Part 3. Multiplexing PDH SDH

7/29/2019 Part 3. Multiplexing PDH SDH

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Multiplexing


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Multiplexing

Multiplexing (also known as muxing) is a method by which multiple

analog message signals or digital data streams are combined into onesignal over a shared medium.


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Space-Division Multiplexing (SDM)-

simply implies different point-to-point wires for different channels.

Analogue stereo audio cable ( Multi pair telephone cable)

Switched star network( analog telephone access network)

Mesh network.

Wired space-division multiplexing is typically not considered as multiplexing.Space-Division Multiplexing is achieved by multiple antenna elements forming

a phased array antenna.

Multiple-Input and Multiple-Output (MIMO),

Single-Inputand Multiple-Output (SIMO)

Multiple-Input and Single-Output (MISO)

Types of Multiplexing


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Frequency-division multiplexing (FDM)

Assignment of non-overlapping frequency ranges to each user or signal ona medium. Thus, all signals are transmitted at the same time, each using

different frequencies.

A multiplexor accepts inputs and assigns frequencies to each device.



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Time-division multiplexing (TDM) is a type of digital (or

rarely analog) multiplexing in which two or more bit streams or signalsare transferred apparently simultaneously as sub-channels in one

communication channel, but are physically taking turns on the channel.



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The time domain is divided into several recurrent time slots of fixed

length, one for each sub-channel


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Code-division multiplexing(CDM)- is a technique in which each channel

transmits its bits as a coded channel-specific sequence of pulses. This codedtransmission typically is accomplished by transmitting a unique time-

dependent series of short pulses, which are placed within chip times within the

larger bit time.

All channels, each with a different code, can be transmitted on the same fiber and

asynchronously demultiplxed Allows numerous signals to occupy a single

transmission channel, optimizing the use of available bandwidth,



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Multiplexing Hierarchies and

Transport Technologies


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E1 / T1

E1 (FIRST ORDER EUROPE TRANSMISSION STANDARD)

E1 Frame Format-Frame is composed from 256 bits that are divided to 32Time Slots (TS) x 8 bits per sec

T1 Frame Format-T1 circuits operate at 1.544 Mbit/s. These circuits were

originally carried using a line code called Alternate Mark Inversion (AMI)


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2.048 Mbps SIGNAL

1 Bit Rate 2.048Mbps+-50ppm

2 Input Signal 64 kbps

3 No. of Channels 30+2

4 Bit duration 488ns

5 No. of bits per Time Slots 8

6 Time Slot duration 3.9us

7 No. of TS per frame 32

8 Frame duration 125us

9 No. of frames per multi frame 16

10 MF duration 2ms

11 Frame alignment B0011011s use n

international networks

otherwise 0


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PDH

Plesiochronous Digital Hierarchy

The PDH high capacity transmission networks are based

on a hierarchy of digital multiplexed signals: E.1 to E.4.

The basic building block is the primary rate of 2.048 Mb/s(E.1). This could be made up of 30 x 64 Kb/s voice

channels. This would then be multiplexed up to a higher

rate for high capacity transmission.


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Line coding Hierarchy


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Line coding in PDH systems

PDH Signal Line coding used as per standards

64kbps AMI (Alternate Mark Inversion)

2.048Mbps HDB3 (High Density Block 3)

8.448 Mbps HDB3 (High Density Block 3)

34.368 Mbps HDB3 (High Density Block 3)

139.364 Mbps CMI (Code Mark Inversion )


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SDH Basics


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Introduction

SDH (Synchronous Digital Hierarchy) is a standard for

telecommunications transport

Specification are written by ITU-T

First Introduced into the telecommunication networks in 1992

Based on overlaying a synchronous multiplexed signal onto a

light stream transmitted over fibre-optic cable.

SDH is also defined for use on radio relay links, satellite links,

and at electrical interfaces between equipment.


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Advantages of SDH

A reduction in the amount of equipment and an increase in

network reliability.

The provision of overhead and payload bytes the overhead

bytes permitting management of the payload bytes on an

individual basis and facilitating centralized fault sectionalization

The definition of a synchronous multiplexing format for carrying

lower-level digital signals (such as 2 Mbit/s, 34 Mbit/s, 140Mbit/s) which greatly simplifies the interface to digital switches,

digital cross-connects, and add-drop multiplexers.

