IP Basics#02

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What is Transmission

Transmission is the act of transporting information from one location toanother via a signal.

Transmit means to issue signals to the network medium

Transmission refers to either the process of transmitting or the progress of

signals after they have been transmitted.

5V

0V

Analog

5V

0V

Digital

Signal Types:

Both types of signals are generated by electrical current, the pressure of which is measured in volts

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An analog signal, like other waveforms, is characterized by fourfundamental properties: amplitude, frequency, wavelength andphase

A waves amplitude Frequency

Phase

Digital signals composed of pulses precise

positive voltages and zero voltages

Signal Types

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Modulation & Digitization

Transmission of digital data over an analog line is achieved using by the

technique called modulation.

Three basic types of modulation are possible:

Amplitude Modulation (AM) Frequency Modulation (FM) Phase Modulation (PM)

Digitization is essentially the opposite of modulation. Whereas in modulationa digital signal is modulated over an analog signal for transmission, in

digitization an analog signal is converted into digital format through a process

of sampling.

A popular digitization technique isPulse Code Modulation (PCM)

Sampling an analog signal

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Simplex

Half-duplex

Full-duplex

Channel

Transmission Direction

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Multiplexing

Allows multiple signals to travel simultaneously over one medium

In order to carry multiple signals, the mediums channel is logicallyseparated into multiple smaller channels, or sub channels

A device that can combine many signals on a channel, a multiplexer(mux), is required at the sending end of the channel

At the receiving end, a demultiplexer (demux) separates the combinedsignals and regenerates them in their original form

There are two basic multiplexing methods:

Frequency Division Multiplexing (FDM)

Time Division Multiplexing (TDM)

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Transmission Media

Transmission Media

Wired Media(Guided Media)

Wireless Media(Unguided Media)

Twisted Pair

Coaxial cable

Optical fiber

Terrestrial MicrowaveSatellite Communication

Radio wave
http://en.wikipedia.org/wiki/Image:RG-59.jpghttp://en.wikipedia.org/wiki/Image:FTP_cable3.jpg

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Media Characteristics

Five characteristics are considered when choosing a datatransfer media:

Throughput Costs Size and Scalability

Connectors Noise Immunity

The type of media least susceptible to noise is fiber-optic cable

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Choosing The Right Transmission Medium

Most environments will contain a combination of thesefactors; you must therefore weigh the significance of each

Areas of high EMI Distance

Security Existing infrastructure Growth

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Communication Model

Network

Link

Transport

Application

Presentation

Session

Transport

Network

Link

Physical

The 7-layer OSI Model The 4-layer Internet model

ApplicationFTP

ASCII/Binary

IP

TCP

Ethernet

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10Packet Encapsulation

The data is sent down the protocol stack

Each layer adds to the data by prepending headers

22Bytes 20Bytes 20Bytes 4Bytes

64 to 1500 Bytes

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What is a Transmission Network?

Telecom. Office

Switching NE

Transmission NE Telecom. Office

Switching NE

Transmission NE

Loop

(Twist Pair

Digital Loop Carrier

xDSL

Wireless Local Loop)

Trunk

(PDH, SDH overOptical Cable)

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Components of Transmission Network

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Transport Technologies and Protocols

PDH

Plesiochronous Digital Hierarchy

SDHSynchronous Digital Hierarchy

D-WDM

Dense Wavelength Division Multiplexing

C-WDMCoarse Wavelength Division Multiplexing

OTN

Optical Transport Network (G.709)

ASTN / ASON - Automatic Switched Telecommunication / OpticalNetwork

Data (Ethernet)

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Evolution of Digital Access

Voiceband

Modem

ISDN

ADSL

FTTH

FTTx,

VDSL2,

ADSL2plus

(FTTC/FTTB)

Enhanced

Copper

Hybrid Fibre/Copper

Pure Fibre

Diff A T h l i

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Different Access Technologies

Telephone Copper wires POTS ISDN

xDSL

Fiber Communciation Point to Point Point to Multipoint

Mobile Communication GSM

3G/WCDMA

HSPA

LTE

Wh Fib ??

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Why Fiber??

Access speed is no longer the limitation for services

Fixed access Mobile access

Example Download of a 10M ppt file

2h 20 min

24 min

10 sec

(8Mb/s)

1,6 sec

(50Mb/s)

0,8

sec

(100Mb/s)

3,5 min

6 sec

0,8

sec

(100Mb/s)

Wh t i Fib t th H (FTTH)?

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What is Fiber to the Home (FTTH)?

An OAN in which the ONU is on or within the customers premise.

Although the first installed capacity of a FTTH network varies, the

upgrade capacity of a FTTH network exceeds all other

transmission media.

