Sdh~different Overview

The Synchronous Digital Hierarchy (SDH) - II part by JM Caballero

© Trend Communications

Transportation of a 2 Mbit/s circuit

2Mbit/s C

2Mbit/s

SDH D

PBX A

PBX B

Section

Mapping of the 2 Mbit/s circuit x64 2,5 Gbit/s

STM-16 x16

622 Mbit/s

STM-4 x4

155 Mbit/s

STM-1

x1

x1

AUG

AU-4

I) NS (A

STM-0

C-4

x3 x3

51 Mbit/s

x1

VC-4

x1

TUG-3

AU-3

TU-3

VC-3

(ANSI)

VC-3 x7 (AN SI)

C-3

x7 x1 TUG-2

TU-2

VC-2

C-2

TU-12

VC-12

C-12

TU-11

VC-11

C-11

x3

(AN

x4

ATM:2144kbit/s E1:2048kbit/s

SI)

Mapping for the insertion (transmission) of the 2 Mbit/s circuit. At the ind of the path, for extracting the circuit (reception) the process is the inverse. © Trend Communications

Transportation of a 2 Mbit/s circuit

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55

Asynchronous mapping into a C-12 container (i) 136 bytes I

: Information bits of the 2 Mbit/s circuit

Public Network (1)

I : Bits with extra information

(32 x 8 bits)

: bytes with information bits and extra information

(2)

S

: stuffing bits

125 s

µ

S R

2Mbit/s 50

I (32 x 8 bits )

(1)

SSSSSSSS

(2) C 1C 2OOOOSS (3) C 1C 2O O O O S S (4)

(3)

500

µs

µs

C-12

I

C 1C 2S S S S S J 1

(32 x 8 bits)

(5) J 2 I I I I I I I S: Stuffing Ci: Justification criteria O: Overhead J1: Positive justification J2: Negative justification

S R

0

(4) (5)

S R

VC-12

I (31 x 8 bits) S

The public network can be a RDSI circuit, Frame Relay, ATM, leased... •

mapping of the 2 Mbit/s signal into the C2 container witch is synchronous with the network

•

The mapping is performed in four blocks of the same multicontainer of 500 µs

•

justification bits are added

© Trend Communications

Transportation of a 2 Mbit/s circuit

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Synchronous mapping in a C-12 container (ii)

client network

F ixed mode 34 b y t e s

2Mbit/s

32 bytes 31 bytes

CAS

CCS

TS0 Channels 1 to 15

TS0 Channels 1 to 15

TS16 Channels 16 to 30

Channels 16 Channels 17 to 31

10RRRRRR

I

1 2 5 ms

C-12

(32 bytes ) R

VC-12

This mapping maintains the byte synchronism of the 2 Mbit/s circuit and makes the connection of nx64k data/voice services easier because all 30 channels are directly located •

the container is sinchronous with the 2 Mbit/s signal

•

The signal is framed in a 125 µs frame

•

There isn’t justification for adjusting clock drifts because is synchronous

© Trend Communications

Transportation of a 2 Mbit/s circuit

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55

Creation of the VC12 virtual container (iii) VC-12

client network

140 bytes .

v5

35 bytes

2Mbit/s

I 32 bytes R J2

35 bytes 500 µs

I 32 bytes

500 µs

35 bytes

C-12 125 µs

50

R N2 I 32 bytes

VC-12

R K4

35 bytes

I 31 bytes R

0

µs

125 µ s

TU-12

POH (Path Overhead )

: V5 J2 N2 K4

The path overhead (POH) is added to the multiframe resulting the VC-12 © Trend Communications

Transportation of a 2 Mbit/s circuit

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55

Aligning and multiplexing (iv)

v1

TU-12 1 1

125 µs

4

PTR

35 bytes

9

PTR: V1, V2, V3 ó V4 V1: 1st pointer byte V2: 2nd pointer byte V3: 3rd pointer byte V4: reserved

35 bytes

H4 = XXXXXX00

VC-12 50 0

v2

35 bytes

H4 = XXXXXX01

TU-12

v3

35 bytes

125 µs

x3

H4 = XXXXXX10

TUG-2

v4

35 bytes

µs

H4 = XXXXXX11

•

The TU have a pointer (V5) in a fixed location witch identifies the carried information (the VC12)

•

The pointer points to the LO-POH overhead

•

A VC12 is a 4 element multiframe and need four TU14 frames for being transported

© Trend Communications

Transportation of a 2 Mbit/s circuit

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Multiplexing and creation of TUG2 (v)

1

TU-12 #1

TU-12 #2

TU-12 #3

1

1

1

4

PTR A

1

4

PTR B

1

35 bytes

35 bytes 9

9

x3 12

1

TUG-2

PTR PTR PTR A B C

9 bytes of tu-12#1

9 bytes of tu-12#1

9 bytes of tu-12#1

9 bytes of tu-12#1

9

TU-12

35 bytes

9

1

4

PTR C

TUG-3

TUG-2

•

Three TU-12 are multiplexed in a byte oriented way in a new structure

•

The pointers are always in the firsts locations

•

The result is a Group of TU-12 known as TUG-2

© Trend Communications

125 µs

Transportation of a 2 Mbit/s circuit

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A new multiplexing forms a TUG3 (vi) TUG-2 #1 1

