PacketCable™ 1.0 Architecture Framework
`Technical Report
`
`PKT-TR-ARCH-V01-991201
`
`Notice
`
`This PacketCable technical report is a cooperative effort
`undertaken at
`the direction of Cable Television
`Laboratories, Inc. (CableLabs®) for the benefit of the
`cable industry. Neither CableLabs, nor any other entity
`participating
`in
`the creation of
`this document,
`is
`responsible for any liability of any nature whatsoever
`resulting from or arising out of use or reliance upon this
`document by any party. This document is furnished on
`an AS-IS basis and neither CableLabs, nor other
`participating entity, provides any representation or
`warranty, express or implied, regarding its accuracy,
`completeness, or fitness for a particular purpose.
`
` Copyright 1999 Cable Television Laboratories, Inc.
`
`All rights reserved.
`
`GTL 1014
`IPR of U.S. Pat. No. 7,529,357
`
`ª
`

`

`PacketCable™ 1.0 Architecture Framework Technical Report
`
`PKT-TR-ARCH-V01-991201
`
`Abstract
`
`This technical report describes the architecture framework for PacketCable(cid:228)
`networks including all major system components and network interfaces necessary
`for delivery of PacketCable services. The intended audience for this document
`includes
`developers
`of
`equipment
`intended
`to
`be
`conformant
`to
`PacketCable specifications, and network architects who need to understand the
`overall PacketCable architecture framework.
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`PacketCable™ 1.0 Architecture Framework Technical Report
`
`Document Status Sheet
`
`Document Control Number: PKT-TR-ARCH-V01-991201
`Document Title: PacketCable™ 1.0 Architecture Framework Technical
`Report
`Revision History: D01-991201: release
`
`Date: December 1, 1999
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`
`TABLE OF CONTENTS
`
`1 INTRODUCTION ............................................................................................... 1
`
`1.1 PacketCable Overview.......................................................................................1
`1.2 PacketCable Motivation.....................................................................................1
`1.3 PacketCable Project Phasing............................................................................2
`
`2 PACKETCABLE 1.0.......................................................................................... 3
`
`2.1 PacketCable Architecture Framework..............................................................4
`2.2 PacketCable Zones and Domains.....................................................................5
`2.3 PacketCable 1.0 Specifications ........................................................................5
`2.4 PacketCable 1.0 Design Considerations ..........................................................6
`2.4.1 General Architectural Goals ........................................................................7
`2.4.2 Call Signaling ..............................................................................................7
`2.4.3 Quality of Service........................................................................................8
`2.4.4 CODEC and Media Stream .........................................................................9
`2.4.5 Device Provisioning and OSS .....................................................................9
`2.4.6 Security.......................................................................................................9
`3 PACKETCABLE FUNCTIONAL COMPONENTS........................................... 10
`
`3.1 Multimedia Terminal Adapter (MTA) ...............................................................10
`3.1.1 MTA Functional Requirements..................................................................11
`3.1.2 MTA identifiers ..........................................................................................11
`3.2 Cable Modem (CM) ..........................................................................................12
`3.3 HFC Access Network.......................................................................................12
`3.4 Cable Modem Termination System (CMTS) ...................................................12
`3.4.1 CMTS Gate...............................................................................................13
`3.5 Call Management Server (CMS) ......................................................................13
`3.6 PSTN Gateway .................................................................................................14
`3.6.1 Media Gateway Controller (MGC) .............................................................15
`3.6.2 Media Gateway (MG) ................................................................................15
`3.6.3 Signaling Gateway (SG)............................................................................16
`3.7 OSS Back Office Components........................................................................17
`3.7.1 TGS ..........................................................................................................17
`3.7.2 Dynamic Host Configuration Protocol Server (DHCP) ...............................18
`3.7.3 Domain Name System Server (DNS) ........................................................18
`3.7.4 Trivial File Transfer Protocol Server or HyperText Transfer Protocol Server
`(TFTP or HTTP).................................................................................................18
`3.7.5 SYSLOG Server (SYSLOG)......................................................................18
`3.7.6 Record Keeping Server (RKS ) .................................................................18
`3.8 Announcement Server (ANS)..........................................................................18
`3.8.1 Announcement Controller (ANC)...............................................................19
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`3.8.2 Announcement Player (ANP) ....................................................................19
