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Network Architectures for a Multi-Service Broadband Internet. George Clapp 973-829-4610 clapp@research.telcordia.com Monday, September 8, 2014. Growth in the Number of Hosts NetSizer. http://www.netsizer.com/daily/table.html. Worldwide Business-to-Business E-Commerce.
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Network Architectures for a Multi-Service Broadband Internet George Clapp 973-829-4610 clapp@research.telcordia.com Monday, September 8, 2014
Growth in the Number of HostsNetSizer http://www.netsizer.com/daily/table.html
Worldwide Business-to-Business E-Commerce 7% of $105T total global sales transactions GartnerGroup January 26, 2000 http://gartner12.gartnerweb.com/public/static/aboutgg/pressrel/pr012600c.html
Access to the Internet • Stanford Institute of Quantitative Study of Society • Polled 4,113 individuals; 2,689 households http://www.stanford.edu/dept/news/report/news/february16/internetsurvey-216.html
Increasing Use with Time http://www.stanford.edu/dept/news/report/news/february16/internetsurvey-216.html
Link 45% 40% Wheat, First, ... 35% Yankee 30% Jupiter 25% Kagan 20% Average 15% 10% 5% 0% Market Demand for Internet/Online Services Percentage of US Households 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
25 20 Millions of High Speed Users 15 Total BBD + ISDN Market ADSL (Bellcore) Cable Modems (Kagan) ISDN BRI (IDC 98) 10 5 0 1997 1998 1999 2000 2001 2002 2003 2004 Market Demand for High Speed Access
ForecastsOne View Source: IDC/Link 9/98
Simplistic but true Traffic Growth RatesVoice grows at 3% per year; data grows at 100% per year Voice Data
Parts of a Network Other carriers Operations Premises Access Metropolitan Backbone(long-haul) Switching Transmission
Access Networks Hybrid Fiber Coax (HFC) Optical Network Unit (ONU) HUB Digital Subscriber Line (DSL) xDSL xDSL Modem Fiber in the loop (FITL)Fiber to the X (FTTx) ONU Access Multiplexer(s) Wireless Voice Switch POTS (Plain Old Telephone Service)
Cable Networks Information Head end Few hundred thousand homes passed Primary Hub Primary Hub Primary Hub Few tens of thousands homes passed Secondary Hub Secondary Hub Node Node Node Node Few hundred to thousand homes passed
Cable NetworksAnother View with Neighborhoods http://www.webproforum.com/hfc_dwdm/
PacketCable Architecture MTA CableModem PSTN CMTS HFC access network PSTN Gateway Media Gateway (MG) Call Management Server (CMS) ManagedIP Network Signaling Gateway Announcement Server MG Controller HFC access network CMTS OSS Back Office Servers and Applications MTA CableModem PSTN: Public Switched Telephone Network CMTS: Cable Modem Termination System MTA: Multimedia Terminal Adapter
Multimedia Cable Network Systems (MCNS)Data over Cable System Interface Specifications (DOCSIS) Cable Distribution Network PSTN Gateway CMTS CMTS PSTN V Head End HFC HFC MTA MTA
ILEC/PTO V Cable Voice over IP Architecture VoIP Infrastructure Cisco HFC Network IP Network CPE Cable Modem GigaBit Switch Routers Packet Over Sonet VoIP Trunking Gateway Integrated CMTS/HeadEnd Router
Cable Voice over IP Architecture cont’d OC-12 GSR12008 GSR12008 BACKBONE ROUTERS OC-12 CAMPUS SWITCH ROUTER Cat8500 Cat8500 TRUNK GATEWAYS AS5300 V V V V CMTS/ HEADEND ROUTER uBR7246 Public Telephone Network Optical Nodes
Typical HFC Frequency Plan Upstream Downstream • Upstream and downstream data channels are shared Ch2 Ch 78 5 MHz 42 MHz 54 MHz 550 MHz 750,860 MHz, 1 GHz 2-way services AM Video Digital Video 2-way services 320 Kbps to 10 Mbps 30 to 40 Mbps/6 MHz channel
Class 5 Switch Asymmetric Digital Subscriber Line DSLAM: Digital Subscriber Line Access Multiplexer ATM Switch Fabric To ISPs, IXCs ADSL ADSL Modem
ADSL Access http://www.3com.com/solutions/dsl/dsl_tech_microwt.html#_Toc389638794
ADSL is dedicated point-to-point technology ADSL peak rate is 6 Mbps downstream; average rate is typically 1-2 Mbps ADSL upstream rates are typically 1/10 of downstream Cable modem is a shared bus (typically 100 customers) Cable modem peak rate is 30-40 Mbps shared over all customers currently active Cable modem systems typically have a single shared upstream channel at lower rate Differences between ADSL and HFC
ADSL Downstream: 1 Mbps to 8 Mbps Upstream: 128 kbps to 640 kbps Range: 12 kft to 18 kft G.lite Downstream: 1.5 Mbps Upstream: 512 kbps Range: 18 kft VDSL Downstream: 13 Mbps to 52 Mbps Upstream: 1 Mbps to 4 Mbps Range: 1 kft to 4 kft For use off of DLC RDT or FTTC ONU IDSL Downstream: 128 kbps Upstream: 128 kbps Range: 18 kft No POTS HDSL Downstream: 1.544/2.048 Mbps Upstream: 1.544/2.048 Mbps Range: 12 kft Requires Two Pair Used for commercial T1/E1 service Taking the majority (70% of U.S. in 1996) market for T1s SDSL (One Pair HDSL) Downstream: 784 kbps Upstream: 784 kbps Range: 12 kft No POTS Types of xDSL
