Multiplexing in SONET

(1)

By-:

Er. Amit Mahajan

ULTIPLEXING

ONET

(2)

(3)

Introduction to SONET

•

SONET stands for “Synchronous Optical Network”,

and Is a method for communicating digital

information using laser or

information using laser or LED’

LED’s and a single

s and a single clock

clock

is used to handle the timing, control and

functionality of all the network equipments .

CPE

TX

CPE

RX

LED

_RX

FIBER

(4)

Introduction to SONET

•

SONET is a standard, which is established in

United States of America and in Canada,

while

while a

a similar

similar standard

standard synchronous

synchronous digital

digital

hierarchy (SDH) is established in Europe.

•

Basic building block of SONET is STS-

Basic building block of SONET is

STS-1

1 51.840

51.840 Mbps

Mbps

• •

SDH

SDH =

= STM-1

STM-1 =

= 155.520

155.520 Mbps

Mbps

• •

(5)

SONET Multiplexing

DS3

44.736 DS1 1.544

DS2 6.312

E1 2.048

ATM

150 Mbps

STS-1

STS-3c

OC-

n

Scrambler

E/O

51.84 Mbps

Overhead

STS Mux

STS-

n l l l l l l

Overhead

(6)

SONET Frame

90

9 * *

/

*

/ = .

90 9 8 bits byte

8000 frames sec

51 840 Mbps

(7)

SONET Frame

* * *

= .

86 9 8 8000

49 536 Mbps

/

%

(8)

An 2.488 gigabit/sec SONET STS-1

TO STS-48 Byte Multiplexer and

De-multiplexer.

•

This

paper

describes

the

Architecture

, Implementation and

Results of high speed components

of the byte multiplexer and

de-multiplexer.

(9)

(10)

De-Mux / Framer

Works at higher speed

Works at lower speed

,

Consists of byte alignment circuitry and

(11)

Program 1

_{library IEEE;} _{use IEEE.STD_LOGIC_1164.all;}



_{entity mux is}  _port(  _{a : in STD_LOGIC;}  _{clk : in STD_LOGIC;}  _{b : buffer STD_LOGIC;}  _{c : buffer STD_LOGIC}  _); _{end mux;}



_{--}} End of automatically maintained section}



_{architecture mux of mux is}

 _{constant M_d:time:=10ns;} _begin  _{pmux:process(a,clk)}  _{variable temp1:std_logic} _;  _{variable temp2:std_logic} _;  _begin

(12)

program 2(cascaded

multiplexer)

_{library IEEE;} _{use IEEE.STD_LOGIC_1164.all;}



_{entity mux is}  _port(  _{a : in STD_LOGIC;}  _{clk: in STD_LOGIC;}  _{ctrl: in std_logic_vector(0 to 1);}  _{b : buffer STD_LOGIC;}  _{c : buffer STD_LOGIC;}  _{d,e,f,g : buffer STD_LOGIC;}  _{h,i,j,k : buffer STD_LOGIC}  _);

_{end mux;}



_{--}} End of automatically maintained section}



_{architecture mux of mux is}

 _{constant M_d:time:=10ns;} _begin

(13)

program 2(cascaded

multiplexer)



 _{if clk'event and clk='1' then}  _temp1:=a;  b<=temp1 ;  _{case ctrl is}  _{when "00"=> temp3:=b;}  when "01"=> temp4:=b;  _{when "10"=> temp5:=b;}  _{when "11"=> temp6:=b;}  _{when others =>temp12:='X';}  _{end case;}



 _end _if;

 _{if clk'event and clk='0' then}  _temp2:=a;  c<=temp2;  _{case ctrl is}  _{when "00"=> temp7:=c;}  when "01"=> temp8:=c;  _{when "10"=> temp9:=c;}  _{when "11"=> temp10:=c;}

(14)

(15)

Mux / Phase Aligner

(16)

Result and conclusion

•

When

de-mux/framer and

mux/phase

aligner

are

connected back

to

back

separately. They

give BER 10

-12.

•

When

the

total

architecture are

connected back

to back. BER is

(17)

Metro- Ring Case Study

TDM Upgrade path

-:

WDM upgrade path

we build

multiple virtual rings at

different wavelengths over

.

the same pair of fiber

- .

Let it be working at speed OC 3

suppose the capacity on the ring is

exhausted and Only a pair of fiber

, . .

is available i e no spare fiber

available

(18)

(19)

(20)

Metro- Ring Case Study



CONCLUSION



The TDM upgrade is not future proof, while

the WDM upgrade path more future proof as

the capacity of the existing ring is future

scalable by adding additional ADMs at

different wavelengths. Although we can

increase the capacity of the existing ring by

using TDM upgrade but at higher cost of

scrap.



