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OTN NEWBIES
1
FOREWORD
According to the ITU-T Recommendation G.709, an Optical Transport Network (OTN) is composed of a set of optical network elements connected by optical fiber links. The network provides functionality of transport, multiplexing, routing, management, supervision, and survivability of optical channels carrying client signals.
This architecture can be seen as a combination of the advantages of SDH/SONET technology with the flexibility of DWDM. Using OTN, the OAM&P functionality of SDH/SONET is applied to DWDM optical networks.
Compared to SDH/SONET, OTN has the following advantages:
• Stronger error correction mechanisms
• More levels of tandem connection monitoring
• Transparent transport of client signals
• Switching scalabilityIntroduction
Page2
ABOUT THIS COURSE
This course is based on the following ITU-T
recommendations:
ITU-T G.709
ITU-T G.805
ITU-T G.806
ITU-T G.798
Page3
LEARNING GUIDE
Just little Basics
4
CONTENTS
1. OTN Introduction
2. Typical OTN Scenarios
Page5
CONTENTS
1. OTN Introduction
1.1 OTH
1.2 OTN Port Structure
1.3 Multiplexing/Mapping Principles and Bit Rates
1.4 Overhead Description
1.5 Maintenance Signals and Functions of Different Layers
1.6 Alarms and Performance Events
Page6
OTN
Optical transport network (OTN)
An OTN network is composed of a set of
optical NEs connected by optical fiber links.
These NEs are able to provide functions
such as transport, multiplexing, routing,
management, supervision, and protection
(survivability) of client signals, according to
the requirements specified in REC. G.872.
Page7
FEATURES OF OTN
Compared with SDH and SONET networks, an OTN
network has the following features:
Ultra capacity with high accuracy, T-bit/second per fiber
over DWDM lines
Service transparency for client signals
Asynchronous mapping, powerful FEC function, simplified
network design, and reduced costs
Compared with traditional WDM networks, an OTN
network has the following features:
Enhanced OAM and networking capabilities for all services
Dynamic electrical/optical-layer grooming
Page8
OTN STANDARD SYSTEM
Structure
OTN
OTN network structure G.872
ASON network structure G.8080
Structure and
mapping Generic frame protocol (GFP) G.7041
Link capacity adjustment scheme (LCAS) for virtual concatenation signals G.7042
Ports on an OTN network G.709
Equipment
functions
and
features
Features of function blocks of equipment on an OTN network G.798
Transport network equipment features: description methods and general functions G.806
Physical-layer
features Optical ports for intra-office systems G.693
Optical security rule and requirements in an optical transport system G.664
Physical-layer ports on an OTN network G.959.1
Network
protection
Linear protection on an OTN network G.873.1
Ring protection on an OTN network G.873.2
Jitter and
performance
Jitter and shift control on an OTN network G.8251
Bit error performance parameters and specifications on international channels of multiple carriers on an OTN network G.8201
Equipment
management
Management features of NEs on an OTN network G.874
OTN network: Protocol-neutral management information model for the network element G.874.1
9
OTN NETWORK LAYERS AND PORT STRUCTURE
OPUk: optical channel payload unit-k
ODUk: optical channel data unit-k
OTUk: completely standardized optical
channel transport unit-k
OTUkV: functionally standardized
Optical channel transport unit-k
OCh: optical channel with full
functionality
OChr: optical channel with reduced
functionality
OMS: optical multiplex section
OTS: optical transmission section
OPS: optical physical section
OTM: optical transport module
Page10
ODUk (ODUkP and ODUkT)
OPUk
OTUk OTUkV OTUk OTUkV
OCh OChr
OMSn
OTSn OPSn
IP/MPLS ATM Ethernet STM-N
OTM-0.m
OTM-nr.m
OTM-n.m
OTM-N.M CONTAINMENT RELATIONSHIPS
“n” represents the maximum number of wavelengths that can be supported at the lowest bit rate
supported by the wavelengths. “m” equals 1, 2, 3, 12, 23, or 123.
OTS_OH, OMS_OH, OCh_OH and COMMS OH information fields are contained in the OOS.