TUG-2 #7 1

12

1

TUG-2

9

9

1 1

12

1

2

N

x7 86

#1 #2 #3 #4 #5 #6 #7 #1

TUG-3

P 3

I

125 µs

x3 S

S

VC-4

9

T U G -3 •

Seven TUG-12 are multiplexed in a byte oriented way and they form a new structure named TUG-3

•

Size 7x12=84 columns, plus 2 stuffing columns gives 86 columns

•

The pointers that identifies the information are always in fixed positions

© Trend Communications

Transportation of a 2 Mbit/s circuit

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55

Creation of the VC-4 virtual container (vi) TUG-3 #1 1

TUG-3 #2

86

1

TUG-3 #3 1

86

1

1

1

9

9

9

10

11

12

13

14

86

TUG-3 x3

270

J1 B3

VC-4

C2 G1 F2

S

S

H4 F3 K3 9

AU-4

N1

VC4-POH

•

A new multiplexing of three TUG-3 is executed to create a VC-4

•

Size 3x86=258 columns, plus 2 stuffing columns gives 260 columns

•

Then the POH overhead and the stuffing S bytes are added and the VC-4 is completed

© Trend Communications

Transportation of a 2 Mbit/s circuit

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Creation of the STM-1 frame (vii)

STM-1

9 10

1

RSOH

10

VC-4

11

VC-4

270

270

J1 B3 C2 G1 MSOH

AU-4

F2 H4 F3 K3 N1

POH

STM-1

•

A AU4 pointer that points to the first byte of the VC-4 is included

•

The AU4 is in a fixed position of the frame. This fact allows its location

•

This operation is known as alingment

© Trend Communications

Transportation of a 2 Mbit/s circuit

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A VC12 multiframe request four STM-1 frames

500ms 1

S T M -1

S T M -1

1 2 5 ms J1

S T M -1

S T M -1 9

B3 C 2 G1 F2

R

R

H4

9

V C -4

F3 K3 9

N1

V1

x3

TUG-3

TUG-3

TUG-3

H 4 = 00 12

VC-12 V2

H 4 = 01

x7

VC-12 5 0 0 ms V3

1 1

1

TUG-2 9

PTR

TUG-2

H4= 10

TUG-2

9

VC-12 V4

H 4 = 11

VC-12

x3 A VC12 formed by four need a time interval of 500µs in order to put all four components into © Trend Communications

Transportation of a 2 Mbit/s circuit

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Overheads * * * * * * *J 0 A1 A1 A1 A2 A2 A2 C1 B1

E1

F1

D1

D2

D3

*

*

AU Pointer B2 B2 B2 K1

K2

D4

D5

D6

D7

D8

D9

D10

D11

D12

S1

M1 E2

Section

SDH Overheads NNI

Add Drop Multiplexer C-11, C-12

NNI

Add Drop Multiplexer

Assembling of VC-11 , VC-12

Assembling of VC-11 , VC-12 Assembling of VC-3 , VC-4

C-3, C-4

C-11, C-12

Assembling of VC-3 , VC-4 MUX STM-N

MUX STM-N

C-3, C-4

· · ·

RSOH

RSOH

RSOH

MSOH STM-N SOH VC-3, VC-4 POH VC-11, VC-12 POH

Each overhead is intended to do specific task related with the transmission management at different layers: regeneration, multiplexing and path As the classical protocol tower an overhead is controlled just by one layer but is transparent for the rest of the SDH layers © Trend Communications

Transportation of a 2 Mbit/s circuit

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Path overheads 140 Mbit/s

140 Mbit/s

high order path P O+ H

C4

back up link

PLL

active link

VC4

POH

LTMUX

STM-1

STM-1

LTMUX

RSOH pointer

P O H

Payload

C4

MSOH

Each container (C-n) has associated an overhead, named Path Overhead (POH) with information enough to manage the transmission through the SDH network. The union of C-n and POH is renamed as Virtual Container (VC-n) and is the interchange unit between origin and destination multiplexers. © Trend Communications

Transportation of a 2 Mbit/s circuit

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Higher order path overhead (HO-POH) Path trace, message of 16 or 64 bytes with CRC7 > alarm HP-TIM High Order Path Trace Identifier Mismatch

J1 B3 C2 G1 F2 H4 F3 K3 N1

BIP8 parity control > HO-EBER (Excessive Bit Error Rate) or SD (Signal Degraded) error Path label > HP_SLM (Signal Label Mismatch) error Path status (far signaling, alarm return or far error indication) Path channel (64 kbit/s for voice or data) TU12 multiframe indicator Path channel (64 kbit/s for voice or data) APS path protection > Mismatch K3 alarm Byte for tandem connection monitoring purposes

G1:

REI (FEBE)

FERF

RFI RDI

Unused

FEBE (Far End Block Errors) > HO-FEBE or HP-REI (Remote Error Indicator) error or LP-REI if it is a VC3 If 0 HO/HP FERF o HP-RDI (Remote Defect Indication) alarm shows a remote AIS alarm detected, or a LP-REI if it is a VC3 RFI/RDI (Remote Failure Indication) > RFI alarm indication

C2: 00 unequiped > HP/LP-UNEQ defect, unequiped 01 unspecified 02 TUG structure 03 blocked TU 04 34 or 45 Mbit/s © Trend Communications

12: 140 Mbit/s 13: ATM 14: DQDB 15: FDDI

H4: > TU-LOM alarm Loss of Multiframe xxxxxx00 - pointer points V1 xxxxxx01 - pointer points V2 xxxxxx10 - pointer points V3 xxxxxx11 - pointer points V4

