docsis® rev. a00. items for discussion agenda docisis docsis 3.0 docsis/eurodocsis overview of...

DOCSIS®

Rev. A00

Items for discussion

Agenda

DOCISISDOCSIS 3.0

DOCSIS/EuroDOCSIS Overview of Standards, Features &

Benefits

DOCSIS 3.0/EuroDOCSIS 3.0 CATV Market Dynamics New Technical Directions & Features Network Preparation

DOCSIS® 2Confidential & Proprietary Information of VeEX Inc

DOCSIS Review

3Confidential & Proprietary Information of VeEX Inc

Overview, Features & Benefits

DOCSIS system Enables transparent bi-directional of Internet Protocol (IP) traffic, between the cable system headend and

customer location

DOCSIS specification 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

An Overview

DOCSIS

DOCSIS® Confidential & Proprietary Information of VeEX Inc 4

Transparent IP traffic

Wide Area Network

Cable Network (HFC)

CMTS Cable Modem CPE

CM/CPE Interface

CMTS/WAN Interface

Milestones

DOCSIS


HFC Spectrum Allocation

DOCSIS


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

EuroDOCSISUS

Analog VideoPAL

Digital VideoMPEG/DVB + VOD

EuroDOCSISDS

5MHz 65 87 108 862MHz

FM

Upstream Downstream

80

Europe

US DOCSISUS

Analog VideoNTSC

Digital VideoMPEG/DVB + VOD

US DOCSISDS

5MHz 42 87 108 862MHz

FM

Upstream Downstream

80

North America

The DOCSIS Specification defines Modulation and Coding Schemes outlined in the following table for the Upstream

Upstream Physical Layer

DOCSIS


The DOCSIS Specification defines Modulation and Coding Schemes outlined in the following table for the Downstream

Downstream Physical Layer

DOCSIS


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)

Power Ranging

DOCSIS


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.

CM Protocol Stack

DOCSIS


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

Media Access Control (MAC)

DOCSIS


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

DHCP Server & Process

DOCSIS


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)

Time of Day (TOD) Server

DOCSIS


TFTP Server

DOCSIS


TFTP (Trivial File Transfer Protocol) Server In accordance with RFC 1350 UDP port 69 Small and easy to implement with read and write to and from remote servers

The following settings are mandatory in the TFTP configuration file: 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 3.0

CATV Market Dynamics

Confidential & Proprietary Information of VeEX Inc 15

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

Business Drivers

DOCSIS 3.0


Higher Bandwidth Applications

DOCSIS 3.0

Digital Photos

Gaming

MP3 WMV

DVD Blu-ray

SDTV HDTV Mobile

Video

iPod Walkman

You Tube

VODDVR/PVR

Data & VoIP

Home Networks

Web 2.0


Consumers greed for speed

DOCSIS 3.0

18DOCSIS® Confidential & Proprietary Information of VeEX Inc

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

Services driving Channel Bonding

DOCSIS 3.0


DOCSIS 3.0

New Technical Directions & Features

Confidential & Proprietary Information of VeEX Inc 20

Major Feature Overview

DOCSIS 3.0


Channel bonding basically means data is transmitted to/from Cable Modems using multiple individual RF channels instead of a single channel

Channel Bonding

DOCSIS 3.0


Using DOCSIS 3.0, data is transmitted to cable modems using multiple channels

Throughput Compared

DOCSIS 3.0


DOCSIS VersionDate Rates – Annex A

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

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

Upstream PHY Modes

DOCSIS 3.0


5MHz 42MHz or 65MHz

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

Downstream Channel Bonding

DOCSIS 3.0


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

Upstream Channel Bonding

DOCSIS 3.0


P1P3 P2P4

US1

US2

U3

Request 1000 bytes

Grant 200

Grant 300 bytes

Grant 500 bytes

CMTS

Cable Modem

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

Upstream Requests and Grants

DOCSIS 3.0


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

MAC Domain

DOCSIS 3.0


MDD Descriptor Describes Plant topology

Plant Topology Describes fiber nodes and how they

are split/combined

Ambiguity Resolution 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

New MAC Functions

DOCSIS 3.0


CM Control report Used to force actions such as reboot,

or channel muting.

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

New MAC Management Messages (partial list)

DOCSIS 3.0


During initialization, the CM downloads a configuration file from the cable operator

The Config file defines: Quality of Service (QoS) parameters

Priority, rate limiting, bandwidth guarantees, etc. Filters

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

CM Provisioning

DOCSIS 3.0


Authentication & Key Exchange

Cable Modem Registration

DOCSIS 3.0


Scan digital channels & acquire QAM/FEC/MPEG lock of DOCSIS DS & DOCSIS PID

SYNC, UCD, MAP messages

Select upstream channel listed in MDD

MDD message

Tune additional downstream frequencies to determine service group

B-INIT-RNG-REQ message

DHCP DISCOVER packet

REG-REQ message

DHCP RESPONSE packet

DHCP REQUEST packet

DHCP OFFER packet

Transition to ranging station maintenance

REG-ACK message

REG-RSP message

BPI+ initialization if configured

TOD Request/Response messages

TFTP Request/Response messages

Provides Rx-Chan(s)

Receive Rx-Chan(s) configuration

Confirm all Rx Channels

Cable Modem

Receive MAC Domain Descriptor (MDD) Message

Find Initial Maintenance interval in MAP messagesSend RNG-REQ, receive RNG-RSP, adjust Txmitter

CMTS

Establish IPv4 or IPv6 communication via DHCP

Download Configuration File (TFTP)

Send REG-REQ, receive REG-RSP, send REG-ACK

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)

Better Network Security

DOCSIS 3.0


IPv6 in Cable Networks

DOCSIS 3.0


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 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.

Quick Summary

DOCSIS 3.0


Network Preparation

DOCSIS 3.0

36Confidential & Proprietary Information of VeEX Inc

Basic steps for being prepared

DOCSIS 3.0


Where can more RF bandwidth come from?

DOCSIS 3.0


Reclaim Analog bandwidth for more digital spectrum More QAM channels for Digital Broadcast, VoD, SDV and DOCSIS

Node splits Reduce the homes passed per HFC node, reducing contention/home for Unicast services

Switched Digital Video (SDV) Transmit only the content being actively watched

Efficient channel use Manage channel lineup, fill the gaps, and mitigate noise to utilize available spectrum

1GHz upgrade Make new spectrum for new CPE above 860 MHz

Bandwidth Management

DOCSIS 3.0


Today 870MHz

Soon 1GHz

How much can we gain with spectrum changes?

DOCSIS 3.0

250 Mbps

500 Mbps

1000 Mbps


Information Sources

Acknowledgements


Common terms in DOCSIS systems

Acronyms/Abbreviations



Thank you.Any questions?

docsis® rev. a00. items for discussion agenda docisis docsis 3.0 docsis/eurodocsis overview of...

Documents

data link layer

layer model

frequency spectrum

cable system headend

hfc network

downstream spectrum

end userupstream spectrum

cmts cmdocsis network