The optical supervisory channel (OSC) is used to transmit OOSs.
Page11
OCCp OCCp OCCp
OCh payload
ODUk FEC OH
OPUk OH
Client signal
OPUk payload OH OPUk
ODUk
OTUk[V]
OCh
OCG-n.m
OTM-n.m OTSn OH
OMSn OH
OC
Co
OChOH
OC
Co
OC
Co
OMU-n.m
Non
-associa
ted O
H
OOS
Com
mon
managem
ent
OH
OT
M-n
. m
OTM overhead signal (OOS)
l 2
l 1
l n
l OSC
OTM-NR.M CONTAINMENT RELATIONSHIPS
Fixed channel spacing, irrelevant to the signal rate
1 < n ≤ 16; m = 1, 2, 3, 12, 23, or 123
Without optical supervisory channels
Page12
OCCp OCCp OCCp
OCh payload
ODUk FEC OH
OPUk OH
Client signal
OPUk payload OH OPUk
ODUk
OTUk[V]
OChr
OCG-nr.m
OTM-nr.m
OT
M-1
6r.
m
l 2
l 1
l 16
OTM-0.M CONTAINMENT RELATIONSHIPS
The OTM 0.m supports a non-colored optical channel on a single optical span with
3R regeneration at each end.
m = 1, 2, or 3
Without optical supervisory channels
Page13
OCh payload
ODUk FEC OH
OPUk OH
Client signal
OPUk payload OH OPUk
ODUk
OTUk[V]
OChr
OTM-0.m OPS0
OT
M-0
.m
OTN PORTS
User to network interface (UNI)
Network node interface (NNI)
Inter-domain interface (IrDI)
Intra-domain interface (IaDI)
Between equipment provided by different vendors (IrVI)
Within subnet of one vendor (IaVI)
The completely standardized OTUk is used at OTM IrDIs and OTM IaDIs.
The partly standardized OTUk is used at OTM IaDIs.
Page14
OTM
UNI
OTM NNI
IaDI-IrVI
OTM NNI
IaDI-IaVI
OTM NNI
IaDI-IaVI
Network Operator B
Vendors X Vendors Y
OTM
NNI
IrDI
Network
Operator
C
USER
A
CONTENTS
1. OTN introduction
1.1 Optical transport hierarchy
1.2 OTN interface structure
1.3 Multiplexing/mapping principles and bit rates
1.4 Overhead description
1.5 Maintenance signals and function for different layers
1.6 Alarm and performance events
Page15
OTN MULTIPLEXING AND MAPPING STRUCTURE
Page16
Mapping
Multiplexing
ODTUG3
ODTUG2
OChr
OChr
OChr
OCh
OCh
OCh
OTU3[V]
OTU2[V]
OTU1[V]
Client signal
Client signal
OPU3 ODU3
OCCr
OCCr
OCCr
OCC
OCC
OCC
OCG-nr.m
1 ≤ i+j+k ≤ n
OCG-n.m
1 ≤ i+j+k ≤ n
OPU2 ODU2
1 OPU1 ODU1
OTM-nr.m
OTS, OMS, OCh, COMMS OSC OOS
OTM-n.m
4
1
1 4
16 1
1 1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
i
j
k
i
j
1
Clie
nt s
ign
al
1
OTM-0.m
k
OTN Multiplexing and Mapping Structure
17
OTN Multiplexing and Mapping Structure
18
O
PU
flex
OPU4
OPU3
OPU2
OPU0
OPU1
Client service rate
1.238G
2.488G
9.995G
40.149G
104.134G
10.312G OPU2e
LO OPU
OP
Ufle
x(G
FP
)
OP
Ufle
x
OP
Ufle
x
LO ODU
New LO ODU signals
1.25G ODU0
10.3G ODU2e
104G ODU4
ODUflex
OTN Service Bearing Capability (LO
ODU)
19
OTN LINE BEARING CAPABILITY
(HO ODU)
OP
U3e2/2
1
(OD
U0
, OD
U1
, OD
U2
, OD
U2
e, O
DU
flex)
OP
U3/2
0
(OD
U1
, OD
U2
)
OP
U2/2
1
(OD
U0
, OD
U1
, OD
Ufle
x)
OP
U2/2
0
(OD
U1
)
OP
U4
/21
(OD
U0
, OD
U1
, OD
U2
, OD
U2
e, O
DU
