SDH Alarms

Tejas Networks SDH Alarms

© Tejas Networks India Ltd., 2006, Proprietary Information

Organisation of Slides

SDH section hierarchy SDH objects, nomenclature Downstream and Upstream Alarms understanding rules RS alarms MS alarms HP / LP alarms Description of Alarms Alarm Masking and Suppressed Secondary Alarms Alarm propagation examples © Tejas Networks India Ltd., 2006, Proprietary Information

SDH Section Hierarchy

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)

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SDH Section Hierarchy (…contd.) Points to Remember: Without opening RS, one can not do operation with MS and/or open MS Without opening MS, one can not do operation with HP and/or open HP Without opening HP, one can not do operation with LP and/or open LP Consequences •

So, for Tejas nodes, even if one is making a VC4 level pass-through (an operation with HP without opening it), he/she is opening MS & therefore terminating the MS

•

One can change any HPOH field (e.g., J1 transmitted trace) only when one is opening HP (e.g., VC12 level cross-connect exists on AU4 mapping), but not when HP is not disturbed (e.g., VC4 level pass-through on AU4 mapping)

Points to Remember: For Tejas nodes, for AU4 mapping, one can make VC4 and VC12/VC11 level and not VC3 level pass-through for E1/DS1 traffic Consequences

•

If in a STM-1 node, multiple (say, 18) E1/DS1 traffic have to be passed-through with some other traffic added/dropped from that node, one has to make multiple (18) VC12 level pass-through © Tejas Networks India Ltd., 2006, Proprietary Information

Section Hierarchy (examples) Example 1 RS

RS

Reg. ADM 1

ADM 2 MS

Example 2 RS

RS (VC4)

ADM 1

ADM 2 MS

(STM 1)

ADM 3 MS

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Section Hierarchy (examples) (… contd.)

Example 3 (for AU4 mapping only)

E1

RS

RS

RS

MS

MS

MS

VC12

VC4

VC12

VC12

A

B

C

D

HP

HP

LP

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E1

Section Hierarchy (examples) (… contd.)

#1 E1 – between A & E

Example 4a (for STM1 capacity & AU4 mapping only) F V C

VC

12

E3

#2 E1 – between F & H

E1

E3 – between F & G

3

RS – A-B, B-C, C-D, D-E, F-B, C-G, E-H MS – A-B, B-C, C-E, F-B, C-G, E-H

C

Reg.

E E1

VC12

A

D

B

HP – A-B, B-C, C-E

V 3

LP – F-H

C

HP – F-B, B-C, C-E, E-H

E3

G

HP – F-B, B-C, C-G LP – F-G

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E1

12

LP – A-E

VC

E1

VC12

H

Section Hierarchy (examples) (… contd.)

#1 E1 – between A & E

Example 4b (for STM4 capacity & AU4 mapping only) F V C

VC

12

E3

#2 E1 – between F & H

E1

E3 – between F & G

3

RS – A-B, B-C, C-D, D-E, F-B, C-G, E-H ----- VC 4

MS – A-B, B-C, C-E, F-B, C-G, E-H Within STM # 1

STM # 1

C

Reg.

E E1

VC12

A

B

STM # 2

D

STM # 2

STM # 1

HP – A-E

V 3

LP – F-H

C

HP – F-C, C-H

E3

G

HP – F-C, C-G LP – F-G

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E1

12

LP – A-E

VC

E1

VC12

H

SDH objects, nomenclature

3 different kinds of objects: • STM port (STM-1 / STM-4 / STM-16) • AU (AU-3 / AU-4 / AU-4-4c / AU-4-16c) – Higher-order object (present even if no HO cross-connect) • TU (TU-11 / TU-12 / TU-2 / TU-3)

– Lower-order object (present only if LO cross-connect exists)

Nomenclature • STM-1 chassis – slot – port (these fields are product specific) • AU-4 • AU-3

chassis – slot – port – STM # – 1 chassis – slot – port – STM # – K (for AU-3 mapping)

