<s>
Voice	B-Application
over	I-Application
Internet	I-Application
Protocol	I-Application
(	O
VoIP	B-Application
)	O
recording	O
is	O
a	O
subset	O
of	O
telephone	B-Protocol
recording	I-Protocol
or	O
voice	O
logging	O
,	O
first	O
used	O
by	O
call	O
centers	O
and	O
now	O
being	O
used	O
by	O
all	O
types	O
of	O
businesses	O
.	O
</s>
<s>
There	O
are	O
many	O
reasons	O
for	O
recording	O
voice	B-Application
over	I-Application
IP	I-Application
call	O
traffic	O
such	O
as	O
:	O
reducing	O
company	O
vulnerability	O
to	O
lawsuits	O
by	O
maintaining	O
recorded	O
evidence	O
,	O
complying	O
with	O
telephone	O
call	O
recording	O
laws	O
,	O
increasing	O
security	O
,	O
employee	O
training	O
and	O
performance	O
reviews	O
,	O
enhancing	O
employee	O
control	O
and	O
alignment	O
,	O
verifying	O
data	O
,	O
sharing	O
data	O
as	O
well	O
as	O
customer	O
satisfaction	O
and	O
enhancing	O
call	O
center	O
agent	O
morale	O
.	O
</s>
<s>
By	O
definition	O
,	O
Voice	B-Application
over	I-Application
IP	I-Application
is	O
audio	O
converted	O
into	O
digital	O
packets	O
and	O
then	O
converted	O
to	O
IP	O
packets	O
.	O
</s>
<s>
VoIP	B-Protocol
recording	I-Protocol
is	O
accomplished	O
either	O
by	O
sniffing	O
the	O
network	O
or	O
by	O
having	O
the	O
packets	O
duplicated	O
and	O
directed	O
to	O
the	O
recorder	O
—	O
passive	O
recording	O
or	O
active	O
recording	O
,	O
respectively	O
.	O
</s>
<s>
Sniffing	O
(	O
passive	O
recording	O
)	O
is	O
done	O
by	O
connecting	O
to	O
the	O
switched	B-Protocol
port	I-Protocol
analyzer	I-Protocol
(	O
SPAN	O
)	O
port	O
which	O
allows	O
the	O
VoIP	B-Protocol
recording	I-Protocol
unit	O
to	O
monitor	O
all	O
network	O
traffic	O
and	O
pick	O
out	O
only	O
the	O
VoIP	B-Application
traffic	O
to	O
record	O
by	O
either	O
MAC	O
address	O
or	O
by	O
IP	B-Protocol
address	I-Protocol
.	O
</s>
<s>
This	O
is	O
usually	O
done	O
by	O
connecting	O
an	O
Ethernet	O
cable	O
being	O
between	O
the	O
VoIP	B-Protocol
recording	I-Protocol
unit	O
and	O
the	O
router	O
,	O
switch	O
,	O
or	O
hub	O
.	O
</s>
<s>
Via	O
the	O
SPAN	B-Protocol
port	I-Protocol
,	O
the	O
recorder	O
will	O
"	O
sniff	O
"	O
for	O
signaling	O
and	O
RTP	B-Protocol
(	O
Real	B-Protocol
Time	I-Protocol
Protocol	I-Protocol
)	O
packets	O
that	O
have	O
the	O
identifying	O
information	O
contained	O
in	O
the	O
headers	O
of	O
the	O
packets	O
is	O
designated	O
to	O
record	O
.	O
</s>
<s>
There	O
are	O
two	O
main	O
ways	O
to	O
capture	O
the	O
RTP	B-Protocol
packets	O
with	O
the	O
SPAN	B-Protocol
port	I-Protocol
.	O
</s>
<s>
One	O
can	O
SPAN	O
the	O
VoIP	B-Application
Gateway	O
port	O
,	O
giving	O
all	O
the	O
in/out	O
bound	O
traffic	O
and	O
offers	O
one	O
point	O
of	O
contact	O
for	O
recording	O
.	O
</s>
<s>
However	O
,	O
this	O
method	O
cannot	O
capture	O
internal	O
,	O