3, O
DU
3e
2, O
DU
flex)
OP
U3/2
1
(OD
U0
, OD
U1
, OD
U2
, OD
U2
e, O
DU
flex)
OP
U1
(O
DU
0)
LO ODU rate
ODU0
ODU1
ODU2
ODU3
ODU4
ODU2e
HO OPU
OD
Ufle
x
OD
Ufle
x
OD
Ufle
x
OD
Ufle
x(G
FP
)
ODU3e2
New HO ODU signals
2.5G ODU1
41.7GG ODU3e2
(G.sup43)
104G ODU4
Signals with extended
capabilities
– 10G ODU2
– 40G ODU3
20
OTUK FRAME RATE
OTU Type OTU Nominal Bit Rate OTU Bit Rate Tolerance
OTU1 255/238 x 2488320 kbit/s
20 ppm
OTU2 255/237 x 9953280 kbit/s
OTU3 255/236 x 39813120 kbit/s
OTU4 255/227 x 99532800 kbit/s
Note 1: The nominal OTUk rates are approximately 2666057.143 kbit/s (OTU1), 10709225.316
kbit/s (OTU2), 43018413.559 kbit/s (OTU3) and 111809 973.568 kbit/s (OTU4).
Note 2: OTU0, OTU2e and OTUflex are not specified in this recommendation. ODU0 signals
are transported over ODU1, ODU2, ODU3 or ODU4 signals, ODU2e signals are transported
over ODU3 and ODU4 signals, and ODUflex signals are transported over ODU2, ODU3 and
ODU4 signals.
OTUk rate = 255/(239 - k) x STM-N frame rate
ODUK FRAME RATE
ODU Type ODU Nominal Bit Rate ODU Bit Rate Tolerance
ODU0 1244160 kbit/s
20 ppm
ODU1 239/238 x 2488320 kbit/s
ODU2 239/237 x 9953280 kbit/s
ODU3 239/236 x 39813120 kbit/s
ODU4 239/227 x 99532800 kbit/s
ODU2e 239/237 x 10312500 kbit/s 100 ppm
ODUflex for CBR
client signals
239/238 x Client signal bit rate Client signal bit rate tolerance, with a
maximum of 100 ppm
ODUflex for GFP-F
mapped client
signals
Pre-set bit rate 20 ppm
Note: The nominal ODUk rates are approximately 2498775.126 kbit/s (ODU1), 10037273.924 kbit/s
(ODU2), 40319218.983 kbit/s (ODU3), 104794445.815 kbit/s (ODU4) and 10399525.316 kbit/s
(ODU2e).
ODUk rate = 239/(239 - k) x STM-N frame rate
OPUK FRAME RATE
OPU Type OPU Payload Nominal Bit Rate OPU Payload Bit Rate Tolerance
OPU0 238/239 x 1244160 kbit/s
20 ppm
OPU1 2488320 kbit/s
OPU2 238/237 x 9953280 kbit/s
OPU3 238/236 x 39813120 kbit/s
OPU4 238/227 x 99532800 kbit/s
OPU2e 238/237 x 10312500 kbit/s 100 ppm
OPUflex for CBR client
signals
Client signal bit rate Client signal bit rate tolerance, with a
maximum of 100 ppm
OPUflex for GFP-F
mapped client signals
238/239 x ODUflex signal rate 20 ppm
OPU1-Xv X x 2 488 320 kbit/s
20 ppm
OPU2-Xv X x 238/237 x 9953280 kbit/s
OPU3-Xv X x 238/236 x 39813120 kbit/s
Note: The nominal OPUk payload rates are approximately 1238954.310 kbit/s (OPU0 Payload), 2488320.000 kbit/s
(OPU1 payload), 9995276.962 kbit/s (OPU2 payload), 40150519.322 kbit/s (OPU3 payload), 104355975.330 (OPU4
payload) and 10356012.658 kbit/s (OPU2e payload). The nominal OPUk-Xv payload rates are approximately X x
2488320.000 kbit/s (OPU1-Xv payload), X x 9995276.962 kbit/s (OPU2-Xv payload) and X x 40150519.322 kbit/s
(OPU3-Xv payload).
