<s>
oSIP	B-Protocol
is	O
a	O
free	B-Application
software	I-Application
library	O
for	O
VoIP	B-Application
applications	O
implementing	O
lower	O
layers	O
of	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
(	O
SIP	O
)	O
.	O
</s>
<s>
Started	O
in	O
September	O
2000	O
and	O
published	O
in	O
April	O
2001	O
,	O
oSIP	B-Protocol
is	O
among	O
the	O
oldest	O
SIP	O
open	O
source	O
stack	O
still	O
being	O
developed	O
and	O
maintained	O
.	O
</s>
<s>
The	O
project	O
was	O
made	O
part	O
of	O
the	B-Application
GNU	I-Application
Project	I-Application
as	O
GNU	B-Protocol
oSIP	I-Protocol
in	O
2002	O
.	O
</s>
<s>
,	O
the	O
"	O
eXtended	O
osip	B-Protocol
"	O
library	O
.	O
</s>
<s>
An	O
extension	O
of	O
oSIP	B-Protocol
for	O
softphone	O
implementation	O
written	O
by	O
Aymeric	O
Moizard	O
.	O
</s>
<s>
Linphone	B-Protocol
.	O
</s>
<s>
Linphone	B-Protocol
has	O
been	O
the	O
first	O
project	O
based	O
on	O
oSIP	B-Protocol
and	O
eXosip	O
.	O
</s>
<s>
Jami	B-Protocol
(	O
software	O
)	O
.	O
</s>
<s>
FreeSWITCH	B-Language
.	O
</s>
