<s>
Packet	B-Protocol
Forwarding	I-Protocol
Control	I-Protocol
Protocol	I-Protocol
(	O
PFCP	B-Protocol
)	O
is	O
a	O
3GPP	O
protocol	O
used	O
on	O
the	O
Sx/N4	O
interface	O
between	O
the	O
control	O
plane	O
and	O
the	O
user	O
plane	O
function	O
,	O
specified	O
in	O
TS	O
29.244	O
.	O
</s>
<s>
PFCP	B-Protocol
and	O
the	O
associated	O
interfaces	O
seek	O
to	O
formalize	O
the	O
interactions	O
between	O
different	O
types	O
of	O
functional	O
elements	O
used	O
in	O
the	O
Mobile	O
Core	O
Networks	O
as	O
deployed	O
by	O
most	O
operators	O
providing	O
4G	O
,	O
as	O
well	O
as	O
5G	O
,	O
services	O
to	O
mobile	O
subscribers	O
.	O
</s>
<s>
packet	O
forwarding	O
for	O
IPv4	B-Protocol
,	O
IPv6	B-Protocol
-	O
or	O
possibly	O
even	O
Ethernet	O
with	O
future	O
5G	O
deployments	O
-	O
between	O
the	O
various	O
supported	O
wireless	O
RANs	O
and	O
the	O
PDN	O
representing	O
the	O
Internet	O
or	O
an	O
enterprise	O
network	O
)	O
.	O
</s>
<s>
PFCP	B-Protocol
's	O
scope	O
is	O
similar	O
to	O
that	O
of	O
OpenFlow	B-Protocol
,	O
however	O
it	O
was	O
engineered	O
to	O
serve	O
the	O
particular	O
use-case	O
of	O
Mobile	O
Core	O
Networks	O
.	O
</s>
<s>
PFCP	B-Protocol
is	O
also	O
used	O
on	O
the	O
interface	O
between	O
the	O
control	O
plane	O
and	O
user	O
plane	O
functions	O
of	O
a	O
disaggregated	O
BNG	O
,	O
as	O
defined	O
by	O
the	O
BroadBand	O
Forum	O
in	O
.	O
</s>
<s>
Albeit	O
similar	O
to	O
GTP	B-Protocol
in	O
concepts	O
and	O
implementation	O
,	O
PFCP	B-Protocol
is	O
complementary	O
to	O
it	O
.	O
</s>
<s>
The	O
PFCP	B-Protocol
protocol	O
is	O
used	O
on	O
the	O
following	O
3GPP	O
mobile	O
core	O
interfaces	O
:	O
</s>
<s>
PGW-U	O
,	O
UPF	O
)	O
,	O
by	O
establishing	O
,	O
modifying	O
or	O
deleting	O
PFCP	B-Protocol
Sessions	O
.	O
</s>
<s>
User	O
plane	O
packets	O
shall	O
be	O
forwarded	O
between	O
the	O
CP	O
and	O
UP	O
functions	O
by	O
encapsulating	O
the	O
user	O
plane	O
packets	O
using	O
GTP-U	B-Protocol
encapsulation	O
(	O
see	O
3GPP	O
TS	O
29.281	O
 [ 3 ] 	O
)	O
.	O
</s>
<s>
For	O
forwarding	O
data	O
from	O
the	O
UP	O
function	O
to	O
the	O
CP	O
function	O
,	O
the	O
CP	O
function	O
shall	O
provision	O
Packet	O
Detection	O
Rules	O
(	O
PDR	O
)	O
per	O
PFCP	B-Protocol
session	O
context	O
,	O
with	O
the	O
Packet	O
Detection	O
Information	O
(	O
PDI	O
)	O
identifying	O
the	O
user	O
plane	O
traffic	O
to	O
forward	O
to	O
the	O
CP	O
function	O
and	O
with	O
a	O
Forwarding	O
Action	O
Rule	O
(	O
FAR	O
)	O
set	O
with	O
the	O
Destination	O
Interface	O
"	O
CP	O
function	O
side	O
"	O
and	O
set	O
to	O
perform	O
GTP-U	B-Protocol
encapsulation	O
and	O
to	O
forward	O
the	O
packets	O
to	O
a	O
GTP-u	B-Protocol
F-TEID	O
uniquely	O
assigned	O
in	O
the	O
CP	O
function	O
