<s>
This	O
synchronisation	O
is	O
provided	O
by	O
the	O
communication	O
network	O
,	O
in	O
most	O
cases	O
Industrial	B-Protocol
Ethernet	I-Protocol
.	O
</s>
<s>
Many	O
ad-hoc	O
synchronization	O
schemes	O
exist	O
,	O
so	O
IEEE	O
published	O
a	O
standard	O
Precision	B-Protocol
Time	I-Protocol
Protocol	I-Protocol
IEEE	B-Protocol
1588	I-Protocol
or	O
"	O
PTP	O
"	O
,	O
which	O
allows	O
sub-microsecond	O
synchronization	O
of	O
clocks	O
.	O
</s>
<s>
The	O
PTP	O
Industrial	O
Profile	O
(	O
PIP	O
)	O
is	O
a	O
standard	O
of	O
the	O
IEC	O
62439-3	O
that	O
specifies	O
in	O
its	O
Annex	O
C	O
two	O
Precision	B-Protocol
Time	I-Protocol
Protocol	I-Protocol
IEEE	B-Protocol
1588	I-Protocol
/	O
IEC	B-Protocol
61588	I-Protocol
profiles	O
,	O
L3E2E	O
and	O
L2P2P	O
,	O
to	O
synchronize	O
network	O
clocks	O
with	O
an	O
accuracy	O
of	O
1	O
μs	O
and	O
provide	O
fault-tolerance	O
against	O
clock	O
failures	O
.	O
</s>
<s>
The	O
IEC	O
62439-3	O
PTP	O
profiles	O
are	O
applicable	O
to	O
most	O
Industrial	B-Protocol
Ethernet	I-Protocol
networks	O
,	O
for	O
synchronized	O
drives	O
,	O
robotics	O
,	O
vehicular	O
technology	O
and	O
other	O
applications	O
that	O
require	O
precise	O
time	O
distribution	O
,	O
not	O
necessarily	O
using	O
redundant	O
networks	O
.	O
</s>
<s>
The	O
IEC	O
62439-3	O
profile	O
L2P2P	O
has	O
been	O
adopted	O
as	O
IEC/IEEE	B-Protocol
61850-9-3	I-Protocol
by	O
the	O
power	O
utility	O
industry	O
to	O
support	O
precise	O
time	O
stamping	O
of	O
voltage	O
and	O
current	O
measurement	O
for	O
differential	O
protection	O
,	O
wide	O
area	O
monitoring	O
and	O
protection	O
,	O
busbar	O
protection	O
and	O
event	O
recording	O
.	O
</s>
<s>
The	O
IEC	O
62439-3	O
Annexes	O
belongs	O
to	O
the	O
Parallel	B-Protocol
Redundancy	I-Protocol
Protocol	I-Protocol
and	O
High-availability	B-Protocol
Seamless	I-Protocol
Redundancy	I-Protocol
standard	O
suite	O
for	O
high	O
availability	O
automation	O
networks	O
.	O
</s>
<s>
The	O
PIP	O
relies	O
on	O
the	O
IEEE	B-Protocol
1588	I-Protocol
topology	O
,	O
consisting	O
of	O
grandmaster	O
clocks	O
(	O
GC	O
)	O
,	O
ordinary	O
clocks	O
(	O
OC	O
)	O
,	O
boundary	O
clocks	O
(	O
BC	O
)	O
,	O
transparent	O
clocks	O
(	O
TC	O
)	O
and	O
hybrid	O
clocks	O
(	O
HC	O
=	O
TC&OC	O
)	O
.	O
</s>
<s>
IEC	O
62439-3	O
Annex	O
B	O
specifies	O
the	O
L2PTP	O
profile	O
for	O
substation	O
automation	O
IEC/IEEE	B-Protocol
61850-9-3	I-Protocol
.	O
</s>
<s>
IEC	O
62439-3	O
Annex	O
C	O
specifies	O
two	O
profiles	O
,	O
L3E2E	O
and	O
L2P2P	O
,	O
that	O
are	O
subsets	O
of	O
IEEE	O
Std	O
1588	O
Precision	B-Protocol
Time	I-Protocol
Protocol	I-Protocol
(	O
PTP	O
)	O
when	O
clocks	O
are	O
singly	O
attached	O
.	O
</s>
<s>
IEC	O
62439-3	O
Annex	O
D	O
is	O
a	O
tutorial	O
for	O
IEEE	B-Protocol
1588	I-Protocol
that	O
concentrates	O
only	O
on	O
PIP	O
.	O
</s>
<s>
L3E2E	O
:	O
End-to-end	O
measurement	O
(	O
Delay_Req/Delay_Resp	O
)	O
over	O
Layer	O
3	O
(	O
Internet	B-Protocol
Protocol	I-Protocol
)	O
to	O
fulfill	O
the	O
requirements	O
of	O
ODVA	O
;	O
</s>
<s>
IEC	O
TR	O
61850-90-4	O
(	O
Network	O
engineering	O
guidelines	O
)	O
gives	O
advice	O
on	O
the	O
use	O
of	O
IEC/IEEE	B-Protocol
61850-9-3	I-Protocol
in	O
substation	O
automation	O
networks	O
.	O
</s>
<s>
IEC	O
62439-3	O
Annex	O
C	O
specifies	O
requirements	O
in	O
addition	O
to	O
IEEE	B-Protocol
1588	I-Protocol
:	O
</s>
<s>
Technical	O
responsibility	O
rests	O
with	O
IEC	O
SC65C	O
WG15	O
,	O
which	O
is	O
committed	O
to	O
keep	O
the	O
IEC	O
62439-3	O
profile	O
L2P2P	O
and	O
IEC/IEEE	B-Protocol
61850-9-3	I-Protocol
aligned	O
.	O
</s>