The availability of a set of generic standards, which enable multi-

vendor interoperability.

The definition of a flexible architecture capable of

accommodating future applications, with a variety of

transmission rates.


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SDH Signal

The basic format of an SDH signal allows it to carry manydifferent services in its Virtual Container (VC) because it is

bandwidth-flexible.

This capability allows for such things as the transmission of

high-speed packet-switched services, ATM, contribution

video, and distribution video. However, SDH still permits

transport and networking at the 2 Mbit/s, 34 Mbit/s, and 140

Mbit/s levels, accommodating the existing digital hierarchy

signals.

In addition, SDH supports the transport of signals based onthe 1.5 Mbit/s hierarchy.


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PDH Bit Rates

SignalDigital Bit

RateChannels

E0 64Kbit/s One 64Kbit/s

E1 2.048Mbit/s 32 E0

E2 8.448Mbit/s 128 E0

E3 34.368Mbit/s 16 E1

E4 139.264Mbit/s 64 E1


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SDH Bit Rates

Signal Digital Bit Rate Channels

STM-0 51.84 Mbit/s 21 E1

STM-1 155.52 Mbit/s 63 E1 or 1E4

STM-4 622.08 Mbit/s 256 E1 or 4 E4

STM-16 or

2.4Gbps2488.32 Mbit/s

1008 E1 or

16 E4

STM-64 or10 Gbps

9953.28 Mbit/s 4032 E1 or64 E4

STM-256 or

40Gbps39813.12Mbit/s

16128 E1 or

256 E4


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Flexibility of SDH

2 Mbit/s

140 Mbit/s

34 Mbit/s

8 Mbit/s

1.5 Mbit/s

6 Mbit/s

45 Mbit/s

STS-1 (OC-1) 52 Mbit/s

STM-1 STS-3 (OC-3) 155 Mbit/s

STM-64 STS-192 (OC-192) 10 Gbit/s

STM-16 STS-48 (OC-48) 2.5 Gbit/s

STM-4 STS-12 (OC-12) 622 Mbit/s

PDH ETSI

PDH USA

SONET USA

SDH ITU-T

STM-0 52 Mbit/s


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All SDH Mappings

STM-N

AU-3 VC-3 C3

VC-3TU-3TUG-3

C-4VC-4AU-4AUG

AUG

AUG

C2

C12

C11

TUG-2 VC-2TU-2

VC-12TU-12

VC-11TU-11

STM-0

ATM 2.144 M

E4 139.264 M

ATM 1.6 M

ATM 149.760M

ATM 48.384 M

ATM 6.874M

E3 34.368 MT3 44.736 M

T2 6.312 M

E1 2.048 M

T1 1.544 M

* 3

*7

* 3

*7

* 4

* 3

* Pointer ProcessingMultiplexingAligning

Mapping

AUG Administrative Unit GroupAU Administrative UnitTUG Tributary Unit GroupTU Tributary UnitVC Virtual ContainerC Container


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STM-1 Frame Structure

MSOH

RSOH

AU pointer

Payload

1

3

5

9

9 rows

N 9 N 261

N 270 columns

SOH: Section OverheadAU: Administration Unit RSOH: Repeater Section Overhead

MSOH: Multiplexer Section Overhead


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STM-1 Frame Structure


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Virtual Container Size

SDH Digital Bit Rate Size of VC

VC-11 1.728 Mbit/s9 rows,

3 columns

VC-12 2.304 Mbit/s 9 rows,4 columns


12 columns

VC-3 48.96 Mbit/s 9 rows,85 columns


261 columns

f l d


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Position of VC-4 in Payload Area

2mbps C12 (32+2)--------------VC 12 (34+1)-------TU 12 (35+1)----

TUG 2 ((9*4) X 3=108)-

TUG3[9*{(12*7)+2}=774]-

(Stuffing Bytes) Path Overhead byte Pointer Byte 3 X TU12 7 X TUG 2

VC-4 [9*{86+86+86+3)]=9*261=2349)- AU-4 -STM-1

3 X TUG 3 POH+2 Stuffing byte

STM 1 f


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STM-1 frame structure

Section

Overhead

SOH STM-1 has 9 (different) columns of transport overhead !

