chapter 10 broadband network management: access networks chapter 10 network management: principles...

Chapter 10

Broadband Network Management:

Access Networks

Chapter 10

Network Management: Principles and Practice© Mani Subramanian 2000

10-1

Notes

Broadband Access Networks

SDH / SONETWAN

BusinessCustomers

Cable ModemCustomerNetwork

OC-n /STS-n

Link

Figure 10.1 Broadband Access Networks

HFCNetwork

CableModem

DSLCustomer

Network

xDSLModem

TelephoneLoop

WirelessCustomerNetwork

CableModem

Head End

CentralOffice

Equipment

Router/ATM Switch

Router/ATM Switch

Wireless& Telephone

Loop

Satellite Communicationand/or Telephone Loop

• Three categories of customer base:• Corporate or enterprise• Service providers• Residence or SOHO


10-2

Chapter 10

Notes

SDH / SONETWAN

BusinessCustomers

Cable ModemCustomerNetwork

OC-n /STS-n

Link

Figure 10.1 Broadband Access Networks

HFCNetwork

CableModem

DSLCustomer

Network

xDSLModem

TelephoneLoop

WirelessCustomerNetwork

CableModem

Head End

CentralOffice

Equipment

Router/ATM Switch

Router/ATM Switch

Wireless& Telephone

Loop

Satellite Communicationand/or Telephone Loop

• Five types of access networks• OC-n / STS-n link• Gateway to service providers (not shown)• HFC / Cable modem• DSL• Wireless

• Fixed wireless • Satellite communication


10-3

Chapter 10

Broadband Access Networks

Notes

Access TechnologiesBroadband

AccessTechnology

xDSL WirelessHFC

HDSLADSL VDSL

Figure 10.2 Broadband Access Technologies

Telephony-Return

Two-Way

MMDSISM LMDS

SatelliteCommunication

Telephony-Return

Two-Way

One-Way

Two-Way


10-4

Chapter 10

Notes


AccessTechnology

xDSL WirelessHFC

HDSLADSL VDSLTelephony-

ReturnTwo-Way

MMDSISM LMDS


Telephony-Return

Two-Way

One-Way

Two-Way

• Hybrid fiber coaxial technology plant / cable modem at customer premises

• Telephony return is one-way, downstream (forward direction) cable, upstream (reverse direction) telephone• Two-way downstream at high frequency band and upstream at low frequency band

• Carries voice, video and data• Upstream bandwidth requirements less compared to downstream bandwidth


10-5

Chapter 10

Notes


AccessTechnology

xDSL WirelessHFC


ReturnTwo-Way

MMDSISM LMDS


Telephony-Return

Two-Way

One-Way

Two-Way

• xDSL: Digital subscriber line technology• Asymmetric DSL (ADSL)• High-speed DSL (HDSL)• Very-high speed DSL (VDSL)

• Uses existing local loop telephone facilities


10-6

Chapter 10

Notes


AccessTechnology

xDSL WirelessHFC


ReturnTwo-Way

MMDSISM LMDS


Telephony-Return

Two-Way

One-Way

Two-Way

• Wireless: Terrestrial fixed wireless systems• Instructional scientific and medical (ISM): 902 - 928 MHz (0.5 mile) and 2400 - 2483 MHz (15 miles)• Multichannel multipoint distribution service (MMDS) 2500 - 2686 MHz (35 miles)• Local multipoint distribution service 27,500 - 28,350 MHz and 31,000 - 31,300 MHz (3 miles)


10-7

Chapter 10

Notes


AccessTechnology

xDSL WirelessHFC


ReturnTwo-Way

MMDSISM LMDS


Telephony-Return

Two-Way

One-Way

Two-Way

• Satellite communication• Telephony return is one-way, downstream wireless, upstream telephone• Two-way downstream and upstream wireless


10-8

Chapter 10

Notes

HFC Network

HeadEnd

FiberNode

CableModem

2-WAYCOAX

NIU Network Interface Unit

Fiber

CableModem

WAN

ISP

Satellite

NIU

NIU

FiberNode

Ethernet

Workstation

TV Monitor

Amplifier

• Fiber - 2 one-way transmission• Coaxial - 2-way transmission• 2-way amplifiers• Fiber node: optical - RF conversion


