<s>
A	O
single	B-Architecture
point	I-Architecture
of	I-Architecture
failure	I-Architecture
(	O
SPOF	B-Architecture
)	O
is	O
a	O
part	O
of	O
a	O
system	O
that	O
,	O
if	O
it	O
fails	O
,	O
will	O
stop	O
the	O
entire	O
system	O
from	O
working	O
.	O
</s>
<s>
SPOFs	B-Architecture
are	O
undesirable	O
in	O
any	O
system	O
with	O
a	O
goal	O
of	O
high	O
availability	O
or	O
reliability	O
,	O
be	O
it	O
a	O
business	O
practice	O
,	O
software	B-Application
application	I-Application
,	O
or	O
other	O
industrial	O
system	O
.	O
</s>
<s>
Systems	O
can	O
be	O
made	O
robust	O
by	O
adding	O
redundancy	O
in	O
all	O
potential	O
SPOFs	B-Architecture
.	O
</s>
<s>
The	O
assessment	O
of	O
a	O
potential	O
SPOF	B-Architecture
involves	O
identifying	O
the	O
critical	O
components	O
of	O
a	O
complex	O
system	O
that	O
would	O
provoke	O
a	O
total	O
systems	O
failure	O
in	O
case	O
of	O
malfunction	O
.	O
</s>
<s>
A	O
fault-tolerant	B-General_Concept
computer	I-General_Concept
system	I-General_Concept
can	O
be	O
achieved	O
at	O
the	O
internal	O
component	O
level	O
,	O
at	O
the	O
system	O
level	O
(	O
multiple	O
machines	O
)	O
,	O
or	O
site	O
level	O
(	O
replication	O
)	O
.	O
</s>
<s>
One	O
would	O
normally	O
deploy	O
a	O
load	O
balancer	O
to	O
ensure	O
high	O
availability	O
for	O
a	O
server	B-Architecture
cluster	I-Architecture
at	O
the	O
system	O
level	O
.	O
</s>
<s>
In	O
a	O
high-availability	O
server	B-Architecture
cluster	I-Architecture
,	O
each	O
individual	O
server	O
may	O
attain	O
internal	O
component	O
redundancy	O
by	O
having	O
multiple	O
power	O
supplies	O
,	O
hard	O
drives	O
,	O
and	O
other	O
components	O
.	O
</s>
<s>
Since	O
a	O
data	O
center	O
is	O
often	O
a	O
support	O
center	O
for	O
other	O
operations	O
such	O
as	O
business	O
logic	O
,	O
it	O
represents	O
a	O
potential	O
SPOF	B-Architecture
in	O
itself	O
.	O
</s>
<s>
Paul	O
Baran	O
and	O
Donald	O
Davies	O
developed	O
packet	B-Protocol
switching	I-Protocol
,	O
a	O
key	O
part	O
of	O
"	O
survivable	O
communications	O
networks	O
"	O
.	O
</s>
<s>
Such	O
networks	O
including	O
ARPANET	O
and	O
the	O
Internet	O
are	O
designed	O
to	O
have	O
no	B-Architecture
single	I-Architecture
point	I-Architecture
of	I-Architecture
failure	I-Architecture
.	O
</s>
<s>
Multiple	O
paths	O
between	O
any	O
two	O
points	O
on	O
the	O
network	O
allow	O
those	O
points	O
to	O
continue	O
communicating	O
with	O
each	O
other	O
,	O
the	O
packets	O
"	B-Protocol
routing	I-Protocol
around	I-Protocol
"	I-Protocol
damage	I-Protocol
,	O
even	O
after	O
any	O
single	O
failure	O
of	O
any	O
one	O
particular	O
path	O
or	O
any	O
one	O
intermediate	O
node	O
.	O
</s>
<s>
In	O
software	B-General_Concept
engineering	I-General_Concept
,	O
a	O
bottleneck	O
occurs	O
when	O
the	O
capacity	O
of	O
an	O
application	B-Application
or	O
a	O
computer	O
system	O
is	O
limited	O
by	O
a	O
single	O
component	O
.	O
</s>
<s>
The	O
objective	O
is	O
to	O
make	O
those	O
particular	O
sections	O
of	O
code	O
perform	O
as	O
fast	O
as	O
possible	O
to	O
improve	O
overall	O
algorithmic	B-General_Concept
efficiency	I-General_Concept
.	O
</s>
<s>
The	O
concept	O
of	O
a	O
single	B-Architecture
point	I-Architecture
of	I-Architecture
failure	I-Architecture
has	O
also	O
been	O
applied	O
to	O
fields	O
outside	O
of	O
engineering	O
,	O
computers	O
,	O
and	O
networking	O
,	O
such	O
as	O
corporate	O
supply	O
chain	O
management	O
and	O
transportation	O
management	O
.	O
</s>
<s>
In	O
transportation	O
,	O
some	O
noted	O
recent	O
examples	O
of	O
the	O
concept	O
's	O
recent	O
application	B-Application
have	O
included	O
the	O
Nipigon	O
River	O
Bridge	O
in	O
Canada	O
,	O
where	O
a	O
partial	O
bridge	O
failure	O
in	O
January	O
2016	O
entirely	O
severed	O
road	O
traffic	O
between	O
Eastern	O
Canada	O
and	O
Western	O
Canada	O
for	O
several	O
days	O
because	O
it	O
is	O
located	O
along	O
a	O
portion	O
of	O
the	O
Trans-Canada	O
Highway	O
where	O
there	O
is	O
no	O
alternate	O
detour	O
route	O
for	O
vehicles	O
to	O
take	O
;	O
and	O
the	O
Norwalk	O
River	O
Railroad	O
Bridge	O
in	O
Norwalk	O
,	O
Connecticut	O
,	O
an	O
aging	O
swing	O
bridge	O
that	O
sometimes	O
gets	O
stuck	O
when	O
opening	O
or	O
closing	O
,	O
disrupting	O
rail	O
traffic	O
on	O
the	O
Northeast	O
Corridor	O
line	O
.	O
</s>
<s>
The	O
concept	O
of	O
a	O
single	B-Architecture
point	I-Architecture
of	I-Architecture
failure	I-Architecture
has	O
also	O
been	O
applied	O
to	O
the	O
fields	O
of	O
intelligence	O
.	O
</s>
<s>
Edward	O
Snowden	O
talked	O
of	O
the	O
dangers	O
of	O
being	O
what	O
he	O
described	O
as	O
"	O
the	O
single	B-Architecture
point	I-Architecture
of	I-Architecture
failure	I-Architecture
"	O
–	O
the	O
sole	O
repository	O
of	O
information	O
.	O
</s>
<s>
A	O
component	O
of	O
a	O
life-support	O
system	O
that	O
would	O
constitute	O
a	O
single	B-Architecture
point	I-Architecture
of	I-Architecture
failure	I-Architecture
would	O
be	O
required	O
to	O
be	O
extremely	O
reliable	O
.	O
</s>