peer-to-peer	O
(	O
phone	O
to	O
phone	O
)	O
calls	O
because	O
their	O
VoIP	B-Application
traffic	O
is	O
sent	O
directly	O
between	O
the	O
phones	O
and	O
does	O
n't	O
flow	O
through	O
the	O
gateway	O
port	O
.	O
</s>
<s>
Duplication	O
and	O
redirection	O
requires	O
setting	O
up	O
a	O
VLAN	B-General_Concept
and	O
including	O
all	O
the	O
phones	O
within	O
the	O
VLAN	B-General_Concept
.	O
</s>
<s>
Then	O
SPAN	O
that	O
VLAN	B-General_Concept
.	O
</s>
<s>
The	O
disadvantage	O
is	O
that	O
not	O
all	O
phones	O
at	O
times	O
are	O
on	O
a	O
VLAN	B-General_Concept
or	O
the	O
same	O
VLAN	B-General_Concept
,	O
so	O
multiple	O
SPANS	O
are	O
needed	O
.	O
</s>
<s>
Another	O
method	O
is	O
to	O
use	O
a	O
concept	O
called	O
RSPAN	B-Protocol
(	O
remote	O
SPAN	O
)	O
,	O
in	O
which	O
the	O
VLAN	B-General_Concept
's	O
that	O
are	O
set	O
to	O
SPAN	O
are	O
trunked	O
across	O
switches	O
to	O
a	O
receiving	O
switch	O
.	O
</s>
<s>
VoIP	B-Application
is	O
usually	O
implemented	O
as	O
a	O
cost-saving	O
measure	O
over	O
POTS	O
(	O
Plain	O
old	O
telephone	O
systems	O
)	O
.	O
</s>
<s>
The	O
same	O
holds	O
true	O
now	O
for	O
VoIP	B-Protocol
recording	I-Protocol
.	O
</s>
<s>
Most	O
recording	O
vendors	O
are	O
able	O
to	O
record	O
the	O
various	O
standards	O
of	O
VoIP	B-Application
such	O
as	O
G.711	B-Algorithm
,	O
G.729a/b	O
and	O
G.723	B-Algorithm
and	O
software-only	O
solutions	O
as	O
compared	O
to	O
the	O
intensive	O
hardware	O
and	O
software	O
associated	O
with	O
legacy	O
PBX	O
recording	O
.	O
</s>
<s>
Today	O
,	O
most	O
of	O
the	O
VoIP	B-Application
vendors	O
are	O
offering	O
VoIP	B-Protocol
recording	I-Protocol
methods	O
specific	O
to	O
their	O
VoIP	B-Application
call	I-Application
and	O
communications	O
management	O
servers	O
.	O
</s>
<s>
These	O
vendors	O
are	O
offering	O
what	O
is	O
referred	O
to	O
as	O
active	O
VoIP	B-Protocol
recording	I-Protocol
where	O
the	O
recording	O
vendor	O
's	O
solution	O
becomes	O
an	O
"	O
active	O
"	O
participant	O
within	O
the	O
call	O
for	O
recording	O
purposes	O
.	O
</s>
<s>
"	O
Passive	O
"	O
call-recording	B-Protocol
software	I-Protocol
works	O
by	O
using	O
packet	B-Protocol
filter	I-Protocol
technology	O
to	O
listen	O
for	O
VoIP	B-Application
calls	I-Application
on	O
the	O
LAN	O
on	O
a	O
monitored	O
port	O
.	O
</s>
<s>
The	O
RTP	B-Protocol
stream	O
is	O
then	O
captured	O
and	O
converted	O
to	O
a	O
WAV	O
file	O
for	O
storage	O
and	O
retrieval	O
.	O
</s>
<s>
VoIP	B-Application
calls	I-Application
can	O
be	O
recorded	O
via	O
streaming	O
audio	O
recording	O
applications	O
.	O
</s>
<s>
Most	O
call	O
centers	O
and	O
other	O
organizations	O
required	O
to	O
record	O
calls	O
would	O
more	O
often	O
use	O
a	O
recording	O
system	O
offered	O
by	O
the	O
softphone	B-Protocol
or	O
IP	O
PBX	O
.	O
</s>