10-9

Chapter 10

Notes

HFC Network

HeadEnd

FiberNode

CableModem

2-WAYCOAX

NIU Network Interface Unit

Fiber

CableModem

WAN

ISP

Satellite

NIU

NIU

FiberNode

Ethernet

Workstation

TV Monitor

Amplifier

• Head end:• Signals from multiple sources multiplexed• Frequency conversion for local signal

• Network interface device (NID) / unit (NIU) Demarcation point between customer network and service provider networks• Cable modem: RF Ethernet, analog telephony, and video


10-10

Chapter 10

Notes

Comparative Speeds(Source: Cable Labs)

Telephone Modem 28.8 kbps 6 - 8 minutesISDN 64 kbps 1 -1.5 minutesCable Modem 10 Mbps Approximately 1 second


10-11

Chapter 10

Notes

HFC Technology• Broadband LAN• Asymmetric bandwidth allocation for 2-way communication• RF spread-spectrum that carries multiple signals over HFC• RF spectrum allocation to carry multimedia services - voice, video and data


10-12

Chapter 10

Notes

Broadband LAN

CableModem A

CableModem B

CableModem C

HeadEnd

Upstream Signal5 - 42 MHz

Downstream Signal50 - 860 MHz Termination

Termination

Figure 10.4 Broadband LAN


10-13

Chapter 10

Notes

Digital-to-Analog Encoding

Modem Modemcarrier

Channelbandwidth

time frequency

Digital DigitalModulated analog

Figure 10.5 Digital-to-Analog Encoding

time

1

0

1

0

• bit rate• symbol rate• number of levels n = 2k • bit rate = symbol rate x k


10-14

Chapter 10

Notes

Modulation Schemes• Amplitude shift keying• Frequency shift keying• Phase shift keying• Quadrature phase shift keying

• Four levels ( 00, 01. 10, 11)• Relatively insensitive to noise• Used for low-band upstream

• Quadrature amplitude modulation (not 4-levels)• Combination of AM and PM• 16-QAM = 8 PM x 2 AM or 4 PM x 4 AM• Used for higher-band downstream


10-15

Chapter 10

Notes

Cable Modem

Upstream DownstreamToshiba 2.56 Msym/sec 5.36 Msym/secRCA DCM105 10 Mbps 38 MbpsCisco 10 Mbps 38 MbpsLANcity 10 Mbps 10 MbpsMotorola 10 Mbps 40 Mbps

• HFC uses tree topology• Downstream in broadcast mode• Upstream transmission by cable modem coordinated by head end• Data over cable service specifications (DOCSIS) for cable modem ensures interoperability• One-way cable modem uses telco-return


10-16

Chapter 10

Notes

Functions of Cable ModemTermination System

• Equipment at the head end• All cable modems terminated on the head end• Gateway to the external network• Multiplexes and demultiplexes signals• Frequency converts upstream to downstream signals• Can be designed either as a bridge or router


10-17

Chapter 10

Notes

HFC Plant• Multiple fiber pairs run from head end to fiber node; each pair carries 2 one-way signals• Head end converts all (telephony, digital video, data, and analog video) signals to optical carrier to transmit on the fiber• Houses are connected from fiber node via coaxial cables• Coaxial cable are in tree topology and carries 2-way signal• Amplifiers on the coaxial cable have 2-way amplifiers that amplify the signals in both directions• “Drop from coaxial cable to NID (also called NIU) - called “Tap-to-TV” in CATV


10-18

Chapter 10

Notes

RF Spectrum

Upstream(Reverse)5-42 MHz

GuardBand

42-54 MHz

Downstream (Forward)54-750 MHz

AnalogVideo

54-550 MHz

DigitalVideo

560-700 MHz

DigitalData Services550-560 MHz

Telephony700-750 MHz

Upstream (Reverse)5-42 MHz

DigitalVideo Control

6-8 MHz

DigitalData Services

10-25 MHz

Telephony25-40 MHz

Figure 10.6 An Example of RF Frequency Assignment


10-19

Chapter 10

DOCS Reference Architecture

HeadEnd

CableModem

SubscriberPC

1HFC LinkWAN

Cable Modem DataTermination System

(CMTS)