`4 PROTOCOL INTERFACES............................................................................. 20
`
`4.1 Call Signaling Interfaces .................................................................................20
`4.1.1 Network-based Call Signaling (NCS) Framework......................................21
`4.1.2 PSTN Signaling Framework ......................................................................22
`4.2 Media Streams .................................................................................................23
`4.3 MTA Device Provisioning................................................................................25
`4.4 SNMP Element Management Layer Interfaces...............................................26
`4.5 Event Messages Interfaces .............................................................................26
`4.5.1 Event Message Framework.......................................................................26
`4.6 Quality-of-Service (QoS) .................................................................................28
`4.6.1 QoS Framework........................................................................................28
`4.6.2 Layer Two vs. Layer Four MTA QoS Signaling..........................................30
`4.6.3 Dynamic Quality-of-Service.......................................................................31
`4.7 Announcement Services .................................................................................33
`4.7.1 ANS Physical vs. Logical configuration .....................................................34
`4.8 Security ............................................................................................................34
`4.8.1 Overview...................................................................................................34
`4.8.2 Device Provisioning Security.....................................................................38
`5 NETWORK DESIGN CONSIDERATIONS ...................................................... 41
`
`5.1 Time Keeping and Reporting Issues ..............................................................41
`5.2 Timing for Playout Buffer Alignment with Coding Rate................................41
`5.3 IP Addressing...................................................................................................41
`5.4 Dynamic IP Addressing Assignment..............................................................42
`5.5 FQDN Assignment ...........................................................................................43
`5.6 Priority Marking of Signaling and Media Stream Packets.............................43
`5.7 Fax Support......................................................................................................44
`5.8 Analog Modem Support ..................................................................................45
`
`6 FUTURE CONSIDERATIONS......................................................................... 46
`
`APPENDIX A. ACKNOWLEDGEMENTS........................................................... 47
`
`APPENDIX B. REFERENCES ........................................................................... 48
`
`APPENDIX C. GLOSSARY................................................................................ 51
`
`APPENDIX D. EXAMPLE DELAY BUDGETS ................................................... 61
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`Figures
`• Figure 1. PacketCable Reference Architecture ......................................................... 4
`• Figure 2. Zones and Administrative Domains............................................................ 5
`• Figure 3. PacketCable Component Reference Model ..............................................10
`• Figure 4. E-MTA Conceptual Functional Architecture ..............................................12
`• Figure 5. Call Signaling Interfaces ...........................................................................20
`• Figure 6. RTP Media Stream Flows in a PacketCable Network ...............................23
`• Figure 7. RTP Packet Format ..................................................................................24
`• Figure 8. PacketCable Provisioning Interfaces.........................................................25
`• Figure 9. Representative Event Messages Architecture...........................................27
`• Figure 10. Event Message Interfaces ......................................................................27
`• Figure 11. PacketCable QoS Signaling Interfaces ...................................................28
`• Figure 12. Annoucement Services Components and Interfaces...............................33
`• Figure 13. PacketCable Security Interfaces .............................................................36
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`Tables
`• Table 1 PacketCable 1.0 Specifications and Reports................................................ 6
`• Table 2. Call Signaling Interfaces ............................................................................21
`• Table 3. Device Provisioning Interfaces ...................................................................25
`• Table 4. Event Message Interfaces..........................................................................27
`• Table 5. QoS Interfaces for Standalone and Embedded MTAs................................29
`• Table 6. QoS Interfaces...........................................................................................29
`• Table 7. Announcement Interfaces ..........................................................................34
`• Table 8. Security Interfaces .....................................................................................37
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`1 INTRODUCTION
`
`1.1 PacketCable Overview
`PacketCable™ is a project conducted by Cable Television Laboratories, Inc.