OPUk payload rate = 238/(239 - k) x STM-N frame rate
ODUK (TDM)
Low-rate ODUk signals are multiplexed into
high-rate ODUk signals using time-division
multiplexing:
A maximum of four ODU1 signals are multiplexed
into one ODU2 signal using time-division
multiplexing.
Hybrid j (j 4) ODU2 and 16-4j ODU1 signals are
multiplexed into one ODU3 signal using time-division
multiplexing.
Multiple LO ODUi[j] signals at different levels are
multiplexed into one HO ODUk signal.
Page24
ODU1 MULTIPLEXED INTO ODU2
ODTU12: optical channel data tributary unit 1 into 2
ODTUG2: optical channel data tributary unit group 2
JOH: justification overhead
Page25
ODU1
OH ODU1 ODU1 payload
ODTU12 JOH
ODU1 ODTU12
ODU2 OH
OPU2
OH
ODU2 payload
OPU2
ODU2
ODTU12 JOH
ODU1 ODTU12
JOH ODU1 ODTUG2
ODTUG2
OPU2 payload
ODU1 MULTIPLEXED INTO ODU2
ODU1 floats in one quarter of the OPU2 payload area.
An ODU1 frame travels cross multiple ODU2 frame boundaries.
Page26
OTU2 OTU2 FEC
Client-layer signal
(STM-16, ATM, or GFP) ODU1
ODU1OH
Alignment
ODU2
x4
Client Layer Signal (for example, STM-16) ODU1 OH O
PU
1 O
H
Client Layer Signal (for example, STM-16) ODU1 OH O
PU
1 O
H
Client Layer Signal (for example, STM-16) ODU1 OH O
PU
1 O
H
Client-layer signal (STM-16, ATM, or GFP) ODU1 OH
ODU2 OH
OP
U2 O
H
OPU2 Payload ODU2 OH
Alignment
OP
U2 O
H OTU2
OH
Client Layer Signal (for example, STM-16) ODU1 OH O
PU
1 O
H
Client Layer Signal (for example, STM-16) ODU1 OH O
PU
1 O
H
Client Layer Signal (for example, STM-16) ODU1 OH O
PU
1 O
H
Client-layer signal (STM-16, ATM, or GFP) ODU1 OH
OP
U1 O
H
Alignment
Alignment
OP
U1 O
H
OP
U1 O
H
ODU1 AND ODU2 MULTIPLEXED INTO ODU3
ODTU23: optical channel data tributary unit 2 into 3
ODTU13: optical channel data tributary unit 1 into 3
Page27
ODU1 OH ODU1 ODU1 payload
ODTU13 JOH
ODU1 ODTU13
ODU3 OH
OPU3 OH
ODU3 payload
OPU3
ODU3
ODTU23 JOH
ODTU23 JOH
ODU1 ODTUG3
ODTUG3
OPU3 payload
ODU2 OH ODU2 ODU2 payload
ODTU23 JOH
ODU2 ODTU23
ODTU13 JOH
ODU2 ODTU13 JOH
ODU2 ODU1
OH
Payload Area
client data
stuff
server frame or multi-frame
0
memory
Pserver?
Pserver
client data
indication =
read/write
enable
payload area
frame start
clock
Cm(t)
enable
GMP can automatically adapt CBR services to an OTN container. It is the key
technology for an OTN network to bear multiple services.
Service rate information transmitted in overheads
Sigma-delta algorithm
M byte bit width
Separation of data and clocks
GMP Mapping
28
ODUflex
OH
OH Services with
a fixed bit rate
Client signals
Packet services
Client services
OH
GMP TSi TSj
ODUflex
OH BMP
TSi TSj
GMP
GFP
Map CBR services to ODUflex services using synchronized packet encapsulation.
Map packet services to ODUflex services using GFP.