Limitations and Obstacles to xDSL • Distance limited, Maximum loop length dependent on • Data rate • Gauge makeup • Bridged Tap • Load Coils • Noise • Crosstalk • Serving Arrangement - Copper vs. DLC
Total Loop Length • National Segmentation 41% Urban 50% Suburban 9% Rural
40% 35% 30% 25% Percent of total lines 20% 15% 10% 5% 0% Fiber fed DLC Copper fed DLC GTE NYNEX BellSouth Ameritech U S WEST National Total Southwestern Bell Bell Atlantic Pacific Telesis Digital Loop Carrier • Digital Loop Carrier (DLC) Solution Needed • Over 20% of US loops served by DLC • Much higher in some regions of the country • Majority of new growth served by DLC • Many of the affluent, suburban, prime ADSL subscriber neighborhoods served by DLC 1998 DLC Deployment
National Loop Statistics • Load Coils • Approximately 2% - 8% of all loops are loaded • xDSL will not operate over loaded lines • Bridged Tap • Approximately 70%-80% of all loops have one or more Bridged Tap • Bridged Tap are generally not a problem. • Lowers SNR by a few dB resulting in small decrease in range • Bridged-tap at or very close to the Quarter-wavelength length may cause more problems
Spectral Compatibility • T1 lines and ADSL • Near End Cross Talk (NEXT) from T1 can nearly stop downstream ADSL • NEXT from ADSL can disrupt T1 • Repeatered HDSL and ADSL • HDSL repeaters can destroy ADSL on long loops. • ADSL and VDSL • NEXT from ADSL can significantly hurt VDSL signals • Unbundling xDSL, and different CLECs • May cause incompatibilities between various flavors of xDSL
Summary • xDSL allows LECs to deploy high speed data services quickly and economically over their existing infrastructure • At the same time, the xDSL addressable market is constrained by the existing infrastructure • Loop Qualification is a necessity • DLC solutions are necessary to unlock more potential subscribers
Emergence of “Double-Bubble” Networks Incumbent Local Exchange Carriers (ILECs) build out a separate IP network PSTN Gateway Gateway IP Network
Dense Wave Division Multiplexing • Multiplex wavelengths into a single optical fiber • Lucent WaveStar OLS 400G supports up to 80 optical channels of 2.5 Gb/s each over a single fiber http://www.webproforum.com/dwdm/topic01.html
New Options in Protocol Stacks IP ATM IP IP SONET/SDH SONET/SDH IP ATM WDM Optical Network Physical Fiber Plant
SONETADM IP Router SONET ADM W D M W D M SONET ADM SONET ADM IP Router DWDM as Capacity Expansion ATM uplink on OC-3c OC-3c OC-48 OC-48 ATM Switch ATM uplink on OC-3c OC-48 OC-48 OC-3c ADM: Add Drop Multiplexer
Elimination of SONET ATM uplink on OC-48 OC-48 IP Router W D M W D M ATM Switch IP Router OC-48 ATM uplink on OC-48
Revisiting Cable Networks with DWDM http://www.webproforum.com/hfc_dwdm/index.html
Backbone IP Network NMS(s) Cable Modem WDMEMS Internet IPEMS IPRouter Cable IPRouter WDM Cable Access IPRouter WDM WDM WDM IPRouter
Target Internet Backbone Architecture Routers Servers WDM
The Quality of Service ChallengeTransmission of voice through data networks • 150 msec one way delay • Minimum jitter buffer of 15 msec • 1-2% packet loss Delay Losses Jitter
The delays are already almost acceptablebut there are wide variations
Congestion happens! • Loss of transmission resource • Olympic games, earth-quake, TV show...
Diffserv and Edge Control:Solving the QoS challenge Managed IP backbone Edge router Customer
Evolution of the NetworkTwo options for quality of service Diffserv Bandwidth 1: Rising tide 2: Retooling
Different Requirements for Voice and Data • Voice • Sensitive to delay and jitter • Low tolerance for packet loss • Data • Delay insensitive • Packet loss dramatically reduces throughput • Small buffers • VoIP delays lie within acceptable bounds; compliance with loss bounds are ensured only for low loads of TCP traffic • Severe degradation of TCP performance even at very low loads since the buffers are unable to accept even small bursts that are generated by a TCP flow • Large buffers • Good throughput for TCP • VoIP traffic suffers a sharp increase in jitter at even moderate buffer sizes
Conclusion • Continued exponential growth in size and functionality of the Internet • Thanks for fiber optics, network technology is keeping pace with demand