	B-Protocol
destination	O
address	O
in	O
an	O
Ethernet	O
frame	O
.	O
</s>
<s>
However	O
,	O
in	O
the	O
case	O
of	O
AFDX	B-Protocol
,	O
this	O
virtual	O
link	O
ID	O
identifies	O
the	O
data	O
carried	O
rather	O
than	O
the	O
physical	O
destination	O
.	O
</s>
<s>
The	O
virtual	O
link	O
ID	O
is	O
a	O
16-bit	O
unsigned	B-Algorithm
integer	I-Algorithm
value	O
that	O
follows	O
a	O
constant	O
32-bit	O
field	O
.	O
</s>
<s>
Each	O
virtual	O
link	O
is	O
allocated	O
dedicated	O
bandwidth	O
[	O
sum	O
of	O
all	O
VL	O
bandwidth	O
allocation	O
gap	O
(	O
BAG	O
)	O
rates	O
x	O
MTU ]	O
with	O
the	O
total	O
amount	O
of	O
bandwidth	O
defined	O
by	O
the	O
system	O
integrator	O
.	O
</s>
<s>
However	O
,	O
total	O
bandwidth	O
cannot	O
exceed	O
the	O
maximum	O
available	O
bandwidth	O
on	O
the	O
network	B-Application
.	O
</s>
<s>
Each	O
VL	O
is	O
frozen	O
in	O
specification	O
to	O
ensure	O
that	O
the	O
network	B-Application
has	O
a	O
designed	O
maximum	O
traffic	O
,	O
hence	O
determinism	O
.	O
</s>
<s>
Also	O
the	O
switch	O
,	O
having	O
a	O
VL	O
configuration	O
table	O
loaded	O
,	O
can	O
reject	O
any	O
erroneous	O
data	O
transmission	O
that	O
may	O
otherwise	O
swamp	O
other	O
branches	O
of	O
the	O
network	B-Application
.	O
</s>
<s>
Data	O
are	O
read	O
in	O
a	O
round-robin	B-Algorithm
sequence	O
among	O
the	O
virtual	O
links	O
with	O
data	O
to	O
transmit	O
.	O
</s>
<s>
Also	O
sub-virtual	O
links	O
do	O
not	O
provide	O
guaranteed	O
bandwidth	O
or	O
latency	O
due	O
to	O
the	O
buffering	O
,	O
but	O
AFDX	B-Protocol
specifies	O
that	O
latency	O
is	O
measured	O
from	O
the	O
traffic	O
regulator	O
function	O
anyway	O
.	O
</s>
<s>
BAG	O
stands	O
for	O
bandwidth	O
allocation	O
gap	O
,	O
this	O
is	O
one	O
of	O
the	O
main	O
features	O
of	O
the	O
AFDX	B-Protocol
protocol	O
.	O
</s>
<s>
Therefore	O
,	O
in	O
a	O
network	B-Application
with	O
multiple	O
switches	O
(	O
cascaded	O
star	O
topology	O
)	O
,	O
the	O
total	O
number	O
of	O
virtual	O
links	O
is	O
nearly	O
limitless	O
.	O
</s>
<s>
Since	O
AFDX	B-Protocol
utilizes	O
the	O
Ethernet	O
protocol	O
at	O
the	O
MAC	B-Protocol
layer	I-Protocol
,	O
it	O
is	O
possible	O
to	O
use	O
high	O
performance	O
COTS	O
switches	O
with	O
Layer	B-Protocol
2	I-Protocol
routing	O
as	O
AFDX	B-Protocol
switches	O
for	O
testing	O
purposes	O
as	O
a	O
cost-cutting	O
measure	O
.	O
</s>
<s>
However	O
,	O
some	O
features	O
of	O
a	O
real	O
AFDX	B-Protocol
switch	O
may	O
be	O
missing	O
,	O
such	O
as	O
traffic	O
policing	O
and	O
redundancy	O
functions	O
.	O
</s>
<s>
The	O
AFDX	B-Protocol
bus	O
is	O
used	O
in	O
Airbus	O
A380	O
,	O
Boeing	O
787	O
,	O
Airbus	O
A400M	O
,	O
Airbus	O
A350	O
,	O
Sukhoi	O
Superjet	O
100	O
,	O
ATR	O
42	O
,	O
ATR	O
72	O
(	O
-600	O
)	O
,	O
AgustaWestland	O
AW101	O
,	O
AgustaWestland	O
AW189	O
,	O
AgustaWestland	O
AW169	O
,	O
Irkut	O
MC-21	O
,	O
Bombardier	O
Global	O
Express	O
,	O
Bombardier	O
CSeries	O
,	O
Learjet	O
85	O
,	O
Comac	O
ARJ21	O
,	O
Comac	O
C919	O
and	O
AgustaWestland	O
AW149	O
.	O
</s>