• • • •

chassis – slot – port – STM # chassis – slot – port – STM # chassis – slot – port – STM # chassis – slot – port – STM #

TU-3 TU-2 TU-12 TU-11

– K (for AU-4 mapping) –K–L – K – L – M (M = 1 to 3) – K – L – M (M = 1 to 4)

Note: STM # = 1 (for STM-1) = 1 to 4 (for STM-4) like that,

K = 1 to 3, L = 1 to 7

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Downstream & Upstream Downstream direction for a fault condition Along the direction of fault condition received OR Towards the Back-plane of the node receiving fault condition Upstream direction for a fault condition Opposite of the direction of fault condition received OR Away from the Back-plane of the node receiving fault condition Downstream & Upstream direction for a node not fixed Depends on direction of fault condition (abbreviated as FC) Downstream Upstream FC 1 FC 2

ADM 1

Downstream Upstream

ADM 2

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ADM 3

Alarm Understanding Rules Rule 1

Alarms reported are alarms received

Alarm reported

FC 1 ex. a

ADM 1

ADM 2 Alarm reported

FC 1 ex. b ADM 1

ADM 2

Rule 2

Alarms are reported on SDH Objects © Tejas Networks India Ltd., 2006, Proprietary Information

Alarm Understanding Rules (…contd.) Rule 3

3a. No Object => No Alarms reported ex.

NO TU12 (1-1-1)

Note:

FC on TU12 (1-1-1)

ADM 1

NO Alarm reported for FC on TU12 (1-1-1)

ADM 2

3b. Object Mismatch => No Alarms reported ex.

WHY?

TU11

See slide 9

(1-1-1) FC on TU12 (1-1-1)

ADM 1

These two examples are not possible for AU object

NO Alarm reported for FC on TU12 (1-1-1)

ADM 2

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Alarm Understanding Rules (…contd.) Rule 4

4a. No PT XC => No Alarms pass-through NO VC4

ex. a

PT (1) FC on AU4 (1)

ADM 1

NO Alarm pass-through

ADM 2

ADM 3 Alarm reported for FC on AU4 (1)

NO VC12

ex. b

PT (1-1-1)

ADM 1

NO Alarm pass-through

FC on TU12 (1-1-1)

ADM 2

ADM 3 NO Alarm reported for FC on TU12 (1-1-1)

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Alarm Understanding Rules (…contd.)

4b. Bigger PT XC => No Alarms reported & Alarm pass-through STM-1

VC4

ex. a

links FC on TU12 (1-1-1)

ADM 1

Alarm pass-through for

ADM 2

FC on TU12 (1-1-1)

ADM 3 NO Alarm reported for FC on TU12 (1-1-1)

4c. Smaller PT XC => No Alarms reported (always ??) & Alarm pass-through but on smaller object STM-1

VC12

ex. b

(1-1-1)

ADM 1

Alarm pass-through for FC on TU12 (1-1-1)

What if Same size PT XC ?

links

FC on TU3 (1)

ADM 2

ADM 3 NO Alarm reported for FC on TU3 (1)

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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

RSOH bytes

LOF (Loss of Frame) based on A1, A2 bytes

A1 A2 B1 E1

J0 F1

TIM (Trace Identifier Mismatch) based on J0 byte

D1 D2 D3

SF (Signal Fail) based on B1 byte SD (Signal Degrade) based on B1 byte

Note: The order in which the alarms are written is important, as we will see later while discussing Alarm masking

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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

B2 K1 K2 D4 D5 D6 D7 D8 D9 D10 D11 D12 S1 M1 E2

Note 1: The order in which the alarms are written is important, we will see later while discussing Alarm 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 port © Tejas Networks India Ltd., 2006, Proprietary Information

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)

