Driven by market evolution towards triple-play services, cable operators in emerging markets are seeking standardized and digital fiber-based solutions for economical and future proof access technologies. Much of the demand is driven by the need to provide higher bandwidth packet transport for Internet connectivity, video and voice services.

Data Over Cable Systems Interface Standard (DOCSIS®) is a standardized technology for services over cable and thus has strong interoperability between system providers. It also provides robust Quality of Service (QoS) methods, ensuring packet delivery during periods of network congestion. Traditionally, DOCSIS runs on linear fiber (or HFC) to provide service and is not naturally applicable for digital fiber. Cisco has bridged the gap by introducing a new access technology called the Remote PHY.

The Cisco Remote PHY solution provides a cost-effective digital fiber-based DOCSIS solution that uses Ethernet PON (EPON), Gigabit-capable Passive Optical Networks (GPON), or Metro Ethernet (MetroE) as the transmission network between the Cisco CMTS and CM. Both the PON technology and DOCSIS is used in the same network.

• Simple and low cost PON transmission as opposed to costly HFC transformation.

• Reduced investment cost including capital and operational expenditure.

• Low-cost yet highly stable Cisco GS7000 node (includes only the PHY layer).

• Reduced CMTS hardware complexity.

• No restriction on Converged Interconnect Network (CIN) network.

• Futureproof architecture. Easy to migrate as the hardware and control functions are on separate layers.

• End-to-end QoS assurance provided by DOCSIS.

• Support for all DOCSIS services.

• Support for existing DOCSIS network provisioning system.

• High access bandwidth.

• With deep fiber, the optical noise contribution to SNR is eliminated. As a result, the remote QAM modulator runs at higher orders of modulation as compared to a centralized QAM modulator.

The Cisco CCAP RF line card for remote PHY architecture is available in two flavours:

• CBR-LC-8D31-16U30—This RF line card with the downstream and upstream PHY modules can be connected with the Cisco GS7000 node by configuring it using the card cBR-CCAP-LC-40G r-phy command.

• CBR-CCAP-LC-40G-R—This RF line card with no downstream and upstream PHY modules can be connected with the Cisco GS7000 node.

The Cisco Digital Physical Interface Card (DPIC) transmits and receives RF signals between the subscriber and headend over the hybrid fiber-coaxial (HFC) system and is DOCSIS-compliant. This interface card is designed specifically for the Cisco cBR router and conforms to the Integrated CMTS (I-CMTS) architecture. The PID is cBR-DPIC-8X10G.

The DPIC is installed in the CMTS and connected to the Cisco GS7000 node via the EPON, GPON, or Metro Ethernet. It supports both downstream and upstream traffic. Both the downstream and upstream traffic share the same ports.

Onboard Failure Logging

The Onboard Failure Logging (OBFL) feature enables the storage and collection of critical failure information in the nonvolatile memory of a Field Replaceable Unit (FRU), like a route processor (RP) or line card. The data stored through OBFL assists in understanding and debugging the field failures upon Return Material Authorization (RMA) of a RP or line card at repair and failure analysis sites. OBFL records operating temperatures, voltages, hardware uptime, and any other important events that assist board diagnosis in case of hardware failures.

For more information about the feature, see Onboard Failure Logging.

Note	The sample output provided in the Onboard Failure Logging guide may vary slightly for the Cisco CMTS routers.

The Cisco Remote PHY Device (RPD) has two variants – The standard RPD and the newer Intelligent RPD (iRPD). The standard RPD resides inside the Cisco GS7000 node while the Intelligent RPD (iRPD) resides inside the Intelligent Node. Below are some of its features:

• Full spectrum DOCSIS 3.0 support

• Full spectrum DOCSIS 3.1 support

• Converged broadcast, narrowcast, and VOD video support

• Out of Band (OOB) signaling support

• Dual 10GBE SFP/SFP+ backhaul connectivity

• Support of Daisy Chain architecture topology

• CCAP support

• Support of optical overlay architectures

Additionally, the Cisco Intelligent Remote PHY Device (iRPD) provides an interface to the Intelligent Node RF section.This interface supports control plane communication that allows more extensive diagnostic and configuration control. The Intelligent Node supports touch-less configuration, per port spectrum capture, power-savings mode, and other enhanced features.

Figure 1. Cisco RPD

The Cisco Remote PHY solution supports the Single Controller Sharing architecture. In this architecture, multiple Cisco GS7000 equipments share the downstream and upstream channels of a Cisco RF line card in a cisco cBR chassis.

Figure 2. Single Controller Sharing Architecture

The topologies supported by the Cisco Remote PHY solution include:

• Ethernet Based Networking

• PON

Figure 3. Standard Deployment

Figure 4. Path Redundancy Deployment

Figure 5. Daisy Chain Deployment

Figure 6. Redundant Ring Deployment