The analysis clearly shows that, if we have

exhausted ring at lower bit-rate then the TDM

upgrade path is followed as compared to

WDM. But at higher bit-rates above OC-48 the

WDM upgrade path is more future proof and

cost effective.

(21)

References

1. Network For Computer Scientists and Engineer by

Shakhil Akhatar.

2. ATM Transport and Integrity By Tosng- Ho-Wo And

Noriaki Yoshikai.

3. SONET/SDH Demystify by Steven Shaperd.

4. Optical N/w Design and Implimentation by Vivek

Alwayn.

5. D.K.

Mynbaeu

&

L. Scheiner,

‘Fiber

optic

Communication Technology, Pearson Edu. Asia

6. Uyless Black, ‘Optical Networks’, Pearson education

7. Optical Network by Rajiv Raja swami .

8. Mehcan Bagheri, Dennis T. Kong, Wayne S. Holden,

Fernando C. xrizany, Derek D. Mahoney, and

Douglas C. Larson “An Experimental 2.488

Gigabit/Sec SONET STS-3C to STS-48 byte

Multiplexer And Demultiplexer”

(22)

References

9.Data

Communications

and

Networking by Behrouz A Forozan.

10.Online lecture (in CD )

11.Synchronous Optical Network; R.J.

Riehl;

Defence

Information

Systems Agency.

12.Computer Communications; K.G.

Beauchamp

and

G.S.Poo;

International Thompson Computer

Press.

(23)

(24)

Section overhead

ü

A1,A2-:used to identify

the beginning of the

frame to receiving

equipment

for

synchronization

purposes. The pattern

is the hexadecimal

number

0xF628

(1111

0110

0010

1000)

ü

C1-: Identification byte-:

to

numbering

the

STS-1 in STS-N.

ü

B1-:

Bit

interleave

parity byte.

ü

E1-: which is used by

(25)

Section overhead

ü

F1-:

is

user

configurable

and

can be employed for

a

variety

of

purposes. It is not

standardized.

Can

be

used

for

application

management

or

network

management.

ü

D1,D2,D3-: DCC is a

192kbps

data

C1

R

(26)

Line Overhead

Ø

H1,H2(pointer byte)

Ø

_{H3 (Pointer Action}

Byte). if more than

783 bytes

are

ready

to

be

transmitted with in

single

125 ms.

Then it is placed in

this byte.

Ø

B2-: this is a Bit

interleaved parity

byte for LOH and is

used to carry error

checking

(27)

Line Overhead

ü

K1,K2

(Automatic protection switching).

ü

D4-D12(Data

comm.

Channel)

is

a

576kbps,

OAM&P

Information such as

control

signal,

monitoring,

alarm

information etc.

ü

Z1,Z2

future

growth

bytes.

ü

E2Order-wire byte-: is

used

by

the

technician as a voice

channel

(64kbps)

while

troubleshoot

Z1

Z2

(28)

Path Overhead

v

_{J1 (Trace byte)-: used by the}

CPE at the end to ensure that

it is properly connected to the

transmitting device by using

64-byte repeating code.

v

_{B3 (path BIP) For error checking}

of path overheads of previous

frame.

v

_{C2(Path signal label) is used to}

tell a receiving device what is

actually contained in the SPE.

This permits the simultaneous

transport of multiple traffic

(29)

Path Overhead

Ø

_{G1 (Path Status Byte) used to}

communicate

overall

transmission status of duplex

circuited.

Ø

_{F2 (User byte) to transport}

network management data.

Ø

_{H4 (indicator) which points the}

starting

of

the

virtual

tributaries.

(30)

(31)

Pointer Bytes H1,H2

Ø

H1,H2 pointer byte-:Is a 16 bit

payload pointer.



Ø

Pa y lo a d p o in te r is o n ly o f

,

1 0 b its corre sp o n d in g 7 8 3

(

* =

lo ca tio n s in S P E

8 6 9

).

7 8 3



(32)

Pointer Bytes H1,H2

.

IF payload starts from the beginning of the byte then no proplem

IF payload starts from

1 st

_{bit of the byte in}

,

.

SPE then no problem It

can be easily predicted

.

by last 10 bits

1 BYTE in SPE

(33)

Pointer Bytes H1,H2

.

IF payload starts from the beginning of the byte then no proplem

If starts from 4

th

,

bit

the

exact

location

can

be

.

detected by NDF

1 BYTE in SPE

(34)

(35)

K1,K2(Automatic protection

switching).

•

In case of failure

of one fiber it

automatically

route the traffic

on the backup

fiber.