J1

H1, H2, H3 – AU Pointer bytes

HP-AIS reported based on H1, H2 bytes

B3

HP-LOP (Loss of Pointer) based on H1, H2 bytes

C2

Note 1: Same as before

HP-UNEQ (unequipped) based on C2 byte

G1

Note 2: HP-Alarm is also

HP-TIM based on J1 byte

F2

or Alarm on AU

HP-SF based on B3 byte

H4

LP-Alarm is also

HP-SD based on B3 byte

called AU-Alarm

called TU-Alarm or Alarm on TU

HP-RDI based on G1 byte -- bit 5 © Tejas Networks India Ltd., 2006, Proprietary Information

F3 K3 N1

H O P O H b y t e s

HP / LP Alarms (…contd.) Note 1: Same as before

LP-AIS reported based on V1, V2 bytes

Note 2: Whole of this slide assumes

LP-LOP based on V1, V2 bytes

TU2/TU12/TU11 for LP. If there

LOM (Loss of Multiframe) based on H4 byte – bits 7,8

is TU3 with AU4 mapping, then also it is LP but Pointers & POH

HP-PLM / SLM (Payload / Signal Label Mismatch) bytes will be like HO based on C2 byte LP-UNEQ based on V5 byte – bits 5,6,7

LOPOH bytes

V1, V2, V3 – TU Pointer bytes

V5 J2 N2 K4

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

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Description of Alarms LOS Received power is less than Laser receiver sensitivity (All bits interpreted as ‘0’) Tx off / misconnectivity

ex.

Fiber Cut

Rx off / misconnectivity

Tx Rx

ADM 1

LOS

Rx Received power is less than Laser receiver sensitivity (Low power transmitted, Span is longer than specified, Fiber gets deformed etc. etc.)

Tx

ADM 2

LOS clears when 2 consecutive framing patterns are received & no new LOS condition is detected

LOF Anything other than “F6 28 (Hex)” in any (?) of the A1 A2 bytes (within a STM frame) -- for consecutive 5 frames (625 Ms) -- for consecutive 24 frames (3 ms)

OOF (Out of Frame) clearing 2 frames 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) © Tejas Networks India Ltd., 2006, Proprietary Information

Description of Alarms (…contd.) TIM (J0) Received J0 trace (1/16 byte(s)) != Expected J0 trace (1/16 byte(s)) Exp trace = A to B P1 Tx trace = A to B

A

Exp trace = C to B

Rx trace = C to B

P2

B

Tx trace = C to B

C

Rx trace = A to B

SF (B1/B2/B3/V5) 3 4 5 Equivalent BER exceeds alarm generation threshold ( 1 in 10 / 1 in 10 / 1 in 10 ) SD (B1/B2/B3/V5)

5

9

Equivalent BER exceeds alarm generation threshold ( 1 in 10 to 1 in 10 ) 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 © Tejas Networks India Ltd., 2006, Proprietary Information

Description of Alarms (…contd.) Generation of AIS & RDI Upon Receiving traffic affecting RS alarm, a Reg. generates AIS towards downstream side (all ‘1’ in whole STM frame)

Upon Receiving traffic affecting RS alarm, a ADM generates MS-AIS towards downstream side (all ‘1’ in whole STM frame minus RSOH) & generates MS-RDI towards upstream side (in K2 byte b6 -- b8 set as ‘110’)

Upon Receiving traffic affecting HP alarm, a ADM generates AU-AIS towards downstream side (all ‘1’ in whole AU) & generates HP-RDI towards upstream side (in G1 byte b5 set as ‘1’) © Tejas Networks India Ltd., 2006, Proprietary Information

Description of Alarms (…contd.) Upon Receiving traffic affecting LP alarm, a ADM generates TU-AIS towards downstream side (all ‘1’ in whole TU) & generates LP-RDI towards upstream side (in G1 byte b5 set as ‘1’ for TU3 || in V5 byte b8 set as ‘1’ for TU2/12/11)

Reception of AIS & RDI (condition should persist for consecutive 3 to 5 frames) Bytes and bits involved in Reception for RDIs remain unchanged Reception for MS-AIS

in K2 byte b6 -- b8 received as ‘111’

for AU-AIS

All ‘1’ in H1, H2 bytes (for TU3 AIS also)

for TU-AIS

All ‘1’ in V1, V2 bytes (TU2/12/11)