Map ODUflex services to HO OPUk services using GMP.
ODUflex
29
CONTENTS
1. OTN introduction
1.1 Optical transport hierarchy
1.2 OTN interface structure
1.3 Multiplexing/mapping principles and bit rates
1.4 Overhead description
1.5 Maintenance signals and function for different layers
1.6 Alarm and performance events
Page30
OOS
TTI: trail trace identifier
PMI: payload missing indication
OCI: open connection indication
BDI-O: backward defect indication - overhead
BDI-P: backward defect indication - payload
FDI-O: forward defect indication - overhead
FDI-P: forward defect indication - payload
Page31
Non-a
ssocia
ted
overh
ead
OT
Sn
n
3 2
OC
h
1
General management communication
OM
Sn
FDI-O
FDI-P
OCI
BDI-O
BDI-P
PMI
FDI-P
FDI-O
BDI-O
BDI-P
PMI
TTI
OOS functions subject
to standardization. Bit
rate and format are not
standardized.
OPTICAL-LAYER FUNCTION
Page32
OT
Sn
BDI-O
BDI-P
PMI
TTI MI_TxTI
aPMI
RI_BDI-P
RI_BDI-O
Payload OTSn OH
dLOS_P
Payload and OH combined together APR control
OA, DCM
The OTS source function is used as an example.
Page33
OTN FRAME FORMATS (K = 1, 2, OR 3)
38
25
40
80
1
7
8
14
1
5
16
1
7
38
24
1
2
3
4
OPU k payload O
PU
k O
H
OPUk - optical channel payload unit
ODUk
OH
ODUk - Optical Channel Data Unit
Client signal
mapped in
OPUk payload
Client signal
OTUK
FEC
OTUk
OH
OTUk - Optical Channel Transport Unit
Alignment
Alignment
K:
1 - 2.5G
2 - 10G
3 - 40G
33
OTN ELECTRICAL OVERHEAD OVERVIEW
Page34
ODUk OH TCMACT: tandem connection monitoring
activation/deactivation control channel
TCMi: tandem connection monitoring i
FTFL: fault type and fault location reporting
channel
PM: path monitoring
EXP: experimental
GCC1/2: general communication channel
1/2
APS/PCC: automatic protection switching
coordination channel/protection
communication control channel
Alignment OH FAS: frame alignment signal
MFAS: multiframe alignment signal
OTUk OH SM: section monitoring
GCC0: general communication channel 0
RES: reserved for future international
standardization
OPUk OH PSI: payload structure identifier
JC: justification control
NJO: negative justification opportunity
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS MFAS SM GCC0 RES JC RES
17
FRAME ALIGNMENT SIGNAL
Page35
Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
OA1 OA1 OA1 OA2 OA2 OA2
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS MFAS SM GCC0 RES JC RES
17
Frame alignment signal (FAS)
A six-byte OTUk-FAS signal is defined in row 1 and columns 1 to 6 of
the OTUk overhead.
OA1 is 0xF6 (1111 0110) and OA2 is 0x28 (0010 1000).
MULTIFRAME ALIGNMENT SIGNAL
Page36
MFAS OH byte
MF
AS
se
qu
en
ce
1 2 3 4 5 6 7 8
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 0 0 0 0 1 0 0
.
.
.
.
.
.
1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
. .
Multiframe alignment signal (MFAS)
It is defined in row 1 and column 7.
The value of the MFAS byte is increased by
OTUk/ODUk frame and the MFAS byte provides a
maximum of 256 multiframes.
Individual OTUk/ODUk overhead signals may use this
central multiframe to lock their 2, 4, 8, 16, or 32
multiframes to the main frame.
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS SM GCC0 RES JC RES
17
MFAS
OTUK SECTION MONITORING OVERHEAD
Page37
Trail trace identifier (TTI)
A one-byte overhead is defined to transport 64-byte TTI
signals.
The 64-byte TTI signal should be aligned with the OTUk
multiframe and transmitted four times per multiframe.
