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Cisco DOCSIS 3.0 Downstream Solution Design and Implementation Guide
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Preface
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Solution Overview
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Cisco DOCSIS 3.0 Downstream Solution Components
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Cisco DOCSIS 3.0 Downstream Architecture
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Implementing and Configuring the Solution
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Monitoring and Troubleshooting Narrowband and Wideband Components
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Cisco DOCSIS 3.0 Downstream Solution Release 1.0 and 2.0 Component Compatibility Matrix
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Table Of Contents
Solution Description and Scope
Cisco and Scientific Atlanta Equipment
Solution Overview
Note
The information provided in this document for Cisco DOCSIS 3.0 Downstream Solution is specific to Cisco IOS Releases 12.2(33)SCB and 12.3(23)BC. For information that is specific to Cisco IOS Releases 12.3(21)BC and12.3(21a)BC3, refer to the Cisco Cable Wideband Solution Design and Implementation Guide for these releases.
This chapter provides an overview of the Cisco DOCSIS 3.0 Downstream Solution, and contains the following major topics:
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In this document, the terms wideband channel, bonded channel, and bonding group have the same meaning: a logical grouping of one or more physical radio frequency (RF) channels over which MPEG-TS packets are carried.
Solution Description and Scope
Cisco IOS Release 12.3(23)BC introduces the DOCSIS 3.0 Downstream Solution. In the Cisco Modular CMTS (M-CMTS) implementation, the downstream channels over the Downstream External PHY Interface (DEPI) are processed and encapsulated by the Cisco shared port adapter (SPA) and therefore they are also referred to as SPA downstream (DS) channels. The SPA DS channels can be used either as primary-capable channels (narrowband channels), or as part of bonded channels (wideband channels), or both. The solution provides narrowband data services to support DOCSIS 1.x/2.0 modems and wideband data services to support DOCSIS 3.0 modems over existing hybrid fiber coaxial (HFC) networks and allows DOCSIS 1.x/2.0 and DOCSIS 3.0 modems to share the same SPA DS channel. With wideband data services, multiple SPA DS channels are aggregated into a single logical wideband channel (bonding group) that delivers higher bandwidth to the wideband cable modem than was previously possible with DOCSIS 2.0 technology. This aggregation of the SPA DS channels is referred to as channel bonding.
The maximum bandwidth supported depends on the number of SPA DS channels that can be aggregated into a wideband channel.
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The Cisco DOCSIS 3.0 Downstream Solution, Release 2.0, can be deployed in parallel with DOCSIS 1.X/2.0 technology. The CMTS supports DOCSIS 1.X/ 2.0 modems on Cisco uBR10-MC5X20 line card channels as well as on the primary-capable SPA downstream channels, and it supports wideband cable modems via bonded SPA DS channels, delivering significantly higher throughput.
The solution provides the following capabilities:
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Primary-capable channels are SPA DS channels (also known as SPA RF channels) associated with the upstream channels from the Cisco uBR10-MC5X20 line card. These downstream channels carry SYNC messages as well as Upstream Channel Descriptors (UCD) and Mini-slot Allocation Packet (MAP) messages for at least one upstream channel. They may also carry primary MAC Domain Descriptor (MDD) messages for DOCSIS 3.0 modems.
This capability:
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Provides primary-capable downstream channel selection to facilitate channel bonding and reliability of voice-enabled modems.
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Provides high availability support for modems on SPA DS channels.
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Architecture and Scope
The Cisco DOCSIS 3.0 Downstream Solution, Release 2.0, includes these major components:
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The WCMTS is the component located at the cable television system headend or distribution hub and exchanges digital signals with cable modems in a cable network to enable data connectivity to a wide-area network.
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The Cisco Wideband SIP for the 1-Gbps wideband SPA is a carrier card that inserts into a router like a line card and enables cable operators to offer high-speed broadband connectivity. The SIP provides no network connectivity on its own. The Wideband SPA that inserts into the bay of the SIP provides ports for network connectivity.
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The DTCC supplies centralized DOCSIS clock and time-stamp distribution to the cable line cards within the WCMTS. This card allows synchronization of the DOCSIS clock and time stamp to an external DTI server.
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The DTI server provides DOCSIS clock generation in an M-CMTS architecture. It ensures that the DOCSIS time stamp and frequency between the modular CMTS core, edge QAM device and upstream are synchronized to nanosecond levels.
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The edge QAM device is a network element that is separate from the CMTS. It allows operators to leverage the same network resources to support multiple types of services, such as data, voice, and video.