Switch / Router

Servers

Operations Support System/Element Manager

2

3

Com

biner

Transmitter

Receiver

Fiber

Security & AccessController

5

Splitter&Filter

Mod

Demod

Term

Telco Return

4

Video

Data

6

6

INTERFACES:1 CMCI Cable Modem to CPE Interface2 CMTS-NSI CMTS Network Side Interface3 DOCS-OSSI Data Over Cable Services Operations Support System Interface4 CMTRI Cable Modem to Telco Return Interface5 DOCSS Data Over Cable Security System6 RFI Cable Modem to RF Interface

6

Source: CableLabs

Notes• The architecture shows two-way (HFC link) and one-way (HFC link & telco return).


10-20

Chapter 10

Notes

CMTS Components


(CMTS)

Switch / Router

Servers


2

3

Com

biner

Transmitter

Receiver

Fiber


5

Splitter&Filter

Mod

Demod

Term

Video

Data

6

6

• Switch / router routes the traffic between cable modems and to the external network. It interfaces to CMTS via the terminator (term).• Modulator (mod) and demodulator (demod) transform digital data from and to analog format.• Combiner and splitter and filter perform the complimentary functions of mux’ing and demux’ing.• Transmitter converts the RF signals to optical carrier; receiver down-converts the optical signal.• Servers handle the applications and databases.• Security is managed by the security and access controller.• OSS and element manager perform network and service management.


10-21

Chapter 10

Notes

DOCS Interfaces

• Three groups of interfaces:• Data interfaces

• Cable modem to CPE (1)• CMTS-NSI (2)

• Operations support systems and telco-return• OSS (3)• Telco-return (4)

• RF and security• DOCS security system (5)• RF interface (6)

HeadEnd

CableModem

SubscriberPC

1HFC LinkWAN


(CMTS)

Switch / Router

Servers


2

3

Com

biner

Transmitter

Receiver

Fiber


5

Splitter&Filter

Mod

Demod

Term

Telco Return

4

Video

Data

6

6

6


10-22

Chapter 10

Notes

HFC Management: Challenges

• More complex than either computer network or telecommunication network• Involves both physical and data layers• Multiple physical facilities• Legacy cable system• Multimedia service• RF spectrum management• Service and business management important for MSOs and customer• Shared media impacts security and bandwidth• Security and privacy of home network


10-23

Chapter 10

Notes

HFC Protocol Architecture

SNMP

TCP / UDP

Modem ApplicationsSNMP Agent

IP

ATMLink

HFCLink

EthernetLink

EthernetLink

HFCLink

SNMP, FTP,HTTP, ETC

TCP / UDP

Applications

IP

Cable ModemHead End

Figure 10.8 Protocol Layer Architecture in HFC System

SONET

SNMP, FTP,HTTP, ETC

TCP / UDP

Applications,SNMP Manager

IP

Subscriber PC

• Head end has both NM applications and manager• Cable modems have SNMP agents• NMS can be regionalized; then, head ends could behave as RMONs


10-24

Chapter 10

Notes

HFC / CM Management• Cable modem management

• CMTS management

• HFC link management

• RF spectrum management


10-25

Chapter 10

Notes

CM Management MIBs

• Three categories of MIBs• Standard MIBs:

• system, interfaces, ifMIB•CM and CMTS interfaces

• docIfMIB .. RF Interfaces in CM and CMTS, base line privacy and QoS• docsTrCmMIB .. telephony-return interface

•CM and CMTS objects•docsDevMIB

docsDev (69)system (1)

mib-2(internet.2.1)

transmission (10)interfaces (2)

ifMIB (31)

docsIfMib (127)

Figure 10.9 Cable Modem Management MIBs

docsTrCmMIB (128)


10-26

Chapter 10

DOCS Documentation

tr-docs-ossiw08-961016 OSSI Frameworksp-ossi-i02-990113 OSSI Specification Overviewsp-ossi-rfi-i03-990113 OSSI RF Interface Specificationdraft-ietf-ipcdn-interface-mib-03.txt,January 1998

MCNS Interface MIB

sp-ossi-bpi-i01-980331.pdf OSSI Baseline Privacy Interface MIBdraft-ietf-ipcdn-cable-device-mib-07.txt,February 20, 1999

DOCSIS Cable Device MIB

draft-ietf-ipcdn-mcns-bpi-mib-00.txt,January 17, 1999

Baseline Privacy MIB

draft-ietf-ipcdn-rf-interface-mib-07.txt,February 17, 1999

DOCSIS RF Interface MIB

draft-ietf-ipcdn-tri-mib-00.txt, July 30,1998

Telephony-return interface MIB forCable Modems and CMTS

draft-ietf-ipcdn-qos-mib-00.txt, August7, 1998

DOCSIS Quality of Service MIB

SP-CMCI-I02-980317, 03/17/98 Cable Modem to Customer Premisesequipment Interface (CMCI)Specification

SP-NSI-I01, 07/22/96 Cable Modem Termination system -network side Interface specification

SP-OSSI-BPI-I01-980331 Operations Support system Interfacespecification Baseline Privacy InterfaceMIB

SP-CMTRI-I01-970804 Cable Modem Telephony returnInterface Specification

SP-RSMI-I01-980204 Removable Security Module InterfaceSpecification - Interim

SP-BPI-I02-990319 Baseline Privacy InterfaceSpecification

SP-SSI-I01-970506 Security System SpecificationSP-RFIv1-I01-990311 RF Interface Specification

Notes


10-27

Chapter 10

DOCS Interface MIB

docsQosMIB (6)

docsFlowToClassTable (6)

docsBpiMIB (5)

docsSidToClassTable (5)

docsQosIpPktClassTable (1)

docsIfMIB(127)

docsIfMIBObjects (1)

docsIfNotification (2)

docsIfConformance(3)

docsIfBaseObjects(1) docsIfCmtsObjects (3)

docsIfCmObjects (2)

docsBpiMIBObjects(1)

docsBpiNotification(2)

docsBpiConformance(3)

transmission(mib-2 10)

docsQosEthPktClassTable (2)

docsQosFlowTable (4)docsQosServiceClassGroup (3)

docsQosMIBObjects(6)

Notes


10-28

Chapter 10

Notes

RF MAC Interface

Network Layer

RF MAC Layer

Downstream1 Upstream1 Upstream2

RF Physical Layer

Figure 10.11 RF MAC Interface

• Multiple RF channels upstream and downstream• Layered structure• Specified using RFC 1573 ifMIB


10-29

Chapter 10

Notes

DOCS Cable Device MIBEntity OID Description

docsDevMIBObjects docsDev 1 Objects of the cablemodem and CMTS device

docsDevBase docsDevMIBObjects 1 Extends MIB-II SystemGroup with objectsneeded for cable devicesystem management

docsDevNmAccessTable docsDevMIBObjects 2 Defines the minimumlevel of SNMP accesssecurity

docsDevSoftware docsDevMIBObjects 3 Provides information fornetwork-downloadablesoftware upgrades

docsDevServer docsDevMIBObjects 4 Provides informationabout the progress of theinteraction with variousprovisioning servers

docsDevEvent docsDevMIBObjects 5 Provides control andlogging for eventreporting

docsDevFilter docsDevMIBObjects 6 Configures filters at linklayer and IP layer forbridged data traffic

docsDevCpe docsDevMIBObjects 7 CPE IP management andanti-spoofing group oncable modems


10-30

Chapter 10

HFC Failure Models

Window

(Modem voltage)

Smooth

(Connector loss)

Sharp

(Signal/Noise)

Event Index

Failu

re P

roba

bility


10-31

Chapter 10

Notes

Link & Spectrum Management• HFC Link Management

• Signal strength critical• Requires continuous monitoring of amplifiers using transponders (CheetahNet)• Legacy system requires proxy server

• RF Spectrum Management• Allocation of spectrum for services - upstream and downstream• Frequency agility management


10-32

Chapter 10

Notes

DSL Access Technology

• Why is DSL attractive? • Shannon limit of data rate is 30,000 bps

(3-KHz, 30 dB S/N channel)• Digital transmission over loop (DSL) improves

data rate• T1/DS1 (1.544Mbps) 18,000 feet• T2/DS2 (6.312 Mbps) 12,000 feet


10-33

Chapter 10

Notes

DSL Limitations• Loop conditions with no direct copper to the house • Loaded coils in loop (used to increase analog

distance) cannot carry digital signal• Modern subdivisions have fiber to the neighborhood

or curb with digital mux• Operating company inventory dated (administrative

issue)


10-34

Chapter 10

Notes

xDSL Technologies Copper Access Transmission Technologies [ADSL Forum]

Name Meaning Data rate Mode Cable ApplicationsModem Voice Band

Modems1200 bps to28,800 bps

Duplex 2-pair Low data ratedatacommunications

ISDN IntegratedServices DigitalNetwork

160 kbps Duplex ISDN serviceVoice and datacommunications

HDSL High data rateDigitalSubscriber Line

1.544 Mbps2.048 Mbps

DuplexDuplex

2-pair T1/E1 serviceFeeder plant,WAN, LANaccess, serveraccess

SDSL Single lineDigitalSubscriber Line

1.544 Mbps2.048 Mbps

DuplexDuplex

1-pair Same as HDSLplus premisesaccess forsymmetricservices

ADSL AsymmetricDigitalSubscriber Line

1.5 to 9 Mbps16 to 640 kbps

DownUp

1-pair Internet access,video demand,simplex video,LAN access,interactivemultimedia

VDSL Very high datarate DigitalSubscriber Line

13 to 52 Mbps1.5 to 2.3Mbps

DownUp

2-pair Same as ADSLplus HDTV


10-35

Chapter 10

Notes

ADSL Network

• ADSL .. Asymmetric Digital Subscriber Line• ATU-C ADSL transmission unit - central office• ATU-C ADSL transmission unit - remote/residence• Splitter separates voice and data

ATU-CBroadband

NetworkSplitter Splitter ATU-R

ADSLLoop

Voice Voice

Figure 10.13 ADSL Access Network


10-36

Chapter 10

Notes

ADSL Spectrum Allocationwith Guard Band

FDM

Frequency

POTS

Upstream Downstream

1.1 MHz4 KHz 25 KHz 200 KHz

• POTS .. Plain old telephone service


10-37

Chapter 10

Notes

ADSL Spectrum Allocationwith Echo Cancellation

Echo Cancellation

Frequency

POTS

Upstream Downstream

1.1 MHz4 KHz 25 KHz 200 KHz

• Echo cancellation separates upstream and downstream signals• Increases (low-frequency) upstream bandwidth


10-38

Chapter 10

Notes

Modulation Schemes• Carrierless amplitude phase (CAP) modulation • Discrete multiTone modulation (DMT): 4kHz tones• Both CAP and DMT are QAM-based• DMT outperforms CAP

• 4-to-1 downstream throughput• 10-to-1 upstream throughput• Rate adaptive•On-going active monitoring• Maximum loop variation coverage• Standard and hence interoperability


10-39

Chapter 10

Notes

ADSL ForumTR-001 ADSL Forum System Reference ModelTR-005 ADSL Network Element Management SystemTR-006 SNMP-based ADSL LINE MIB; see also draft-

ietf-adslmib-adsllinemib-09.txtTR-014 DMT Line Code Specific MIBTR-015 CAP Line Code Specific MIBTR-016 CMIP-based Network Management Framework

• ADSL Forum is an industry consortium to• achieve interoperability• accelerate implementation• address end-to-end system operation• security• management

• Physical layer standard T1-413 (ANSI)


10-40

Chapter 10

Notes

VDSL Network

CentralOffice

OpticalNetworkUnit

VDSLVDSL

HomeNetwork

TwistedPair

Fiber

• Used in FTTN configuration• Asymmetric band allocation (similar to ADSL)• Fiber carries multiple channels to ONU• Channels demultiplexed at ONU and carried to customer premises on multiple twisted pairs• Shorter distance of twisted pairs permission of higher data rate - 55.2 Mbps downstream and 2.3 Mbps upstream


10-41

Chapter 10

ADSL Network

TE(s)ISDN

ServiceSystems

BroadbandNetwork

NarrowbandNetwork

AccessNode ATU-C ATU-R

PDN

SMSettop

SMPC I/O

TE(s)TV

TE(s)PC

SMISDN

PublicNetwork

PremisesNetwork

PrivateNetwork

STM

ATM

ATM

Transport Modes

ADSL Access Network

ADSLLLLLLL

ADSL

OSOS

ATM STM

PacketNetwork

On-line ServicesInternet Access

LAN AccessInteractive Video

Video Conf

Packet

Packet

ADSL Asynchronous Digital Subscriber LineATM Asynchronous Transfer ModeSTM Synchronous Transfer ModeTE Terminal EquipmentOS Operations SystemPDN Premises Distribution NetworkSM Service Module

Figure 10.16 Overall Network and ADSL

Notes


10-42

Chapter 10

Notes

Transport Modes• Synchronous transport mode (STM)

• Bit synchronous transmission ( T1/E1)• End-to-end packet mode

• Used for SOHO (IP packets)• ATM / STM

• ATM WAN (Public network) and STM access network

• ATM / Packet• ATM WAN and packet access network (IP)

• End-to-end ATM


10-43

Chapter 10

ADSL System Reference Model

NetworkManagement

T

ATU-R

AccessNode

ATU-C

ATU-C

ATU-C

ATU-C

BroadbandNetwork

NarrowbandNetwork

DigitalBroadcast

PSTN

PremisesDistribution

Network

T-SMU-C

POTS-C POTS-R

Loop

Splitter

Phone(s)

U-C2 U-R2VAVC U-R

T.E.

T.E.

T.E.

T.E.

B

Interfaces: B Auxiliary data input such as a satellite feed to Service Module (TE) POTS-C Interface between PSTN and POTS splitter at network end POTS-R Interface between phones and POTS splitter at premises end T Interface between Premises Distribution Network and Service Modules T/SM Interface between ATU-R and Premises Distribution Network U-C Interface between Loop and ATU-C (analog) U-C2 Interface between POTS splitter and ATU-C U-R Interface between Loop and ATU-R (analog) U-R2 Interface between POTS splitter and ATU-R V A Logical interface between ATU-C and Access Node V C Interface between Access Node and network

TE Terminal EquipmentPOTS Plain Old Telephone ServicePSTN Public Switched Telephone Network

Figure 10.17 ADSL System Reference Model

(ADSL Forum)

Notes


10-44

Chapter 10

Notes

Interfaces• An interface can have multiple physical connections • V interface

• VC interface between access node and external network and interfaces

• U interfaces - off the splitters; Will be eliminated with ADSL-Lite• POTS interfaces - low pass filter interfaces for POTS• T and B are customer premises network interfaces

• T between PDN and service modules• B auxiliary data input (e.g., satellite feed)


10-45

Chapter 10

Notes

ADSL Channeling Schemes

• Transport bearer channels• Seven AS downstream channels - multiples (1-, 2-, 3- or 4-) T1 rate of 1.536 Mbps• Three LS duplex channels - 160. 384, and 576 Kbps

•Buffering scheme• Fast channel: uses fast buffers for real-time data• Interleaved channel: used for non-real-time data• Both fast and interleaved channels carried on the same physical channel

ATU-C ATU-RDownstream bearer channels

Duplex bearer channels

ATU-C ATU-RFast channel

Interleaved channel


10-46

Chapter 10

Management Reference Model

Network Termination

Splitter-C

BroadbandNetwork

PHYLayer

SwitchATU-C

HighPassFilter

LowPassFilter

Splitter-R

HighPassFilter

LowPassFilter

HomeNetwork

PHYLayer

SwitchATU-R

ServiceModule

ServiceModule

Loop

U-C U-RPSTN PSTN

Telephone Setor

Voice-Band ModemPOTS

T/ST-RV-C

U-C2U-R2

Interfaces: T-R Interface between ATU-R and Switching layers T/S Interface between ADSL Network Termination and customer installation or home network U-C Interface between Loop and ATU-C (analog) UC2 Interface between POTS splitter and ATU-C U-R Interface between Loop and ATU-R (analog) U-R2 Interface between POTS splitter and ATU-R V-C Logical interface between ATU-C and a digital network element such as one or more switching systems

Figure 10.18 ADSL Forum System Reference Model for Management

Notes


10-47

Chapter 10

Notes

Management Elements• Management of elements done across V-interface:

• Management communications protocol across V-interface• Management communications protocol across U-interfaces• Parameters and operations across ATU-C• Parameters and operations across ATU-R• ATU-R side of the T interface

• Note addition of physical layer and switching in the management architecture representation• Management of physical layer involves:

• Physical channel• Fast channel• Interleaved channel

• Management of type of line encoding• DMT• CAP


10-48

Chapter 10

Notes

Signal Power and Data Rate Mgmt

Maximum noise margin

Upshift noise margin

Downshift noise margin

Minimum noise margin

Target noise margin

Reduce power

Increase power

Decrease rate if noise margin < Downshift noise margin

Increase rate if noise margin > Upshift noise margin

Steady state operation

Steady state operation

Figure 10.19 Noise Margins

• Five levels of noise margin• Signal power controlled by noise margin• Data rate: Increase or decrease based on threshold margins• Data rate adaptation modes: Manual (1), automatic at start-up (2), and dynamic (3)


10-49

Chapter 10

Configuration Mgmt ParametersParameter Component Line Description

ADSL Line type ADSL Line N/A Five types: no channel, fast,interleaved, either or both

ADSL Line coding ADSL Line N/A ADSL coding typeTarget noise margin ATU-C/R Phy Noise margin under steady

state (BER=<10-7)

Max. noise margin ATU-C/R Phy Modem reduces power abovethis threshold

Min. noise margin ATU-C/R Phy Modem increases power belowthis margin

Rate adaptation mode ATU-C/R Phy Mode 1: ManualMode 2: Select at start-upMode 3: Dynamic

Upshift noise margin ATU-C/R Phy Threshold for modem increasesdata rate

Min. time interval for upshiftrate adaptation

ATU-C/R Phy Time interval to upshift

Downshift noise margin ATU-C/R Phy Threshold for modemdecreases data rate

Min. time interval for downshiftrate adaptation

ATU-C/R Phy Time interval to downshift

Desired max. rate ATU-C/R F/I Max rates for ATU-C/RDesired min. rate ATU-C/R F/I Min. rates for ATU-C/RRate adaptation ratio ATU-C/R Phy Distribution ratio between fast

and interleaved channels foravailable excess bit rate

Max. interleave delay ATU-C/R F/I Max. transmission delayallowed by interleaving process

Alarm thresholds ATU-C/R Phy 15-minute count threshold onloss of signal, frame, poser anderror-seconds

Rate up threshold ATU-C/R F/I Rate-up change alarmRate down threshold ATU-C/R F/I Rate-down change alarmVendor ID ATU-C/R Phy Vendor ID assigned by T1E1.4Version No. ATU-C/R Phy Vendor specific versionSerial No. ATU-C/R Phy Vendor specific Serial No.


10-50

Chapter 10

Notes

Fault ManagementParameter Component Line DescriptionADSL Line status ADSL Line Phy Indicates operational and

various types of failures ofthe link

Alarms thresholds ATU-C/R Phy Generates alarms on failuresor crossing of thresholds

Unable to initialize ATU-R ATU-C/R Phy Initialization failure of ATU-Rfrom ATU-C

Rate change ATU-C/R Phy Event generation when ratechanges when crossing ofshift margins in bothupstream and downstream

• Failure indication of physical channel by NMS• Failure indication of logical channels• Failure indication of ATU-C/R• Self-test of ATU-C/R as per T1.413• Noise margin threshold alarms• Rate change due to noise margin


10-51

Chapter 10

Notes

Performance ManagementParameter Component Line DescriptionLine attenuation ATU-C/R Phy Measured power loss in dB

from transmitter to receiverATU

Noise margin ATU-C/R Phy Noise margin in dB of theATU with respect to receivedsignal

Total output power ATU-C/R Phy Total output power from themodem

Max. attainable rate ATU-C/R Phy Max. currently attainabledata rate by the modem

Current rate ATU-C/R F/I Current transmit rate towhich the modem is adapted

Previous rate ATU-C/R F/I Rate of the modem beforethe last change

Channel data block length ATU-C/R F/I Data block on which CRCcheck is done

Interleave delay ATU-C/R F/I Transmit delay introducedby the interleaving process

