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Transcript
Session 11 Broadband Management MJ11/0704 Adapted from Network Management: Principles and Practice © Mani Subramanian 2000 and solely used for Network Management course at Universitas Bina Nusantara 1 Broadband Access Networks Cable Modem Network Cable Modem HFC CM Head End Central Office Telephone Loop XDSL Mode m MJ11/0704 DSL Network 2 Access Technologies Broadband Access Technology HFC TelephonyReturn xDSL TwoWay ADSL HDSL VDSL ISM MMDS OneWay MJ11/0704 Satellite Communication Wireless LMDS TelephonyReturn TwoWay TwoWay 3 Access Technologies • 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 MJ11/0704 4 Access Technologies • xDSL: Digital subscriber line technology • Asymmetric DSL (ADSL) • High-speed DSL (HDSL) • Very-high speed DSL (VDSL) • Uses existing local loop telephone facilities MJ11/0704 5 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 MJ11/0704 6 HFC Network • Fiber - 2 one-way transmission • Coaxial - 2-way transmission • 2-way amplifiers • Fiber node: optical - RF conversion •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 MJ11/0704 7 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 MJ11/0704 10-12 8 Broadband LAN Downstream Signal 50 - 860 MHz Head End Cable Modem A Cable Modem B Upstream Signal 5 - 42 MHz MJ11/0704 Termination Cable Modem C Termination 9 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 MJ11/0704 10 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 MJ11/0704 11 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 MJ11/0704 12 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 MJ11/0704 Digital Data Services 10-25 MHz Telephony 25-40 MHz 13 DOCS Reference Architecture 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 5 Splitter& Filter Demod Operations Support System/ 3 Element Manager Combiner Video Cable Modem Receiver Security & Access Controller The architecture shows two-way (HFC link) and one-way (HFC link & telco return). MJ11/0704 14 CMTS Components Cable Modem Data Termination System (CMTS) Mod Switch / Router 2 Term 6 Fiber 5 Splitter& Filter 6 Servers MJ11/0704 Transmitter Data Demod Operations Support System/ 3 Element Manager Combiner Video Receiver Security & Access Controller 15 CMTS Components • 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 demuxing. • 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. MJ11/0704 16 CMTS Components • 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) MJ11/0704 17 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 MJ11/0704 18 HFC Protocol Architecture Head End Applications, SNMP Manager SDH Cable Modem 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 • Head end has both NM applications and manager • Cable modems have SNMP agents • NMS can be regionalized; then, head ends could behave as RMONs MJ11/0704 19 HFC / CM Management • Cable modem management • CMTS management • HFC link management • RF spectrum management MJ11/0704 20 CM Management MIBs mib-2 (internet.2.1) system (1) interfaces (2) docsDev (69) transmission (10) ifMIB (31) docsIfMib (127) MJ11/0704 docsTrCmMIB (128) 21 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 MJ11/0704 22 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) docsBpiConformance docsBpiMIBObjects (1) (3) docsBpiNotification (2) docsQosMIBObjects (6) docsQosIpPktClassTable (1) docsQosEthPktClassTable (2) docsQosServiceClassGroup (3) MJ11/0704 docsFlowToClassTable (6) docsSidToClassTable (5) docsQosFlowTable (4) 23 RF MAC Interface Network Layer RF MAC Layer Downstream1 Upstream1 Upstream2 RF Physical Layer • Multiple RF channels upstream and downstream • Layered structure • Specified using RFC 1573 ifMIB MJ11/0704 24 DOCS Cable Device MIB Entity docsDevMIBObjects Description Objects of the cable modem and CMTS device docsDevBase docsDevMIBObjects 1 Extends MIB-II System Group with objects needed for cable device system management docsDevNmAccessTable docsDevMIBObjects 2 Defines the minimum level of SNMP access security docsDevSoftware docsDevMIBObjects 3 Provides information for network-downloadable software upgrades docsDevServer docsDevMIBObjects 4 Provides information about the progress of the interaction with various provisioning servers docsDevEvent docsDevMIBObjects 5 Provides control and logging for event reporting docsDevFilter docsDevMIBObjects 6 Configures filters at link layer and IP layer for bridged data traffic docsDevCpe docsDevMIBObjects 7 CPE IP management and anti-spoofing group on cable modems MJ11/0704 OID docsDev 1 25 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 MJ11/0704 26 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 MJ11/0704 27 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) MJ11/0704 28 xDSL Technologies Copper Access Transmission Technologies [ADSL Forum] Name Meaning Modem Voice Band Modems ISDN Mode Cable Duplex 2-pair Integrated 160 kbps Services Digital Network High data rate 1.544 Mbps Digital 2.048 Mbps Subscriber Line Duplex SDSL Single line 1.544 Mbps Digital 2.048 Mbps Subscriber Line Duplex 1-pair Duplex ADSL Asymmetric 1.5 to 9 Mbps Down Digital 16 to 640 kbps Up Subscriber Line 1-pair VDSL Very high data 13 to 52 Mbps