SDH/SONET alarms & performance monitoring

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SDH/SONET
ALARMS & PERFORMANCE MONITORING

• Standards
• Alarms Introductions and Examples
• Performance Monitoring Parameters
• FAQs
Contents

Bell Communications Research (Bellcore, BCR)
prepares equipment standards for NorthAmerican community
ANSI CommitteeT1
prepares telecommunications standards (rates and formats)
creator of SONET
ANSI (American National Standards Institute) accredited
sponsored by ATIS (Alliance forTelecommunications Industry Solutions)
ITU-T G.826,G.783
Standards

Alarms Introductions and Examples

Alarm Overview





V1
V2
V5 

1. RS
2. MS
3. HP
4. AU
5. TU
6. LP
7. PPI
SDH Frame

A1 A1 A1 A2 A2 A2 J0
B1 E1 F1
D1 D2 D3
H1 H1 H1 H2 H2 H2 H3 H3 H3
B2 B2 B2 K1 K2
D4 D5 D6
D7 D8 D9
D10 D11 D12
S1 Z1 Z1 Z2 Z2 M1 E2
R
S
O
H
M
S
O
H
AU
Pointer
J1
B3
C2
G1
F2
H4
F3
K3
N1
VC-4 POH
The SDH Frame
VC-11 VC-12 VC-2
V5 V5 V5
25 34 106
N2 N2 N2
25 34 106
K4 K4 K4
25 34 106
Lower order
VC-n POH
Number of bytes of
data separating fields.

A1, A2 RS-LOF Provides a frame alignment pattern [A1 =11110110, A2 = 00101000]. The frame alignment word of an
STM-n frame is 3 X n A1 bytes followed by 3 X n A2 bytes.
J0 RS-TIM Regenerator section trace. [16 byte frame including CRC7 (1st byte.) Supports continuity testing
between transmitting and receiving device on each regenerator section.
Z0 Spare. Reserved for future international standardisation.
B1 RS-EXC
RS-DEG
Provides regenerator section monitoring. The regenerator section BIP-8 provides end-to-end error
performance monitoring across an individual regenerator section and is calculated over all bits of the
previous STM-n frame after scrambling. Computed value is placed in B1 byte before scrambling
E1 Provides local orderwire channel for voice communications between regenerators, hubs and remote
terminal locations.
F1 Allocated to user’s purpose [e.g. temporary data/voice channel connection for special maintenance
applications]
D1-D3 COMMS 192 kb/s message based data communications channel providing administration, monitor, alarm and
maintenance functions between regenerator section termination equipment
RSOH [Regenerator Section Overhead]
SDH FrameB1 – Is not supported in OM4000 NE’s due to redundancy and
this NE is primarily used as an ADM

B2 MS-EXC
MS-DEG
Provides multiplex section error monitoring. The BIP-n X 24, of an STM-n frame, provides end-
to-end error performance monitoring across an individual multiplex section and is calculated over
all bits of the previous STM-n frame except for the first three rows of SOH. Computed value is
placed in B2 byte before scrambling.
K1, K2 MS-AIS
MS-RDI
Two bytes allocated for APS signalling for multiplex section protection.
K2 [b6-b8] contains MS-RDI and MS-AIS status information.
D4-D12 COMMS Provides 576 kb/s data communication channel between multiplex section termination
equipment. Used to carry network administration and maintenance information.
S1 Synchronisation status messages. S1 [b5-b8] indicates which of the four levels of
synchronisation is being used at the transmit end of a multiplex section.
M1 MS-REI Multiplex section remote error indication [MS-REI]. Conveys the number of B2 errors detected
by downstream equipment.
E2 Provides express orderwire channel for voice communications between multiplex section
terminating equipment
H1-H3 AU-AIS
TU-AIS [TU-3]
AU-LOP
TU-LOP [TU-3]
AU pointer bytes are associated with, but not part of, the MSOH. The pointer contained in H1
and H2 points to the location where the VC-n begins. The last ten bits [b7-b16] of H1, H2 carry
the pointer value [0 to 782]. The H3 bytes are ‘pointer action’ bytes and carry ‘live’ information
from a VC4, during the STM-n frame in which negative pointer adjustment occurs
MSOH [Multiplex Section Overhead]
SDH FrameMSP Protocol Bytes K1 [b1-4] –
type of request [b5-8] – channel number K2 [b1-4] –
channel bridging [b5] – protection architecture

HO-POH [Higher order path Overhead]
J1 HP-TIM [VC-4]
LP-TIM [VC-3]
The first byte in the virtual container. Its location is indicated by the AU pointer [H1,H2
bytes]. Provides a higher order trail trace identifier [64-byte free format string or 16-byte
frame including CRC7. Supports end-to-end monitoring of a higher order path.
B3 HP-EXC
HP-DEG
LP-EXC+DEG [VC-3]
Provides higher order path error monitoring. The BIP-8 is calculated over all bits of
previous VC-n. Computed value is placed in B3 byte before scrambling.
C2 HP-AIS
LP-AIS [VC-3]
HP-UNEQ+PLM
LP-UNEQ+PLM [VC-3]
High order signal label. Indicates composition or the maintenance status of the associated
container.
G1 HP-REI + RDI
LP-REI + RDI [VC-3]
Higher order path status. Send status and performance monitoring information from
receiving path terminating equipment to originating equipment. Allows status and
performance of two-way path to be monitored at either end. G1 REI [b1-b4] RDI [b5]
F2 Higher order path user channel. Allocated for network operator communications between
path terminations.
H4 HP-LOM Position indicator. Multiframe phase indication for TU structured payloads. H4 [b7-b8]
F3 Higher order path user channel. Allocated for network operator communications between
path terminations
K3 Higher order path automatic protection switching [b1-b4]. The rest of the bits [b5-b8] are
allocated for future use.
N1 Higher order tandem connection monitoring. There are two possible implementations
described in Annex C and Annex D of ITU-T G.707. In Annex C, the N1 byte provides a
tandem connection incoming error count [IEC] and the remaining four bits provide an end-
to-end data link
SDH Frame

V5 [VC-12]
LP-AIS [b5-b7]
LP-REI [b3]
LP-RDI [b8]
LP-EXC [b1-b2]
LP-UNEQ [b5-b7]
LP-PLM [b5-b7]
Provides BIP-2 error checking, signal label and path status information.
J2 LP-TIM [VC-12] Lower order trail trace identifier [16 byte frame including CRC7]. Supports end-to-
end monitoring of a lower order path
N2 Lower order tandem connection monitoring. Contains BIP-2 error checking, AIS,
tandem connection REI [TC-REI], outgoing error indication [OEI] and a 76-byte
multiframe containing a tandem connection access point identifier [TC-APid].
K4 Lower order path automatic protection switching [b1-b4] and enhanced remote
defect indication [b5-b7].
LO-POH [Lower order path Overhead]
SDH Frame

Anomalies, defects and alarms
 Alarm
 A human observable indication that draws attention to a failure usually giving an indication of
the severity of the fail
 The report to the user of a defect
 Anomaly
 The smallest discrepancy which can be observed between the actual and desired
characteristics of an item. The occurrence of a single anomaly does not constitute an
interruption in the ability to perform a required function. Anomalies are used as the input for
the Performance Monitoring [PM] process and for the detection of defects
 A single occurrence of, or commencement of a pre-defined condition
 Defect
 The density of anomalies has reached a level where the ability to perform a required function
has been interrupted. Defects are used as input for PM, the control of consequent actions, and
the determination of faults cause
 The persistent or repeated occurrence of an anomaly for a pre-defined duration or
number of repetitions

Defect naming
 The origin of defect naming can be confusing.
 The following points should help when dealing with the nomenclature
 Defects derived from path overheads begin: LP, HP, LPOM or HPOM.
 Defects derived from section overheads begin: RS or MS.
 Defects related to conditions affecting a wholeVC and its pointer begin: AU orTU. AU is used forVC-4s.
TU is used forTU-3s,TU-2s andTU-12s. Defect types beginningTU are not distinguishable.
 When distinguishing LP and LPOM remember that LPs will be present when traffic is terminated and
LPOMs when traffic is un-terminated.
 A defect type (e.g. LP-EXC) has two parts:
 Part 1 is a "function point“
 Part 2 is an "alarm category".
 Example: LP-EXC.This defect is detected at the LP function point - the "low order path termination"
function point.The category of the defect is "EXC" - EXCessive bit errors.
 Excessive bit errors in aVC-3 will give an LP-EXC defect, as will excessive bit errors in a
VC-12.The two defects share their type but they have distinct instances. When the corresponding alarm is
reported to the user the type and instance will be reported.