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WCMs are modems that are DOCSIS 3.0-compliant and support downstream channel bonding.
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NCMs are modems that are DOCSIS 1.x/2.0-compliant and support data from a single RF channel.
Figure 1-1 presents a simplified view of the Cisco DOCSIS 3.0 Downstream Solution. In Figure 1-1, three SPA RF channels are bonded into a wideband channel (bonding group).
Figure 1-1 Cisco DOCSIS 3.0 Downstream Solution
In Cisco IOS Release 12.2(33)SCB, the following components have been added to the scope of the DOCSIS 3.0 Downstream Solution:
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The Cisco SIP-600 is a high-performance, feature-rich SPA interface processor (SIP) that functions as a carrier card for shared port adapters (SPAs) on the Cisco uBR10012 router. The SIP is compatible with one or more platform-independent SPAs.
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In addition to the Cisco Wideband SPA, the Cisco SIP-600 also supports the following Gigabit Ethernet SPAs:
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In Scope
The scope of the Cisco DOCSIS 3.0 Downstream Solution, Release 2.0, comprises fully tested and supported Cisco and Scientific Atlanta components, as well as selected third-party components tested for interoperability by Cisco.
The following aspects of the solution are in scope:
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Device configuration that is in scope for this document is limited to the Wideband SIP and Wideband SPA. Comprehensive documentation for other CMTS components is provided in the existing Cisco uBR10012 documentation set, which is accessible at www.cisco.com.
For information on edge QAM device installation and software configuration, refer to the vendor's edge QAM device documentation.
Out of Scope
The Cisco DOCSIS 3.0 Downstream Solution-related information in this document pertains to the components listed in "In Scope" section above. Not included in the scope of the Cisco DOCSIS 3.0 Downstream Solution are the hardware and software components that make up the remainder of the cable data network.
For the Cisco DOCSIS 3.0 Downstream Solution, Release 2.0, cable network management tools and operations support system (OSS) facilities for wideband cable are outside the scope of the solution.
Solution Key Features
In the Cisco IOS Release 12.3(23)BC, DOCSIS 3.0 Downstream Solution, provides the following key features:
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Represents the narrowband capability of a SPA DS channel.
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Primary-capable channels provide narrowband data services to support DOCSIS 1.x/2.0 modems.
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Provides up to 48 SPA DS channels plus 40 built-in DS channels in addition to the downstream channels on Cisco uBR10-MC5X20 line cards for DOCSIS 1.x/2.0 traffic.
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Provides narrowband data services to support DOCSIS 1.x/2.0 modems and wideband data services to support DOCSIS 3.0 modems over existing hybrid fiber coaxial (HFC) networks and allows DOCSIS 1.x/2.0 and DOCSIS 3.0 modems to share the same SPA RF channel.
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In Cisco IOS Release 12.2(33)SCB, the following additional features are supported on the DOCSIS 3.0 Downstream Solution:
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The DOCSIS WFQ Scheduler is an output packet scheduler that provides output scheduling services on both WAN uplink interfaces and DOCSIS downstream interfaces.
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The Cable Modem Termination Service (CMTS) new feature enables dynamic bandwidth sharing (DBS) on modular cable and wideband cable interfaces.
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CMTS supports voice services on voice-enabled wideband (WB) cable modems.
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The Wideband Modem Resiliency feature provides the best possible service in the event of non-primary radio frequency (RF) channel disruptions to ensure that a cable modem (CM) remains operational. With the implementation of this feature, the Cable Modem Termination System (CMTS) does not force a cable modem to perform a MAC reset if the CM loses connectivity to the CMTS on one or all of its non-primary RF channels.
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The DOCSIS 3.0 Downstream Bonding for Bronze Certification feature helps cable operators offer new, more bandwidth-intensive services by adding one or more additional downstream quadrature amplitude modulation (QAM) channels to the standard broadband DOCSIS system.
Solution Components
Cisco DOCSIS 3.0 Downstream, Release 2.0, consists of Cisco and Scientific Atlanta components that are tested, documented, and fully supported by Cisco or Scientific Atlanta. Also, third-party equipment, although not fully supported by Cisco, has been selected and tested for interoperability with the solution components.
Cisco and Scientific Atlanta Equipment
For the Cisco DOCSIS 3.0 Downstream, Release 2.0, the following Cisco and Scientific Atlanta equipment has been tested in the context of the solution.
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Third-Party Equipment
For the Cisco DOCSIS 3.0 Downstream Solution, Release 2.0, Table 1-1 lists the third-party component, vendor, and the basic functionality each component provides.
