<s>
IP	O
hard	O
pipe	O
,	O
defined	O
in	O
IETF	O
RFC	O
7625	O
,	O
is	O
an	O
IP	O
network-based	O
technology	O
that	O
provides	O
bandwidth	B-Algorithm
guarantee	O
and	O
low	O
delay	O
for	O
services	O
.	O
</s>
<s>
Conventional	O
IP	B-Protocol
networks	I-Protocol
allow	O
bandwidth	B-Algorithm
reuse	O
,	O
but	O
do	O
not	O
allow	O
key	O
services	O
to	O
exclusively	O
use	O
fixed	O
bandwidth	B-Algorithm
.	O
</s>
<s>
Even	O
if	O
traffic	O
bursts	O
occur	O
in	O
the	O
soft	O
pipe	O
,	O
they	O
cannot	O
preempt	O
hard	O
pipe	O
bandwidth	B-Algorithm
.	O
</s>
<s>
IP	O
hard	O
pipe	O
reserves	O
bandwidth	B-Algorithm
and	O
ensures	O
low	O
delay	O
for	O
services	O
,	O
and	O
therefore	O
can	O
be	O
used	O
to	O
carry	O
leased	O
line	O
services	O
of	O
high-value	O
customers	O
.	O
</s>
<s>
As	O
carrier	O
networks	O
are	O
evolving	O
to	O
IP	O
,	O
customers	O
with	O
strict	O
bandwidth	B-Algorithm
,	O
delay	O
,	O
and	O
security	O
requirements	O
prefer	O
SDH(Synchronous Digital Hierarchy )	O
networks	O
.	O
</s>
<s>
Therefore	O
,	O
carriers	O
expect	O
to	O
migrate	O
their	O
customer	O
network	O
to	O
the	O
IP	B-Protocol
network	I-Protocol
to	O
reduce	O
maintenance	O
costs	O
and	O
facilitate	O
user	O
management	O
.	O
</s>
<s>
IP	O
hard	O
pipe	O
is	O
an	O
IP	O
network-based	O
end-to-end	O
transmission	O
technology	O
that	O
provides	O
bandwidth	B-Algorithm
guarantee	O
and	O
low	O
delay	O
through	O
dedicated	O
hardware	O
and	O
independent	O
pipes	O
,	O
allowing	O
IP	B-Protocol
networks	I-Protocol
to	O
provide	O
end-to-end	O
transmission	O
services	O
with	O
SDH	O
service	O
quality	O
.	O
</s>
<s>
IP	O
hard	O
pipe	O
also	O
provides	O
service-specific	O
SLA	O
(	O
service-level	O
agreement	O
)	O
monitoring	O
and	O
granular	O
OAM	O
,	O
ensuring	O
smooth	O
evolution	O
of	O
SDH	O
networks	O
to	O
IP	B-Protocol
networks	I-Protocol
.	O
</s>
<s>
•	O
Reduces	O
SDH	O
network	O
construction	O
investments	O
and	O
costs	O
for	O
maintaining	O
both	O
SDH	O
and	O
IP	B-Protocol
networks	I-Protocol
.	O
</s>
<s>
When	O
SDH	O
networks	O
run	O
out	O
of	O
warranty	O
,	O
new	O
services	O
can	O
be	O
rolled	O
out	O
on	O
IP	B-Protocol
networks	I-Protocol
,	O
and	O
key	O
services	O
of	O
high-value	O
VIP	O
customers	O
can	O
be	O
deployed	O
on	O
newly	O
established	O
networks	O
.	O
</s>
<s>
In	O
the	O
IP	O
hard	O
pipe	O
solution	O
,	O
the	O
NMS	O
centrally	O
manages	O
bandwidth	B-Algorithm
resources	O
and	O
uniformly	O
provisions	O
services	O
.	O
</s>
<s>
The	O
service	O
bandwidth	B-Algorithm
and	O
source	O
and	O
destination	O
devices	O
are	O
manually	O
specified	O
for	O
VIP	O
customers	O
.	O
</s>
<s>
Carriers	O
must	O
plan	O
the	O
logical	O
hard	O
pipe	O
network	O
on	O
existing	O
IP	O
bearer	O
networks	O
and	O
reserve	O
the	O
hard	O
pipe	O
bandwidth	B-Algorithm
on	O
physical	O
interfaces	O
.	O
</s>
<s>
For	O
example	O
,	O
if	O
an	O
enterprise	O
user	O
wants	O
to	O
establish	O
a	O
leased	O
line	O
between	O
two	O
sites	O
over	O
a	O
carrier	O
's	O
network	O
,	O
the	O
carrier	O
first	O
makes	O
service	O
plans	O
and	O
then	O
performs	O
uniform	O
service	O
deployment	O
and	O
provisioning	O
based	O
on	O
the	O
committed	O
bandwidth	B-Algorithm
.	O
</s>