`(CableLabs®) and its member companies. The PacketCable project is aimed at
`defining interface specifications that can be used to develop interoperable equipment
`capable of providing packet-based voice, video and other high-speed multimedia
`services over hybrid fiber coax (HFC) cable systems utilizing the DOCSIS protocol.
`PacketCable utilizes a network superstructure that overlays the two-way data-ready
`broadband cable access network. While the initial PacketCable offering will be
`packet-based voice communications for existing and new cable subscribers, the long-
`term project vision encompasses a large suite of packet-based capabilities.
`The objective of the PacketCable Architecture Technical Report is to provide a high
`level reference framework that identifies the functional components and defines the
`interfaces necessary to implement the capabilities detailed in the individual
`PacketCable specifications as listed in section 2.3.
`
`1.2 PacketCable Motivation
`The emergence of the Internet Protocol (IP) as the standard transport for packet data
`networks has enabled a revolution in communications service and applications. This
`online revolution is evidenced by the widespread use of email, chat groups, music,
`video, and the exponential growth of the World Wide Web, for entertainment,
`information exchange, online commerce, and a wide range of the new and innovative
`services. New classes of IP based information appliances are also emerging, including
`multimedia personal computers, IP based set top boxes, and IP based voice and video
`phones.
`In recent years the growth of a worldwide IP based data network, coupled with the
`exponential growth in the number of households that have online access, have
`resulted in an enabling environment for offering integrated voice and data services
`over a common broadband cable access network and IP transport backbone. While
`the initial application of IP voice technology was for toll bypass services, particularly
`high-cost international toll service, the technology has now matured to the point
`where it is feasible to offer IP-based voice communications services comparable to
`those offered by telecommunications carriers on the PSTN.
`With the success of the DOCSIS standardization effort, the QoS enhancements of
`DOCSIS 1.1, and the acceleration of major cable system upgrades for two way
`capacity, the infrastructure is in place for development and deployment of packetized
`voice and video applications. These applications can be deployed with minimal
`incremental cost, providing a technically distinctive and cost-effective alternative for
`subscribers’ voice communications needs, as well as a platform for introducing the
`next generation of voice and other real time multimedia services.
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`1.3 PacketCable Projec t Phasing
`The PacketCable architecture is designed to be a robust, complete, end-end
`broadband architecture that supports voice, video, and other multimedia services. The
`architecture is capable of supporting millions of subscribers over multiple cable
`operator networks.
`It is understood that the initial focus of the PacketCable architecture must support the
`time-to-market business considerations of CableLabs Member Companies for
`deploying packet-based services. Going forward, the PacketCable architecture must
`continue to evolve to meet Member business requirements and to accommodate
`advances resulting from the maturing of IP-based technology. The PacketCable
`project will release specifications that define this architecture in a phased approach
`according to technical feasibility and business priority. As new PacketCable
`specifications are released,
`they will complement
`the previously
`released
`specifications.
`From time to time this document refers to the voice communications capabilities of a
`PacketCable network in terms of “IP Telephony.” The legal/regulatory classification
`of IP-based voice communications provided over cable networks and otherwise, and
`the legal/regulatory obligations, if any, borne by providers of such voice
`communications, are not yet fully defined by appropriate legal and regulatory
`authorities. Nothing in this document is addressed to, or intended to affect, those
`issues. In particular, while this document uses standard terms such as “call,” “call
`flow,” “telephony,” etc., it should be recalled that while a PacketCable network
`performs activities analogous to these PSTN functions, the manner by which it does
`so differs considerably from the manner in which they are performed in the PSTN by
`telecommunications carriers, and that these differences may be significant for
`legal/regulatory purposes. Moreover, while reference is made here to “IP Telephony,”
`it should be recognized that this term embraces a number of different technologies
`and network architecture, each with different potential associated legal/regulatory
`obligations. No particular legal/regulatory consequences are assumed or implied by
`the use of this term.