Transportation of a 2 Mbit/s circuit

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Lower order path overhead (HO-POH) C2, C12, C11 V5

Path Overhead

J2

Low Order Path Trace

N2

Reserved for its use by the operator. It can be used for tandem connection monitoring

K4

V5:

Tandem connection monitoring (TCM) Trace protection bits 1-4 APS bits 5-7RDI

BIP-2

REI (FEBE)

RFI

L1

L2

L3

RDI

BIP-2 bit 1: odd bit parity of de previous VC. bit 2: even bit parity REI (Receive Error Indication) > LP - REI error shows the detection of a far error RFI (Remote Failure Indication) > LP - RFI alarm, path protection indicator L1-L3 VC path label > P - SLM alarm Signal Label Mismatch 000 - Unequipped > LP-UNEQ alarm 001 - Unspecified status 010 - Asynchronous floating 011 - Synchronous floating bit oriented 100 - Synchronous floating byte oriented RDI (Remote Defect Indication) > LP - RDI defect

© Trend Communications

Transportation of a 2 Mbit/s circuit

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RSOH

Section overhead (SOH) * * * * * * *J 0 A1 A1 A1 A2 A2 A2 C 1 B1

E1

F1

D1

D2

D3

*

*

MSOH

AU Pointer B2 B2 B2 K1

K2

D4

D5

D6

D7

D8

D9

D10

D11

D12

S1

M1 E2

* Non scrambled bytes X Bytes reserved for national use ^ Media dependent bytes.

A1= 11110110 A2= 00101000: frame alingment B1: Bit interleaved parity, regenerator section (BIP-8) B2: Bit interleaved parity, multiplexer section (BIP-24) J0/C1: STM-1 identifier in STM-n

D1..D3: 192 kbit data communications channel D4..D12: 576 kbit/s data communications channel E1: 64 Kbit/s voice service channel between regenerators E2: 64 Kbit/s voice service channel between multiplexers F1: 64 Kbit/s voice or data service channel between regenerators K1, K2: APS protection channel > wrong K1, K2 alarm K1: Request of a channel bits 1-4 : kind of request (manual, signal failure(SF), degradation(SD)...) bits 5-8 : requested channel number K2: far answer bits 1-4: connected channel number (0=null channel) bit 5: architecture type (0 for 1+1, and1 for 1:n) bit 6-9: > MS AIS alarm if 1111, > error indication if 110 S1: clock source 10101010 - valid 01010101 - invalid 0000 - unknown 0010 - G.811 primary clock - G.812 transit clock bits 5-8 0100 1000 - G.812 local clock 1011 - G.813 synchronous equipment 1111 - non synchronized M1: re-sending of B2 errors, coded over 8 bits implies REI (FEBE)

Path overheads can detect transmission errors from the receiver side but it can’t identify where those errors rose. This is one of the missions of the section overhead: RSOH (Regenerator Section Overhead) and MSOH (Multiplexer Section Overhead) © Trend Communications

Transportation of a 2 Mbit/s circuit

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Overhead management (i) LO-PTE

SDH MUX

HO-PTE

REG

DXC

ADM

REG

REG

M >N

M >N

HO-PTE

LO-PTE 2M

2M STM-1

STM-N

STM-M

STM-M

STM-M

STM-M

STM-1

STM-M

STM-N

HO-PTE

LO-PTE

34M

34M

140M

140M

STM-N P PD DH H

REGENERATOR

REGENERATOR

REGENERATOR

REGENERATOR

REGENERATOR

REGENERATOR

SECTION

SECTION

SECTION

SECTION

SECTION

SECTION

MULTIPLEXING

MULTIPLEXING

MULTIPLEXING

SECTION

SECTION

SECTION

HIGH ORDER PATH

LOW ORDER PATH

LO-POH HO-POH

© Trend Communications

LO-POH RSOH/MSOH

RSOH

RSOH/MSOH

RSOH

RSOH/MSOH

RSOH

RSOH/MSOH

HO-POH

Transportation of a 2 Mbit/s circuit

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Overhead management (ii) Lower order path Higher order path Multiplexer section Regenerator section Regenerator section LO POH

HO POH

VC11 VC12

VC3 VC4

MSOH RSOH

RSOH

B1

RSOH MSOH

HO POH

LO POH

VC3 VC4

VC11 VC12

B1 B2 B3 V5

V5 J2 K4 N2

B1 B3-G1 B2-M1 J0 J1 J0 C2-H4 K3 K1-K2 E1-F1 F2-F3 E2 D4-D12 D1-D3 N1 -

multiplexer

B1 J0 E1-F1 D1-D3 -

B1 J0 E1-F1 D1-D3 -

regenerator

B1 B2-M1 B3-G1 J0 J1 J0 C2-H4 K1-K2 K3 E1-F1 F2-F3 E2 D1-D3 D4-D12 N1

V5 J2 K4 N2

multiplexer

Cada tara es gestionada exclusivamente por dos nivel correspondientes pareja contiguas de elementos de red contiguos. Ningún otro nivel pude manipularlos lícitamente. © Trend Communications