TTI structure:
16-byte SAPI: source access point identifier
16-byte DAPI: destination access point identifier
32-byte operator specified information
Operator specified
TTI BIP-8
BEI/BIAE BD
I
RES
1 2 3 4 5 6 7 8
1 2 3 IA
E
63
32
0
15
16
31
SAPI
DAPI
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS GCC0 RES JC RES
17
MFAS SM
OTUK SECTION MONITORING OVERHEAD
Bit interleaved parity-8 (BIP-8)
For section monitoring and a one-byte error detection code signals are defined.
This byte provides a bit interleaved parity-8 (BIP-8) code.
OTUk BIP-8 is computed over bits in the OPUk (columns 15 to 3824) area of OTUk
frame i, and inserted in the OTUk BIP-8 overhead location in OTUk frame i+2.
Page38
BIP8
OPUk
1 14 15 3824
Frame i
Frame i+1
Frame i+2
OTUK SECTION MONITORING OVERHEAD
Backward error indication/backward incoming
alignment error (BEI/BIAE)
A four-bit BEI and BIAE signal is defined.
This signal is used to transmit in the upstream
direction the count of interleaved-bit blocks and
incoming alignment error (IAE) conditions.
During an IAE condition the code "1011" is inserted
into the BEI/BIAE field and the error count is ignored.
Otherwise the error count (0-8) is inserted into the
BEI/BIAE field.
Page39
Operator specified
TTI BIP-8
BEI/BIAE BD
I
RES
1 2 3 4 5 6 7 8
1 2 3 IA
E
63
32
0
15
16
31
SAPI
DAPI
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS GCC0 RES JC RES MFAS SM
OTUK SECTION MONITORING OVERHEAD
Backward defect indication (BDI)
A single-bit BDI signal is defined to transmit the
signal failure status detected by the section
termination sink function in the upstream direction.
BDI is set to "1" to indicate an OTUk backward
defect indication; otherwise, it is set to "0".
Page40
Operator specified
TTI BIP-8
BEI/BIAE BD
I
RES
1 2 3 4 5 6 7 8
1 2 3 IA
E
63
32
0
15
16
31
SAPI
DAPI
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS GCC0 RES JC RES
17
MFAS SM
OTUK SECTION MONITORING OVERHEAD
Incoming alignment error (IAE)
A single-bit IAE signal is defined to allow the S-
CMEP ingress point to inform its peer S-CMEP
egress point that an alignment error in the incoming
signal has been detected.
IAE is set to "1" to indicate a frame alignment error;
otherwise it is set to "0".
RES (reserved)
Two bits are reserved (RES) for future international
standardization. They are set to "00".
Page41
Operator specified
TTI BIP-8
BEI/BIAE BD
I
RES
1 2 3 4 5 6 7 8
1 2 3
IAE
63
32
0
15
16
31
SAPI
DAPI
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS GCC0 RES JC RES
17
MFAS SM
OTUK GCC0 AND RES OVERHEAD
General communication channel (GCC0)
Two bytes are allocated in the OTUk overhead to support a general
communications channel between OTUk termination points.
A clear channel is located in row 1 and columns 11 and 12.
RES (reserved)
Two bytes of the OTUk overhead are reserved for future international
standardization.
They are located in row 1 and columns 13 and 14.
They are set to all “0”s.
Page42
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4
PM
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
ODUK PATH MONITORING OVERHEAD
Page43
TTI / BIP-8 / BEI / BDI
For path monitoring, this overhead’s functions are
the same as those of the OTUk SM signal, except
that BEI signals do not support the BIAE function.
They are located in row 3 and columns 10 to 12.
Operator specified
TTI BIP-8
BEI BD
I
STAT
1 2 3 4 5 6 7 8
1 2 3
63
32
0
15 16
31
SAPI
DAPI
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4 TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM
ODUK PATH MONITORING OVERHEAD
Page44
Operator specified
TTI BIP-8
BEI BD
I
STAT
1 2 3 4 5 6 7 8
1 2 3
63
32
0
15 16
31
SAPI
DAPI
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2 TCM1
TCM4 TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM
Bit 678 Status
000 Reserved for future international standardization
001 Normal path signal
010 Reserved for future international standardization
011 Reserved for future international standardization
100 Reserved for future international standardization
101 Maintenance signal: ODUk - LCK
110 Maintenance signal: ODUk - OCI
111 Maintenance signal: ODUk - AIS
Status (STAT)
For path monitoring, three bits are defined as status bits.