RS overhead is 3 rows * 9 columns

Pointer overhead is 1 row * 9 columns

MS overhead is 5 rows * 9 columns

SPE is 9 rows * 261 columns

270 columns

RSOH

MSOH


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TX END

TX END


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RX END

RX END


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Section Overhead

The STS-1 overhead consists of 3 rows of section overhead

frame sync (A1, A2) section trace (J0) error control (B1)

section orderwire (E1) Embedded Operations Channel (Di)

6 rows of line overhead

pointer and pointer action (Hi) error control (B2) Automatic Protection Switching signaling (Ki) Data Channel (Di) Synchronization Status Message (S1) Far End Block Error (M0) line orderwire (E2)

A1 A2 J0

B1 E1 F1

D1 D2 D3

H1 H2 H3

B2 K1 K2

D4 D5 D6

D7 D8 D9

D10 D11 D12

S1 M0 E2

section

overhead

line

overhead


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SDH Mapping

S i


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SDH Pointers

SDH provides payload pointers to permit differences in thephase and frequency of the Virtual Containers (VC-N) with

respect to the STM-N frame. Lower-order pointers are also

provided to permit phase differences between VC-1/VC-2 and

the higher-order VC-3/VC-4.

On a frame-by-frame basis, the payload pointer indicates the

offset between the VC payload and the STM-N frame by

identifying the location of the first byte of the VC in the

payload. In other words, the VC is allowed to float within

the STM-1 frame capacity.


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SDH need to be highly reliable (five nines)

Down-time should be minimal (less than 50 msec)

So systems must repair themselves (no time for manual intervention)

Upon detection of a failure (dLOS, dLOF, high BER)

the network must reroute traffic (protection switching)from working channel to protection channel

The Network Element that detects the failure (tail-end NE)initiates the protection switching

The head-end NE must change forwarding or to send duplicate traffic

Protection switching is unidirectionalProtection switching may be revertive (automatically revert to working channel)

Head End Tail-End

working channel

protection channel

SDH Protection


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How does it work?

Head-end and tail-end NEs have bridges (muxes)

Head-end and tail-end NEs maintain bidirectional signaling channel

Signaling is contained in K1 and K2 bytes ofprotection channel

K1 tail-end status and requests K2 head-end status

Head-End Bridge Tail-End Bridge

working channel

protection channel signaling channel


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Linear 1+1 protection

Simplest form of protection

Can be at OC-n level (different physical fibers)

or at STM/VC level (called Sub Network Connection Protection)

or end-to-end path (called trail protection)

channel A

channel B

Head-End BridgeTail-End Bridge


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Linear 1:1 protection

Head-end bridge usually sends data on working channel

When tail-end detects failure it signals (using K1) to head-end

working channel

protection channel

extra traffic



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Linear 1:N protection

In order to save BW

we allocate 1 protection channel for every N working channels

working channels

protection channel


T fib F fib i


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Two fiber vs. Four-fiber rings

Four-fiber ringsfully redundant at OC level

can support bidirectional routing at line layerTwo-fiber rings

support unidirectional routing at line layer

2 fibers in opposite directions

U idi ti l Bidi ti l


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Unidirectional vs. Bidirectional

Unidirectional routing

working channel B-A same direction (e.g. clockwise) as A-Bmanagement simplicity: A-B and B-A can occupy same timeslotsInefficient: waste in ring BW and excessive delay in one direction

A

BA-B

B-A

A

B

B-A

A-B

C

B-C

C-B


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High transmission rates Transmission rates up to 40Gbit/s can be achieved in modern SDH

systems. SDH is therefore the most suitable technology for backbones,which can be considered as being the super highways in todaystelecommunications networks.

Simplified add & drop function Compared with the older PDH systems, it is much easier to extract and

insert low-bit rate channels from or into the high-speed bit streams inSDH. It is no longer necessary to de multiplex and then re multiplexthe plesiochronous structure, a complex and costly procedure at thebest of the times.

High availability and capacity matching With SDH, network providers can react quickly and easily to the

requirements of their customers. For example, leased lines can beswitched in a matter of minutes. The network provider can usestandardized network elements that can be controlled and monitoredfrom the central location by means of a telecommunication networkmanagement (TMN) system.

Advantages of SDH


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Reliability Modern SDH networks include various automatic back-up and repair

mechanisms to cope with system faults. Failure of a link or an networkelement does not lead to failure of the entire network which could bea financial disaster for the network provider.