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`2 PACKETCABLE 1.0
`‘PacketCable 1.0’ is a CableLabs definition for the first release of specifications that
`define the PacketCable reference architecture.
`In this version of the architecture framework, the emphasis is on specification of the
`subscriber environment and its interface requirements to the PacketCable network
`including the DOCSIS HFC access network, Call Management Server, media servers,
`PSTN gateway, and MTA device provisioning components. The requirements for
`these functional components and the standardized interfaces between components are
`defined in detail in the PacketCable 1.0 specifications. In later versions, additional
`component interfaces will be defined.
`PacketCable 1.0 consists of a variety of functional components, each of which must
`work in harmony to create a consistent and cost-effective delivery mechanism for
`packet-based services. This distributed architecture allows incremental development
`and deployment of new features and services, leaving room for implementation
`flexibility and product innovation. A key focus of the initial PacketCable release is
`the definition of low-cost subscriber equipment and a network architecture that
`supports low cost packet-based services. Follow-on phases of this project will
`continue to add support for advanced subscriber-side functionality. This may require
`evolution in the PacketCable call signaling, QoS security, provisioning, and billing
`protocols.
`PacketCable allows the use of proprietary vendor-specific solutions for interfaces not
`defined in specifications. Over time, as additional PacketCable interface protocols are
`defined, these proprietary interfaces will need to be updated in order to be compliant
`with PacketCable specifications.
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`2.1 PacketCable Archi tecture Framework
`
`At a very high level, the PacketCable 1.0 architecture contains three networks: the
`“DOCSIS HFC Access Network”, the “Managed IP Network” and the PSTN. The Cable
`Modem Termination System (CMTS) provides connectivity between the “DOCSIS HFC
`Access Network” and the “Managed IP Network”. Both the Signaling Gateway (SG) and
`the Media Gateway (MG) provide connectivity between the “Managed IP Network” and
`the PSTN. The reference architecture for PacketCable 1.0 is shown in Figure 1.
`
`Embedded MTA
`Client
`
`MTA
`
`Cable
`Modem
`
`HFC access
`network
`(DOCSIS)
`
`CMTS
`
`Embedded MTA
`Client
`
`MTA
`
`Cable
`Modem
`
`HFC access
`network
`(DOCSIS)
`
`CMTS
`
`Call
`Management
`Server
`
`(CMS)
`
`Managed IP Network
`
`Announcement
`Server
`
`Announcement
`Controller
`(ANC)
`
`Announcement
`Player
`(ANP)
`
`Media Gateway
`Controller
`(MGC)
`
`Media Gateway
`(MG)
`
`Signaling Gateway
`(SG)
`
`PSTN
`
`OSS
`Back Office
`Servers and
`Applications
`
`- Ticket Granting Server (TGS)
`- DHCP Servers
`- DNS Servers
`- TFTP or HTTP Servers
`- SYSLOG Server
`- Record Keeping Server (RKS)
`- Provisioning Server
`
`Figure 1. PacketCable Reference Architecture
`The DOCSIS HFC access network provides high-speed, reliable, and secure transport
`between the customer premise and the cable headend. This access network may provide
`all DOCSIS 1.1 capabilities including Quality of Service. The DOCSIS HFC access
`network includes the following functional components: the Cable Modem (CM), Multi-
`media Terminal Adapter (MTA), and the Cable Modem Termination System (CMTS).
`The Managed IP network serves several functions. First, it provides interconnection
`between the basic PacketCable functional components responsible for signaling, media,
`provisioning, and quality of service establishment. In addition, the managed IP network
`provides long-haul IP connectivity between other Managed IP and DOCSIS HFC
`networks. The Managed IP network includes the following functional components: Call
`Management Server (CMS), Announcement Server (ANS), several Operational Support
`System (OSS) back-office servers, Signaling Gateway (SG), Media Gateway (MG), and
`Media Gateway Controller (MGC).