They indicate the presence of a maintenance signal.
ODUK TCM OVERHEAD
Page45
TTIi/BIP-8i/BEIi/BIAEi/BDIi
For each tandem connection monitoring field,
this overhead’s functions are the same as
those of OTUk SM signals.
Six fields of the ODUk TCM overhead are
defined in row 2 and columns 5 to 13, and
row 3 and columns 1 to 9 of the ODUk
overhead.
TTIi BIP-8i
BEIi/BIAEi BD
Ii
STATi
1 2 3 4 5 6 7 8
1 2 3
63
32
0
15 16
31
SAPI
DAPI
Operator specific
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS RES JC RES MFAS SM GCC0
PM TCM1 TCM2 TCM3
TCM6 TCM5 TCM4
ODUK TCM OVERHEAD
Page46
TTIi BIP-8i
BEIi/BIAEi BD
Ii
STATi
1 2 3 4 5 6 7 8
1 2 3
63
32
0
15 16
31
SAPI
DAPI
Operator specified
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI GCC2 APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM TCM1
Bit 678 Status
000 No source TC
001 In use without IAE
010 In use without IAE
011 Reserved for future international standardization
100 Reserved for future international standardization
101 Maintenance signal: ODUk -LCK
110 Maintenance signal: ODUk -OCI
111 Maintenance signal: ODUk -AIS
TCM2 TCM3
TCM6 TCM5 TCM4
STAT (status) For each tandem connection monitoring field, three
bits are defined as status bits.
They indicate the presence of a maintenance signal if there is an incoming alignment error at the source TC-CMEP, or if there is no source TC-
CMEP active.
NESTED AND CASCADED ODUK MONITORED
CONNECTIONS
Page47
A1 B1 C1 C2 B2 B3 B4 A2
A1 - A2
B1 - B2
C1 - C2
B3 - B4
TCM1 TCM1
TCM2
TCM1
TCM2
TCM3
TCM1
TCM2
TCM1 TCM1
TCM2
TCM1
TCM2
TCM3
TCM4
TCM5
TCM6
TCMi TCM OH field not in use TCMi TCM OH field in use
TCM2
TCM3
TCM4
TCM5
TCM6
TCM2
TCM3
TCM4
TCM5
TCM6
TCM3
TCM4
TCM5
TCM6
TCM3
TCM4
TCM5
TCM6
TCM3
TCM4
TCM5
TCM6
TCM4
TCM5
TCM6
OVERLAPPED ODUK MONITORED CONNECTIONS
Page48
A1 B1 C1 C2 B2 A2
A1 - A2
B1 - B2
C1 - C2
TCM1 TCM1
TCM2
TCM1
TCM2
TCM3
TCM1
TCM2
TCM1
TCMi TCM OH field not in use TCMi TCM OH field in use
TCM2
TCM3
TCM4
TCM5
TCM6
TCM2
TCM3
TCM4
TCM5
TCM6
TCM3
TCM4
TCM5
TCM6
TCM3
TCM4
TCM5
TCM6
TCM4
TCM5
TCM6
ODUK TCM ACT COORDINATION PROTOCOL
Page49
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2
TCM4 TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM TCM1
GCC2
TCM activation/deactivation (TCMACT)
A one-byte TCM activation/deactivation field is located in row 2 and
column 4.
Its definition is to be defined in future.
ODUK GCC1/GCC2
Page50
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2
TCM4 TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM TCM1
GCC2
General communication channel (GCC1/GCC2)
Two fields of the two bytes are allocated in the ODUk overhead to support
two general communication channels between any two NEs with access to
the ODUk frame structure (for example, at 3R regeneration points).
The bytes for GCC1 are located in row 4 and columns 1 and 2, and the
bytes for GCC2 are located in row 4 and columns 3 and 4 of the ODUk
overhead.