rate Digital 1.5 to 2.3 Subscriber Line Mbps 2-pair HDSL MJ11/0704 Data rate 1200 bps to 28,800 bps Duplex 2-pair Duplex Down Up 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 29 ADSL Network Broadband Network ADSL Loop ATU-C Splitter Splitter Voice Voice ATU-R • ADSL .. Asymmetric Digital Subscriber Line • ATU-C ADSL transmission unit - central office • ATU-C ADSL transmission unit - remote/residence • Splitter separates voice and data MJ11/0704 30 ADSL Spectrum Allocation With Guard Band FDM Upstream POTS 4 KHz MJ11/0704 25 KHz Downstream 200 KHz Frequency 1.1 MHz 31 ADSL Spectrum Allocation With Echo Cancellation Echo Cancellation Upstream POTS 4 KHz 25 KHz 200 KHz Downstream 1.1 MHz Frequency • Echo cancellation separates upstream and downstream signals • Increases (low-frequency) upstream bandwidth MJ11/0704 32 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 MJ11/0704 33 ADSL Network Private Network Public Network Premises Network ADSL Access Network OS Service Systems OS Broadband Network Narrowband Network Access Node Packet Network ATU-C ATU-R ADSL ADSL PDN SM Settop TE TV SM PC I/O TE PC SM ISDN TE ISDN STM Packet ATM STM Packet ATM ATM Transport Modes ADSL ATM STM TE OS PDN SM MJ11/0704 Asynchronous Digital Subscriber Line Asynchronous Transfer Mode Synchronous Transfer Mode Terminal Equipment Operations System Premises Distribution Network Service Module 34 ADSL System Reference Model VC U-C2 U-C VA T B ATU-C Broadband Network ATU-C Narrowband Network ATU-C ATU-C Access Node MJ11/0704 T-SM Splitter Digital Broadcast Network Management U-R U-R2 Loop T.E. ATU-R T.E. T.E. POTS-C PSTN POTS-R T.E. Premises Distribution Phone(s) Network 35 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) MJ11/0704 36 ADSL Channeling Schemes ATU-C Downstream bearer channels ATU-R Duplex bearer channels ATU-C Fast channel ATU-R Interleaved channel • 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 MJ11/0704 37 Management Reference Model T-R V-C T/S Service Module Network Termination Broadband PHY Network 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 MJ11/0704 38 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 MJ11/0704 39 Signal Power and Data Rate Mgmt Maximum noise margin Upshift noise margin Target noise margin Downshift noise margin Minimum noise margin Reduce power Increase rate if noise margin > Upshift noise margin Steady state operation Steady state operation Decrease rate if noise margin < Downshift noise margin Increase power • • • • MJ11/0704 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) 40 Configuration Mgmt Parameters MJ11/0704 Parameter ADSL Line type Component ADSL Line ADSL Line coding Target noise margin ADSL Line ATU-C/R Max. noise margin ATU-C/R Min. noise margin ATU-C/R Rate adaptation mode ATU-C/R Upshift noise margin ATU-C/R Min. time interval for upshift rate adaptation Downshift noise margin 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 ATU-C/R Line Description N/A Five types: no channel, fast, interleaved, either or both N/A ADSL coding type Phy Noise margin under steady state (BER=<10 -7) Phy Modem reduces power above this threshold Phy Modem increases power below this margin Phy Mode 1: Manual Mode 2: Select at start-up Mode 3: Dynamic Phy Threshold for modem increases data rate Phy Time interval to upshift 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. 41 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 Phy ATU-C/R 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 • 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 MJ11/0704 42 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 • Line attenuation • Noise margin • Output power • Data rate • Data integrity check • Interleave channel delay • Error statistics MJ11/0704 43 ADSL SNMP MIB adslForum (1.3.6.1.4.1.xx) adslMIB (1) adslLineMib (1) adslTraps (2) adslConformance (2) adslMibObjects(1) adslLineTable (1) adslAtucPhysTable (2) adslAturPhysTable (3) adslAtucChanTable (4) adslAturChanTable (5) adslAtucPerfDataTable (6) adslAturPerfDataTable (7) adslAtucIntervalTable (8) adslDMTMib (1) MJ11/0704 adslLineAlarmConfProfileTable(15 adslLineConfProfileTable(14) ) adslAturChanIntervalTable (13) adslAtucChanIntervalTable(12) adslAturChanPerfDataTable (11) adslAtucChanPerfDataTable (10) adslAturIntervalTable (9) adslLCSMib (16) adslCAPMib (1) 44 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 MJ11/0704 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 45 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 MJ11/0704 46 Configuration Profile: Mode I - Dynamic ADSL-Line 1 ifIndex i1 ADSL Line Entry j1 Interleaved Chan k1 2 x i2 profileIndex Configuration Profile Table 1 Profile-1 2 Profile-2 n Profile-n Fast Chan Entry ADSL Line Entry j2 Interleaved Chan k2 Fast Chan Entry ix ADSL Line Entry jx Interleaved Chan kx MJ11/0704 ifTable Fast Chan Entry 47 Configuration Profile:Mode II - Static ADSL-Line 1 ifIndex i1 j1 k1 2 i2 j2 x MJ11/0704 ifTable profileIndex Configuration Profile Table i1 Profile-i1 ADSL Line Entry Interleaved Chan Fast Chan Entry ADSL Line Entry i2 Profile-i2 Interleaved Chan k2 Fast Chan Entry ix ADSL Line Entry jx kx Interleaved Chan ix Profile-in Fast Chan Entry 48