These back-up circuits are also monitored by a management system.

Future-proof platform for new services

Right now, SDH is the ideal platform for services ranging from POTS,ISDN and mobile radio through to data communications (LAN, WAN,etc.), and it is able to handle the very latest services, such as video ondemand and digital video broadcasting via ATM that are graduallyestablished.

Interconnection SDH makes it much easier to setup gateways between different

network providers and to SONET systems. The SDH interfaces areglobally standardized, making it possible to combine networkelements from different manufacturers into a network. The result is areduction in equipment costs as compared with PDH.

Advantages of SDH


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SDHPointers & Overheads

Objective


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Objective

Regenerator Section Overhead

Multiplex Section Overhead

Path Overhead

Pointers


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STM-1 Frame Format

9 Rows

Administrative Unit

Capacity of the

Virtual Container

+

Pointers

12

3

4

5

6

7

8

9

RegeneratorSectionOverhead

MultiplexSection

Overhead

H3H1 H2Pointers

STM-1 = 270 Columns (2430 bytes)

H1H1H1 H2 H2H2H3 H3H3

Frame =125s Frame = 125sFrame =125s

Overhead width = 9 columns

Regenerator Section Overhead RSOH


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A1 A1 A1 A2 A2 A2 J0

B1 E1 F1

D1 D2 D3

Regenerator

Section

Regenerator Section Overhead - RSOH



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A1 A2 J0B1 E1 F1

D1 D2 D3

Framing (A1,A2)

Start of the STM-1 frame

A1, A2 The Frame Alignment Word

is used to recognize the beginningof an STM-N frame

A1: 1111 0110 = F6 (HEX)

A2: 0010 1000 = 28 (HEX)

Section Trace or Future Growth (J0)

J0 carries section trace message.

Path Trace. It is used to give a path through an

SDH Network a "Name". This message (Name)

enables the receiver to check the continuity of its

connection with the desired transmitter

Local Orderwire (E1)

Channel for voice communications between any

two NEs. Engineering Orderwire (EOW). It can

be used to transmit speech signals between

Regenerator Sections for operating andmaintenance purposes

Section User Channel (F1)

A 64kb/s user channel.

User Channel. It is used to transmit data

and speech for service and maintenance

Bit Error Monitoring

Bit Error Monitoring. The B1 Byte contains the

result of the parity check of the previous STM

frame, before scrambling of the actual STM

frame. This check is carried out with a Bit

Interleaved Parity check (BIP-8).

Data communication channel (DCC_R)

Provides a single 192 kb/s channel for

Management .

This channel is used to transmit managementinformation via the STM-N frames



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1st row = Unscrambled bytes. Their contents should therefore be monitored

X = Bytes reserved for national use

D = Bytes depending on the medium (satellite, radio relay system, ...)The Regenerator Section OverHead uses the first three rows & nine columns in the STM-1 frame

A1, A2 The Frame Alignment Word is used to recognize the beginning of an STM-N frame

A1: 1111 0110 = F6 (HEX)

A2: 0010 1000 = 28 (HEX)

J0: Path Trace. It is used to give a path through an SDH Network a "Name". This message (Name)

enables the receiver to check the continuity of its connection with the desired transmitter

B1: Bit Error Monitoring. The B1 Byte contains the result of the parity check of the previous STMframe, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved

Parity check (BIP-8).

E1 Engineering Orderwire (EOW). It can be used to transmit speech signals between Regenerator

Sections for operating and maintenance purposes

F1 User Channel. It is used to transmit data and speech for service and maintenance

D1 to D3 Data Communication Channel at 192 kbit/s (DCCR). This channel is used to transmit

management information via the STM-N frames

Multiplex Section Overhead - MSOH
http://en.wikipedia.org/wiki/BIP-8http://en.wikipedia.org/wiki/File:Regenerator_Section_OverHead_in_the_STM-1_frame.jpghttp://en.wikipedia.org/wiki/BIP-8http://en.wikipedia.org/wiki/BIP-8http://en.wikipedia.org/wiki/BIP-8