Transportation of a 2 Mbit/s circuit

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Pointers

Section

The pointer mechanism 10

+

VC-4

11

270

J1 B3 C2 G1 F2 H4 F3 K3 N1

H1 Y Y H2 1

POH

1 H3 H3 H3

All the elements inside the SDH network must be synchronized with only one master clock but: •

is very difficult avoid little deviations in clock signals

•

networks of different operators and with different master clocks must be connected

•

Long filter buffers bring delays to the received signal

A solution is to use moving pointers. These buffers don’t avoid using input buffers but the their size is smaller an so the delay A pointer points to the POH control information of the VC traffic channel © Trend Communications

Pointers

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AU-4 and TU-3 pointers 10

+

Y H2 1

TU-3

270 2

J1 B3 C2 G1 F2 H4 F3 K3 N1

H1 Y

VC-4

11

H1 H2 H3

1

3

B3

+

C2 G1

POH

1 H3 H3 H3

N

N

N

N

1

0

I

D

I

D

I

D

I

F2

H3

H2

H1

D

I

H4 F3

D negative justification

NDF

K3

positive justification 9

pointer value

N1

(10 bits)

N

: new data flag (NDF)

I

: increase bit

D

: decrease bit

Y: 1011SS11 (unspecified SS bits)

VC-3 N D F enabled: N D F disabled :

1

0

0

1

0

1

1

0

1: 11111111

•

Bits 1 0 of the H1 byte shows that it is an AU-4 or TU-3

•

Range of AU-4: from 0 to 782

•

Range of TU-3: from 0 to754

•

H3 is formed by 3 bytes if it is an AU-4 or 1 byte if it is a TU-3

•

Invert five D bits for negative justification and five I bits for positive justification

•

Concatenation indication (CI): H1=1001RR11, H2=11111111

•

Null pointer indication (NPI) (only TU-3): H1=1001RR11, H2=11100000

© Trend Communications

86

J1

Pointers

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TU-2 and TU-12 pointers TU-12 1 1

v1

4

35 bytes

H4 = X X X X X X00 1

PTR

1

v2

35 bytes

1 2 5 ms 9

v3

P T R : V1, V2, V3 ó V4

V1: V2: V3: V4:

35 bytes

1 st pointer byte 2 n d pointer byte 3 rd byte (action) reserved

35 bytes

5 0 0 ms

107 bytes

9

PTR: V1, V2, V3 ó V4

H4 = X X X X X X 10

N

N

N

N

S

S

I

D

I

D

I

D

I

D

I

D

negative justification

: New data flag (NDF)

N D F enabled : N D F disabled :

positive justification

1

0

0

1

0

1

1

0

S S

size

0 0 1 0

TU-2 TU-12

I

: increase bit

D

v2

107 bytes

H4 = X X X X X X 01

5 0 0 ms

v3

107 bytes

H4 = X X X X X X 1 0

107 bytes

H4 = X X X X X X 1 1

: decrease bit

•

Range of TU-2: from 0 to 427

•

Range of TU-12: form 0 to 139

•

For negative justification invert five D bits, for positive invert five I bits

•

Concatenation indication (CI) V1 = 1001RR11, V2 = 11111111

© Trend Communications

H4 = X X X X X X 00

pointer value (10 bits)

NDF

N

107 bytes

v4

V3

V2

V1 H4 = X X X X X X 1 1

12

PTR

1 2 5 ms

H4 = X X X X X X01

v4

35 bytes

v1

TU-2

Pointers

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Pointer Regeneration

© Trend Communications

Pointers

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Pointer reading

AU Pointer

0 0 0 1 1 1

125µs

J1

J1

Drop the VC-4

781781781782782782 AU Pointer

0 0 0 1 1 1

125µs

J1

781781781782782782

© Trend Communications

Pointers

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Pointer adjustment

© Trend Communications

Pointers

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Justification mechanism

© Trend Communications

Pointers

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Case 1: clock transparency (i) C 2

R2 D

R1 1

3

2Mbit/s

STM-1

STM-1

B

5

6

A

R3 4

E

1 - B doesn’t see pointer movement because the 2 Mbit/s frame and the STM-1 are created in A with the same clock. B send the STM-1 with R2 and the pointer moves like a function f (R1 -R2) 2 - Nothing happens because C multiplexer uses the same clock like B 3 - The VC4 will be extracted like R1 altough the STM-1 has arrived with R2 frecuency. At B the STM is sent at R3 and the pointer moves like a function f (R1-R3) © Trend Communications

Pointers

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Case 1: clock transparency (ii) C 2

clo

!!! y c n e r a sp n a r ck t

R2 D

R1 1

3

2Mbit/s

STM-1

STM-1

B R3

4

5

A 6

E

4 - E multiplexer doesn’t generate pointer movement because it uses the same clock like D 5 - At B the VC4 is extracted like R1 altough it has arrived in the STM-1 at a R3 frequency. At B the STM-1 is sent at R3 and the pointer moves like f(R1-R2). 6 - A multiplexer receive the STM-1 like R2 but the VC12 arrives at the first rate R1!!

© Trend Communications

Pointers

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Case 2 C 2

R2 D

R1 1

3

2Mbit/s

STM-1

STM-1

B R3

4

5

6

A

E

If the R1 clock synchronizes R2 then the STM-1 frame won’t have pointer movements beacuse: •

R1 = R2 then f(R1-R2) = f(0) = Cte.

