<s>
MPLS	B-General_Concept
Fast	I-General_Concept
Reroute	I-General_Concept
(	O
also	O
called	O
MPLS	B-General_Concept
local	I-General_Concept
restoration	I-General_Concept
or	O
MPLS	B-General_Concept
local	I-General_Concept
protection	I-General_Concept
)	O
is	O
a	O
local	O
restoration	O
network	O
resiliency	B-General_Concept
mechanism	O
.	O
</s>
<s>
It	O
is	O
actually	O
a	O
feature	O
of	O
resource	B-Protocol
reservation	I-Protocol
protocol	I-Protocol
(	O
RSVP	B-Protocol
)	O
traffic	O
engineering	O
(	O
RSVP-TE	B-Protocol
)	O
.	O
</s>
<s>
In	O
MPLS	B-General_Concept
local	I-General_Concept
protection	I-General_Concept
each	O
label	O
switched	O
path	O
(	O
LSP	O
)	O
passing	O
through	O
a	O
facility	O
is	O
protected	O
by	O
a	O
backup	O
path	O
which	O
originates	O
at	O
the	O
node	O
immediately	O
upstream	O
to	O
that	O
facility	O
.	O
</s>
<s>
This	O
node	O
which	O
redirects	O
the	O
traffic	O
onto	O
the	O
preset	O
backup	O
path	O
is	O
called	O
the	O
Point	O
of	O
Local	O
Repair	O
(	O
PLR	O
)	O
,	O
and	O
the	O
node	O
where	O
a	O
backup	O
LSP	O
merges	O
with	O
the	O
primary	O
LSP	O
is	O
called	O
Merge	B-General_Concept
Point	I-General_Concept
(	O
MP	O
)	O
.	O
</s>
<s>
This	O
mechanism	O
(	O
local	B-General_Concept
protection	I-General_Concept
)	O
provides	O
faster	O
recovery	O
because	O
the	O
decision	O
of	O
recovery	O
is	O
strictly	O
local	O
.	O
</s>
<s>
For	O
comparison	O
,	O
when	O
recovery	O
mechanisms	O
are	O
employed	O
at	O
the	O
IP	B-Protocol
layer	O
,	O
restoration	O
may	O
take	O
several	O
seconds	O
which	O
is	O
unacceptable	O
for	O
real-time	O
applications	O
(	O
such	O
as	O
VoIP	O
)	O
.	O
</s>
<s>
In	O
contrast	O
,	O
MPLS	B-General_Concept
local	I-General_Concept
protection	I-General_Concept
meets	O
the	O
requirements	O
of	O
real-time	O
applications	O
with	O
recovery	O
times	O
comparable	O
to	O
those	O
of	O
shortest	B-Protocol
path	I-Protocol
bridging	I-Protocol
networks	O
or	O
SONET	B-Protocol
rings	I-Protocol
(	O
<	O
50	O
ms	O
)	O
.	O
</s>
<s>
There	O
are	O
two	O
distinct	O
approaches	O
to	O
local	B-General_Concept
protection	I-General_Concept
:	O
(	O
1	O
)	O
one-to-one	O
local	B-General_Concept
protection	I-General_Concept
(	O
detour	O
)	O
(	O
2	O
)	O
many-to-one	O
local	B-General_Concept
protection	I-General_Concept
(	O
facility	O
backup	O
)	O
.	O
</s>
<s>
The	O
backup	O
path	O
terminates	O
by	O
merging	O
back	O
with	O
the	O
primary	O
path	O
at	O
a	O
node	O
called	O
the	O
Merge	B-General_Concept
Point	I-General_Concept
(	O
MP	O
)	O
.	O
</s>