Defect Correlation
 If a defect is subject to correlation
 it will NOT be raised if another alarm is present.
 Aim of defect correlation
 The aim of correlation is to present to the operator only the alarm closest to the source cause of a
set of related defects. This reduces the amount of fault analysis required of the operator and the
traffic on communication channels.
 Example:
 If EXC is present it will hide the presentation of TIM, PLM, UNEQ etc.
 More specifically EXC will ‘mask’TIM, PLM and UNEQ alarms.
A masks B
HP-EXC
HP-TIM HP-PLM HP-UNEQ
A
B

Card Fail Card Fault Wrong Card Unexpected Card
Alarm raised on the card/slot instance
A
B
= ‘A masks B’
Plug In Unit Defect Correlation
• Plug In Unit [PIU] related defects
– For a given instance of PIU in a slot
– All defects present within that PIU will be masked

PPI LOS
A
B
= ‘A masks B’
PPI UNEXP SGNL
PPI EXC
PPI DEG PPI AIS INT LP IP BUFFER INT HP IP BUFFER
PPI LOF
PPI LOM
PDHTraffic Defect Correlation

AU AIS
AU LOPMS DEG
MS EXC
MS AIS
RSTIMQECC COMMS FAIL
RS LOF
ES CMI
RS LOS RS UNEXPECTED SIGNAL
MS RDI
MS RDI
HPOM EXC
HPOMTIM HPOM PLM HPOM UNEQ
= ‘A masks B’
A
B
= ‘A masks B, dependent
on AIS consequent
action configuration of A
A
B
SDH traffic DEFECT correlation

HP EXC
INT HP OP BUFF HP DEG HP LOM
TU LOP
HPTIM HP PLM HP UNEQ HP RDI
HP REIPPI LOF
TU AIS
INTTU LOP
INTTU AIS
LP EXC
LPOM EXC
LPOM TIM LPOM PLM LPOM UNEQ
LP TIM LP PLM LP UNEQ LP RDI
LP REI
LP DEGINT LP OP BUFFER
= "A masks B if B'sTU
type isTU-12"
A
B

What is a path?
 A path is an end to end circuit
 The ends of a LO path are where traffic is brought into SDH or removed from SDH
 Paths carryVCs
 LOVCs are
 generated where traffic is brought into SDH
 and terminated where it is removed
 HOVCs are
 Generated / terminated where traffic is brought into SDH or when LOVCs are brought into / removed from a
HOVC
Low Order Path
Multiplexer
Regenerator
High Order Path

Carrying a 2 Meg circuit in a STM frame
 2M example where
 High order paths are
 encased in STM frames when they pass between nodes
 Low order paths are
 threaded through high order paths
2M PDH
LO path
HO path
MS
RS
Multiplexor Regenerator
STM-1 tributary with a LO
connection
2M trib

SONET Layers
DS1
DS3
DS1
STS Path
Line
Section
Photonic
VT Path
DS3
Section SectionSectionSection
Line LineLine
STS Path STS Path
VT Path
Path
Terminating
Equipment
(PTE)
Section
Terminating
Equipment
(STE)
Line
Terminating
Equipment
(LTE)
Path
Terminating
Equipment
(PTE)
Path
Terminating
Equipment
(PTE)
STS Path
Line
Section
Photonic
Section
Photonic
STS Path
Line
Section
Photonic
VT Path
Line
Section
Photonic

 There are four sections – Regenerator Section (RS), Multiplex Section (MS), Higher
Order Path Section (HP), and Lower Order Path Section (LP)
RS is a part (section) of the optical fibre network, within which RSOH part of SDH frame
is NOT opened
 MS is a part (section) of the optical fibre network, within which MSOH part of SDH frame
is NOT opened
 HP is a part (section) of the optical fibre network, within which higher order VC part of
SDH frame is NOT opened (it may be opened only for interpreting HOPOH)
 LP is a part (section) of the optical fibre network, within which lower order VC part of
SDH frame is NOT opened (it may be opened only for interpreting LOPOH)
SDH Section Hierarchy

SDH
Interface cross-connect
unit
SDH
Interface
PDH interface
High order part
Downlink signal
flow
Downlink signal flow & High order part

SDH
Interface cross-connect
unit
SDH
Interface
PDH interface
Low order part
Uplink signal flow & Low order part
Uplink signal flow

AIS (Alarm Indication Signal)
Two Common Alarms
Inserts the all “1”s signal into the Low level circuits, Indicating that the signal is
unavailable.Common AIS alarms include MS_AIS,AU_AIS,TU_AIS and E1_AIS.
Indicates the alarm transferred back to the home station from the opposite
station after the opposite station has detected alarms of LOS (loss of signal),
AIS andTIM (trace identifier mismatch). Common RDI alarms include
MS_RDI, HP_RDI and LP_RDI.
RDI (Remote Defect Indication)

Alarms & Performance of High Order Part
A B C D E F G
STM-N Cross-connect
Unit
SPI RST MST MSP MSA HPT
Uplink signal Flow
Downlink signal Flow
SDH Interface to Cross-connect Unit

Diagram of Alarm Generation
Frame synchronizer& RS
overhead processor
(RST)
MS overhead processor
(MST)
Pointer processor& HP
overhead processor
(MSA, HPT)
LOS
LOF
B1 Err
A1,A2
B1
AIS
MS_AIS
B2 Err
K2
B2
MS_REI
M1
MS_RDI
K2
“1” AIS
AU_AIS
AU_LOP
H1,H2
H4
B3 Err
J1
HP_SLM
C2
“1”
HP_LOM
HP_TIM
HP_UNEQ
HP_REI
HP_RDI
H1,H2
C2
B3
G1
G1
“1” X
C
S
STM-N
Optical
Signal
Downlink signal flow Alarm report or return
Signal transfer point (Insert down all "1"s
signal)
Alarm termination point (Report
to SCC unit)

 Optical receiving
 Optical/electrical conversion (O/E)
 O/E module checks Optical signal (If no light in the input signal, optical power excessively
low or high or the code type mismatch, R_LOS alarm will be reported)
 A1, A2 and J0 bytes detecting
 Search the framing bytes (R_OOF, R_LOF)
 Extract the line synchronous timing source
 J0 byte (J0_MM)
 Scramble
 B1 byte detecting
 BIP-8 computing to check bit error (B1_SD, B1_EXC, SES, RSUAT)
 Process F1, D1 - D3 and E1 bytes
Downlink Signal Flow
Frame synchronizer and RS overhead processor

 K1 and K2 bytes detecting
 SF and SD detection
 Process D4–D12, S1 and E2 bytes
 MSP protection function
 MS_AIS, MS_RDI
 B2 byte detecting
 BIP-8 computing to check bit error (B2_SD and B2_OVER)
 M1 bytes (MS_REI)

Pointer processor and HP overhead processor
 H1 and H2 bytes detecting
 Frequency and phase alignment
 Locate each VC-4 and send it to High order path overhead processor
 Generate AU_AIS, AU_LOP
 J1, C2, B3 and G1 bytes detecting
 J1 Bytes (HP_TIM)
 C2 Bytes (HP_UNEQ, HP_SLM)
 B3 bit error detecting (B3_SD, B3_OVER, SES, HVCUAT)
 H4 Bytes (For VC12 signal, HP_LOM)
 G1 Bytes (HP_RDI, HP_REI)
 F3, K3, N1 Bytes (Reserved)

Uplink Signal Flow
Pointer processor and HP overhead processor
 Generates N High order path overhead bytes
 J1, C2, B3, G1, F2, F3 and N1 Bytes
 Return alarm to the remote end
 HP_RDI (G1)
 HP_REI (G1)
 AU-4 pointers generating
 Pointer processor generates N AU-4 pointers