Note: 1) For generating MS-AIS / AU-AIS / TU-AIS, the ADM need not be a term. equip. for MS / HP / LP 2) Upon receiving MS-AIS / AU-AIS / TU-AIS also, the ADM generates MS-AIS / AU-AIS / TU-AIS towards downstream & generates MS-RDI/HP-RDI/LP-RDI towards upstream 3) Some alarms are by default traffic affecting or non traffic affecting, whereas some alarms can be made traffic affecting by user action © Tejas Networks India Ltd., 2006, Proprietary Information

Description of Alarms (…contd.) Example of generation of AIS, RDI MS-AIS (Gen) AU-AIS TU-AIS (Gen) Any traffic affecting LP RS Alarm HP Alarm or or TU-AIS MS-AIS AU-AIS (Rx) (Rx)

MS-RDI HP-RDI LP-RDI

ADM

Example of reception of TU-AIS, LP-RDI TU-AIS (Rx) Any traffic affecting RS/HP/LP Alarm VC12

VC12

VC12

E1

E1 ADM 1

LP-RDI (Rx)

ADM 2

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ADM 3

Description of Alarms (…contd.) AU/TU-LOP (AU-LOP is not reported in Tejas nodes, as always valid AU pointer values are sent) 8/9/10 consecutive invalid AU/TU pointers received or 8/9/10 consecutive NDF (New Data Flag) received (other than in a concatenation indicator) (cleared when 3 equal valid pointers received)

AU-LOP

Ex. VC4

VC4

E4

E4 ADM 1

AU-LOP

ADM 2

ADM 3 TU-LOP

Ex. VC12

VC12

E1

E1 ADM 1

TU-LOP

ADM 2

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ADM 3

Description of Alarms (…contd.) HP/LP-UNEQ All ‘0’ in C2 byte for at least 5 frames (for AU4/AU3/TU3) ‘000’ in V5 byte, bits 5,6,7 for at least 5 multi-frames (for TU2/12/11) AU Sig. Label

ex.

HP-UNEQ

UNEQuipped

AU has

AU has

no XC

no XC ADM 1

HP-UNEQ AU Sig. Label

ex.

UNEQuipped

AU Sig. Label

ADM 2

TUG-structured

AU has VC12

no XC

E1 ADM 1

HP-UNEQ

UNEQuipped

AU Sig. Label

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ADM 2

Description of Alarms (…contd.) LOM Multiframe information not recovered from H4 byte (bits 7,8) for 1 to 5 ms (i.e., 2 to 10 multi-frames) Note: LOM is an alarm concerning LP, but inferred from HOPOH byte – so, it will be reported on a HO object TIM (J1/J2) (Default action is to “Ignore TIM”) Concept is like TIM (J0), but a) Remember Section Hierarchy – Tx trace (J1/J2) can not be edited within a HP/LP

E1

VC12

VC4

VC12

VC12

A

B

C

D

Tx trace can be edited for J0, J1, J2 all

Tx trace can be edited for J0 only

Tx trace can be edited for J0, J1 only

b) All trace lengths are now 16/64 bytes © Tejas Networks India Ltd., 2006, Proprietary Information

E1

Description of Alarms (…contd.) HP/LP-PLM (SLM) (Default action is to “Report PLM, but no Downstream AIS”) Mismatch in ‘own’ and ‘received’ signal label in C2 byte for at least 5 frames (for AU4/AU3/TU3) in V5 byte, bits 5,6,7 for at least 5 multi-frames (for TU2/12/11) AU Sig. Label

ex.

TUG-ST

TUG-ST

UNEQ

UNEQ

AU has

VC12

E1 ADM 1

ex.