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`The individual network components that are shown in Figure 1 are described in detail in
`Section 3.
`
`2.2 PacketCable Zones and Domains
`
`Administrative Domain 1
`
` CMS
`
`MSO A
`Zone 1
`
`Administrative Domain 2
`
`PSTN Gateway
`
`PSTN
`
`V
`
`CMS
`
`MSO B
` Zone 3
`
`Managed
`IP Backbone
`
`PSTN Gateways
`
`PSTN
`
`MSO A
` Zone 2
`
`V
`
`PSTN Gateway
`PSTN
`
`V
`
`CMS
`
`MSO C
`Zone 4
`
`Administrative Domain 3
`
`Figure 2. Zones and Administrative Domains
`A PacketCable zone consists of the set of MTAs in one or more DOCSIS HFC access
`networks that are managed by a single functional CMS as shown in Figure 2.
`Interfaces between functional components within a single zone are defined in the
`PacketCable 1.0 specifications. Interfaces between zones (e.g., CMS-CMS) have not
`been defined and will be addressed in future phases of the PacketCable architecture.
`A PacketCable domain is made up of one or more PacketCable zones that are
`operated and managed by a single administrative entity. A PacketCable domain may
`also be referred to as an administrative domain. Interfaces between domains have not
`defined in PacketCable 1.0 and will be addressed in future phases of the PacketCable
`architecture.
`
`2.3 PacketCable 1.0 Sp ecifications
`PacketCable 1.0 consists of the eleven Specifications and three Technical Reports
`shown in Table 1.
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`Table 1 PacketCable 1.0 Specifications and Reports
`
`PacketCable Specification
`Reference Number
`
`Specification Name
`
`PKT-SP-CODEC
`PKT-SP-DQOS
`PKT-SP-EC-MGCP
`PKT-SP-EM
`PKT-SP-ISTP
`PKT-SP-MIBS
`PKT-SP-MIBS-MTA
`PKT-SP-MIBS-NCS
`PKT-SP-PROV
`PKT-SP-SEC
`PKT-SP-TGCP
`
`PacketCable Technical Report
`Reference Number
`
`Audio/Video Codecs
`Dynamic Quality-of-Service
`Network-Based Call Signaling (NCS)
`Event Messages
`Internet Signaling Transport Protocol (ISTP)
`MIB Framework
`MTA MIB
`NCS MTA MIB
`MTA Device Provisioning
`Security
`PSTN Gateway Call Signaling Protocol
`
`Technical Report Name
`
`PKT-TR-CF
`PKT-TR-ARCH
`PKT-TR-OSS
`
`Call Flows
`Architecture Framework
`OSS Overview
`
`2.4 PacketCable 1.0 De sign Considerations
`In order to enable real-time multimedia communications across the cable network
`infrastructure, PacketCable specifications define protocols in the following areas:
`• Call Signaling
`• Quality of Service
`• Media Stream Transport and Encoding
`• Device Provisioning
`• Event Messaging
`• Security and Privacy
`• Operational Support Systems
`This section provides an overview of the high-level design goals and concepts used in
`developing the specifications that define the PacketCable 1.0 reference architecture.
`Individual PacketCable specifications should be consulted to obtain detailed protocol
`requirements for each of these areas.
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`2.4.1 General Architectural Goals
`• Enable voice quality capabilities comparable to or better than the PSTN as perceived
`by the end-user.
`• Provide a network architecture that is scalable and capable of supporting millions of
`subscribers.
`• Ensure the one-way delay for local IP access and IP egress (i.e. excluding the IP
`backbone network) is less than 45ms.
`• Support primary and secondary line residential voice communications capabilities.
