<s>
It	O
is	O
designed	O
to	O
be	O
implementable	O
on	O
either	O
network	B-Application
servers	I-Application
or	O
user	B-Application
agent	I-Application
servers	I-Application
.	O
</s>
<s>
On	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
Servers	O
(	O
SIP	O
servers	O
)	O
,	O
CPL	O
has	O
been	O
used	O
to	O
control	O
the	O
session	O
protocol	O
based	O
on	O
user	O
defined	O
preferences	O
.	O
</s>