Uplink Signal Flow
 Set multiplex section overhead (MSOH) Bytes
 K1, K2, D4-D12, S1, M1, E2 and B2 Bytes
 Return alarm to the remote end
 MS_RDI (K2)
 MS_REI (M1)

Uplink Signal Flow
Frame synchronizer and RS overhead processor
 Set regenerator section overhead (RSOH) Bytes
 A1, A2, J0, E1, F1, D1-D3 and B1 Bytes
 Frame synchronizer and scrambler scrambles STM-N electrical signals
 E/O

Alarms & Performance of Low Order
Part
PDH Interface to Cross-connect Unit
G H I J K
PDH InterfaceCross-connect
Unit
HPA LPT LPA PPI
Uplink signal Flow
Downlink signal Flow

Part
Diagram of Alarm Generation
PDH Physical InterfaceLow Order Path AdaptationHigh Order PathAdaptation& Low
Order PathTermination
E1
Interface
E1
Interface
(PPI)(LPA)(HPA, LPT)
LP_TFIFO
All “1”
LP_SLM
LP_UNEQ
V1,V2
H4
BIP 2
J2
TU_AIS
V5
HP_LOM
LP_TIM
TU_LOP
LP_REI
LP_RDI
V5
V5
X
C
S
V5
V1,V2
LP_RFIFO
E1_AIS All “1” T_ALOS
E1_AISX
C
S
Downlink signal flow Alarm report or return
Signal transfer point (Insert down all "1"s
signal)
Alarm termination point (Report
to SCC unit)

Alarms & Performance of Low Order Part
High Order Path Adaptation& Low Order PathTermination
 V1, V2 and V3 bytes detecting
 Demap the VC-4 into VC-12s
 Pointers of all VC-12s are decoded
 TU_AIS, TU_LOP
 V5 Bytes detecting
 LP_RDI( b8), LP_UNEQ, LP_SLM( b5-b7), LP_REI( b3)
 BIP-2 computing to check bit error( b1-b2)
 H4 Bytes detecting
 HP_LOM
 J2 Bytes detecting
 LP_TIM

Alarms & Performance of Low Order Part
Low Order Path Adaptation& PDH Physical Interface
 Low Order Path Adaptation
 Recover data stream and the related clock reference signals
 Detect LP_RFIFO alarm
 PDH Physical Interface
 Forming a 2048 kbit/s signal

Part
Uplink Signal Flow
Low Order Path Adaptation& PDH Physical Interface
 Low Order Path Adaptation
 Data adaptation
 Detect LP_TFIFO alarm
 PDH Physical Interface
 Clock extraction and dada regeneration
 Detect and terminate the T_ALOS alarm
 Detect E1_AIS alarm

Part
Uplink Signal Flow
High Order Path Adaptation& Low Order Path
 Low Order Path Termination
 Insert POH in the C-12 (C-12 to VC-12)
 V5 byte (Insert "signal label" in the b5-b7, calculate BIP-2, set the
result to the b1 and b2)
 High Order Path Adaptation
 Adapt VC-12 into TU-12
 Map TU-12 into High order VC-4

Suppression Correlation between SDH
Alarms
R_LOS
R_LOF
R_OOF
AU_AIS AU_LOP B1_SD B2_SD
HP_TIM HP_SLM HP_LOM HP_UNEQB3_EXEC
B3_SD TU_AIS TU_LOP BIP_EXEC
LP_UNEQ LP_TIM LP_SLM BIP_SD
MS_RDI
HP_RDI
LP_RDI
A B A suppress B
J0_MM MS_AIS B1_EXEC B2_EXEC
A1, A2 Bytes
RSOH,
MSOH
(Except
A1,A2)
 Suppression
Relationship

More on Alarms

Alarm Understanding Rules
Rule 1
Rule 2
FC 1
Alarm reported
Alarm reported
FC 1
ADM 1 ADM 2
ex. a
ADM 1 ADM 2
ex. b
Alarms reported are alarms received
Alarms are reported on SDH Objects

Alarm Understanding Rules (…contd.)
Rule 3
ADM 1 ADM 2
ex.
3a. No Object => No Alarms reported
FC onTU12 (1-1-1)
NOTU12
(1-1-1)
3b. Object Mismatch => No Alarms reported
FC onTU12 (1-1-1)
TU11
(1-1-1)
ADM 1 ADM 2
ex.
Note:
These two
examples are
not possible
for AU object
WHY?
See slide 9
NO Alarm reported for FC
onTU12 (1-1-1)
NO Alarm reported for FC
onTU12 (1-1-1)

Rule 4
4a. No PT XC => No Alarms pass-through
FC on AU4 (1)
NOVC4
PT (1)
Alarm reported for FC
on AU4 (1)
FC onTU12 (1-1-1)
ADM 1 ADM 2 ADM 3
ex. a
ADM 1 ADM 2 ADM 3
ex. b
NO Alarm pass-through
NOVC12
PT (1-1-1)
NO Alarm pass-through
NO Alarm reported for
FC onTU12 (1-1-1)

4b. Bigger PT XC => No Alarms reported & Alarm pass-through
FC onTU12 (1-1-1)
Alarm pass-through for
FC onTU12 (1-1-1)
NO Alarm reported
for FC onTU3 (1)
VC4
ADM 1 ADM 2 ADM 3
ex. a
STM-1
links
4c. Smaller PT XC => No Alarms reported (always ??) &
Alarm pass-through but on smaller object
FC onTU3 (1)
VC12
(1-1-1)
NO Alarm reported
for FC onTU12 (1-1-1)
ADM 1 ADM 2 ADM 3
ex. b
STM-1
links
Alarm pass-through for
FC onTU12 (1-1-1)
What if Same size PT XC ?www.mapyourtech.com44

Guide Lines
 Alarms reported are alarms received
 Object---- No Object
---- Object Mismatch
 Privilege of the NE
 Upstream / Downstream

RS Alarms
RS alarms are those, which can be reported even by a pure Regenerator
(who has privilege of opening (interpreting & rewriting) only RSOH)
LOS (Loss of Signal)
based on whole RSOH
LOF (Loss of Frame)
based on A1, A2 bytes
TIM (Trace Identifier Mismatch)
based on J0 byte
SF (Signal Fail)
based on B1 byte
SD (Signal Degrade)
based on B1 byte
D3D2D1
F1E1B1
J0A2A1
RSOH bytes
Note:The order in which the alarms are written is important,
as we will see later while discussingAlarm masking

Description of Alarms
LOS
Received power is less than Laser receiver sensitivity (All bits interpreted as ‘0’)
ADM 1 ADM 2
ex.
TxRx
RxTx
LOSTx off / misconnectivity Rx off / misconnectivity
Fiber Cut
Received power is less than
Laser receiver sensitivity
(Low power transmitted,Span is longer than
specified, Fiber gets deformed etc. etc.)
LOF
Anything other than “F6 28 (Hex)” in any (?) of the A1 A2 bytes (within a STM frame)
-- for consecutive 5 frames (625 µs)  OOF (Out of Frame)  clearing 2 frames
-- for consecutive 24 frames (3 ms)  LOF  clearing 24 frames
Note: Prolonged LOS => LOF, but not always LOF => LOS
(this fact will be used as one of the Alarm Masking logic later)
LOS clears when 2 consecutive framing patterns are received & no new LOS condition is detected

Description of Alarms (…contd.)
TIM (J0)
Received J0 trace (1/16 byte(s)) != Expected J0 trace (1/16 byte(s))
Note: For both SF & SD, alarm clearing threshold is 1 decade lower than generation
threshold, e.g., Gen.Thr. is 1 in 1000 or higher => Clg.Thr. is 1 in 10000 or lower
SF (B1/B2/B3/V5)
Equivalent BER exceeds alarm generation threshold ( 1 in 10 / 1 in 10 / 1 in 10 )
3 4 5
5 9
SD (B1/B2/B3/V5)
Equivalent BER exceeds alarm generation threshold ( 1 in 10 to 1 in 10 )
P1
P2
A B C
Rx trace = C to B
Rx trace = A to B
Tx trace = A to B
Exp trace = A to B
Tx trace = C to BExp trace = C to B

