CX150-D3+ Product Introduction
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Transcript CX150-D3+ Product Introduction
DOCSIS®
Rev. A00
Agenda
Items for discussion
DOCSIS/EuroDOCSIS
Overview of Standards, Features &
Benefits
DOCSIS 3.0/EuroDOCSIS 3.0
CATV Market Dynamics
New Technical Directions & Features
Network Preparation
DOCSIS®
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DOCISIS
DOCSIS 3.0
2
DOCSIS Review
Overview, Features & Benefits
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DOCSIS
An Overview
DOCSIS system
DOCSIS specification
Enables transparent bi-directional of Internet Protocol (IP) traffic, between the cable system headend and
customer location
Defines PHY & MAC layer protocols for communication & Ethernet frame transport between CMTS & CM
DOCSIS network comprises:
Cable Modem Termination System (CMTS) located at the headend
Cable Network - an all-coaxial or hybrid-fiber/coax (HFC) cable network
Cable Modem (CM) located at the Customer Premise
Transparent IP traffic
Wide Area
Network
Cable Network
(HFC)
CMTS
Cable Modem
CM/CPE
Interface
CMTS/WAN
Interface
DOCSIS®
CPE
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DOCSIS
Milestones
DOCSIS 1.0 (1999)
• 1st products certified (CableLabs started project in 1996)
• Open standard for high-speed data over cable
• Modest security, Best-effort service
DOCSIS 1.1 (2000)
• Quality-of-Service (QoS) service flows
• Baseline Privacy Interface (BPI+) Certificates
• Improved privacy & encryption process
DOCSIS 2.0 (2002)
• Improved throughput & robustness on Upstream
• 64/128 QAM modulation & higher symbol rates with FEC
• Programmable interleaving to upstream channels
DOCSIS 3.0 (2006)
• Channel bonding (4U/4D) for increased capacity
• IPv6 support
• Improved security (AES)
DOCSIS®
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DOCSIS
HFC Spectrum Allocation
The frequency spectrum used in an HFC network is split into two parts:
Downstream spectrum which delivers services from the headend to the end user
Upstream spectrum for sending traffic from the end user to the operator
Europe
FM
Analog Video
PAL
EuroDOCSIS
US
5MHz
65 80 87
108
Downstream
North America
FM
Analog Video
NTSC
US DOCSIS
US
42
Upstream
DOCSIS®
EuroDOCSIS
DS
862MHz
Upstream
5MHz
Digital Video
MPEG/DVB + VOD
80 87
Digital Video
MPEG/DVB + VOD
108
US DOCSIS
DS
862MHz
Downstream
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DOCSIS
Upstream Physical Layer
The DOCSIS Specification defines Modulation and Coding Schemes outlined in
the following table for the Upstream
DOCSIS®
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DOCSIS
Downstream Physical Layer
The DOCSIS Specification defines Modulation and Coding Schemes outlined in
the following table for the Downstream
DOCSIS®
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DOCSIS
Power Ranging
Ranging is used to synchronize CMs and align them with the CMTS
TDMA requires coarse alignment (±800 nsec)
S-CDMA requires accurate alignment (±1 nsec)
CM sends a RNG-REQ message
CMTS responds with a RNG-RSP message
Contains Timing Adjust (Resolution = 0.3815 nsec)
also Power adjust, Frequency adjust, Pre-EQ parameters
Ranging is a two-step process:
Initial maintenance (coarse time alignment)
Periodic station maintenance (fine time alignment)
DOCSIS®
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DOCSIS
CM Protocol Stack
DOCSIS MAC
Forms part of the data link layer that supports topology dependent functions
Uses services of the Physical Layer to provide services to the Logical Link Control (LLC)
In the OSI 7-layer model, the Media Access Control is a part of layer 2, the data link layer.