HP-PLM (SLM)

TUG-structured

HP-PLM (SLM) TUG ST

UNEQuipped

VC12

E1 ADM 1

AU Sig. Label Asynch. C4

TUG ST

no XC

Asynch. C4

VC4 Asynch. C4

Asynch. C4

ADM 2

ADM 2

VC12 TUG ST

HP-PLM (SLM) on all ports © Tejas Networks India Ltd., 2006, Proprietary Information

TUG ST

E1 ADM 3

Masking of Alarms Why? Do not want to crowd the alarm reporting page ( and thereby confuse the user) with those alarms, not required for unearthing the root cause When? (The logics) Logic 1 (when the alarms are related) if ( FC1 ==> FC2 but FC2 =/=> FC1 ) then ( Mask FC2 in presence of FC1 ) ex. 1a) LOS ==> LOF but LOF =/=> LOS

Note: When FC1 clears, FC2 may or may not clear – in the later case FC2 will be reported now

1b) LOS ==> HP-UNEQ but HP-UNEQ =/=> LOS

2) AU-AIS reported because of MS/AU-AIS generated ==> HP-RDI and TU-AIS & LP-RDI(s) reported (if TU object(s) are there) 3) HP-UNEQ because of no XC at other end ==> TU-LOP(s) (if TU object(s) are there) 4) AU/TU-AIS reported ==> AU/TU-LOP

but not vice-versa but not vice-versa

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but not vice-versa

Masking of Alarms (…contd.) Logic 2 (when the alarms are not related) if ( FC1 has higher priority than FC2 )

Note: When FC1 clears, FC2 will be reported

then ( Mask FC2 in presence of FC1 ) ex. 1) AU/TU-LOP has higher priority than HP/LP-UNEQ (if one is not getting the starting location of VC, how to look at what is happening within VC) 2) HP/LP-TIM, if action is chosen as “Report TIM, Downstream AIS” (i.e. traffic affecting) has higher priority than HP/LP-RDI (first correct received problem, then only look for problem in other direction) 3) HP/LP-TIM has higher priority than HP/LP-PLM (first correct mis-connection, then see signal label problem within correct correction) 4) HP/LP-UNEQ has higher priority than HP/LP-TIM (even if traffic affecting) (what to gain by correcting mis-connection, if even after that traffic can not be carried)

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Secondary Suppressed Alarms (SSA) AIS and RDI are secondary alarms – they are “indications”, not root causes These alarms on a pass-through node is normally not reported in the main alarm page, they are reported in a separate page called “suppressed secondary alarms page” These alarms on a path terminating node is reported in the main alarm page as “terminating” alarms AU-AIS and HP-RDI are not suppressed, even for pass-through nodes, for Tejas products Traffic affecting FC ex.

VC12

VC12

TU-AIS (terminating)

VC12 E1

E1 ADM 1

ADM 2 LP-RDI (terminating)

ADM 3 LP-RDI (SSA)

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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 green © Tejas Networks India Ltd., 2006, Proprietary Information

Alarm Propagation Examples (…contd.) Example 1 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

A

B

HP-RDI HP-RDI AU4 Signal Label Unequipped

Note: 1) if AU-3 mapping, then what happens? 2) In newer version of Tejas software, UNEQ is not reported for this root cause

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Alarm Propagation Examples (…contd.) Example 2 Assumption: AU-4 Mapping on both ports,

Root Cause: NO XConnect on the port of B

HP-SLM default action is “report SLM, no downstream AIS” Signal Label TUG-structure HP-RDI LP-RDI HP-RDI HP-SLM

VC12 E1

HP- UNEQ

A

TU-LOP

AU4 Signal Label Unequipped Invalid TU Pointer value

Note: LP-RDI is not reported on B (See Rule 3a) © Tejas Networks India Ltd., 2006, Proprietary Information

B

Alarm Propagation Examples (…contd.) Example 3 Assumption: AU-4 Mapping on both ports of A & C Root Cause: Fiber cut in the link from A to B MS-AIS AIS LOS

AU-AIS TU-AIS

VC-12

VC-12 E1

MS-RDI

E1

A

HP-RDI LP-RDI

B (Reg.)