ODUK APS/PCC CHANNEL
Page51
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2
TCM4 TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM TCM1
GCC2 APS/PCC
Automatic protection switching/protection communication control
(APS/PCC)
A four-byte ODUk-APS/PCC signal is defined in row 4 and columns 5 to 8 of the
ODUk overhead.
For linear protection schemes, bit assignments for these bytes and the bit oriented
protocol are given in ITU-T G.873.1. Bit assignment and byte oriented protocol for
ring protection schemes are to be defined in future.
A maximum of eight levels of nested APS/PCC signals may be present in this field.
ODUK FTFL CHANNEL
Fault Type & Fault Location (FTFL)
One byte is allocated in the ODUk overhead to transport a 256-byte FTFL
message.
The byte is located in row 2 and column 14 of the ODUk overhead.
The 256-byte FTFL message consists of two 128-byte fields. The forward
field is allocated in bytes 0 to 127 of the FTFL message. The backward field is
allocated in bytes 128 to 255 of the FTFL message.
Page52
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2
TCM4 TCM ACT
GCC1
RES JC
RES JC
NJO PSI APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM TCM1
GCC2
FTFL
ODUK EXPERIMENTAL AND RESERVED OVERHEAD
Experimental (EXP)
Two bytes are allocated in the ODUk overhead for experimental use.
They are located in row 3 and columns 13 and 14 of the ODUk overhead.
There is no requirement for forwarding the EXP overhead over different (sub)networks.
RES
9 bytes are reserved in the ODUk overhead for future international standardization.
They are located in row 2 and columns 1 to 3, and row 4 and columns 9 to 14 of the
ODUk overhead.
They are set to all “0”s.
Page53
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2
TCM4 TCM ACT
GCC1
FTFL RES JC
RES JC
NJO PSI APS/PCC
FAS RES JC RES
17
MFAS SM GCC0
PM TCM1
GCC2
EXP
RES
RES
OPUK PAYLOAD STRUCTURE IDENTIFIER
Payload structure identifier (PSI)
One byte is allocated in the OPUk
overhead to transport a 256-byte payload
structure identifier (PSI) signal.
It is aligned with the ODUk multiframe.
PSI[0] contains a one-byte payload type.
PSI[1] to PSI[255] are mapping and
concatenation specific.
Page54
255
0
1
PT
Mapping
and concatenation
specific
RES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
2
3
4
TCM3
TCM6 TCM5
TCM2
TCM4 TCM ACT
GCC1
RES JC
RES JC
NJO APS/PCC RES
EXP
FAS RES JC RES
17
MFAS SM GCC0
PM TCM1
GCC2
FTFL
PSI
PAYLOAD TYPE CODE POINTS
MSB 1234 LSB 1234 Hex Code Meaning
0000 0001 01 Experimental mapping
0000 0010 02 Asynchronous CBR mapping
0000 0011 03 Bit synchronous CBR mapping
0000 0100 04 ATM mapping
0000 0101 05 GFP mapping
0000 0110 06 Virtual Concatenated signal
0001 0000 10 Bit stream with octet timing mapping
0001 0001 11 Bit stream without octet timing mapping
0010 0000 20 ODU multiplex structure
0101 0101 55 Not available
0110 0110 66 Not available
1000 xxxx 80-8F Reserved codes for proprietary use
1111 1101 FD NULL test signal mapping
1111 1110 FE PRBS test signal mapping
1111 1111 FF Not available Page55
OPUK MAPPING SPECIFIC OVERHEAD
Justification control/negative justification opportunity/reserved
(JC/NJO/RES)
Seven bytes are reserved in the OPUk overhead for the mapping and concatenation
specific overhead.
These bytes are located in rows 1 to 3 and columns 15 and 16, and row 4 and
column 16.
255 bytes in the PSI are reserved for mapping and concatenation specific purposes.
Page56
RES
1
2
3
4
TCM3
TCM6 TCM5
TCM2
TCM4 TCM ACT
GCC1
RES JC
JC
APS/PCC RES
EXP
FAS RES JC RES MFAS SM GCC0
PM TCM1
GCC2 PSI
FTFL
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
RES
NJO
THANKS FOR BEING PATIENT
57