DOCSIS®
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DOCSIS
Media Access Control (MAC)
Media Access Control (MAC) Sub-Layer
Controls access to the Physical Layer (the channel)
Allows multiple users to share a communications channel
Separate physical channels (upstream/downstream) controlled by the CMTS
No direct peer-to-peer (CM-to-CM) communication
Downstream MAC
Only one transmitter (CMTS) and multiple receivers (CMs)
Quality of Service (QoS) can be assured by:
Token bucket rate limiting, Reserved data rates, Traffic Priority
Upstream MAC
Multiple transmitters (CM) with One receiver (CMTS)
The CMTS arbitrates access to the channel
Each upstream channel is described in mini-slots
MAP messages are broadcast downstream to describe which CM can transmit and when
Access Control is Reservation based
DOCSIS®
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DOCSIS
DHCP Server & Process
DHCP Server
Assigns IP addresses to client computers
Addresses are “leased” to clients (Cable Modems or CPEs) for a period of time
IP addresses can be reserved for specific clients or assigned from “pools”
Clients may be authenticated based on their MAC address
Address may be assigned from different “pools” based on extended options
DHCP Process
The DHCP server requests the following parameters from the Cable Modem (CM):
IP address of the CM
IP address of the TFTP Server (for DOCSIS Configuration file)
IP address of the DHCP Relay Agent (if DCHP server resides on a different network)
TFTP/DOCSIS Configuration file name
Subnet Mask to be used by the CM
Default IP Gateway
Time of Day Server and SYSLOG Server IP address
DOCSIS®
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DOCSIS
Time of Day (TOD) Server
Time of Day (ToD) Server
Internet Time Protocol (ITP) per RFC 868
UDP and TCP requests honored on port 37
32-bit value defining the number of seconds since 00:00 (midnight January 1, 1900 GMT)
DOCSIS®
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DOCSIS
TFTP Server
TFTP (Trivial File Transfer Protocol) Server
The following settings are mandatory in the TFTP configuration file:
In accordance with RFC 1350
UDP port 69
Small and easy to implement with read and write to and from remote servers
Network Access Configuration Setting
Class of Service Configuration Setting
The following settings are optional:
Downstream Frequency
Upstream Channel ID
Vendor ID
Baseline Privacy
SNMP Write-Access Control, SNMP MIB Object & SNMP IP Address (if applicable)
Software Server IP Address
CPE Ethernet MAC Address
Vendor-Specific Configuration (if applicable)
DOCSIS®
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DOCSIS 3.0
CATV Market Dynamics
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DOCSIS 3.0
Business Drivers
Support new high bandwidth services of 50 to 100Mbps
Migrate existing customers to higher tier services
Better and more robust data encryption
Provide more IP address space using IPv6
Limit and reduce node splits
Reduce overall cost of CMTS ports
Independent scalability of upstream & downstream
DOCSIS®
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DOCSIS 3.0
Higher Bandwidth Applications
Web 2.0
Digital
Photos
Home
Networks
Data &
VoIP
Gaming
MP3
WMV
VOD
DVR/PVR
DVD
Blu-ray
You Tube
SDTV
HDTV
DOCSIS®
Mobile
Video
iPod
Walkman
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DOCSIS 3.0
Consumers greed for speed
DOCSIS®
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DOCSIS 3.0
Services driving Channel Bonding
High bandwidth residential data and content
Video and photo uploads
Proliferation of social networking sites and applications
IP Video over DOCSIS (VDOC)
High definition Video to multiple devices
PCs, hybrid STBs, portable devices
High bandwidth Internet streaming
High Bandwidth Video conferencing
Cisco TelePresence
Commercial service
High bandwidth symmetrical data services
Bonded E1/T1 circuit emulation
High bandwidth Ethernet / L2VPN services
DOCSIS®
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DOCSIS 3.0
New Technical Directions & Features
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DOCSIS 3.0
Major Feature Overview
Increased DS bandwidth
• Bonded Downstream Channels
• 56Mbps (RAW) each, 448Mbps Total
Increased US bandwidth
• Bonded Upstream Channels
• 27Mbps (RAW) each, 122Mbps Total
IPv6
• IPV6 allows for 3.4x1038 IP addresses
• IP addresses are lengthened from 32 bits to 128 bits
Backwards compatibility
• Existing DOCSIS 1.0, 1.1 and 2.0 systems
• Scalable deployment with easy subscriber migration
IP Multicast
• IPTV-type applications
• Efficient “switched-video-like” bandwidth usage
Commercial
• E1 & T1 circuit emulation
Network Security
DOCSIS®
• Early Authentication and Encryption (EAE) and AES
128bit encryption which is more robust and secure
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DOCSIS 3.0
Channel Bonding