OAN: Optical Access Network

ONU: Optical Network Unit OLT: Optical Line Termination

CO/HE//

ONUOLT

OAN

Wh FTTH? Fib V C

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Why FTTH? Fibre Vs Copper

Copper Uses electricity

Opaque

Electrically conductive material

Susceptible to EMI

High thermal expansion

Ductile material

Subject to corrosion and

galvanic reactions

Fortunately, its recyclable

Glass Uses light

Transparent

Dielectric material-

nonconductive

EMI immune

Low thermal expansion

Brittle, rigid material

Chemically stable

FTTH A hit t

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FTTH Architecture

FTTP Full Build

Small Businesses

New BuriedDevelopment

Splitter

OLT

ONT

Splitter

ONT

ONTONT

Splitter

ONT

ONT

Splitter

ONT

ONT

CopperFeeder

CircuitSwitch

Small Businesses

Office Parks

Residential CopperDistribution

|

FTTP Overlay

ONT

ONT

ONT

Splitter

Hub

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PDH


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plesiochronous

Nearly synchronised, a term describing a communicationsystem where transmitted signals have the same nominaldigital rate but are synchronised on different clocks.

According to ITU-T recommendations, corresponding signalsare plesiochronous if their significant instants occur atnominally the same rate, with any variation in rate beingconstrained within specified limits.

[Pronunciation? /ples'ee-oh-kroh'nus/?]


Multiplexing Hierarchy in ETSI PDH

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Primary Rate

E1, 2.048Mbit/s +/- 50ppm

E1 2Mbit PCM frame

31 x 64kbit/s

A

D

8

000Hz

8000 samples/sec.

ith 8 bit(1 byte)/sample= 64000bit/s (E0)

Structured E1

Pay load 31 x 64kbit/s,

E0 64kbit Time Slots ChannelsMuxed byte by byte

Frame

Synchronization

64kbit/sTime slot 0

Frame length=125s

Voice



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4

3

2

1

0

Level Europe North America Japan

139,264 kbit/s139,264 kbit/s 139,264 kbit/s139,264 kbit/s 97,728 kbit /s97,728 kbit /s

34,368 kbit/s34,368 kbit/s 44,736 kbit/s44,736 kbit/s 32,064 kbit/s32,064 kbit/s

8,448 kbit/s8,448 kbit/s 6,312 kbit/s6,312 kbit/s

2,048 kbit/s2,048 kbit/s

64 kbit/s64 kbit/s

1,544 kbit/s1,544 kbit/s

64 kbit/s64 kbit/s

x 4

x 4

x 4

x 32

. . .

x 3 x 3

x 7 x 5

x 4

. . .

x 24

Drawbacks of a PDH Network

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Drawbacks of a PDH Network

Not able to identify channels within a signal of higher

order Could have been overcome with large scale ASIC integration

Transmux or skipmux interfaces were designed for SDH

Need to fully de-multiplex to access any constituent lower order signal, henceadd/drop is very complex and expensive

Not standardised for rates above 140 Mb/s - 565 Mb/s systems were designed and extensively deployed, but were proprietary Regionally different hierarchies

US based on 270 Mb/s, Europe 140 Mb/s, Japan 100 Mb/s

Proprietary network management

And, very limited in-band management capability Limited surveillance and management features

No standardised protection capability

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SDH & NG-SDH

Why SDH?

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Why SDH?

Do transport PDH traffic without the typical draw back ofPDH technology, accessing to low rate channels without

unpacking everything:

Multiplexing structure

Standardised higher bit rate systems Common set of line rates between SONET and SDH -

cheaper components

Better management and communications

Protection functionality - line and path options

SDH Multiplexing Structure

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SDH Multiplexing Structure

STM-256

STM-64

STM-16

STM-4

STM-1

STM-0

AUG-256

AUG-64

AUG-16

AUG-4

AUG-1

1 x

1 x

1 x

1 x

1 x

4 x

4 x

4 x

4 x

AU-3

AU-4

AU-4-4c

AU-4-16c

AU-4-64c

AU-4-256c

1 x

3 x

1 x

1 x

1 x

1 x

1 x

VC-3

VC-4

VC-4-64c

VC-4-16c

VC-4-4c

VC-4-256c

C-3

C-4

C-4-64c

C-4-16c

C-4-4c

C-4-256c

C-11

C-12

C-2VC-2

VC-12

VC-11

TU-2

TU-12

TU-11

TUG-2

1 x

3 x

4 x

7 x

1 x

VC-3TU-3TUG-3

7 x

3 x

LEGEND:

N x MULTIPLEXING(N is multiplexing factor)

ALIGNING

MAPPING

xxxPOINTER

PROCESSING

40Gb/s

10Gb/s

2.5Gb/s

622Mb/s

155Mb/s

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Microwave

What is Microwave Communication ?