In points 3 and 5 will be yet exist pointer movements. In order to finish with all movements R1 must be synchronized with R3 too. © Trend Communications

Pointers

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Pointer actions 1 VC-4 frame = 261 x9 x 8 bits = 18792 bits VC-4 transmission rate =

∆f

=

P actions

f0

∆f

.

s

18792 bits 125

24 bits 1 action

s

= 150336000 bit/s

µ

1 s

.

150336000 bits

=

P x 1.6E-7: clock adjustement got with P pointer movements

P = P x 1.6E-7

f0 P MAX : maximum pointer activity only one pointer movement is possible in four frames

2000 200 20

Forbidden PMAX =

1 acción

. 4 tramas

1 trama 125

= 2000 acciones/s

µs

∆f m a x = 2 0 0 0 x 1 , 6 E - 7 = 3 , 2 x 1 0 E - 4 f0

that is the maximum frequency correction

2 0.2 0.02

f

∆

f0

P shows how many pointer movements are made in one second while the horizontal axis shows de frequency correction met © Trend Communications

Pointers

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STM-N frame creation 270

270

1

1

261

9

1

1 til C a r g a# ú

de

9

261

1

9

1

2 til C a r g a# ú

TUG

1

270

1

de

261

9

Nt i l d e C a r g a# ú

9

TUG

9

TUG

123...N123...N RSOH

3 4

123...N123...N 9

5

MSOH 9

N x 9

N x 261

STM-N

Multiplexing process in STM-N, N=4,16, 64 STM-1 at 155Mbit/s, STM-4 at 622Mbit/s, STM-16 at 2,5Mbit/s, STM-64 at 10Gbit/s

© Trend Communications

Pointers

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Concatenation and multiplexing

STM-0

(SONET STS-1)

STM-1 (SONET STS-3c)

H1

H2

H3

pointer increments in a byte oriented way

3 bytes

H1

Y

x 3 frames

Y

H2

3 bytes

1

1

H3

3 bytes

H3

H3

1 increment = 3 bytes

3 bytes

x 4 frames

STM-4 (SONET OC-12)

H1

Y

.......

12 bytes

Y

H2

1

.......

12 bytes

1

H3

H3 ....... H3

1 increment = 12 bytes

12 bytes

In a STM-N frame that is the result of STM-1 frame multiplexion there are 4 pointers of lower order STM-M (N=4M) and the useful load is divided for each component. One concatenated STM-N groups all the useful load for only one client. For example, an ATM network, that is, there are only one pointer for the load.

© Trend Communications

Pointers

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Maintenance

Section

Anomalies, Defects, Errors, Alarms and Failures •

Anomaly: Is the least disagreement that can be observed between the measured and the expected characteristics of a network element without service interruption (for example a parity error)

•

Defect: A defect level is reached when de anomaly density is high enough to interrupt a requested function (for example a loss of signal).

•

Damage: A damage is is produced when a function can’t finish a requested action. This situation doesn’t comprise incapacities caused by preventive maintenance.

•

Fault: The cause of a damage without interruption for a time long enough that makes possible to consider that a network element can’t achieve a recuested function

•

Alarm: An obserbable indication that points to a fault (revealed damage) that usually shows an indication of the damage depth, for example a LED or a siren

Errors reflect anomalies and alarms show defects and ofen those words are used to speak about the formers. All are grouped under the common term of events.

© Trend Communications

Maintenance

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Causes for the disfunctions Nowadays, high capacity transmission systems are robust but they are yet vulnerable to some effects like: •

Termal noise, always present in regeneration systems. It is produced by electron activity due to temperature. This noise is matematically well modelled and it follows a gaussian distribution

•

Degraded lasers, often lasers lose capabilities due to the use and their power decreases. In this situation de signal/noise ratio may be poor

•

Rayleigh scattering, in radio systems

•

Rain and humidity atenuations

•

Electrostatic discharges, lightnings and human discharges when equipment is touched without preventions

•

Satellites and radiotransmitters are often affected by sun radiations

•

Degradation of electric connections, most of the systems are optoelectric and metalic parts are exposed to oxidation and erosion processes

•

Bad synchronization of network elements is one of the most important error causes. Jitter and wander effects are intications of potential problems

•

Design errors in equipment or infrastuctures

© Trend Communications

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SDH events associated with sections Level

RSOH

MSOH

Event

Type

LOS LOF OOF LSS EFAS Error B1 MS-AIS MS-RDI Error B2 MS-REI

Alarm

Total signal absence

Alarm

Loss of frame

Alarm

© Trend Communications

Out of frame Loss of signal synchronization

A1-A2

Frame alignment sequence error

Error

B1

Verification of BIP-8 parity error

Alarm

K2=xxxxx111

Alarm indication signal, multiplexer section

Indication

K2=xxxxx110

Remote defect indication, multiplexer section

Error

B2

Indication

M1=nnnnnnnn

B1

E1

F1

D1

D2

D3

B2 B2 B2 K1

K2

D4

D5

D6

D7

D8

D9

D10

D11

D12

S1

Cause

Alarm

Puntero AU

MSOH

A1-A2

Alarm

* * * * * * *J 0 A1 A1 A1 A2 A2 A2 C1

RSOH

How

*

Verification of BIP-24 parity error Remote error indication, multiplexer section

*

Are events associated with the SOH overheads and the network elements that manage them. That is, they are the Regeneration and Multiplexing Sections

M1 E 2

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SDH events associaded with paths