MS Alarms
MS alarms are those, which can be reported by a Add-Drop Multiplexer, irrespective of
cross-connect configuration
(who has privilege of opening (interpreting & rewriting) RSOH, MSOH, AU pointers plus
opening HOPOH(s) / TU Pointers / LOPOH(s) depending upon cross-connect configuration)
AIS (Alarm Indication Signal)
reported based on K2 byte -- bits 6,7,8
SF (Signal Fail)
based on B2 bytes
SD (Signal Degrade)
based on B2 bytes
RDI (Remote Defect Indication)
based on K2 byte -- bits 6,7,8
MSOH bytes
K2K1B2
D6D5D4
D9D8D7
E2M1S1
D12D11D10
Note 1:The order in which the alarms are written is important, we will see later while discussingAlarm masking
Note 2: MS-AIS is also called Line-AIS or AIS on STM port
MS-RDI is also called Line-RDI or RDI on STM portwww.mapyourtech.com49

Description of Alarms (…contd.)
Example of generation of AIS, RDI
ADM
Any traffic affecting RS Alarm or MS-AIS (Rx)
MS-AIS (Gen)
MS-RDI
Any traffic affecting HP Alarm or AU-AIS (Rx)
AU-AIS (Gen)
HP-RDI
Any traffic affecting LP Alarm orTU-AIS (Rx)
TU-AIS (Gen)
LP-RDI
Example of reception ofTU-AIS, LP-RDI
ADM 1 ADM 2 ADM 3
E1 E1
VC12 VC12 VC12
TU-AIS (Rx)
LP-RDI (Rx)
Any traffic affecting RS/HP/LP Alarm

HP / LP Alarms
HP / LP alarms are those, which can be reported by a Add-Drop Multiplexer, having
HO / HO & LO object (LO object => LO cross-connect)
(who has privilege of “opening (interpreting & rewriting) RSOH, MSOH, AU Pointers plus
at least interpreting HOPOH(s)” / “opening (interpreting & rewriting) RSOH, MSOH, AU
Pointers, HOPOH(s), TU Pointers plus at least interpreting LOPOH(s)”
depending upon cross-connect configuration)
HP-AIS reported based on H1, H2 bytes
HP-LOP (Loss of Pointer) based on H1, H2 bytes
HP-UNEQ (unequipped) based on C2 byte
HP-TIM based on J1 byte
HP-SF based on B3 byte
HP-SD based on B3 byte
HP-RDI based on G1 byte -- bit 5
Note 1: Same as before
Note 2: HP-Alarm is also
calledAU-Alarm
or Alarm on AU
LP-Alarm is also
calledTU-Alarm
or Alarm onTU
K3
F3
H4
F2
G1
C2
B3
J1
N1
H
O
P
O
H
b
y
t
e
s
H1, H2, H3 – AU
Pointer bytes

HP / LP Alarms (…contd.)
LP-AIS reported based on V1, V2 bytes
LP-LOP based on V1, V2 bytes
LOM (Loss of Multiframe) based on H4 byte – bits 7,8
HP-PLM / SLM (Payload / Signal Label Mismatch)
based on C2 byte
LP-UNEQ based on V5 byte – bits 5,6,7
LP-TIM based on J2 byte
LP-SF based on V5 byte – bits 1,2
LP-SD based on V5 byte – bits 1,2
LP-RDI based on V5 byte -- bit 8
LP-PLM / SLM based on V5 byte – bits 5,6,7
Note 1: Same as before
Note 2: Whole of this slide assumes
TU2/TU12/TU11 for LP. If there
isTU3 with AU4 mapping, then
also it is LP but Pointers & POH
bytes will be like HO
K4
N2
J2
V5
LOPOH bytes
V1, V2, V3 – TU
Pointer bytes

SONET/SDNTerminologyTranslation
SDH
VC-11 (virtual container)
VC-12
VC-2
VC-3
VC-4
TU-11 (tributary unit)
TU-12
TU-2
TU-3
TUG-2 (TU group)
TUG-3
AU-3 = VC-3 + Ptr
AU-4 = VC-4 + Ptr
AUG = 1 x AU-4,
or 3 x AU-3s
STM-1 = AUG + SOH
STM-N = N AUGs + SOH
Regenerator Section
Multiplex Section
SONET
VT-1.5 SPE
VT-2 SPE
VT-6 SPE
STS-1 SPE
STS-3c SPE
VT-1.5 (Virtual Tributary size 1.5)
VT-2
VT-6
no SONET equivalent (like a 50 Mbit/s VT)
VT Group
No SONET equivalent
STS-1 SPE + STS-1 Pointer
STS-3c SPE + STS-3c Pointer
logical entity (not defined)
STS-3
STS-3N
Section Layer
Line Layer
14

Alarm Propagation Examples
For every example,
 Assumption(s) is/are stated
 Root Cause(s) is/are stated
 Diagrammatic representation is made (OFCs are shown in cyan)
 Alarm(s) generated / condition(s) generated for reporting alarms is/are
shown in black
 Alarm(s) existing at a port is/are shown in red
 Alarm(s) masked at a port is/are covered with
 Alarm(s) reported at secondary supprressed alarm page is/are shown
in pink, italicised
 Note(s), whenever required is/are mentioned in greenwww.mapyourtech.com54

Alarm Propagation Examples (…contd.)
Example 1
A B
Assumption: AU-4 Mapping on both ports Root Cause: NO XConnect on both ports
AU4 Signal Label Unequipped
HP-RDI
HP- UNEQ
HP-RDI
HP- UNEQ
HP-RDI
HP-RDI
Note: 1) if AU-3 mapping, then what happens?
2) In newer version of Tejas software, UNEQ is not reported for this root cause

HP-RDI
HP- UNEQ
Signal LabelTUG-structure
HP-SLM
HP-RDI
TU-LOP
Example 2
Assumption: AU-4 Mapping on both ports, Root Cause: NO XConnect on the port of B
A B
E1
VC12
InvalidTU Pointer value
LP-RDI
Note: LP-RDI is not reported on B (See Rule 3a)
HP-SLM default action is “report
SLM, no downstream AIS”

LOS
MS-AIS
AU-AIS
TU-AIS
MS-RDI
HP-RDI
LP-RDI
VC-12 VC-12
E1 E1
A CB
(Reg.)
Example 3
Assumption: AU-4 Mapping on both ports of A & C
Root Cause: Fiber cut in the link from A to B
AIS
MS-RDI
HP-RDI
LP-RDI
Note:The Reg. can not generate any RDI
Actually at C, AU-AIS &TU-AIS conditions are also received

LOS
MS-RDI
HP-RDI
LP RDI
MS-AIS
LP RDIMS-RDI
HP-RDI
E1
E1
VC-12 VC-12
A CB
Example 4
Assumption: AU-4 Mapping on all ports Root Cause: Fiber cut in the link from A to B
VC-12
ADM B VC-12 PT
TU AIS
Note: OnlyTU-AIS is reported on Node C (See Rule 4c)
LP RDI
LP-RDI on B is SSA

LOS
MS-RDI
HP-RDI
LP RDI
MS-AIS
LP RDIMS-RDI
HP-RDI
E1
E1
VC-12 VC-12
A CB
Example 5
Assumption: AU-4 Mapping on all ports Root Cause: Fiber cut in the link from A to B
VC-4
ADM B VC-4 PT
Note: Only AU-AIS is reported on Node C (See Rule 4c)
LP-RDI on B is not reported (See Rule 3b)
AU AIS
TU AIS

InvalidTU Pointers (1-
1-2)
TU-LOP (1-
1-2)
A DCB
E1
(2)
VC-12 (1-1-2)
Example 6
Assumption: AU-4 Mapping on all ports Root cause: NO XConnect on B, C & D for (1-1-2)
E1 (1)E1 (1)
VC-12 (1-1-1)
LP RDI (1-
1-2)
Note: Why E1(1) is shown?
LP-RDI is not reported on B (See Rule 3a)

