<s>
Call	B-Protocol
Admission	I-Protocol
Control	I-Protocol
(	O
CAC	O
)	O
prevents	O
oversubscription	O
of	O
VoIP	B-Application
networks	O
.	O
</s>
<s>
Integrated	O
Services	O
with	O
RSVP	B-Protocol
(	O
which	O
reserve	O
resources	O
for	O
the	O
flow	O
of	O
packets	O
through	O
the	O
network	O
)	O
using	O
controlled-load	O
service	O
ensures	O
that	O
a	O
call	O
cannot	O
be	O
set	O
up	O
if	O
it	O
cannot	O
be	O
supported	O
.	O
</s>
<s>
However	O
,	O
VoIP	B-Application
differs	O
in	O
that	O
it	O
uses	O
RTP	B-Protocol
,	O
UDP	B-Protocol
and	O
IP	B-Protocol
,	O
all	O
of	O
which	O
are	O
connectionless	B-Protocol
protocols	I-Protocol
.	O
</s>