HO Path

LO Path

HO-POH

© Trend Communications

HP-RDI HP-TIM HP-UNEQ HP-PLM HP-REI HP-B3 LP-RDI LP-TIM LP-UNEQ LP-PLM LP-RFI LP-REI LP-B3 BIP-2 J1 B3 C2 G1 F2 H4 F3 K3 N1

Indication Alarm Indication Error Indication Error Indication Alarm Indication Alarm Indication Indication Error Error HO-POH

G1=xxxx1xxx J1 C2=00000000 C2 G1=nnnnxxxx B3 V5=xxxxxxx1 J2 V5=xxxx000x V5=xxxxnnnx V5=xxx1xxxx V5=xx1xxxxx B3 V5=nnxxxxxx

Remote defect indication, higher order path Trace identifier mismatch, higher order path Unequiped higher order path Payload mismatch, higher order path Remote error indication, higher order path B3 parity error, higher order path Remote defect indication, lower order path Trace identifier mismatch, lower order path Unequiped lower order path Payload mismatch, lower order path Remote failure indication, lower order path Remote error indication, lower order path B3 parity error, lower order path BIP-2 Parity error

V5 J2 N2 K4

They are events identified by the pair of multiplexers defining a path. There are two kinds of paths, higher order paths (HOP) lower order paths (LOP) there are two different groups of events.

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SDH events associated with pointers AU-AIS AU-LOP AU-PJE AU Incr AU Decr AU NDF AU Inv TU-LOM TU-AIS TU-LOP TU-PJE TU Incr TU Decr TU NDF

AU ptr

TU ptr

H2

H1 N

N

N

N

1

0

I

D

NDF

I

D D

D D

I

I

: new data flag (NDF) : increase bit

Alarm indication signal, administrative unit Loss of pointer, administrative unit AU pointer justification event AU pointer increased AU pointer decreased New data flag in AU pointer AU pointer inversion Loss of multiframe of tributary unit Alarm indication signal, tributary unit Loss of TU pointer TU pointer justification event TU pointer increased TU pointer decreased New data flag in TU pointer

V1

D

N

negative justification

I

all “1s” H1-H2 H1-H2 H1-H2 H1-H2 H1-H2 H1-H2 H4 “all 1s” V1-V2 V1-V2 V1-V2 V1-V2 V1-V2

H3 D

N

N

S

S

AU ptr

© Trend Communications

D

I

NDF enabled:

D

I

D

I

1

0 0

0 1

1 1

N

0

D

I

D

negative j u s t i f i c a t i o n

positive justification

pointer value (10 bits)

: New data flag (NDF)

N D F enabled: N D F disabled :

Y: 1011SS11 (unspecified SS bits)

I

NDF

NDF disabled :

: decrease bit

N

V3

V2

positive justification

pointer value (10 bits)

N

D

I

Alarm Alarm Pointer Pointer Pointer Pointer Pointer Alarm Alarm Alarm Pointer Pointer Pointer Pointer

1

0

0

0

1

1 1

0

S S

size

0 0 1 0

TU-2 TU-12

I

: increase bit

1: 11111111

TU ptr

D

: decrease bit

They are events identified with pointers. The AU pointer in STM-1 basic frame an the TU pointer in low rate tributaries transported

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Summary of SDH events Level

RSOH

MSOH

HP

LP

AU

TU

© Trend Communications

LOS

ID

Type Alarm

LOF OOF LSS EFAS Error B1 MS-AIS MS-RDI Error B2 MS-REI HP-RDI HP-TIM HP-UNEQ HP-PLM HP-REI HP-B3 LP-RDI LP-TIM LP-UNEQ LP-PLM LP-RFI LP-REI LP-B3 BIP-2 AU-AIS AU-LOP AU-PJE AU Incr AU Decr AU NDF AU Inv TU-LOM TU-AIS TU-LOP TU-PJE TU Incr TU Decr TU NDF TU Inv

Alarm Alarm Alarm Alarm Error Alarm Indication Error Indication Indication Alarma Indication Error Indication Error Indication Alarma Indication Alarma Indication Indication Error Error Alarm Alarm Pointer Pointer Pointer Pointer Pointer Alarm Alarm Alarm Pointer Pointer Pointer Pointer Pointer

How

Meaning Loss of Signal

A1-A2 A1-A2 B1 K2=xxxxx111 K2=xxxxx110 B2 M1=nnnnnnnn G1=xxxx1xxx J1 C2=00000000 C2 G1=nnnnxxxx B3 V5=xxxxxxx1 J2 V5=xxxx000x V5=xxxxnnnx V5=xxx1xxxx V5=xx1xxxxx B3 V5=nnxxxxxx todo “1s” H1-H2 H1-H2 H1-H2 H1-H2 H1-H2 H1-H2 H4 “todo 1s” V1-V2 V1-V2 V1-V2 V1-V2 V1-V2 V1-V2