1-2)
TU-LOP (1-
1-2)
LP RDI (1-
1-2)
Note: LP-RDI at node B is secondary suppressed
TU-AIS at node A is reported as terminating alarm
VC-12 (1-1-2)
A DCB
Example 7
Assumption: AU-4 Mapping on all ports Root cause: NO XConnect on C & D for (1-1-2)
E1 (1)E1 (1)
VC-12 (1-1-1)
E1
(2)
VC-12 (1-1-2)
TU-AIS
(1-1-2)
TU AIS (1-1-2)
LP RDI (1-
1-2)
LP-RDI
(1-1-2)

1-2)
TU-LOP (1-
1-2)
LP RDI (1-
1-2)
Note: K-L-M value need not remain same throughout a particular LP, alarms will
be reported accordingly on different objects
TU-AIS
(1-1-2)
TU AIS (1-1-2)
LP RDI (1-
1-2)
LP-RDI
(1-1-2)
VC-12 (1-1-2)
A DCB
Example 8
Assumption: AU-4 Mapping on all ports Root cause: NO XConnect on C for (1-1-2)
E1 (1)E1 (1)
VC-12 (1-1-1)
E1
(2)
VC-12 (1-1-2)
E1
(2)
VC12(1-1-2)
InvalidTU Pointers
(1-1-2)
TU-LOP (1-
1-2)
LP RDI (1-1-2)

InvalidTU Pointers
(1-1-1)
TU-LOP
(1-1-1)
LP-RDI
(1-1-1)
Note: LP-RDI from A is not reported on B (See Rule 3b).
Why assumption on SLM?
A CB
VC-12(1-1-1)
VC-4 VC-12(1-1-2)
VC-12(1-1-2)E1 (1)
E1 (2)
E1(2)
Example 9
Assumption: AU-4 Mapping on all ports, Root cause: NO XConnect on C for (1-1-1)
VC4 PT at node B,
For each port, HP-SLM default action is “ignore SLM”

LOS
MS-RDI
HP-RDI
LP RDI
TU AIS
LP RDI
MS-AIS
LP RDI MS-RDI
HP-RDI
VC-12VC-12
VC-12
E1
E1
A CB
D
Example 10 (with SNCP)
Assumption: AU-4 Mapping on all ports Root cause: Fiber-cut in the link from A to B
W  A-B-C, P  A-D-C
VC-12
Note: SNCP is always
uni-directional & for
Tejas, it is 1+1

Alarms: Animated Description

SDH Alarms and Consequent Actions
RS-TIM
LOS
LOF RS-BIP
MS-EXCMS-AIS MS-BIPMS-RDI MS-REIMS-DEG
MST
RST
SPI
AU-LOPAU-AIS
MSA
HP-
UNEQ
HPOM
HP-EXCHP-TIM HP-BIPHP-RDI HP-REIHP-DEG
HPOM / HPT
TU-AISHP-
PLM
TU-LOP
HPA
LP-
UNEQ
LPOM
LP-EXCLP-TIM LP-BIPLP-RDI LP-REILP-DEG
LPOM / LPT
LP-PLM
LPA
HP-
LOM

LOS
LINE
TRIB
PDH
NE LINE NE
LOS
MS-RDI
AU/TU-AIS
PDH-AIS
K2=XXXXX110
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S
= SIGNAL PASSED THROUGH
INTERRUPTION,
HW TROUBLE,
ATTENUATION

LOF
LINE
TRIB
PDH
NE LINE NE
LOF
MS-RDI
AU/TU-AIS
PDH-AIS
A1,A2
K2=XXXXX110
PROBLEM ON FRAME
ALIGNMENT WORD
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

RS-TIM
LINE
TRIB
PDH
NE LINE NE
RS-TIM
MS-RDI
AU/TU-AIS
PDH-AIS
JO
K2=XXXXX110
RECEIVED REGENERATOR
SECTION TRACE
IDENTIFIER MISMATCH
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

RS-BIP
LINE
TRIB
PDH
NE LINE NE
RS-BIP
B1ERRORED SIGNAL
NEAR END
PERFORMANCE
COLLECTION
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
LINE NE
MS-AIS
MS-AIS
MS-RDI
AU/TU-AIS
PDH-AIS
K2=XXXXX110
K2=XXXXX111
TROUBLE ON THE
RECEIVED SIGNAL
(LOS, LOF, RS-TIM)
MS-AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

MS-EXC
LINE
TRIB
PDH
NE LINE NE
MS-EXC
MS-RDI
AU/TU-AIS
PDH-AIS
B2
K2=XXXXX110
EXCESSIVE BIT
ERROR RATE
( 1X10 E -3)
NEAR END
PERFORMANCE
COLLECTION
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

MS-BIP
LINE
TRIB
PDH
NE LINE NE
MS-BIP
B2ERRORED SIGNAL
NEAR END
PERFORMANCE
COLLECTION
MS-REI
M1
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

MS-RDI
LINE
TRIB
PDH
NE LINE NE
MS-RDIMS-RDI
K2=XXXXX110TROUBLE ON THE
RX SIDE
(LOS, LOF. RS-TIM,
MS-AIS, MS-EXC,
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

MS-REI
LINE
TRIB
PDH
NE LINE NE
MS-REI
M1
FAR END
PERFORMANCE
COLLECTION
ERRORED SIGNAL
MS-REI
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

MS-DEG
LINE
TRIB
PDH
NE LINE NE
MS-
DEG
MS-REI
B2
M1
DEGRADATION
(1X10 E -5    1X10 E -9 )
NEAR END
PERFORMANCE
COLLECTION
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
NE LINE NE
AU-4 XC
AU-AIS
AU-AIS
PDH-AIS
G1 =XXXX100X
TROUBLE ON THE
RX SIDE
(LOS, LOF, RS-TIM,
MS-AIS, MS-EXC,
HP-RDI
AU-AIS
AU/TU-AIS
AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
NE LINE NE
AU-LOP
AU-LOP
PDH-AIS
G1 =XXXX100X
TROUBLE ON THE
AU POINTER VALUE
(WRONG SETTING
SDH/SONET, DEG,
HW FAILURE)
HP-RDI
AU/TU-AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S
H1,H2

LINE
TRIB
PDH
NE LINE NE
HP-UNEQ
HP-UNEQ
C2 = 00000000
AU-4 CHANNEL
NOT CONNETTED
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
140M
NE LINE NE
HP-TIM
G1 =XXXX100X
HP-TIM
HP-RDI
RECEIVED HIGHER PATH TRACE
IDENTIFIER MISMATCH
HP-TIM
J1
PDH-AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

HP-BIP
LINE
TRIB
PDH
140M
NE LINE NE
ERRORED SIGNAL NEAR END
PERFORMANCE
COLLECTION
HP-BIP
B3
HP-BIP
HP-REI
G1 (1,2,3,4)
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

HP-RDI
LINE
TRIB
PDH
140M
NE LINE NE
HP-RDI
TROUBLE ON THE
RECEIVED HP
(AU-AIS, AU-LOP, HP-TIM,
HP-PLM, HP-EXC)
HP-RDI
HP-RDI
G1 =XXXX100X
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

HP-REI
LINE
TRIB
PDH
140M
NE LINE NE
FAR END
PERFORMANCE
COLLECTION
ERRORED SIGNAL
HP-REI
HP-REI
HP-REI
G1 (1, 2, 3, 4)
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

HP-DEG
LINE
TRIB
PDH
140M
NE LINE NE
NEAR END
PERFORMANCE
COLLECTION
HP-DEG
HP-DEG
HP-REI
G1 (1,2,3,4)
DEGRADATION
(1X10 E -5    1X10 E -9 )
B3
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

HP-EXC
LINE
TRIB
PDH
140M
NE LINE NE
NEAR END
PERFORMANCE
COLLECTION
HP-EXC
HP-EXC
HP-RDI
EXCESSIVE BIT
ERROR RATE
( 1X10 E -3)
B3
G1 =XXXX100X
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
NE LINE NE
HP-PLM
HP-PLM TU-AIS
PDH-AIS
G1 =XXXX100X
UNEXPECTED HIGHER
PATH PAYLOD LABEL
HP-RDI
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S
C2

LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
TU XC
TU-AIS
TU-AIS
TROUBLE ON THE
RX SIDE
(AU-AIS, AU-LOP,
HP-TIM, HP-PLM)
TU-AIS
AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S
LP-RDI
V5 = XXXXXXX1
PDH-AIS
AIS

LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
TU-LOP
TU-LOP
V5 = XXXXXXX1
TROUBLE ON THE
TU POINTER VALUE
(DEGRADATION,
HW FAILURE)
TU-AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S
V1,V2
LP-RDI
PDH-AIS
AIS

LINE
TRIB
PDH
1.5-2-34-
45M
NE LINE NE
LP-TIM
V5 = XXXXXXX1
LP-TIM
LP-RDI
RECEIVED LOWER PATH TRACE
IDENTIFIER MISMATCH
LP-TIM
J2
PDH-AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LP-BIP
LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
ERRORED SIGNAL NEAR END
PERFORMANCE
COLLECTION
LP-BIP
V5 (1, 2)
LP-BIP
LP-REI
V5 (3)
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LP-RDI
LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
LP-RDI
TROUBLE ON THE
RECEIVED LP
(TU-AIS, TU-LOP, LP-TIM,
LP-PLM, LP-EXC)
LP-RDI
LP-RDI
V5 = XXXXXXX1
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LP-REI
LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
FAR END
PERFORMANCE
COLLECTION
ERRORED SIGNAL
LP-REI
LP-REI
LP-REI
V5 (3)
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LP-DEG
LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
NEAR END
PERFORMANCE
COLLECTION
LP-DEG
LP-DEG
LP-REI
V5 (3)
DEGRADATION
(1X10 E -5    1X10 E -9 )
V5 (1, 2)
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
LP-EXC
NEAR END
PERFORMANCE
COLLECTION
LP-EXC
LP-EXC
LP-RDI
EXCESSIVE BIT
ERROR RATE
( 1X10 E -3)
V5 (1, 2)
V5 = XXXXXXX1
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
1.5-2-34-45M
NE LINE NE
LP-PLM
LP-PLM
UNEXPECTED LOWER
PATH PAYLOD LABEL
PDH-AIS
LP-RDI
V5 = XXXXXXX1
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
NE LINE NE
LP-UNEQ
LP-UNEQ
V5 (5, 6, 7) = 000
TU CHANNEL
NOT CONNETTED
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S

LINE
TRIB
PDH
1.5-2M
NE LINE NE
HP-LOM
HP-
LOM
V5 = XXXXXXX1
TROUBLE ON THE
MULTIFRAME ALIGNMENT
WORD
TU-AIS
XXX = DETECTED
XXX = GENERATED
XXX = SENT BACK
XXX = MONITORED
AI
S
H4
LP-RDI
PDH-AIS
AIS

Regenerator Section Multiplex Section Higher Order Path Lower Order Path
A1/A2
J0
B1
K2
B2
M1
K2
C2
J1
B3
G1
G1
H4
C2
V5
J2
V5
V5
V5
V5
LOS
LOF
RS-TIM
RS-BIP
MS-AIS
MS-BIP
MS-REI
MS-RDI
AU-AIS
AU-LOP
HP-UNEQ
HP-TIM
HP-BIP
HP-REI
HP-RDI
TU-AIS
TU-LOP
TU-LOM
HP-PLM
LP-UNEQ
LP-TIM
LP-BIP
LP-REI
LP-RDI
LP-PLM
AIS
AIS
AIS
AIS
AIS
AIS
AIS
Error indicator alarm sent upstream
Alarm indicator sent upstream
Error/alarm detection


Performance Monitoring

www.mapyourtech.com 100
OverheadTermination
LPT HPT MST RST RST MST HPT LPT
RSOH
MSOH
VC-4 POH
VC-12, VC-3 POH
2M, 34M Unit STM-n Unit 2M, 34M Unit
LPT: Lower-order Path termination
HPT: High-order Path termination
MST: Multiplex Section Termination
RST: Regenerator Section Termination
STM-n Unit
STM-n Unit or
140M Unit
STM-n Unit or
140M Unit

OverheadTermination
STM-N unit
STM-N
TSI unit
RST MST HPT LPT
Crossconnect
Level
VC-12 or VC-3
2M or 34M
2M or 34M unit
STM-N unit
STM-N
TSI unit
RST MST HPT
Crossconnect
Level
VC-4
140M
140M unit
STM-N unit
STM-N
TSI unit
RST MST HPT HPT MST RST
Crossconnect
Level
VC-12 or VC-3
STM-N
STM-N unit
STM-N unit
STM-N
TSI unit
RST MST RST
Crossconnect
Level
VC-4
STM-N
STM-N unit
MST

Performance Monitoring Point
• Physical Layer
• Section Layer
• Adaptation
• High/Low-order Path Termination

-Physical Layer-
• Optical Interface
LDBC : Laser Diode Bias Current
• PDH Interface
CV-L : Code Rule Violation
ES-L : Errored Second
SES-L : Severely Errored Second
• External Clock Interface
CV-＊ : Code Rule Violation
ES-＊ : Errored Second)
SES-＊ : Severely Errored Second
＊ : L or P

-Section Layer-
• Regenerator (RS) and Multiplex (MS) Section
ES-＊＊ : Errored Second
SES-＊＊ : Severely Errored Seconds
BBE-＊＊ : Background Block Error
UAS-＊＊ : Unavailable Seconds
OFS-＊＊ : Out of Frame Seconds (OOF)
• Multiplex Section Far-end
ES-MSFE : Errored Second
SES-MSFE : Severely Errored Seconds
BBE-MSFE : Background Block Error
UAS-MSFE : Unavailable Seconds
• Multiplex Section
PSC : Protection Switching Count
PSD : Protection Switching Duration
＊＊ : RS or MS

-Adaptation-
• AU-4 Pointer
PJE (positive) : Pointer Justification Event (positive)
PJE (negative) : Pointer Justification Event (negative)

-PathTermination-
• High/Low-order Path (receiving direction)
ES-＊＊ : Errored Second
SES-＊＊ : Severely Errored Seconds
BBE-＊＊ : Background Block Error
UAS-＊＊ : Unavailable Seconds
• High/Low-order Path (transmitting direction)
ES-＊＊FE : Errored Second
SES-＊＊FE : Severely Errored Seconds
BBE-＊＊FE : Background Block Error
UAS-＊＊FE : Unavailable Seconds
＊＊ : HO or LO

Terms and Definitions
(used by error performance)
EDC : Error Detection Code
Block : block
EB : Errored Block
Defect : defect
ES : Errored Second
SES : Severely Errored Second
BBE : Background Block Error
CV : Code Violation
UAS : Unavailable Second

BIP-8 ofVC-4
1
2
2348
1
1
1
1
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82349
31
262
2
263
2348 2349
Group of 8 bits
VC-4
261
Blo c k ( 1 8 7 9 2 b it s / b lo c k ) B3
BIP-8 check sequence

Block : block
EB : Errored Block
Defect : defect
ES : Errored Second
CV : Code Violation

Generation and Detection of SDH
Performance
Bit Error Generation Mechanism
Mechanism: Bit interleaved parity (BIP)
Transmit end: The result of BIP is placed in the relevant bytes of the
next frame
Receive end: Compare the result of BIP with the bytes of the next
frame
B1: BIP8 for the regenerator section error monitoring function
B2: BIP24 for multiplex section error monitoring function
B3: BIP8 for monitoring the bit error performance ofVC-4
V5: BIP2 for monitoring the bit error performance ofVC-12
Notice:The Sequence of descramble& BIP

Generation and Detection of SDH Performance
B1
B2
B3
V5
RSTMSTHPTLPT LPTHPTMSTRST
Errors occurring in Low order path will not be detected in High order
path, High order bit errors will trigger Low order errors.
Error Detection and Report

Terms
Term Description
BE Errored block, in which one or more bits are in error.
BBE
Background block error, it is an errored block occurring outside of the period
of UAT and SES.
FEBBE Far end block of background error, it is a BBE event detected at the far end.
ES
Errored second, it is a certain second with one or more errored blocks
detected.
FEES Far end errored second, in which an ES event detected at the far end.
SES
Severely errored second, it is a certain second which contains 30% errored
blocks or at least one serious disturbance period (SDP). Here, the SDP is a
period of at least four consecutive blocks or 1ms (taking the longer one)
where the error ratios of all the consecutive blocks are  10-2 or loss of
signal occurs.

