CED WEB EXTRA: PacketCable 2.0 – Design Goals, Strategic Drivers and Architecture

Thu, 11/30/2006 - 7:00pm
Kevin Johns, Project Director, PacketCable Communication Protocols; and Eric Rosenfeld, Director, PacketCable Architecture; for the Advanced Network Systems Dept. at CableLabs.


With more then 32 million broadband customers, the cable industry is the leading provider of broadband services. In less than two years, the cable industry has also become the leading provider of VoIP services, with nearly 7 million customers receiving digital phone service through cable. Backed by their amazing success so far, the cable industry is now laying the foundation for the next generation of real-time communication services based on the Internet Protocols (IP). The development of this foundation will fulfill the cable industry vision of having an IP-services delivery platform that allows the cable industry to offer exciting new services to consumers in a cost-effective manner.

PacketCable™ 2.0 helps make this vision a reality by defining a modular service architecture based upon emerging technologies and existing communications standards. PacketCable 2.0 provides cable operators with a flexible way to deploy the network capabilities required by their specific service offerings, while maintaining interoperability across a variety of devices from multiple suppliers.

This article is the first in a four part series that explains the PacketCable 2.0 project. It describes the PacketCable 2.0 design goals, strategic drivers, and architecture. Subsequent articles will be:

·SIP and QoS - This article discusses PacketCable's use of the SIP protocol and how it is integrated with PacketCable Multimedia to create a holistic service framework.

·Provisioning, Activation, Configuration and Management (PACM), and Security - This article focuses on how PacketCable 2.0 supports a wide variety of client types. Through a uniform configuration framework and flexible security architecture, PacketCable 2.0 provides secure, managed services, regardless of the device or its location.

·The future of PacketCable 2.0 - This article discusses how various applications can use the PacketCable 2.0 architecture.


CableLabs® developed an open architecture called PacketCable to facilitate delivery of IP communication services over broadband cable networks. PacketCable is built on top of the industry’s DOCSIS® 1.1 and 2.0 platforms. PacketCable enables cable operators to deliver voice and multimedia traffic efficiently, securely, and economically within a Quality of Service (QoS)-enabled broadband infrastructure.

CableLabs and its members selected residential telephone service as the first application. To that end, the core set of PacketCable interface specifications (now known as PacketCable 1.0 and 1.5) defines an end-to-end managed VoIP architecture for voice communications within the cable network and for the public switched telephone network (PSTN). Cable operators worldwide are deploying PacketCable platforms for voice services.

CableLabs then developed PacketCable Multimedia, a resource management and policy framework for providing QoS to cable-delivered IP multimedia applications. The PacketCable Multimedia architecture enables a broader range of applications to utilize the QoS-enabled broadband infrastructure.

PacketCable 2.0 continues the evolution of cable’s IP services. It is an application-agnostic architecture that is based on a common network core. The network core is a set of network elements that use standard protocols to register clients in the network and to establish sessions (e.g., voice, video, text). By removing the service logic from the core network, cable operators obtain the ability to use this network core for all of their communication services. This approach provides cable operators with highly integrated networks and enables seamless service delivery across wired and wireless networks, plus it supports a range of service extensions not currently possible in today’s environment.

PacketCable 2.0 will allow the rapid introduction of new services such as fixed mobile convergence (e.g., integration of the cable network with wireless networks), commercial services (e.g., IP Centrex), and cross platform feature integration (e.g., set-top box applications that integrate with the voice service for features such as caller ID display on the TV and the ability to forward incoming calls to voicemail or other telephone numbers).


PacketCable 2.0 is an application-agnostic architecture. As such, functional requirements rather than specific service definitions were the primary drivers. Focusing on generic capabilities that are common to any application resulted in an architecture that is flexible enough to support many different applications. PacketCable 2.0 supports a wide variety of client types (e.g., soft clients, digital voice adaptors, WiFi handsets, and set-top Boxes). PacketCable 2.0 supports the DOCSIS access network QoS without precluding other access networks (i.e., wireless). Finally, PacketCable 2.0 leverages existing cable methods for authentication as well as support for network address translation (NAT) and firewall traversal.

The following figure illustrates the application-agnostic nature of PacketCable 2.0. In the figure, applications reside outside the PacketCable 2.0 core network and use the core network to connect to clients.


PacketCable 2.0 is based upon the Third Generation Partnership Project (3GPP) IP Multimedia Subsystem (IMS). IMS provides a framework for the delivery of IP Multimedia services (i.e., audio, video, text, chat) by defining an architecture that includes component behavior and protocols. The IMS was developed to meet the requirements of the Groupe Speciale Mobile (GSM) wireless industry. IMS has become the Session Initiation Protocol (SIP) service delivery platform of choice for many telecommunication industry sectors, such as wireless, DSL, and cable. However, IMS was developed for the GSM industry, which is a different business, a different service, and has different operational requirements from cable.

In incorporating the IMS into PacketCable 2.0, the cable industry has accelerated the development of PacketCable specifications and the availability of products and services while avoiding re-inventing the SIP service platform. However, IMS currently doesn’t meet all of the cable industry’s requirements. As such, CableLabs is working with 3GPP to enhance the IMS to meet the functional requirements of the cable industry. The objective is to tune IMS to support the cable industry's needs, and then focus on defining value-added applications.


The PacketCable 2.0 architecture provides a modular platform upon which a variety of IP communication services may be built for a diverse set of clients. The architecture is divided into several logical areas or functional groupings. These functional groupings, along with various elements within the groupings, supply the foundations for a wide variety of innovative new services. The following paragraphs and figure describe the PacketCable 2.0 architecture.

PacketCable 2.0 clients connect to the PacketCable 2.0 network through the local network (which is often customer owned and operated), and in turn, through an access network (which can be a DOCSIS network or some other technology). The client, having gained basic network connectivity, then needs to be provisioned.


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