per	O
PFCP	B-Protocol
session	O
and	O
PDR	O
.	O
</s>
<s>
The	O
CP	O
function	O
shall	O
then	O
identify	O
the	O
PDN	O
connection	O
and	O
the	O
bearer	O
to	O
which	O
the	O
forwarded	O
data	O
belongs	O
by	O
the	O
Fully	O
Qualified	O
TEID	O
(	O
F-TEID	O
)	O
in	O
the	O
header	O
of	O
the	O
encapsulating	O
GTP-U	B-Protocol
packet	O
.	O
</s>
<s>
For	O
forwarding	O
data	O
from	O
the	O
CP	O
function	O
to	O
the	O
UP	O
function	O
,	O
the	O
CP	O
function	O
shall	O
provision	O
one	O
or	O
more	O
PDR(s )	O
per	O
PFCP	B-Protocol
session	O
context	O
,	O
with	O
the	O
PDI	O
set	O
with	O
the	O
Source	O
Interface	O
"	O
CP	O
function	O
side	O
"	O
and	O
identifying	O
the	O
GTP-u	B-Protocol
F-TEID	O
uniquely	O
assigned	O
in	O
the	O
UP	O
function	O
per	O
PDR	O
,	O
and	O
with	O
a	O
FAR	O
set	O
to	O
perform	O
GTP-U	B-Protocol
decapsulation	O
and	O
to	O
forward	O
the	O
packets	O
to	O
the	O
intended	O
destination	O
.	O
</s>
<s>
PFCP	B-Protocol
Information	O
Element	O
FormatBit/Byte	O
offset012345678910111213141516171819202122232425262728293031Bytes	O
0	O
..	O
3TypeIE	O
Length	O
(	O
in	O
bytes	O
,	O
not	O
including	O
the	O
first	O
4	O
)	O
Bytes	O
4	O
..	O
IELen	O
+4if	O
(	O
Type	O
>=	O
32768	O
)	O
then	O
Enterprise-ID	O
;	O
else	O
this	O
is	O
part	O
of	O
the	O
PayloadPayload	O
(	O
cont	O
.	O
)	O
</s>
<s>
Grouped	O
IEs	O
are	O
simply	O
a	O
list	O
of	O
other	O
IEs	O
,	O
encoded	O
one	O
after	O
the	O
other	O
like	O
in	O
the	O
PFCP	B-Protocol
Message	O
Payload	O
.	O
</s>
<s>
A	O
Recovery-Timestamp	O
is	O
used	O
to	O
detect	O
if	O
the	O
other	O
peer	O
has	O
been	O
restarted.34PFD	O
Management	O
-XXXCP	O
→	O
UPUP	O
→	O
CPOptional	O
feature	O
,	O
to	O
provision	O
PFDs	O
per	O
Application	O
identifier	O
,	O
outside	O
of	O
the	O
regular	O
PFCP	B-Protocol
sessions.56Association	O
SetupXXXXCP	O
↔	O
UPSetup	O
and	O
update	O
an	O
association	O
between	O
CP	O
and	O
UP	O
functional	O
elements	O
.	O
</s>
<s>
These	O
are	O
the	O
main	O
functional	O
message	O
of	O
the	O
PFCP	B-Protocol
application	O
domain	O
.	O
</s>
<s>
Very	O
similar	O
to	O
GTP-C	B-Protocol
,	O
PFCP	B-Protocol
uses	O
UDP	B-Protocol
.	O
</s>
<s>
For	O
reliability	O
,	O
a	O
similar	O
re-transmission	O
strategy	O
as	O
for	O
GTP-C	B-Protocol
is	O
employed	O
,	O
lost	O
messages	O
being	O
sent	O
N1-times	O
at	O
T1-intervals	O
.	O
</s>
<s>
For	O
User-Plane	O
packet	O
exchanges	O
between	O
the	O
Control	O
and	O
User	O
Plane	O
functional	O
elements	O
,	O
GTP-U	B-Protocol
for	O
the	O
Sx-u	O
interface	O
,	O
or	O
alternatively	O
a	O
simpler	O
UDP	B-Protocol
or	O
Ethernet	O
encapsulation	O
for	O
the	O
N4-u	O
interface	O
(	O
to	O
be	O
confirmed	O
,	O
as	O
standards	O
are	O
still	O
incomplete	O
)	O
.	O
</s>