Term Description
FESES
Far end severely errored second, in which an SES event detected at the
remote end.
CSES
Consecutive severely errored second, in which the SES events
consecutively occur, but last less than 10 seconds.
FECSES
Far end consecutive severely errored second, in which a CSES event
detected at the far end.
UAS
Unavailable second, it is a period of 10 consecutive seconds during which
the bit error ratio per second of the digital signal in either of the
transmission directions of a transmission system is inferior to 10-3 . These
ten seconds are considered to be part of unavailable time.
Terms

Adjust pointers as required in practice, so as to tolerate rate
asynchronization and phase difference of payload signals.That is, perform
pointer justification on information payloads to make the payloads
synchronous with the STM-N frame
Mechanism
Administrative unit pointer (AU_PTR)
Tributary unit pointer (TU_PTR)
Sort
Pointer Justification

H1YY H2 F F H3 H3 H3 VC4
9
row
10………270Column
91
 Locatio
n:
 Causation:
− Network is out of synchronization
 Pointer justification state:
Name
Byte numbering and content of the fourth row in STM-1
frame Rate relation
7 8 9 10 11 12
Zero H3 H3 H3 Info Info Info Information = container
Positive H3 H3 H3 Stuffing Stuffing Stuffing Information< container
Negative Info Info Info Info Info Info Information> container
Generation Mechanism of AU Pointer Justification

 Causation:
− Transformed from AU pointer justification
− The system clock is not consistent with the received clock
− Pointer justification occurs at the upstream NE where the service
passes
Remote detection:
Occur at the local station, report at the remote station
Local detection:
Generate at the local station, report locally
Generation Mechanism ofTU Pointer Justification
Detection and Reporting of Pointer Justification

Relationship between Alarms and Performance
Item Performance Event Alarm Event
Local end Remote end Local end Remote end
RS RSBBE - B1_OVER -
MS MSBBE MSFEBBE B2_OVER MS_REI
HP HPBBE HPFEBBE B3_OVER HP_REI
LP LPBBE LPFEBBE BIP_OVER LP_REI
 Functions of alarm and performance for bit error threshold
crossing
Alarm and Performance are belong to different levels. Alarm
indicates the fault of transmission, performance indicates the signal
degrade of transmission. If the value of performance is high than
threshold it will translate into alarm. For example bit error can
translate into EXC alarm then causes the traffic interrupt.
 Relationship

Relation between ES, SES and BBEBlocksin1sec.period
30 %
1 sec.
ES
SES
EB} BBEnonEB

Block : block
EB : Errored Block
Defect : defect
ES : Errored Second
CV : Code Violation

10 sec. 10 sec.< 10 sec.
Unavailability detected Availability detected
Unavailable period Available period
Error-free second
Severely errored second
SES
Errored second
ES
Unavailable Second

1 day
(Yesterday)
Current 1 day (Today)
data update : every 1 min.
0 : 00 0 : 00
TCA (Threshold Crossing Alert)
1 day accumulation
32 periods with zero suppression
(32) (2) (1)
15 min.
hh : 15n hh : 15(n+1)
Current 15 min.
data update : every 1 min.
15 minute accumulation
TCA (Threshold Crossing Alert)
Storage of PM data
timepast future
0
*
*
0
*
0
*
0
0
0
0
0
0
0
0
0
0
0
0
0
0
△
0
0
0
0
*
*
0
*
*
0
*
0
*
0
0
0
0
0
0
△
0
0
0
0
*
*
item a
item b
item x
item y
item a
item b
item x
item y
memoryold new
Zero Suppression
all zero data with time stamp of △ occurrence
Zero Suppression
PM items of one facility

Bit error defects family
 EXC = EXCessively errored signal
 DEG = DEGraded signal
 CMI = Code Mark Inversion
 All members of the [large] family of bit error defects have a common origin
 errors in the transmission/reception of a signal.
 SDH calculates a parity check and places the results in the overhead.
 Occurs in bothTx and Rx.A difference indicates a bit error in transmission/reception
 Another detection mechanism is for electrical signals
 An invalid sequence is a code violation
 PPI-EXC and ES-CMI defect originate from code violations.
 SDH paths and sections may have EXC and DEG defects [Different degrees of errors]
 EXC represent an ‘EXCessive’ number of bit errors – the signal is so badly errored as to be unusable
 EXC defects represent a bit error ratio of 10-3 or 10-4.
 EXC results in a protection switch at the closure point of a sub-network connection and may be configured
to insert AIS and RDI.
 DEG defects represent a bit error ratio of 10-5 or less
 DEG does not result in a protection switch or raising of any consequent action.

What is Performance Monitoring
 Performance monitoring is used to measureTraffic Quality
 How? – By counting anomalies and defects.
 Why are they needed?
 To diagnose faults in a network OR detect occurrence of dribbling errors.
 Measure a networks performance and its service capability.
 At the edge of the network
 Within the network
 Check service level agreements for end customers and find out whether they have been
satisfied or breached.
 Reporting performance monitoring
 NE collects and logs PMs continuously for all connections.
 EC-1 collects PMs from all NEs in span of control.
 INM collects PMs from the complete network.

Performance Monitoring Points
 Performance Monitoring Points [PMPs]
 are points at which software collects performance monitoring [PM] data. The PM data
is a measure of the quality of the transmission path at that point.
PDH
End User
LP_NE V5, B3
LP_FE V5, G1
TU_PJE
Vc-12
Vc-12
PPI_CV
Vc-4 Vc-4
STM-N
RS-OOF A1, A2
RS-NE B1
MS_NE B2
MS_FE M1
AU_PJE
HP_NE B3
HP_FE G1
Optical Link via Network
PDH
End User
NE1
NE2

Table of PM points
 PMs count will occur at the same points as where alarms will occur
 FE[Far End] PMs are associated with the RDI defect category.
 The destination you are sending to has received your signal in a defective state.
PMP-Type Byte Defects
RS-OOF A1, A2
RS-NE B1 RS-LOS, RS-LOF
MS_NE B2 All RS defects, MS-AIS, MS-EXC
MS_FE M1 MS-RDI
AU_PJE N/A N/A
HP_NE, HPOM_NE B3 All RS, MS defects, AU-AIS, AU-LOP, HP-LOM, HP-TIM, HP-PLM, HP-EXC
HP_FE, HPOM_FE G1 HP-RDI
TU_PJE N/A N/A
LP_FE
LPOM_FE
G1[VC-3]
V5(b3[VC-12]
HP-RDI, LP-RDI
LP_NE
LPOM_NE
B3[VC-3]
V5(b1-b2[VC-12]
All RS, MS, AU, HP defects, TU-AIS, TU-LOP, LP-TIM, LP-PLM, LP-EXC,
INT-LO-BUFFER
ES-CV N/A ES-LOS
PPI-CV N/A PPI-LOS

BIP Errors vs Block Errors
 B1 is an 8 bit parity byte, calculated across the complete SDH frame [2430
bytes for an STM-1 signal].
 B1 byte is generated/terminated at every NE.
 ANSI specifies BIP
 ETSI/ITU specifies Block Errors
 The B1 Byte is treated as 1 block
 The B1 Byte is treated as BIP-8 [since it has 8 bits]
Example
0 1 0 1 0 1 0 1
Transmitted
0 1 1 1 0 1 0 1
0 1 1 1 0 0 0 1
0 0 1 0 0 1 1 0
1 0 1 0 1 0 1 0
Received
= 1 Block Error, = 2 BIP Errors
= 1 Block Error, = 1 BIP Error
= Bit Error

Definition of BBE, ES, SES, UAS
 Background Block Error [BBE]
 A Background Block Error [BBE] is a single errored Block in the SDH frame, not occurring
as part of an SES or a UAS.
 Errored Second [ES]
 An Errored Second [ES] is a second during which at least one anomaly or one defect
occurs, but not occurring as part of a UAS.
 Severely Errored Second [SES]
 A Severely Errored Second [SES] is a second during which at least ‘X’ anomalies or one
defect occurs, but not occurring as part of a UAS. By definition an SES is always an ES.
 Unavailable Second [UAS]
 An Unavailable Second is a second during which the signal is unavailable. It becomes
unavailable at the onset of 10 consecutive seconds that qualify as SES, and continue to be
unavailable until the onset of 10 consecutive seconds that do not qualify as SES.