Loss Of Frame Out Of Frame Loss of Sequence Synchronization Error in Frame Alignment Signal Error B1 Multiplexion Section - Alarm Indication Signal Multiplexion Section - Remote Defect Indication Error B2 Multiplexion Section - Remote Error Indication Higher order Path - Remote Defect Indication Higher order Path - Trace Identifier Mismatch Higher order Path - Unequipped Higher order Path - Payload Label Mismatch Higher order Path - Remote Error Indication Higher order Path - B3 error Lower order Path - Remote Defect Indication Lower order Path - Trace Identifier Mismatch Lower order Path - Unequipped Lower order Path - Payload Label Mismatch Lower order Path - Remote Failure Indication Lower order Path - Remote Error Indication Lower order Path - B3 error Bit Interleave Parity - 2 Administrative Unit - Alarm Indication Signal Adminastrative Unit - Loss Of Pointer Administrative Unit - Pointer Justification Events Administrative Unit pointer - Increment Administrative Unit pointer - Decrement Administrative Unit pointer - New Data Flag Administrative Unit pointer - Inversion Tributary Unit - Loss Of Multiframe Tributary Unit - Alarm Indication Signal Tributary Unit - Loss Of Pointer Tributary Unit - Pointer Justification Events Tributary Unit pointer- Increment Tributary Unit pointer - Decrement Tributary Unit pointer - New Data Flag Tributary Unit pointer - Inversion

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Alarms They happen at different levels: •

in the section level: regeneration y multiplexion,

•

in higher order path and lower order path

An alarm signal (AIS) is activated under standarized criteria and is sent forward to notify the event to the next network element. As an answer to a received AIS a remote defect indication is sent backwards An RDI is indicated in a specific byte while an AIS is a secuence of “1” in the space deticated to the load because de affected element can’t access to the information. Una AIS es una secuancia de bytes todos a “1” en el espacio dedicado a carga puesto que el elemento afectado por la alarma no puede acceder a la información. Mientras que el RDI se indica en un byte específica. A failure sent in a transmission way doesn’t depends on the failure in the other transmission way

© Trend Communications

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ITU alarm detection criteria Alarm

Criteria

OOF

Detection: before 625µs Realignment: before 250µs

LOF

Detection: from 0 to3 ms in OOF Realignment: from 0 to 3 ms without OOF

LOP

Detection: from 8 to 10 invalid ptrs. or from 8 to10 consecutive NDF (New Data Flag) Realignment: 3 consecutive valid pointers

MS-RDI

Detection: 3 consecutive frames with K2=xxxxx110 Realignment: 3 consecutive frames with K2<>xxxxx110

MS-AIS

Detection: 3 consecutive frames with K2=xxxxx111 Realignment: 3 consecutive frames with K2<>xxxxx111

AU-AIS TU-AIS

Detection: 3 consecutive pointers with all bits to 1 (H1-H2 o bien V1-V2) Realignment: 3 consecutive valid pointers or 1 NDF (New Data Flag)

LSS

Loss of Sequence Synchronization: if BER > 2x10-1 in 1s.

LOS

© Trend Communications

Desirable detection: between 10 and 50µs Obligatory detección: before 50µs

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OAM: detected events at the end of a LOP LOW ORDER PATH HIGH ORDER PATH MULTIPLEXER SECTION REGENERATOR

REGENERATOR

SECTION

2M STM-1

SECTION

2M

STM-N

STM-1 HO-PTE

LO-PTE

34M

34M

140M

140M

LO-PTE

HO-PTE

MUX

REG

MUX

HO-PTE

LO-PTE

AU-LOP AU-AIS

PDH AIS (All 1s)

(All 1s)

LO-RDI (V5=xxxxxxx1)

BIP-2 (V5) with errors

LO-REI (V5=nº of detected errors) V 5 = x x nx x x x x ; E r r o r s = 0 . . 2

•

Any loss of pointer (AU-LOP) or an alarm (AU-AIS) generate: a PDH-AIS forwards and a HO-RDI backwards

•

Any parity error in the tributary (V2 bip2) generate a LO-REI backwards

© Trend Communications

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OAM: detected events at the end of a HOP LOW ORDER PATH HIGH ORDER PATH MULTIPLEXER SECTION REGENERATOR

REGENERATOR

SECTION

2M STM-1

SECTION

2M

STM-N

STM-1 HO-PTE

LO-PTE

34M

34M

140M

140M

LO-PTE

HO-PTE

MUX

REG

MUX

HO-PTE AU-LOP AU-AIS

LO-PTE TU-AIS (All 1s)

PDH AIS (All 1s)

(All 1s)

HO-RDI (G1=xxxx1xxx)

LO-RDI (V5=xxxxxxx1)

B3 with errors

HO-REI (G1=nº of detected errors) G 1 = n n n nxxxx; Errors=0..8

AIS: Alarm Indication Signal HO-REI: High Order Remote Error Indication © Trend Communications

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OAM: detected events at the end of a MS LOW ORDER PATH HIGH ORDER PATH MULTIPLEXER SECTION REGENERATOR

REGENERATOR SECTION

2M STM-1

SECTION

2M

STM-N

STM-1 HO-PTE

LO-PTE

34M

34M

140M

140M

LO-PTE

HO-PTE

MUX

REG

MUX

HO-PTE

LO-PTE

L O S

AU-AIS

TU-AIS

L O F

(All 1s)

(All 1s)

PDH AIS (All 1s)

MS-RDI (K2=xxxxx110)

HO-RDI (G1=xxxx1xxx)

LO-RDI (V5=xxxxxxx1)

B2 with errors

MS-REI (M1=nº of detected errors) M1=nnnnnnnn; Errors=0..24

MS-RDI: Multiplexer Section Remote Defect Indication

© Trend Communications

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OAM: Detected events at the end of a RS LOW ORDER PATH HIGH ORDER PATH MULTIPLEXER SECTION REGENERATOR