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What is Microwave Communication ?

A communication system that utilizes the radiofrequency band spanning 2 to 60 GHz. As per IEEE,electromagnetic waves between 30 and 300 GHz arecalled millimeter waves (MMW) instead ofmicrowaves as their wavelengths are about 1 to

10mm. Small capacity systems generally employ the

frequencies less than 3 GHz while medium and largecapacity systems utilize frequencies ranging from 3to 15 GHz. Frequencies > 15 GHz are essentiallyused for short-haul transmission

Elements of a Microwave link

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Elements of a Microwave link

Building Blocks of Microwave link (Tx Section)

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Building Blocks of Microwave link (Tx. Section)

Basic building blocks are:

Modulator : Converts the basband input digital to an intermediate frequencycalled IF.

Transmitter: Modulates a MW carrier with the IF signal RF TX filter:Its a band pass filter that allows only desired frequency to be

transmitted. Branching Network : Branching network isolates Tx and Rx paths in a

microwave equipment. Feeder : Feeder refers to the waveguide that connects Branching network to the

antenna

Frequency Bands

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Frequency Bands

Following are the frequency bands available for commercial use in MW links :

1. 7-8 GHz2. 11 GHz

3. 13 GHz

4. 15 GHz

5. 18 GHz

6. 23 GHz

7. 26 GHz

8. 38 GHz

Each of these bands is divided into further sub-bands. This facilitates to allocatefrequencies to different operators without causing mutual interference in their

networks.

Advantages of Microwave Radio

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Advantages of Microwave Radio

Less affected by natural calamities

Less prone to accidental damage

Links across mountains and rivers are more

economically feasible Single point installation and maintenance

Single point security

They are quickly deployed

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Wavelength Division

Multiplexing

Wavelength Division Multiplexing (WDM)

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g p g ( )

DIFFERENT

WAVELENGTHS ON THESAME FIBRE

1TX1

TX2

TX3

TX4

23

4

WHAT IS WDM?

WDM Technology

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gy

DWDM Dense WDM 50/100GHz spacing (0.4/0.8nm)

High power long reach

80 channel systems

Up to 40Gb/s an more

Tunable lasers 80 channel C band @ OTM-2 (10Gb/s)

CWDM Coarse WDM 2500GHz spacing (20 nm)

Limited reach

8 (16) channel systems Limited capacity (2.5Gb/s SFP based)

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Mobile Network

Typical 2G/3G RAN Backhaul Architecture

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yp

Both, 2G TDM and 3G ATM traffic are backhauled over TDM leased lines

Radio Access Network

Leased lines for backhaul accounts today 40%-60%

of Mobile Operators Operational Expenses (OpEx)

BTS

NodeB

Abis

E1

RNC

Iu

ATM/IMA, n x E1

BSC

A

ATM

SwitchSTM-1

ATM

PDH/SDH

TDM Leased Lines

DXC

E1/

ChSTM-1

E1/

ChSTM-1

E1/

ChSTM-1

Iub

Abis

Iub

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ATM Asynchronous Transfer Mode (ATM) is a cell switching protocol (53-byte cell

length).

ATM provides QoS guarantees. This means that a certain network nodenotifies ATM that the data or service requested requires a certain level ofpriority. Figure shows an ATM cell layout.

P a y l o a dH e a d e r

5 b y te s 4 8 b y te s

5 3 b y te s

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IP IP (Internet Protocol) is a connectionless protocol that is primarily responsible

for addressing and routing packets between network devices.

The packets can be as small as 20 bytes and as large as 64 Kbytes.

Fragment OffsetIdentification Flags

Total lengthType of ServiceIHLVersion

Options (variable) Padding

Header CkecksumTime to Live Protocol

DATA (VARIABLE)

Destination Address

Source Address

4 Bytes

Addresses are 4 bytes long in version 4 and in version 6 they are 16 byteslong. If IP is used with the higher protocol TCP (Transmission Control Protocol) thesmallest packet is 40 bytes long because it has to transmit both headers

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ATM over PDH The ATM cells are mapped onto primary PDH frames as shown in Figure

PDHFrame n

PDHFrame n+1

PDHFrame n+2

PDHFrame n+3

ATM Cell n ATM Cell n+1

The available capacity for ATM traffic in a primary PDH frame (E1) is 30 timeslots, which is equal to 30 bytes. The length of the ATM cell is 53 bytes, thus in anE1 bitstream the maximum ATM cell rate is approximately 4500 cells/s and in one T1bitstream only a rate of 3600 cells/s can be achieved.

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When mapping ATM cells directly onto an SDH frame, one VC4 is used. SeeFigure.