Channel bonding basically means data is transmitted to/from Cable Modems
using multiple individual RF channels instead of a single channel
Using DOCSIS 3.0, data is transmitted to cable modems using
multiple channels
DOCSIS®
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DOCSIS 3.0
Throughput Compared
Date Rates – Annex A
DOCSIS Version
DOCSIS®
Downstream
Upstream
1.1
~ 55.62 (50) Mbps
10.29 (9) Mbps
2.0
~ 55.62 (50) Mbps
30.72 (27) Mbps
3.0 (4 Channels)
~ 222.48 (200+) Mbps
122.88 (108+) Mbps
3.0 (8 Channels)
~ 444.96 (400+) Mbps
122.88 (108+) Mbps
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DOCSIS 3.0
Upstream PHY Modes
Advanced Time Division Multiple Access (A-TDMA)
Used widely in DOCSIS 2.0 and DOCSIS 1.1 systems
CMs transmit one at a time, occupying the entire upstream channel during transmission
Transmissions consist of a preamble, data burst, and guard time
Better immunity to narrowband interferers and generally performs better above 15 MHz
Synchronous Code Division Multiple Access (S-CDMA)
Applicable to DOCSIS 2.0/3.0 systems only
Multiple CMs able to transmit simultaneously with shorter preamble and no guard times
Better immunity to burst noise and performance below 15 MHz
5MHz
DOCSIS®
42MHz or 65MHz
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DOCSIS 3.0
Downstream Channel Bonding
Cable Modem Termination System (CMTS)
A downstream packet stream or flow is distributed to a set of
channels called the Downstream Bonding Group (DBG)
Bonded packets are marked with a sequence #
A Downstream Service ID (DSID) identifies a stream of packets
Cable Modem (CM)
Bonded packets can arrive out of order
Bonded packets are “re-sequenced” using the sequence #
The DSID is used re-sequence each flow or group of flows
independently
DOCSIS®
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DOCSIS 3.0
Upstream Channel Bonding
Upstream Bonding
Packet Striping of a minimum of 4 channels
Delivers in excess of 50 Mbps
Single flow can consume entire bandwidth on multiple Upstream Channels
Implements Continuous Concatenation & Fragmentation (CCF)
Improved form of concatenation and fragmentation needed for DOCSIS 3.0 operation
US1
Request 1000 bytes
CMTS
Grant 200
US2
P4
P3
P2
P1
Grant 300 bytes
U3
Grant 500 bytes
DOCSIS®
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Cable
Modem
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DOCSIS 3.0
Upstream Requests and Grants
Cable Modem (CM)
When a CM is ready to transmit data, it randomly selects a Request contention interval
among all upstream channels
Transmits a 7-byte REQ message to the CMTS, which identifies the CM (from the
Service ID) and specifies the number of bytes in queue
Retransmits the request, if there is no response from the CMTS
Cable Modem Termination System (CMTS)
Queues and prioritizes the incoming REQs
Selects an upstream channel and reserves future mini-slots for the requesting CMs
An individual request can be split into multiple “grants” on different channels
Communicates the grants to the CMs via MAP messages
DOCSIS®
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DOCSIS 3.0
MAC Domain
MAC Domain
Defined as a sub-component of the CMTS
Controls all DOCSIS functions on a set of downstream and upstream channels
Contains at least one DS channel and one US channel
Provides layer 2 data forwarding services between the CMTS and all the CMs registered
to that particular MAC domain
Implements all DOCSIS MAC management message exchanges with CMs across multiple
US & DS channels using a common MAC address
Implements load balancing of CMs and bandwidth of channels
DOCSIS®
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DOCSIS 3.0
New MAC Functions
MDD Descriptor
Plant Topology
Describes fiber nodes and how they
are split/combined
Ambiguity Resolution
Describes Plant topology
Downstream Bonding Group (DBG)
Upstream/Downstream bonding
Sequencing for packet flows
Dynamic Bonding Change (DBC)
Bonding group attributes (low latency)
CM status report
Reports CM condition
DOCSIS®
CM Control report
Used to force actions such as reboot,
or channel muting.
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DOCSIS 3.0
New MAC Management Messages (partial list)
Message
Description
MDD
MAC Domain Descriptor
B-INIT-RNG-REQ
Bonded Initial Ranging Request
DBC-REQ
Dynamic Bonding Change Request
DBC-RSP
Dynamic Bonding Change Response
DBC-ACK
Dynamic Bonding Change Acknowledge
DPV-REQ
DOCSIS Path Verification Request
DPV-RSP
DOCSIS Path Verification Response
CM-STATUS
Cable Modem Status Report
CM-CTRL
Cable Modem Control
REG-REQ-MP
Multipart Registration Request
DOCSIS®
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DOCSIS 3.0
CM Provisioning
During initialization, the CM downloads a configuration file from the cable operator
The Config file defines:
Quality of Service (QoS) parameters
Filters
Priority, rate limiting, bandwidth guarantees, etc.
