Introduction

When a cable company offers Internet access over the cable, Internet information can use the same cables. Putting both upstream and downstream data on the cable television system requires two types of equipment:

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To address this situation, RDK-B does not include DOCSIS. It only includes components that provide an abstraction layer software interface to third party WAN. For the DOCSIS WAN, this component is known as the Cable Modem (CM) Agent. CM Agent provides interfaces for integrating WAN interfaces with RDK-B. RDK-B is not tied to DOCSIS and may be used with any WAN interface. Other RDK-B software components can be created that provide interfaces to other WANs.

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Architecture

• CM Agent is a CCSP component that exposes TR181 parameters related to CM/DOCSIS interface characteristics.
• CM agent provides info like Upstream channels, downstream channels, boot file name, DOCSIS log, etc along with CM interface details.
• Maintains a TR181 data model XML file with dbus object path as /com/cisco/spvtg/ccsp/cm
• Has a layered architecture similar to any other CCSP component

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Access Layer

• Access Layer interfaces with the CCSP message bus
• Receives any set or get calls and pass them onto the DML layer to manage the data which is in the request.

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• This layer makes calls to underlying HAL functions, Linux system calls/commands, third party modules, open-source modules etc.
• This layer will be more component-specific.

Code Flow

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Objects

CMAgent object in its DML layer:

Dmcli

Retrieving  cable modem values using dmcli

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HAL APIs

This hardware abstraction layer (HAL) concept is used for every interface.

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Some example APIs  are listed below: