Chapter 10 Chapter 10 Broadband Network Management: Access Networks Network Management: Principles and Practice © Mani Subramanian 2000 10-1 Chapter 10 Broadband Access Networks Cable Modem Cable Customer Modem Network HFC Network Telephone Loop Cable Modem Head End xDSL Modem DSL Customer Network Central Office Equipment SDH / SONET WAN Router/ ATM Switch Business Router/ Customers ATM Switch OC-n / STS-n Link Satellite Communication and/or Telephone Loop Wireless & Telephone Loop Wireless Customer Network Figure 10.1 Broadband Access Networks Notes • Three categories of customer base: • Corporate or enterprise • Service providers • Residence or SOHO Network Management: Principles and Practice © Mani Subramanian 2000 10-2 Chapter 10 Broadband Access Networks Cable Modem Cable Customer Modem Network HFC Network Telephone Loop Cable Modem Head End xDSL Modem DSL Customer Network Central Office Equipment SDH / SONET WAN Router/ ATM Switch Business Router/ Customers ATM Switch OC-n / STS-n Link Satellite Communication and/or Telephone Loop Wireless & Telephone Loop Wireless Customer Network Figure 10.1 Broadband Access Networks Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-3 Chapter 10 Access Technologies Broadband Access Technology HFC TelephonyReturn xDSL TwoWay ADSL HDSL Satellite Communication Wireless VDSL ISM MMDS OneWay LMDS TelephonyReturn TwoWay TwoWay Figure 10.2 Broadband Access Technologies Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-4 Chapter 10 Access Technologies Broadband Access Technology HFC TelephonyReturn xDSL TwoWay ADSL HDSL Satellite Communication Wireless VDSL ISM MMDS OneWay LMDS TelephonyReturn TwoWay TwoWay Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-5 Chapter 10 Access Technologies Broadband Access Technology HFC TelephonyReturn xDSL TwoWay ADSL HDSL Satellite Communication Wireless VDSL ISM MMDS OneWay LMDS TelephonyReturn TwoWay TwoWay Notes • xDSL: Digital subscriber line technology • Asymmetric DSL (ADSL) • High-speed DSL (HDSL) • Very-high speed DSL (VDSL) • Uses existing local loop telephone facilities Network Management: Principles and Practice © Mani Subramanian 2000 10-6 Chapter 10 Access Technologies Broadband Access Technology HFC TelephonyReturn xDSL TwoWay ADSL HDSL Satellite Communication Wireless VDSL ISM MMDS OneWay LMDS TelephonyReturn TwoWay TwoWay Notes • 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) Network Management: Principles and Practice © Mani Subramanian 2000 10-7 Chapter 10 Access Technologies Broadband Access Technology HFC TelephonyReturn xDSL TwoWay ADSL HDSL Satellite Communication Wireless VDSL ISM MMDS OneWay LMDS TelephonyReturn TwoWay TwoWay Notes • Satellite communication • Telephony return is one-way, downstream wireless, upstream telephone • Two-way downstream and upstream wireless Network Management: Principles and Practice © Mani Subramanian 2000 10-8 Chapter 10 HFC Network Ethernet Cable Modem NIU Satellite WAN Head End Fiber Fiber Node 2-WAY COAX Amplifier NIU ISP Cable Modem NIU Network Interface Unit TV Monitor Workstation Notes • Fiber - 2 one-way transmission • Coaxial - 2-way transmission • 2-way amplifiers • Fiber node: optical - RF conversion Network Management: Principles and Practice © Mani Subramanian 2000 10-9 Chapter 10 HFC Network Ethernet Cable Modem NIU Satellite WAN Head End Fiber Fiber Node 2-WAY COAX Amplifier NIU ISP Cable Modem NIU Network Interface Unit TV Monitor Workstation Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-10 Chapter 10 Comparative Speeds (Source: Cable Labs) Telephone Modem 28.8 kbps ISDN 64 kbps Cable Modem 10 Mbps 6 - 8 minutes 1 -1.5 minutes Approximately 1 second Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-11 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-12 Chapter 10 Broadband LAN Downstream Signal 50 - 860 MHz Head End Cable Modem A Cable Modem B Termination Cable Modem C Upstream Signal 5 - 42 MHz Termination Figure 10.4 Broadband LAN Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-13 Chapter 10 Digital-to-Analog Encoding Digital Modulated analog Modem Digital Modem carrier 1 1 0 time frequency 0 time Channel bandwidth Figure 10.5 Digital-to-Analog Encoding • bit rate • symbol rate • number of levels n = 2k • bit rate = symbol rate x k Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-14 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-15 Chapter 10 Cable Modem • 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 Toshiba RCA DCM105 Cisco LANcity Motorola Upstream 2.56 Msym/sec 10 Mbps 10 Mbps 10 Mbps 10 Mbps Downstream 5.36 Msym/sec 38 Mbps 38 Mbps 10 Mbps 40 Mbps Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-16 Chapter 10 Functions of Cable Modem Termination 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-17 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-18 Chapter 10 RF Spectrum Upstream (Reverse) 5-42 MHz Guard Band 42-54 MHz Downstream (Forward) 54-750 MHz Analog Video 54-550 MHz Digital Data Services 550-560 MHz Digital Video 560-700 MHz Telephony 700-750 MHz Upstream (Reverse) 5-42 MHz Digital Video Control 6-8 MHz Digital Data Services 10-25 MHz Telephony 25-40 MHz Figure 10.6 An Example of RF Frequency Assignment Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-19 Chapter 10 DOCS Reference Architecture Telco Return 4 Head End WAN HFC Link 6 Cable Modem Data Termination System (CMTS) Mod Switch / Router 2 Term 6 Subscriber PC Transmitter Fiber 3 5 Splitter& Filter 6 Servers INTERFACES: 1 CMCI 2 CMTS-NSI 3 DOCS-OSSI 4 CMTRI 5 DOCSS 6 RFI 1 Data Demod Operations Support System/ Element Manager Combiner Video Cable Modem Receiver Security & Access Controller Cable Modem to CPE Interface CMTS Network Side Interface Data Over Cable Services Operations Support System Interface Cable Modem to Telco Return Interface Data Over Cable Security System Cable Modem to RF Interface Source: CableLabs Notes • The architecture shows two-way (HFC link) and one-way (HFC link & telco return). Network Management: Principles and Practice © Mani Subramanian 2000 10-20 Chapter 10 CMTS Components Cable Modem Data Termination System (CMTS) Mod Switch / Router 2 Term 6 Transmitter Fiber Data 6 Servers 3 5 Splitter& Filter Demod Operations Support System/ Element Manager Combiner Video Receiver Security & Access Controller Notes • 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. Network Management: Principles and Practice © Mani Subramanian 2000 10-21 Chapter 10 DOCS Interfaces Telco Return 4 Head End WAN HFC Link 6 Cable Modem Data Termination System (CMTS) Mod Switch / Router 2 Term 6 1 Subscriber PC Transmitter Fiber Data 6 Servers 3 5 Splitter& Filter Demod Operations Support System/ Element Manager Combiner Video Cable Modem Receiver Security & Access Controller Notes • 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) Network Management: Principles and Practice © Mani Subramanian 2000 10-22 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-23 Chapter 10 HFC Protocol Architecture Head End SONET Cable Modem Subscriber PC Applications, SNMP Manager Modem Applications SNMP Agent Applications SNMP, FTP, HTTP, ETC SNMP SNMP, FTP, HTTP, ETC TCP / UDP TCP / UDP TCP / UDP IP IP IP ATM Link HFC Link HFC Link Ethernet Link Ethernet Link Figure 10.8 Protocol Layer Architecture in HFC System Notes • Head end has both NM applications and manager • Cable modems have SNMP agents • NMS can be regionalized; then, head ends could behave as RMONs Network Management: Principles and Practice © Mani Subramanian 2000 10-24 Chapter 10 HFC / CM Management • Cable modem management • CMTS management • HFC link management • RF spectrum management Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-25 Chapter 10 CM Management MIBs mib-2 (internet.2.1) system (1) interfaces (2) docsDev (69) transmission (10) ifMIB (31) docsIfMib (127) docsTrCmMIB (128) Figure 10.9 Cable Modem Management MIBs Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-26 Chapter 10 DOCS Documentation tr-docs-ossiw08-961016 sp-ossi-i02-990113 sp-ossi-rfi-i03-990113 draft-ietf-ipcdn-interface-mib-03.txt, January 1998 sp-ossi-bpi-i01-980331.pdf draft-ietf-ipcdn-cable-device-mib-07.txt, February 20, 1999 draft-ietf-ipcdn-mcns-bpi-mib-00.txt, January 17, 1999 draft-ietf-ipcdn-rf-interface-mib-07.txt, February 17, 1999 draft-ietf-ipcdn-tri-mib-00.txt, July 30, 1998 draft-ietf-ipcdn-qos-mib-00.txt, August 7, 1998 SP-CMCI-I02-980317, 03/17/98 SP-NSI-I01, 07/22/96 SP-OSSI-BPI-I01-980331 SP-CMTRI-I01-970804 SP-RSMI-I01-980204 SP-BPI-I02-990319 SP-SSI-I01-970506 SP-RFIv1-I01-990311 OSSI Framework OSSI Specification Overview OSSI RF Interface Specification MCNS Interface MIB OSSI Baseline Privacy Interface MIB DOCSIS Cable Device MIB Baseline Privacy MIB DOCSIS RF Interface MIB Telephony-return interface MIB for Cable Modems and CMTS DOCSIS Quality of Service MIB Cable Modem to Customer Premises equipment Interface (CMCI) Specification Cable Modem Termination system network side Interface specification Operations Support system Interface specification Baseline Privacy Interface MIB Cable Modem Telephony return Interface Specification Removable Security Module Interface Specification - Interim Baseline Privacy Interface Specification Security System Specification RF Interface Specification Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-27 Chapter 10 DOCS Interface MIB transmission (mib-2 10) docsIfMIB (127) docsIfMIBObjects (1) docsQosMIB (6) docsIfNotification (2) docsBpiMIB (5) docsIfConformance (3) docsIfBaseObjects(1) docsIfCmtsObjects (3) docsIfCmObjects (2) docsBpiMIBObjects (1) docsBpiConformance (3) docsBpiNotification (2) docsQosMIBObjects (6) docsQosIpPktClassTable (1) docsQosEthPktClassTable (2) docsQosServiceClassGroup (3) docsFlowToClassTable (6) docsSidToClassTable (5) docsQosFlowTable (4) Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-28 Chapter 10 RF MAC Interface Network Layer RF MAC Layer Downstream1 Upstream1 Upstream2 RF Physical Layer Figure 10.11 RF MAC Interface Notes • Multiple RF channels upstream and downstream • Layered structure • Specified using RFC 1573 ifMIB Network Management: Principles and Practice © Mani Subramanian 2000 10-29 Chapter 10 DOCS Cable Device MIB Entity docsDevMIBObjects OID docsDev 1 docsDevBase docsDevMIBObjects 1 docsDevNmAccessTable docsDevMIBObjects 2 docsDevSoftware docsDevMIBObjects 3 docsDevServer docsDevMIBObjects 4 docsDevEvent docsDevMIBObjects 5 docsDevFilter docsDevMIBObjects 6 docsDevCpe docsDevMIBObjects 7 Description Objects of the cable modem and CMTS device Extends MIB-II System Group with objects needed for cable device system management Defines the minimum level of SNMP access security Provides information for network-downloadable software upgrades Provides information about the progress of the interaction with various provisioning servers Provides control and logging for event reporting Configures filters at link layer and IP layer for bridged data traffic CPE IP management and anti-spoofing group on cable modems Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-30 Chapter 10 HFC Failure Models Failure Probability Window (Modem voltage) Smooth (Connector loss) Sharp (Signal/Noise) Event Index Network Management: Principles and Practice © Mani Subramanian 2000 10-31 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-32 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-33 Chapter 10 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) Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-34 Chapter 10 xDSL Technologies Copper Access Transmission Technologies [ADSL Forum] Name Meaning Modem Voice Band Modems Data rate 1200 bps to 28,800 bps Mode Duplex ISDN Integrated Services Digital Network High data rate Digital Subscriber Line 160 kbps Duplex 1.544 Mbps 2.048 Mbps Duplex Duplex 2-pair SDSL Single line Digital Subscriber Line 1.544 Mbps 2.048 Mbps Duplex Duplex 1-pair ADSL Asymmetric Digital Subscriber Line 1.5 to 9 Mbps 16 to 640 kbps Down Up 1-pair VDSL Very high data rate Digital Subscriber Line 13 to 52 Mbps 1.5 to 2.3 Mbps Down Up 2-pair HDSL Cable 2-pair Applications Low data rate data communications ISDN service Voice and data communications T1/E1 service Feeder plant, WAN, LAN access, server access Same as HDSL plus premises access for symmetric services Internet access, video demand, simplex video, LAN access, interactive multimedia Same as ADSL plus HDTV Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-35 Chapter 10 ADSL Network Broadband Network ATU-C Splitter Voice ADSL Loop Splitter ATU-R Voice Figure 10.13 ADSL Access Network Notes • ADSL .. Asymmetric Digital Subscriber Line • ATU-C ADSL transmission unit - central office • ATU-C ADSL transmission unit - remote/residence • Splitter separates voice and data Network Management: Principles and Practice © Mani Subramanian 2000 10-36 Chapter 10 ADSL Spectrum Allocation with Guard Band FDM Upstream POTS 4 KHz 25 KHz Downstream 200 KHz Frequency 1.1 MHz Notes • POTS .. Plain old telephone service Network Management: Principles and Practice © Mani Subramanian 2000 10-37 Chapter 10 ADSL Spectrum Allocation with Echo Cancellation Echo Cancellation Upstream POTS 4 KHz 25 KHz 200 KHz Downstream 1.1 MHz Frequency Notes • Echo cancellation separates upstream and downstream signals • Increases (low-frequency) upstream bandwidth Network Management: Principles and Practice © Mani Subramanian 2000 10-38 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-39 Chapter 10 ADSL Forum TR-001 TR-005 TR-006 TR-014 TR-015 TR-016 ADSL Forum System Reference Model ADSL Network Element Management System SNMP-based ADSL LINE MIB; see also draftietf-adslmib-adsllinemib-09.txt DMT Line Code Specific MIB CAP Line Code Specific MIB 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) Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-40 Chapter 10 VDSL Network Central Office Fiber Optical Network Unit VDSL Twisted Pair VDSL Home Network Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-41 Chapter 10 ADSL Network Private Network Public Network Premises Network ADSL Access Network OS Service Systems On-line Services Internet Access LAN Access Interactive Video Video Conf OS Broadband Network Narrowband Network Access Node Packet Network ATU-C ATU-R ADSL LLLLL L ADSL PDN SM Settop TE(s) TV SM PC I/O TE(s) PC SM ISDN TE(s) ISDN STM Packet ATM STM ATM Packet ATM Transport Modes ADSL ATM STM TE OS PDN SM Asynchronous Digital Subscriber Line Asynchronous Transfer Mode Synchronous Transfer Mode Terminal Equipment Operations System Premises Distribution Network Service Module Figure 10.16 Overall Network and ADSL Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-42 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-43 Chapter 10 ADSL System Reference Model VC U-C2 U-C VA T-SM T B Splitter Digital Broadcast ATU-C Broadband Network ATU-C Narrowband Network ATU-C Network Management U-R U-R2 ATU-C T.E. Loop ATU-R T.E. T.E. POTS-C PSTN POTS-R Phone(s) Access Node 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 VA Logical interface between ATU-C and Access Node VC Interface between Access Node and network T.E. Premises Distribution Network TE Terminal Equipment POTS Plain Old Telephone Service PSTN Public Switched Telephone Network Figure 10.17 ADSL System Reference Model Notes (ADSL Forum) Network Management: Principles and Practice © Mani Subramanian 2000 10-44 Chapter 10 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) Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-45 Chapter 10 ADSL Channeling Schemes Downstream bearer channels ATU-R ATU-C Duplex bearer channels Fast channel ATU-C ATU-R Interleaved channel Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-46 Chapter 10 Management Reference Model T-R V-C T/S Service Module Network Termination Broadband Network PHY Layer Switch Switch ATU-C ATU-R PHY Layer Home Network U-C2 Service Module U-R2 High Pass Filter PSTN PSTN Low Pass Filter Splitter-C High Pass Filter Loop U-C U-R Low Pass Filter POTS Telephone Set or Voice-Band Modem Splitter-R 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-47 Chapter 10 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 Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-48 Chapter 10 Signal Power and Data Rate Mgmt Reduce power Maximum noise margin Increase rate if noise margin > Upshift noise margin Upshift noise margin Steady state operation Target noise margin Steady state operation Downshift noise margin Decrease rate if noise margin < Downshift noise margin Minimum noise margin Increase power Figure 10.19 Noise Margins Notes • 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) Network Management: Principles and Practice © Mani Subramanian 2000 10-49 Chapter 10 Configuration Mgmt Parameters Parameter ADSL Line type ADSL Line coding Target noise margin Max. noise margin Min. noise margin Rate adaptation mode Upshift noise margin Min. time interval for upshift rate adaptation Downshift noise margin Component Line Description ADSL Line N/A Five types: no channel, fast, interleaved, either or both ADSL Line N/A ADSL coding type ATU-C/R Phy Noise margin under steady -7) state (BER=<10 ATU-C/R Phy Modem reduces power above this threshold ATU-C/R Phy Modem increases power below this margin ATU-C/R Phy Mode 1: Manual Mode 2: Select at start-up Mode 3: Dynamic ATU-C/R Phy Threshold for modem increases data rate ATU-C/R Phy Time interval to upshift ATU-C/R Min. time interval for downshift rate adaptation Desired max. rate Desired min. rate Rate adaptation ratio ATU-C/R Max. interleave delay ATU-C/R Alarm thresholds ATU-C/R Rate up threshold Rate down threshold Vendor ID Version No. Serial No. ATU-C/R ATU-C/R ATU-C/R ATU-C/R ATU-C/R ATU-C/R ATU-C/R ATU-C/R Phy Threshold for modem decreases data rate Phy Time interval to downshift F/I Max rates for ATU-C/R F/I Min. rates for ATU-C/R Phy Distribution ratio between fast and interleaved channels for available excess bit rate F/I Max. transmission delay allowed by interleaving process Phy 15-minute count threshold on loss of signal, frame, poser and error-seconds F/I Rate-up change alarm F/I Rate-down change alarm Phy Vendor ID assigned by T1E1.4 Phy Vendor specific version Phy Vendor specific Serial No. Network Management: Principles and Practice © Mani Subramanian 2000 10-50 Chapter 10 Fault Management Parameter ADSL Line status Component ADSL Line Line Phy Alarms thresholds ATU-C/R Phy Unable to initialize ATU-R ATU-C/R Phy Rate change ATU-C/R Phy Description Indicates operational and various types of failures of the link Generates alarms on failures or crossing of thresholds Initialization failure of ATU-R from ATU-C Event generation when rate changes when crossing of shift margins in both upstream and downstream Notes • 