C MS-RDI HP-RDI

Note: The Reg. can not generate any RDI

LP-RDI

Actually at C, AU-AIS & TU-AIS conditions are also received © Tejas Networks India Ltd., 2006, Proprietary Information

Alarm Propagation Examples (…contd.) Example 4 Assumption: AU-4 Mapping on all ports ADM B

Root Cause: Fiber cut in the link from A to B

VC-12 PT

MS-AIS LOS VC-12 E1

TU AIS VC-12 LP RDI

MS-RDI

A

HP-RDI LP RDI

VC-12 E1

C

B MS-RDI

LP RDI

HP-RDI

Note: Only TU-AIS is reported on Node C (See Rule 4c) LP-RDI on B is SSA © Tejas Networks India Ltd., 2006, Proprietary Information

Alarm Propagation Examples (…contd.) Example 5 Assumption: AU-4 Mapping on all ports ADM B

Root Cause: Fiber cut in the link from A to B

VC-4 PT

MS-AIS AU AIS LOS VC-12 E1

TU AIS VC-4

VC-12

MS-RDI

A

E1

HP-RDI LP RDI

C

B MS-RDI

LP RDI

HP-RDI

Note: Only AU-AIS is reported on Node C (See Rule 4c) LP-RDI on B is not reported (See Rule 3b) © Tejas Networks India Ltd., 2006, Proprietary Information

Alarm Propagation Examples (…contd.) 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)

E1

VC-12 (1-1-2)

(2)

A

TU-LOP (1-1-2)

B

C

Invalid TU Pointers (1-1-2)

Note: Why E1(1) is shown? LP-RDI is not reported on B (See Rule 3a) © Tejas Networks India Ltd., 2006, Proprietary Information

D

Alarm Propagation Examples (…contd.) 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) LP RDI (1-1-2)

LP RDI (1-1-2) LP-RDI (1-1-2)

E1

VC-12 (1-1-2)

(2)

A

VC-12 (1-1-2) TU-AIS (1-1-2)

B

TU-LOP (1-1-2)

TU AIS (1-1-2)

C Invalid TU Pointers (1-1-2)

Note: LP-RDI at node B is secondary suppressed TU-AIS at node A is reported as terminating alarm © Tejas Networks India Ltd., 2006, Proprietary Information

D

Alarm Propagation Examples (…contd.) 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) LP RDI (1-1-2)

LP RDI (1-1-2)

Invalid TU Pointers (1-1-2)

LP-RDI (1-1-2) E1

VC-12 (1-1-2)

(2)

A

TU-LOP (1-1-2) VC-12 (1-1-2)

TU-AIS (1-1-2)

B

VC12(1-1-2) TU-LOP (1-1-2)

TU AIS (1-1-2)

E1 (2)

C Invalid TU Pointers (1-1-2)

D 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 © Tejas Networks India Ltd., 2006, Proprietary Information

Alarm Propagation Examples (…contd.) 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” LP-RDI (1-1-1)

VC-12(1-1-1)

E1 (1)

VC-4

VC-12(1-1-2)

VC-12(1-1-2) E1(2)

TU-LOP

E1 (2)

A

(1-1-1)

B

C Invalid TU Pointers

Note: LP-RDI from A is not reported on B (See Rule 3b). Why assumption on SLM? © Tejas Networks India Ltd., 2006, Proprietary Information

(1-1-1)

Alarm Propagation Examples (…contd.) Example 10 (with SNCP) Assumption: AU-4 Mapping on all ports W

A-B-C, P

A-D-C

Root cause: Fiber-cut in the link from A to B MS-AIS TU AIS

LOS E1

VC-12

VC-12 MS-RDI

LP RDI

HP-RDI

A

LP RDI

VC-12

MS-RDI

B

LP RDI

HP-RDI

Note: SNCP is always uni-directional & for

VC-12

Tejas, it is 1+1 D © Tejas Networks India Ltd., 2006, Proprietary Information

C

E1

Thank You…

© Tejas Networks India Ltd., 2006, Proprietary Information