`• Leverage existing protocol standards. PacketCable strives to specify open, approved
`industry standards
`that have been widely adopted
`in other commercial
`communication networks. This includes protocols approved by the ITU, IETF, IEEE,
`Telcordia and other communications standards organizations.
`• Leverage and build upon the data transport and Quality of Service capabilities
`provided by DOCSIS.
`• Define an architecture that allows multiple vendors to rapidly develop low-cost
`interoperable solutions to meet Member time-to-market requirements.
`• Ensure that the probability of blocking a call can be engineered to be less than 1%
`during the High Day Busy Hour (HDBH)
`• Ensure that call cutoffs and call defects can be engineered to be less than 1 per
`10,000 completed calls.
`• Support modems (up to V.90 56 kb/s) and fax (up to 14.4 kbps)
`• Ensure that frame slips due to unsynchronized sampling clocks or due to lost packets
`occur less than 0.25 per minute.
`
`2.4.2 Call Signaling
`• Define a network-based signaling paradigm.
`• Provide end-to-end call signaling for the following call models:
`• calls that originate from the PSTN and terminate on the cable network
`• calls that originate on the cable network and terminate on the cable network
`within a single PacketCable zone
`• calls that originate from the cable network and terminate on the PSTN
`• Provide signaling to support custom calling features such as:
`• Call Waiting
`• Cancel Call Waiting
`• Call Forwarding (no-answer, busy, variable)
`• Three-way Calling
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`• Voice mail Message Waiting Indicator
`• Provide signaling to support Custom Local Area Signaling Services (CLASS)
`features such as:
`• Calling Number Delivery
`• Calling Name Delivery
`• Calling Identity Delivery On Call Waiting
`• Calling Identity Delivery Blocking
`• Anonymous Call Rejection
`• Automatic Callback
`• Automatic Recall
`• Distinctive Ringing/Call Waiting
`• Customer Originated Trace
`• Support a signaling paradigm consistent with existing IP telephony standards for
`use within a cable operator’s PacketCable network and when connecting to the
`PSTN.
`• Ability to direct dial any domestic or international telephone number (E.164
`address)
`• Ability to receive a call from any domestic or international telephone number
`supported by the PSTN.
`• Ensure that a new subscriber retains current phone number via Local Number
`Portability (LNP)
`• Ability to use the IXC of choice for intra-LATA toll (local toll) and inter-LATA
`(long distance) calls. This includes pre-subscription and "dial-around" (10-1X-
`XXX).
`• Support Call Blocking/Call Blocking Toll restrictions, (e.g. blocking calls to 900-,
`976-, etc.)
`
`2.4.3 Quality of Service
`• Provide a rich set of policy mechanisms to provide and manage QoS for PacketCable
`services over the access network.
`• Provide admission control mechanisms for both upstream and downstream
`directions.
`• Allow dynamic changes in QoS in the middle of PacketCable calls.
`• Enable transparent access to all of the QoS mechanisms defined in DOCSIS 1.1.
`PacketCable clients need not be aware of specific DOCSIS QoS primitives and
`parameters.
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`• Minimize and prevent abusive QoS usage including theft-of and denial-of service
`attacks. Ensure QoS policy is set and enforced by trusted PacketCable network
`elements.
`• Provide a priority mechanism for 911 and other priority based signaling services.
`
`2.4.4 CODEC and Media Str eam
`• Minimize the effects that latency, packet-loss, and jitter have on voice-quality in the
`IP telephony environment.
`• Define a minimum set of audio codecs that must be supported on all PacketCable
`endpoint devices (MTAs). Evaluation criteria for mandatory codecs are selected as
`those most efficient with respect to voice quality, bandwidth utilization, and
`implementation complexity.
`• Accommodate evolving narrow-band and wide-band codec technologies.
`• Specify echo cancellation and voice activity detection mechanisms.
`• Support for transparent, error-free DTMF transmission and detection.
`• Support terminal devices for the deaf and hearing impaired.
