<s>
In	O
computer	B-Architecture
networking	I-Architecture
,	O
resilience	B-General_Concept
is	O
the	O
ability	O
to	O
"	O
provide	O
and	O
maintain	O
an	O
acceptable	O
level	O
of	O
service	O
in	O
the	O
face	O
of	O
faults	B-General_Concept
and	O
challenges	O
to	O
normal	O
operation.	O
"	O
</s>
<s>
As	O
such	O
,	O
network	O
resilience	B-General_Concept
touches	O
a	O
very	O
wide	O
range	O
of	O
topics	O
.	O
</s>
<s>
In	O
order	O
to	O
increase	O
the	O
resilience	B-General_Concept
of	O
a	O
given	O
communication	O
network	O
,	O
the	O
probable	O
challenges	O
and	O
risks	O
have	O
to	O
be	O
identified	O
and	O
appropriate	O
resilience	B-General_Concept
metrics	O
have	O
to	O
be	O
defined	O
for	O
the	O
service	O
to	O
be	O
protected	O
.	O
</s>
<s>
The	O
importance	O
of	O
network	O
resilience	B-General_Concept
is	O
continuously	O
increasing	O
,	O
as	O
communication	O
networks	O
are	O
becoming	O
a	O
fundamental	O
component	O
in	O
the	O
operation	O
of	O
critical	O
infrastructures	O
.	O
</s>
<s>
Consequently	O
,	O
recent	O
efforts	O
focus	O
on	O
interpreting	O
and	O
improving	O
network	O
and	O
computing	O
resilience	B-General_Concept
with	O
applications	O
to	O
critical	O
infrastructures	O
.	O
</s>
<s>
As	O
an	O
example	O
,	O
one	O
can	O
consider	O
as	O
a	O
resilience	B-General_Concept
objective	O
the	O
provisioning	O
of	O
services	O
over	O
the	O
network	O
,	O
instead	O
of	O
the	O
services	O
of	O
the	O
network	O
itself	O
.	O
</s>
<s>
Note	O
that	O
resilience	B-General_Concept
and	O
survivability	O
are	O
interchangeably	O
used	O
according	O
to	O
the	O
specific	O
context	O
of	O
a	O
given	O
study	O
.	O
</s>
