Extending DOCSIS Trust to IP Overlay Networks

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Solution Overview

Problem

The DOCSIS standard's certification-based security mechanism is not usable on IP-based overlay networks, preventing IP-based network elements from authenticating Customer Premises Equipment (CPE) devices based solely on their source IP address.

Innovation Solution

Extending the trust relationship established between a cable modem and a cable network to CPE devices operating on a service provider network that includes both a cable network and an IP-based overlay network, by using authentication information associated with the authenticated cable modem to authenticate IP-based CPE devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DOCSIS certification-based security mechanism is used to authenticate cable modems, then authentication security is improved, but the authentication information cannot be used on IP-based overlay networks

Engineering Contradiction:

Improveauthentication securityVSAvoidnetwork compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary mechanism that translates DOCSIS authentication information into IP-based authentication credentials. The cable modem termination system (CMTS) acts as a mediator that receives DOCSIS authentication data from the authenticated cable modem and generates corresponding IP authentication credentials, enabling seamless authentication across both DOCSIS and IP-based network layers without compromising security or compatibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms authentication parameters from the DOCSIS domain to the IP domain by mapping DOCSIS authentication credentials (such as cable modem identifiers and authentication tokens) to equivalent IP-based authentication parameters (such as IP addresses, port identifiers, or protocol-specific credentials). This parameter transformation enables the same authentication information to function across different network standards

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If IP-based network elements authenticate CPE devices based on source IP address, then authentication simplicity is improved, but authentication reliability deteriorates due to inability to verify trust relationship

Engineering Contradiction:

Improveauthentication simplicityVSAvoidauthentication reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent implements preliminary authentication action at the DOCSIS layer before the CPE device accesses the IP-based overlay network. The cable modem is authenticated first using DOCSIS certification-based security, establishing a trusted relationship with the network. This preliminary authentication result is then leveraged to automatically authenticate the CPE device on the IP network, eliminating the need for separate IP-based authentication while ensuring reliability through the pre-established trust relationship

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250184327A1Embedded Authentication in a Service Provider Network

Publication Date: 2025.06.05 COMCAST CABLE COMM LLC

AI summary

A computing device may request service from a service provider, and authorization to receive the service may be based, at least in part, on a network access device that is providing the computing device with network access. The service provider may request a value from the computing device, and the value may be based on address information of the computing device and the network access device.