`• Provide mechanisms for codec switching when fax and modem services are required.
`
`2.4.5 Device Provisioning a nd OSS
`• Support dynamic and static provisioning of customer premise equipment (MTA and
`Cable Modem).
`• Provisioning changes should not require reboot of MTA.
`• Allow dynamic assignment and management of IP addresses for subscriber devices
`• Ensure that real-time provisioning and configuration of MTA software does not
`adversely affect subscriber service.
`• Define SNMP MIBs for managing customer premise equipment (MTA).
`
`2.4.6 Security
`• Enable residential voice capabilities with the same or higher level of perceived
`privacy as in the PSTN.
`• Provide protection against attacks on the MTA.
`• Protect the MSO from various denial of service, network disruption and theft of
`service attacks.
`• Design considerations
`include confidentiality, authentication,
`repudiation and access control.
`
`integrity, non-
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`PKT-TR-ARCH-V01-991201
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`3 PACKETCABLE FUNCTIONAL COMPONENTS
`This section describes the functional components present in a PacketCable network.
`Component descriptions are not intended to define or imply product implementation
`requirements but instead to describe the functional role of each of these components
`in the reference architecture. Note that specific product implementations may
`combine functional components as needed. Not all components are required to be
`present in a PacketCable Network.
`The PacketCable architecture contains trusted and untrusted network elements.
`Trusted network elements are typically located within a Cable Operator’s managed
`backbone network. Untrusted network elements, such as the CM and MTA, are
`typically located within the subscriber's home and outside of the MSO’s facility.
`
`CMTS
`
`Router
`
`Embedded
` MTA
`
`MTA/
`CM
`
`Router
`
`Managed IP
`Backbone
`
`Router
`
`Cable Modem
`Termination System
`
`Router
`
`CMTS
`
`OSS Servers
`
`Call Management
`Server
`
`Media Servers
`
`RKS
`
`DNS
`
`DHCP
`
`SNMP
`
`TFTP
`
`SYSLOG
`
`TGS
`
`Call Agent
`
`Gate
`Controller
`
`Announce-
`ment
`Controller
`
`Announcement
`Player
`
`MTA/
`CM
`
`PSTN
`
`PSTN
`Gateways
`
`Media
`Gateway
`Controller
`
`Media
`Gateway
`
`Signaling
`Gateway
`
`Figure 3. PacketCable Component Reference Model
`
`3.1 Multimedia Termin al Adapter (MTA)
`An MTA is a PacketCable client device that contains a subscriber-side interface to the
`subscriber’s CPE (e.g., telephone) and a network-side signaling interface to call
`control elements in the network. An MTA provides codecs and all signaling and
`encapsulation functions required for media transport and call signaling.
`MTAs reside at the customer site and are connected to other PacketCable network
`elements via the HFC access network (DOCSIS). PacketCable 1.0 MTAs are required
`to support the Network Call Signaling (NCS) protocol.
`An embedded MTA (E-MTA) is a single hardware device that incorporates a
`DOCSIS 1.1 cable modem as well as a PacketCable MTA component. Figure 4
`shows a representative functional diagram of an E-MTA.
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`10
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`CableLabs®
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`12/01/99
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`

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`PKT-TR-ARCH-V01-991201
`
`PacketCable™ 1.0 Architecture Framework Technical Report
`
`PacketCable 1.0 specifications only require support for embedded MTAs. Throughout
`this report, unless otherwise noted, the term MTA refers to an embedded MTA.
`
`3.1.1 MTA Functional Requ irements
`An MTA is responsible for the following functionality:
`• NCS call signaling with the CMS
`• QoS signaling with the CMS and the CMTS
`• Authentication, confidentiality and integrity of some messages between the MTA
`and other PacketCable network elements
`• Mapping media streams to the MAC services of the DOCSIS access network
`• Encoding/decoding of media streams
`• Providing multiple audio indicators to phones, suc