DOCSIS IP-video Bypass Architecture (DIBA)

an Architecture for IPTV over Cable

Speaker:陳羿仲Advisor:吳和庭

2012/4/10

1

Outline

• Introduction• Modular CMTS for IP-Video• DOCSIS IP-video Bypass Architecture (DIBA)• DIBA development network• CONTROL PLANE: DIBA LEVERAGES STANDARD PCMM AND CMTS FUNCTIONS• Over-the-top video• References

2

Introduction

• IPTV• Data over Cable Service Interface Specification

(DOCSIS)• Video on Demand (VoD)• MPEG• EdgeQAM (E-QAM) modulator• Cable Modem Termination System (CMTS)

3

4

5

Modular CMTS for IP-Video• The DOCSIS Modular-CMTS (M-CMTS) architecture defined a common Edge-QAM

(E-QAM) architecture in which the E-QAMs are separate from the CMTS core.

• The CMTS core does much of the DOCSIS downstream processing, but the final DOCSIS downstream emerges from the E-QAM.

• A strategy of using M-CMTS to provide IPTV VoD would call for deploying M-CMTS EQAMs for DV-VoD first, and adding M-CMTS core capacity as needed to transition the digital video VoD to IPTV-VoD.

• The M-CMTS core capacity used for IPTV-VoD would quickly exceed the CMTS capacity used for high speed data (HSD). A straightforward implementation of M-CMTS for IPTV, therefore, will require many times the cost of MCMTS core capacity as that currently used for HSD.

6

DOCSIS IP-video Bypass Architecture (DIBA)

• The ‘Hairpin’ Cost• Designed for Economy• Video Encapsulation by DIBA Edge-QAMs• Encapsulation scheme for IP-video

7

The ‘Hairpin’ Cost

8

Video Encapsulation by DIBA Edge-QAMs

• instead of traveling from the edge (or last-hop) router to the CMTS, the packets bypassthe CMTS and instead go to the DIBA Encapsulator/Edge- QAM

• Secondly, the DIBA EdgeQAM is modified to perform the necessary DOCSIS framing on the incoming, video bearing IP packets

• The cable modem cannot distinguish these channels from equivalent ‘un-synchronized’ channels from a CMTS or MCMTS DEPI EdgeQAM

9

Video Encapsulation by DIBA Edge-QAMs

10

Encapsulation scheme for IP-video• Encapsulation is the inclusion of one data structure within

another structure so that the first data structure is hidden for the time being

• Generic Routing Encapsulation (GRE): defined by RFC 2784, is a simple IP packet encapsulation protocol. A GRE tunnel is used when IP packets need to be sent from one network to another, without being parsed or treated like IP packets by any intervening routers

11

Encapsulation scheme for IP-video

12

Design for Economy• DIBA accomplishes the goals of the M-CMTS without the unnecessary

expense of the M-CMTS core processing. It also works with integrated CMTSs

• Operators can deploy independently scalable numbers of downstream channels without changing the MAC domain or the number of upstream DOCSIS channels

• These downstream channels are available for VoD/IP and switched-digital-video/IP. They can also lower the cost to deliver video over DOCSIS service to be competitive with today’s MPEG VoD

13

Design for Economy• A DOCSIS 3.0 cable modem can receive multiple downstream DOCSIS

channels, but only one needs to be fully functional at the MAC layer

• This primary or synchronized channel will convey the DOCSIS timestamps to the CMs; manage ranging to provide the proper time-base to the cable modem; instruct the cable modems when to transmit upstream; deliver other MAC layer messages for cable modem registration, maintenance, etc

14

DIBA development network

15

DIBA development network• PacketCable is an industry consortium founded by CableLabs with the goal

of defining standards for the cable television modem access industry.

• Policy server is a security component of a policy-based network that provides authorization services and facilitates tracking and control of files.

16

CONTROL PLANE: DIBA LEVERAGES STANDARD PCMM AND CMTS FUNCTIONS

• 1. IPTV client requests IP video by way of a SIP invite, which passes first to the Proxy-CSCF. The P-CSCF forwards the service request and QoS requirements to the DIBA application manager. This information then passes to the PCMM policy server, and finally to CMTS.

• 2. CMTS checks authorization of CM for desired class of service and if QoS can be supported.

• 3. The CMTS requests the necessary additional downstream channel capacity on a DIBA E-QAM from the Edge Resource Manager.

• 4. The CMTS configures the CM for the appropriate DOCSIS channel and video flow from the DIBA EdgeQAM.

• 5. CMTS makes available certain additional fields necessary for DIBA encapsulation by the Edge-QAM / Encapsulation Engine, e.g., the CPE MAC address. The CMTS signals OK back to the Policy Server and DIBA Application Manager.

17

CONTROL PLANE: DIBA LEVERAGES STANDARD PCMM AND CMTS FUNCTIONS

• 6. The DIBA application manager configures the edge router so as to identify the IP packets that are to be bypassed, e.g., based on the source and destination IP addresses; source and destination Port numbers; IP protocol type. Thus, instead of being forwarded to the CMTS, packets of the new DIBA video flow will be tunneled to the DIBA EdgeQAM, e.g., by a Generic Routing Encapsulation Tunnel.

• 7. The DIBA App Manager signals OK back to the P-CSCF

• 8. The P-CSCF then forwards the SIP INVITE to the IPTV Server, which forwards it to the VoD server.

• 9. A SIP OK is sent from the VoD server back along this chain to the IP set-top. The video flow begins.

18

Over-the-top video• over-the-top content (OTT) means on-line delivery of video

and audio without the Internet service provider (Comcast, Verizon, etc.) being involved in the control or distribution of the content itself

19

Over-the-top video

20

References• Joyce, G.; Bao, J.; Patrick, M.; Flanagan, D. “DOCSIS IP-Video

Bypass Architecture (DIBA), an Architecture for IPTV over Cable “, Consumer Communications and Networking Conference, 2009. CCNC 2009. 6th IEEE

• Wikipedia• RFC-2784• Cablelabs : http://www.cablelabs.com/

21

Thank you , Q&A