block Windows file sharing (netBIOS, SMB, CIFS)
Privacy (encryption) parameters
The CM then sends a Registration Request message to the CMTS containing the
QoS parameters
DOCSIS®
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DOCSIS 3.0
Cable Modem Registration
Scan digital channels & acquire QAM/FEC/MPEG
lock of DOCSIS DS & DOCSIS PID
SYNC, UCD, MAP messages
MDD message
Receive MAC Domain Descriptor (MDD) Message
CMTS
Tune additional downstream frequencies to
determine service group
Cable
Modem
B-INIT-RNG-REQ message
Authentication & Key Exchange
DHCP DISCOVER packet
DHCP OFFER packet
Select upstream channel listed in MDD
Find Initial Maintenance interval in MAP messages
Send RNG-REQ, receive RNG-RSP, adjust Txmitter
Transition to ranging station maintenance
Establish IPv4 or IPv6 communication via DHCP
DHCP REQUEST packet
DHCP RESPONSE packet
TOD Request/Response messages
TFTP Request/Response messages
REG-REQ message
Download Configuration File (TFTP)
Send REG-REQ, receive REG-RSP, send REG-ACK
REG-RSP message
REG-ACK message
Provides Rx-Chan(s)
Receive Rx-Chan(s) configuration
BPI+ initialization if configured
DOCSIS®
Confirm all Rx Channels
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DOCSIS 3.0
Better Network Security
Secure provisioning prevents unauthorized CMs from accessing the network
Early Authentication and Encryption (EAE)
Provides enhanced security
Authenticates CM after power ranging and before DHCP process
Signaling occurs in the MDD message (TLV 6)
Enabled on either a per CM or per MAC domain basis
CMTS Proxy Server
CMTS acts as a TFTP server to the CM and as a TFTP client to the provisioning server
Config parameters are enforced since CMTS receives the file first
Provides config file authorization
DHCPv6 authentication
New MIC hash algorithm (MMH)
DOCSIS®
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DOCSIS 3.0
IPv6 in Cable Networks
IPv6 is fundamental feature of DOCSIS 3.0 and provides numerous benefits:
New address size and format - 128 bit vs 32 bit addressing
Smarter packet – simplified provisioning, built-in security, improved mobility, etc.
Restores global connectivity – removes Network Address Translation (NAT)
CM operates in bridging or routing modes
CM management stack operation - IPv4 only, IPv6 only or Dual mode
MDD message contains IP type - conveyed between the CMTS and CM
DOCSIS®
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DOCSIS 3.0
Quick Summary
DOCSIS 3.0 review
Physically the same as DOCSIS 2.0 signals
Consists of multiple QAM signals bonded logically together
Bonded channels can be contiguous or non-contiguous:
Contiguous - consists of frequency consecutive signals
Non-contiguous – interspersed with other carriers
MPEG-2 transport for downstream signals
QAM transport for upstream signals
IPv4 or IPv6 support
Enhanced security using EAE, etc.
DOCSIS®
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DOCSIS 3.0
Network Preparation
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DOCSIS 3.0
Basic steps for being prepared
RF
Bandwidth
Availability
DOCSIS®
Headend
and Core
Network
Equipment
Preparation
Verify
QAM64
Upstream
Txmission
Verify
QAM256
Downstream
Txmission
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DOCSIS 3.0
Modem
Emulation
IP/Ethernet
Testing
(Ping, FTP,
RFC2544,
Web)
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DOCSIS 3.0
Where can more RF bandwidth come from?
Expand the plant
to 1GHz
Digital only
systems
Use unusable
old analog
broadcast
channels
Digital Simulcast
migrating
selected analog
channels
Node Splits
DOCSIS 3.0
Switched Digital
Video for SD &
HD content
DOCSIS®
requires a minimum
of 4 to 16
downstream
channels
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CMs are able to
receive 4 DS
channels spread
across a 60MHz
window
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DOCSIS 3.0
Bandwidth Management
Reclaim Analog bandwidth for more digital spectrum
Node splits
Transmit only the content being actively watched
Efficient channel use
Reduce the homes passed per HFC node, reducing contention/home for Unicast services
Switched Digital Video (SDV)
More QAM channels for Digital Broadcast, VoD, SDV and DOCSIS
Manage channel lineup, fill the gaps, and mitigate noise to utilize available spectrum
1GHz upgrade
Make new spectrum for new CPE above 860 MHz
Soon 1GHz
Today 870MHz
DOCSIS®
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DOCSIS 3.0
How much can we gain with spectrum changes?
Extending the US band from 65 MHz to 85 MHz
250 Mbps
• New DOCSIS technology becoming available
• FM band is compromised
• Large network investment required
Creating an upstream band 900 to 1000 MHz
•
•
•
•
Adaptation of DOCSIS (RF up converter)
Ingress noise issue “mostly solved”
862 to 1000 GHz considered an extension of DS band
Huge investment in diplex filters and return amplifiers
New upstream band above 1000 MHz
•
•
•
•
500 Mbps
1000 Mbps
Adaptation of DOCSIS (RF up-converter)
Ingress noise issue solved
Quality concern regarding passives and cables
Investment in diplex filters and return amplifiers
DOCSIS®
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Acknowledgements
Information Sources
DOCSIS®
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Acronyms/Abbreviations
Common terms in DOCSIS systems
DOCSIS®
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Thank you.
Any questions?
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