How to interrupt SES and UAS
 The difference between SES and UAS is conceptually difficult to understand.
 Therefore it is better clarified through the use of a diagram.
 Unavailable periods/detection and available periods/detection are indicated.
<10secs
Unavailability
Detected
10secs <10secs
Unavailable Period
Availability
Detected
Available Period
10secs
= SES = Non SES
Available Period

Processing of B1 byte
 This can be broken down into activities performed in hardware and software.
Calculate B1
block errors
Determine RS
defects
1- Second
Filter
15-Minute
Filter
24-Hour Filter
SDH Frame
SDH Frame
Frame B1
errors
Frame RS
defects, LOS,
LOF
1- second
BBE, ES, SES, UAS
15-minute
BBE, ES, SES, UAS
24-hour
BBE, ES, SES, UAS
15-Minute PM Counts
TIME BBE ES SES UAS
00:00 3 3 1 0
00:15 5 4 0 0
00:30 1 1 0 0
24-Hour PM Counts
BBE ES SES UAS
40 33 0 0
34 16 20 20
21 4 2 0

Calculating B1 block errors.
 The calculation of B1 block errors occurs in hardware.
 Conceptually this can be understood via a diagram.
Frame X Frame X+1 Frame X+2
Calculate
expected B1
byte
Compare
actual with
expected B1
byte
Expected B1 byte
Actual B1 byte
B1 errors
}

1- Second Filter
1-Second Filter
B1 Errors (x) BBE ES SES UAS
x = 0 0 0 0 0
0 < x < 2400 x 1 0 0
x >= 2400 (< 10 secs) 0 1 1 0
x >= 2400 (> 10 secs) 0 0 0 1
Defects BBE ES SES UAS
No Defects 0 0 0 0
LOS, LOF (< 10 secs) 0 1 1 0
LOS, LOF (> 10 secs) 0 0 0 1
1-Second
filter
Frame B1 errors
Frame RS defect,
LOS, LOF
1- second
BBE, ES, SES, UAS
SDH Frame B1 Errors/Defects
DATE TIME FRAME B1 Errors Defects
01/01/2000 00:00:00 0001 0 -
01/01/2000 00:00:00 0002 0 -
01/01/2000 00:00:00 0003 1 -
“ “ “ . .
“ “ “ . .
“ “ “ . .
01/01/2000 00:00:00 7998 0 -
01/01/2000 00:00:00 7999 0 -
01/01/2000 00:00:00 8000 0 -
----
TOTAL B1 Errors (x) = 0001
} 1-Second PM Counts
DATE TIME BBE ES SES UAS
01/01/2000 00:00:00 1 1 0 0
01/01/2000 00:00:01 x x x x
01/01/2000 00:00:02 x x x x

15-Minute Filter
1- second
BBE, ES, SES, UAS
15-Minute
Filter
15-Minute
BBE, ES, SES, UAS
15-Minute PM Counts
01/01/2000 00:00 3 3 1 0
01/01/2000 00:15 x x x x
01/01/2000 00:30 x x x x
1-Second PM Counts
01/01/2000 00:00:00 1 1 0 0
01/01/2000 00:00:01 0 0 0 0
01/01/2000 00:00:02 0 1 1 0
“ “ . . . .
“ “ . . . .
“ “ . . . .
01/01/2000 00:14:57 2 1 0 0
01/01/2000 00:14:58 0 0 0 0
01/01/2000 00:14:59 0 0 0 0
}

24 Hour Filter
1- second
BBE, ES, SES, UAS
24-Hour
Filter
24-Hour
BBE, ES, SES, UAS
}
24-Hour PM Counts
DATE BBE ES SES UAS
01/01/2000 40 33 3 0
02/01/2000 x x x x
03/01/2000 x x x x
“ . . . .
“ . . . .
“ . . . .
1-Second PM Counts
01/01/2000 00:00:00 1 1 0 0
01/01/2000 00:00:01 0 0 0 0
01/01/2000 00:00:02 0 1 1 0
“ “ 30 . . .
“ “ . 30 1 .
“ “ 4 . . .
01/01/2000 23:59:57 0 0 1 0
01/01/2000 23:59:58 5 1 0 0
01/01/2000 23:59:59 0 0 0 0

TIME B1 Errors Defects
1 5 -
2 50 -
3 500 -
4 5000 -
5 0 LOS
6 40 LOS
7 400 LOS
8 4000 LOS
9 2500 LOF
10 2700 -
11 3000 -
12 4000 -
13 5000 -
14 6000 -
15 7000 -
16 0 -
17 50 -
18 0 -
19 100 -
20 0 -
21 30 -
22 0 -
23 35 -
24 0 -
25 0 -
26 0 -
27 40 -
28 0 LOF
29 0 -
BBE= 5 ES= 1 SES= UAS=
BBE= ES= 1 SES= 1 UAS=
BBE= ES= SES= UAS= 1
BBE= ES= SES= UAS=
BBE= ES= SES= UAS=
TOTAL BBE= 595 ES= 15 SES= 11 UAS= 12
B1 errors
5000 > 2400 [<10 secs]
Defects
LOS, LOF (< 10 secs)
Unavailable
Period
B1 errors
X > 2400 [>10 secs]
AND / OR
Defects
LOS, LOF [>10secs]
Unavailability
Detected
Availability
Detected
B1 errors
X < 2400 [>10secs]
AND / OR
Defects
No Defects [>10secs]
Accumulation of PMs over time
10 Second
Period
2 Seconds
that qualify
as SES

Question and Answers
 What is the difference between an anomaly and a defect?
 Anomaly is a single occurrence of, or commencement of a condition
 Defect is a persistent or repeated occurrence of an anomaly
 What is the main difference between a POM alarm and a LO or HO alarm?
 LPs / HPs are present on termination
 POMs are present when traffic is un-terminated
 What is the main principle behind masking?
 Present alarm closet to source
 Reduce the amount of fault analysis and alarm presentation
 A car fail alarm is raised on a PIU,What should you do?
 This alarm needs to be cleared first because it will mask all other alarms raised on the card/slot
instance
 What is the difference between a regenerator and a multiplexer?
 Regenerator terminates the RSOH, MSOH + payload continue, regenerator generates new OH
 Multiplexer fulfils the same function of a regenerator and also terminates / generates a MSOH

 What alarms does the Multiplex SectionTermination give?
 Provides pointer processing and gives AU alarms
 Where are the Low PathTermination points?
 On PDH tributaries
 If an unprotected limb has two POMs present which one is active the Rx or theTx?
 Rx is active
 In a protected connection is a limb has a HPT or LPT present can HPOM/LPOM also be
active?
 Yes
 Which bytes are responsible for the reporting of a LOF alarm, what section overhead are
they found?
 A1 and A2 –In RSOH
 Where isAIS reported in relation to a defect?
 AIS is reported downstream from a defect, a user would look upstream to resolve the
issue

 Why is there no RS-AIS alarm?
 Possibly redundancy [Like theTIM alarms which only has RS-TIM]
 Could also be that RS alarms on regenerators are passive and operate as a pass through.
Multiplexers drop traffic and are better therefore to address issue
 How many consequent actions are there and what are they?
 AIS, RDI/REI and protection switches
 Which alarm is more serious, RDI or REI?
 RDI is more serious
 What type of cards produce CMI alarms?
 Electrical cards [comes from Code Mark Inversion line coding]
 What consequent actions does a DEG alarm produce?
 It doesn’t
 What type of payload would you expect on the raising of a UNEQ alarm?
 0
 What bytes carry PM information and where are they calculated?
 B1, B2 and B3. Calculated in hardware

• Various presentation collected from Internet {Huawei,Tejas,Nortel & Marconi) available free of cost
• www.mapyourtech.com
• www.google.com
For further queries do reach on www.mapyourtech.com
References

Thank You!

SDH/SONET alarms & performance monitoring

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