REGENERATOR

SECTION

2M STM-1

SECTION

2M

STM-N

STM-1 HO-PTE

LO-PTE

34M

34M

140M

140M

LO-PTE

HO-PTE

MUX

REG

MUX

LOS

MS-AIS

LOF

(A1, A2 OK; the rest all 1s)

HO-PTE

AU-AIS (All 1s)

LO-PTE

TU-AIS (All 1s)

PDH AIS (All 1s)

MS-RDI (K2=xxxxx110)

HO-RDI (G1=xxxx1xxx)

LO-RDI (V5=xxxxxxx1)

B1 with errors

© Trend Communications

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Anomaly and defect management phys. regen. section section SPI

RST

multiplexer section (Note 1)

MST

Higher order path MSA

HPOM

HUG

HPC

Lower order path HPT

HPA

LPOM

LUG

LPC

LPT

LOS LOF

“1”

Error B1 regenerated signal

Detection

“1”

MS-AIS Error MS-Exc. (B2) Error MS-BIP (B2)

“1”

Generation Detection/Generation AU-AIS

“1” AIS Insertion

MS-RDI MS-RDI AU-AIS

“1”

AU-LOP “1” HO path signal HOVC with POH y and unspecified useful load

HPC unused output/ HP-UNEQ

HO unequipped signal HP-UNEQ “1”

HP-TIM HP-SLM Error HP-BIP (B3)

TU-AIS

HP-REI HP-RDI HP-RDI HP-REI TU-AIS HP-LOM/TU-LOP

“1” “1”

HPC unused output/ LP-UNEQ

LP-UNEQ LP-TIM LP-SLM Error LP-BIP (B3) LP-REI LP-RDI LP-RDI

“1”

LPA

AIS: Alarm indication signal RDI: Remote defect indication REI: Remote error indication HPA: Higher order path adaptation HPC: Higher order path connection HPOM: Higher order path monitor HPT: Higher order path termination HUG: Higher order unequipped generator LPA: Lower order path adaptation LPC: Lower order path connection LPOM: Lower order path monitor LPT: Lower order path termination LUG: Lower order unequipped generator LOF: Loss of frame LOM: Loss of multiframe LOP: Loss of pointer LOS: Loss of signal MSA: Multiplexer section adaptation MST: Multiplexer section termination RST: Regeneration section termination SPI: SDH physichal interface SLM: Signal label mismatch TIM: Trace identifier mismatch UNEQ: Unequipped signal

LP-REI

© Trend Communications

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AIS formats

RSOH PTR

:X =1

RSOH

RSOH

PTR

PTR

MSOH

MSOH

K2 MSOH

MS-AIS

AU-AIS

TU-AIS

PDH-AIS

•

MS-AIS: All bits excepting the ones of the RSOH are put to the binary value ‘1’.

•

AU-AIS: All bits of the adminsitrative unit are put to ‘1’ but the RSOH and MSOH maintains their codification.

•

TU-AIS: All bits in the tributary unid are put to ‘1’ but the unaffected tributaries and the RSOH and MSOH maintains their codification.

•

PDH-AIS: All the bits in the tributary are ‘1’.

© Trend Communications

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Some conclusions

Section

SDH means infrastructures standardization

Frame Relay

GSM

SDH node

STM-N

SDH ATM

SDH node UMTS

A SDH network can offer transport services to final users or it can be used as a transport infrastructure by a GSM, ISDN, ATM, Frame Relay, UMTS..., network.

© Trend Communications

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Simple and reliable Simple •

Direct tributaries add&drop avoiding the typical PDH mux/demux

•

The tributaries are synchronized to the network

•

Byte oriented justification; stuffing bits are not necessary

•

Tributaries can be drop&insert to the signal dynamically without disturbing the signal.

•

The High efficiency level reached is a consequence of management facilities

•

It is cheaper to provide new service

Reliable •

SDH is byte oriented allowing the integration of telecommunications with computers

•

Automatic reconfiguration is possible to prevent faults

•

Multiplexers provide a high reliability equivalent similar in backbones and in regional areas

•

Hierarchical management of alarms and maintenance functions by the network elements.

© Trend Communications

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New services

Host

Services

IWU Frame

Relay

ATM access

Telephony UMTS Frame Relay GSM

Infrastructures SDH

ATM

SDH link

Superserver

•

As a consequence of higher capacity and quality

•

Transport for high definition audio and video

•

High speed data for Internet or other networks

•

Fast bandwidth management to answer requirements

•

Integration under the same arquitecture circuit and packet networks.

© Trend Communications

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Cost effective

Interconnected rings

PDH access

SDH access point ot point

45 Mb/s

SDH ring 2,5 Gb/s 622 Mb/s

SDH network

•

Universal standard: multivendor

•

Maintains the compatibility with legacy PDH networks

•

Reduces the number of network elements to provide advanced services

•

With just a few network elements is possible to configure a network

•

Simplifies the management because of centralized configurations

•

Fast traffic routing in case of fault

© Trend Communications

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Telecom basis in the next 10 years?

“SDH will be the dominant technology in the next 10 years” as Pioneers Optical Edge Networks Boston (MA) June 2000 said •

IP, MPLS, DWDM, will be attention focus of investements of 2,5 billion $

•

Investements in SONET/SDH tecnology will be about 6 billion $

© Trend Communications

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