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B2 B2 B2 K1 K2

D4 D5 D6

D7 D8 D9

D10 D11 D12

S1 M1 E2

Multiplex

Section

Multiplex Section Overhead MSOH

Multiplex Section Overhead MSOH


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B2 K1 K2

D4 D5 D6

D7 D8 D9

D10 D11 D12S1 M1 E2

Line BIP-24 (B2)

Bit interleaved Parity-24 (BIP-

24) is used for multiplex

section error monitoring. The

B2 Bytes contains the result of theparity check of the previous STM

frame, except the RSOH, before

scrambling of the actual STM

frame. This check is carried out

with a Bit Interleaved Parity check

(BIP24)


Data Communication Channel

(DCC-M)Provides a single 576 kb/s channel

for ManagementAutomatic Protection Switch (APS)

(K1,K2)

Used for APS signaling

K2 (Bit6,7,8) MS_RDI: Multiplex Section

Remote Defect Indication (former

MS_FERF: Multiplex Section Far End

Receive Failure)

Synchronization status or Future growth (S1)

5-8 bits of the byte defines

Synchronous status message.

0000 Quality unknown

0010 G.811 10-11/day frequency drift 0100 G.812T transit 10-9 /day frequency drift

1000 G.812L local 2*10-8/day frequency drift

1011 G.813 5*10-7/day frequency drift

1111 Not to be used for synchronization

Line Remote Error Indicator (M1)

Remote error indication. Conveys the

BIP-24 error count back to the source

MS_REI: Multiplex Section Remote

Error Indicator, number of interleaved

bits which have been detected to be

erroneous in the received B2 bytes.

(former MS_FEBE: Multiplexing Section

Far End Block Errored)

Orderwire (E2)

Order-wire channel for voice and

Data communication between two

NEs

http://en.wikipedia.org/wiki/G.811http://en.wikipedia.org/wiki/G.811http://en.wikipedia.org/wiki/G.811http://en.wikipedia.org/wiki/G.811


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B2 : Bit Error Monitoring. The B2 Bytes contains the result of the parity check of the previous STM frame,

except the RSOH, before scrambling of the actual STM frame. This check is carried out with a Bit Interleaved

Parity check (BIP24)

K1, K2 Automatic Protection Switching (APS). In case of a failure, the STM frames can be routed new withthe help of the K1, K2 Bytes through the SDH Network. Assigned to the multiplexing section protection (MSP)

protocol

K2 (Bit6,7,8) MS_RDI: Multiplex Section Remote Defect Indication (former MS_FERF: Multiplex Section Far

End Receive Failure)

D4 to D12 Data Communication Channel at 576 kbit/s (DCCM). (See also D1-D3 in RSOH above)

S1 (Bit 5 - 8) Synchronization quality level:

0000 Quality unknown

0010 G.811 10-11/day frequency drift0100 G.812T transit 10-9 /day frequency drift

1000 G.812L local 2*10-8/day frequency drift

1011 G.813 5*10-7/day frequency drift

1111 Not to be used for synchronization

E2 Engineering Orderwire (EOW). Same function as E1 in RSOH

M1 MS_REI: Multiplex Section Remote Error Indicator, number of interleaved bits which have been detected

to be erroneous in the received B2 bytes. (former MS_FEBE: Multiplexing Section Far End Block Errored)Z1, Z2 Spare bytes

K1 d K2 A t ti P t ti S it hi (APS
http://en.wikipedia.org/wiki/File:Multiplex_Section_OverHead_in_the_STM-1_frame.jpg


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K1 and K2 - Automatic Protection Switching (APS

channel) bytes

These two bytes are used for MSP (Multiplex Section Protection) signaling between multiplex

level entities for bi-directional automatic protection switching and for communicating Alarm

Indication Signal (AIS) and Remote Defect Indication (RDI) conditions.