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 Network Management: Principles and Practice © Mani Subramanian 2000 10-51 Chapter 10 Performance Management Parameter Line attenuation Component ATU-C/R Line Phy Noise margin ATU-C/R Phy Total output power ATU-C/R Phy Max. attainable rate ATU-C/R Phy Current rate ATU-C/R F/I Previous rate ATU-C/R F/I Channel data block length ATU-C/R F/I Interleave delay ATU-C/R F/I Statistics ATU-C/R Phy F/I Description Measured power loss in dB from transmitter to receiver ATU Noise margin in dB of the ATU with respect to received signal Total output power from the modem Max. currently attainable data rate by the modem Current transmit rate to which the modem is adapted Rate of the modem before the last change Data block on which CRC check is done Transmit delay introduced by the interleaving process 15 minute / 1 day failure statistics Notes • Line attenuation • Noise margin • Output power • Data rate • Data integrity check • Interleave channel delay • Error statistics Network Management: Principles and Practice © Mani Subramanian 2000 10-52 Chapter 10 ADSL SNMP MIB adslForum (1.3.6.1.4.1.xx) adslMIB (1) adslLineMib (1) adslTraps (2) adslConformance (2) adslMibObjects(1) adslLineTable (1) adslLineAlarmConfProfileTable(15 adslAtucPhysTable (2) adslLineConfProfileTable(14) adslAturPhysTable (3) ) adslAturChanIntervalTable (13) adslAtucChanTable (4) adslAtucChanIntervalTable(12) adslAturChanTable (5) adslAtucPerfDataTable (6) adslAturPerfDataTable (7) adslAtucIntervalTable (8) adslAturChanPerfDataTable (11) adslAtucChanPerfDataTable (10) adslAturIntervalTable (9) adslLCSMib (16) adslDMTMib (1) adslCAPMib (1) Figure 10.20 ADSL SNMP MIB Network Management: Principles and Practice © Mani Subramanian 2000 10-53 Chapter 10 Proposed IF Types Higher 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 Notes • Sub-layers handled by ifMIB ifStackTable {ifMib.ifMIBObjects 2} (RFC 1573) • Propose ifTypes adslPhysIf ::= {transmission 94} adslInterIf ::= {transmission 124} adslFastIf ::= {transmission 125} Network Management: Principles and Practice © Mani Subramanian 2000 10-54 Chapter 10 ADSL Interfaces Table MIB Variable Physical Line (i) ifDescr ifType (IANA) ifSpeed NORMAL 94 ATU-C Line Tx rate NULL NORMAL NORMAL NORMAL NORMAL (default: Enable) True NULL ifPhyAddress ifAdminStatus ifOperStatus ifLastChange ifLinkUpDownTrap Enable ifConnectPresent ifHighSpeed Interleaved Channel (j) NORMAL 124 ATU-C channel Tx rate NULL NORMAL NORMAL NORMAL NORMAL (default: Enable) False NULL Fast Channel (k) NORMAL 125 ATU-C channel Tx rate NULL NORMAL NORMAL NORMAL NORMAL (default: Enable) False NULL Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-55 Chapter 10 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 Notes Network Management: Principles and Practice © Mani Subramanian 2000 10-56 Chapter 10 Configuration Profile: Mode I - Dynamic ADSL-Line ifIndex ifTable 1 i1 ADSL Line Entry j1 Interleaved Chan k1 Fast Chan Entry i2 ADSL Line Entry j2 Interleaved Chan k2 Fast Chan Entry ix ADSL Line Entry jx Interleaved Chan 2 x kx profileIndex Configuration Profile Table 1 Profile-1 2 Profile-2 n Profile-n Fast Chan Entry Figure 10.22 Use of Profiles in MODE-I (Dynamic) Network Management: Principles and Practice © Mani Subramanian 2000 10-57 Chapter 10 Configuration Profile: Mode II - Static ADSL-Line ifIndex ifTable 1 i1 ADSL Line Entry j1 Interleaved Chan k1 Fast Chan Entry i2 ADSL Line Entry j2 Interleaved Chan k2 Fast Chan Entry ix ADSL Line Entry jx Interleaved Chan 2 x profileIndex Configuration Profile Table i1 Profile-i1 i2 ix Profile-i2 Profile-in kx Fast Chan Entry Figure 10.23 Use of Profiles in MODE-II (Static) Network Management: Principles and Practice © Mani Subramanian 2000 10-58