IP Basics#02
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1
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
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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
Plesiochronous Digital Hierarchy
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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/?]
Plesiochronous Digital Hierarchy
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
Multiplexing Hierarchy in ETSI PDH
Multiplexing Hierarchy in ETSI PDH
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Multiplexing Hierarchy in ETSI PDH
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