Statistics ATU-C/R PhyF/I

15 minute / 1 day failurestatistics

• Line attenuation• Noise margin• Output power• Data rate• Data integrity check• Interleave channel delay• Error statistics


10-52

Chapter 10

ADSL SNMP MIBadslForum

(1.3.6.1.4.1.xx)

adslMIB(1)

adslConformance (2)adslTraps (2)

adslLineTable (1)

adslAtucPhysTable (2)

adslAturPhysTable (3)

adslAtucChanTable (4)

adslAturChanTable (5)

adslLineAlarmConfProfileTable(15)adslLineConfProfileTable(14)

adslAturChanIntervalTable (13)

adslAtucChanIntervalTable(12)

adslAturChanPerfDataTable (11)adslAtucPerfDataTable (6)adslAtucChanPerfDataTable (10)adslAturPerfDataTable (7)

adslAturIntervalTable (9)adslAtucIntervalTable (8)

adslLCSMib (16)

adslDMTMib (1) adslCAPMib (1)

Figure 10.20 ADSL SNMP MIB

adslLineMib(1)

adslMibObjects(1)


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Chapter 10

Notes

Proposed IF TypesHigher Layer IF

(e.g.: ATM)Higher Layer IF

(e.g.: ATM)

Fast Channel IF(ATU-C & ATU-R)

ifType = Fast (125)ifIndex = k

Interleaved Channel IF(ATU-C & ATU-R)

ifType = Interleaved (124)ifIndex = j

Physical Line IF(ATU-C & ATU-R)

ifType = ADSL (94)ifIndex = i

Figure 10.21 Relationship between ADSL Entries

• Sub-layers handled by ifMIB ifStackTable {ifMib.ifMIBObjects 2} (RFC 1573)• Propose ifTypes adslPhysIf ::= {transmission 94} adslInterIf ::= {transmission 124} adslFastIf ::= {transmission 125}


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Chapter 10

Notes

ADSL Interfaces TableMIB Variable Physical Line (i) Interleaved

Channel (j)FastChannel (k)

ifDescr NORMAL NORMAL NORMALifType (IANA) 94 124 125ifSpeed ATU-C Line Tx

rateATU-C channelTx rate

ATU-C channelTx rate

ifPhyAddress NULL NULL NULLifAdminStatus NORMAL NORMAL NORMALifOperStatus NORMAL NORMAL NORMALifLastChange NORMAL NORMAL NORMALifLinkUpDownTrapEnable

NORMAL(default: Enable)



ifConnectPresent True False FalseifHighSpeed NULL NULL NULL


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Chapter 10

Notes

ADSL Profiles Management• Configuration profile• Performance profile• Alarm profile• Traps

• Generic• Loss of frame• Loss of signal• Loss of power• Error-second threshold• Data rate change• Loss of link• ATU-C initialization failure


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Chapter 10

Configuration Profile:Mode I - Dynamic

ADSL Line Entry

Interleaved Chan

Fast Chan Entry

ADSL Line Entry

Interleaved Chan

Fast Chan Entry

ADSL Line Entry

Interleaved Chan

Fast Chan Entry

Profile-1

Profile-2

Profile-n

profileIndex

1

2

n

Configuration Profile TableifTableifIndex

i1

i2

ix

j1

k1

j2

k2

jx

kx

ADSL-Line

1

2

x

Figure 10.22 Use of Profiles in MODE-I (Dynamic)


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Chapter 10

Configuration Profile:Mode II - Static

ADSL Line Entry

Interleaved Chan

Fast Chan Entry

ADSL Line Entry

Interleaved Chan

Fast Chan Entry

ADSL Line Entry

Interleaved Chan

Fast Chan Entry

Profile-i1

Profile-i2

Profile-in

profileIndex

i1

i2

ix

Configuration Profile Table

ifTableifIndex

i1

i2

ix

j1

k1

j2

k2

jx

kx

ADSL-Line

1

2

x

Figure 10.23 Use of Profiles in MODE-II (Static)


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chapter 10 broadband network management: access networks chapter 10 network management: principles...

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