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IP over ATM

Methods for running IP over ATM are: Classical IP over ATM (also called CLIP). This is the method used in

UTRAN.

Local Area Network Emulation (also called LANE or LAN-Emulation).

Multiprotocol over ATM (also called MPOA).

Multiprotocol Label Switching (Also called MPLS).

Ethernet to enable All-IP RAN

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TDM &Eth/TDM

Packet

TDMEthernet

Packet Overlay for high capacity

TDM

Ethernet

Smooth transition for Ethernet introduction

Packet

TDMTDM

TDM

Packet Trsp

/ WDM

Network flexibility from microwave and optical

Summary: Components of a Transport Network

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Transmission

OSS/NMS/control layer

Core

Aggregation

Access

Terminal

NMS OSS

DWDM NG-SDH

POTPSRPR/

TMPLS/PBT

Router/ GSR

MSC/GMSCGGSN/SGSN

3G

Core

IPTV CoreCMS/HMS

Soft SwitchCS

L3S/BRAS

3GRNC

IPTVEMS

VoIP AG

L2S NodeB

PON OLTDSLAM/MSAN

PC MobilePhone STB/TV

Tele/videoPhone

DXC

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Where Ethernet Fits Into the Mobile

Operators Network Evolution Plans

Mobile Backhaul - Key Market Trends

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Enhanced user-experience demandshigher-speed data rates

HSDPAthe killer application formobile backhaul Flat rate

4G technology (WiMAX and LTE)standardization is in the final stage ofapproval process

Will take 3-4 years till mass deployment

Many operators will use PW as IPsolution till LTE availability in order toskip one hardware upgrade phase

Access is definitely the bandwidthbottleneck

PDH/TDM is not a scalable solution

Backhaul networks migrating to Ethernet

The mobile RAN is migrating fromTDM and ATM to IP/ETH

All IP RAN evolution will happengradually and not in one step

2G/3G Base Stations will co-exist fora long time with 3G taking over gradually

Base Stations with TDM/ATM I/Fswill stay for at last 3~5 years

3G is great, but what is next?

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WiMAX and 4G (LTE) technologies standardization coming soon

Continuous Improvement of Data Capabilities

T1/E1 will not scale, Ethernet is the only solution

Ethernet will be supported in latest releases of NodeB

During this year new NodeB will support Ethernet

This will increase the demand for Ethernet to the cell site

Ethernet Solutions for Cell Backhaul is driven by WCDMA/HSPA Evolution

Ethernet Service Delivery over DifferentAccess Network Technologies

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Ethernet over

SDH (EoS)

Access Network Technologies

10/100BaseT

10/100BaseT

Ethernet overFiber (EoF)

10/100BaseT

10/100BaseT

Ethernet can be delivered over many differenttypes of access network technologies

10/100BaseT

EthernetServiceProvider

Traffic Differentiation and QoS

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Three level of Priorities are required as minimal Priority 1 for Voice and Management

Priority 2 for R99 3G Data

Priority 3 for HSPA/HSUPA

Priority 4 might be needed for HSDPA (Best Effort Service)

Widespread Consensus on the need for PW

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Major operators are deploying PW solutions at the cell site and it playsan important role in the evolution of mobile backhaul networks

to IP/Ethernet T-Mobile, Telecom Italia, Swisscom, Taiwan Mobile and eMobile (Japan) are justfew operators that announce PW deployment in 2007

For many carriers Pseudo-Wire is not a question of if any more but a question ofwhere? and when?

BTSBSC

Carrier Ethernet

RAN

Emulated TDM/ ATM/HDLC PW Service

ETHETH

TDME1

IPETH

R5/4G/

WiMax

PWE3 Cell

Site Device PWE3

GatewayG.823/824

Compliant Clock

ATM RNC R99

RNC R5

ATM/IMA

NodeB

Conclusions

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Migration to IP/MPLS backhaul networks is inevitable

Drivers are RAN capacity growth, IP base stations, and service evolution

Immediate OpEx savings and short ROI

Carriers will deploy Ethernet for 3G and 4G backhaul to realize significant costadvantages and close the gap between mobile revenue and expense

Pseudo-Wire allows OpEx saving with minimal CapEx investment by skipping someupgrades on the way to LTE

Investment protection

Shifting to Ethernet Assurance and other added value features

RAN Evolution versus Revolution

2G/3G Base Stations are collocated and will co-exist for a long timewith 3G taking over gradually

Migration to All IP RAN will happen gradually and not in one step

PW Mobile Backhaul solutions are picking up, becoming mainstream

Pseudo-Wire is the Packet-based RAN Migration Enabler Field proven with large deployment over ANY packet transport network

PW Mobile Backhaul Solutions Available Today..for 2G, 3G, and Beyond

IP Basics#02

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