K1 Byte K2 ByteBits 1-4 Type of request Bits 1-4 Selects channel number

1111 Lock out of Protection Bit 5 Indication of architecture

1110 Forced Switch 0 1+1

1101 Signal Fail High Priority 1 1:n1100 Signal Fail Low Priority Bits 6-8 Indicate mode of operation

1011 Signal Degrade High Priority 111 MS-AIS

1010 Signal Degrade Low Priority 110 MS-RDI

1001 (not used) 101 Provisioned mode is bi-directional

1000 Manual Switch 100 Provisioned mode is unidirectional

0111 (not used) 011 Future use

0110 Wait-to-Restore 010 Future use0101 (not used) 001 Future use

0100 Exercise 000 Future use

0011 (not used)

0010 Reverse Request

0001 Do Not Revert

0000 No Request

Bits 5-8 Indicate the number of the channel requested
http://en.wikipedia.org/wiki/File:Multiplex_Section_OverHead_in_the_STM-1_frame.jpg


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J1

B3

C2

G1

F2

H4

F3

K3

N1

Higher Order Path Overhead HPOH(VC-4 / VC-3)

Path

Overhead


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J1B3

C2

G1F2

H4

F3K3

N1

Path Signal Label (C2)

Indicates the type of payload in

AU This byte specifies whether

the virtual container is equippedor not

and the mapping type in the

respective virtual container

Path Trace (J1)

J1 byte carries the trace

information at path level

Path BIP-8 (B3)

Path error monitoring

Path Status (G1)

Provides status and performance information

back to the remote end This byte is used to

convey the path

terminating status and performance back to

the originating path

terminating equipment. Therefore the bi-

directional path in itsentirety can be monitored, from either end of

the path

Indicator byte (H4)

Carries multiframe informationPath User Channel (F2)

User data channel at path level

Path User Channel (F3)

User data channel at path levelBits 1-4 are allocated for APS.

Bits 5-8 are for future use.

Tandem Connection (N1)IEC for tandem connection

monitoring at TCM source.

Higher Order Path Overhead HPOH(VC-4 / VC-3)


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Lower Order Path Overhead POH(VC-11 / VC-12)

VC-12 VC-11


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Lower Order Path Overhead - POH

V5

J2

N2

K4

Signal Label and parity check

Path Trace (J2)

J2 byte carries the trace

information at lower order path

level

Tandem Connection (N2)

IEC for tandem connection

monitoring at TCM source.

Carries APS information at

lower order path level

RS Al


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RS Alarms

RS alarms are those, which can be reported evenby a pure Regenerator

(who has privilege of opening (interpreting & rewriting) onlyRSOH)

LOS (Los s of Signal)

based on whole RSOH

LOF (Los s of Frame)

based on A1, A2 bytes

TIM (Trace Identi f ier Mismatch)

based on J0 byte

SF (Signal Fail)

based on B1 byte

SD (Sign al 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 discussing Alarm masking

MS Alarms


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MS Alarms

MS alarms are those, which can be reported by a Add-Drop Multiplexer, i r respect ive 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 Indicat ion Signal)

reportedbased on K2 byte -- bits 6,7,8

SF (Signal Fail)based on B2 bytes

SD (Sign al Degrade)

based on B2 bytes

RDI (Remo te Defect Ind icat ion )

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 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

HP / LP Alarms


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HP / LP Alarms

HP / LP alarms are those, which can be reported by a Add-Drop Multiplexer, having

HO / HO & LO object(LO object => LOcross-connect)

(who has privilege of opening (interpreting & rewriting) RSOH, MSOH, AU Pointers plusat leastinterpreting HOPOH(s) / opening (interpreting & rewriting) RSOH, MSOH, AU

Pointers, HOPOH(s), TU Pointers plusat leastinterpreting LOPOH(s)

depending upon cross-connect configuration)

HP-AIS reportedbased on H1, H2 bytes

HP-LOP (Los s 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-SDbased on B3 byte

HP-RDIbased on G1 byte -- bit 5

Note 1: Same as before

Note 2: HP-Alarm is also

called AU-Alarm

or Alarm on AU

LP-Alarm is also

called TU-Alarm

or Alarm on TU

K3

F3

H4

F2

G1

C2

B3

J1

N1

H

O

PO

H

b

y

te

s

H1, H2, H3 AU

Pointer bytes

HP / LP Al ( td )


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HP / LP Alarms (contd.)

LP-AIS reportedbased on V1, V2 bytes

LP-LOP based on V1, V2 bytes

LOM (Loss o f Mult i f rame)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-SDbased on V5 byte bits 1,2

LP-RDIbased 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

is TU3 with AU4 mapping, then

also it is LP but Pointers & POH

bytes will be like HO

K4

N2J2

V5

LOPOH bytes

V1, V2, V3 TU

Pointer bytes


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Thanks

Part 3. Multiplexing PDH SDH

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