Hybrid Unicast Multicast Proxy for Content Delivery

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Solution Overview

Problem

The high peak-to-mean ratio in traffic volumes during live content streaming causes degradation in user quality of experience at the network edge, and existing hybrid unicast-multicast solutions fail to accurately determine real demand for content, as they do not allow client-specific information to be sent to the content server, limiting analytics and billing capabilities.

Innovation Solution

A method involving a first network element that receives multicast segments from a content server, sends an HTTP HEAD request to the server in response to client requests, and generates client-specific segments by combining the HEAD response header with multicast payload, enabling session-specific information exchange and accurate demand monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multicast is used for content delivery, then network efficiency is improved and peak demand is reduced, but client-specific information exchange is lost

Engineering Contradiction:
Improvenetwork efficiencyVSAvoidclient-specific information
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent segments the content delivery process into two distinct parts: multicast transmission for the content payload (improving network efficiency) and unicast HTTP requests for metadata/header information (preserving client-specific information exchange). This segmentation allows each protocol to be used for its optimal function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hybrid proxy server as an intermediary between clients and the content server. This proxy receives unicast requests containing client-specific information, translates them into multicast requests, and forwards responses back to clients. The intermediary enables information exchange that would otherwise be lost in pure multicast architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If unicast is used for content delivery, then client-specific information exchange is enabled, but network efficiency deteriorates during peak demand

Engineering Contradiction:
Improveclient-specific information exchangeVSAvoidnetwork efficiency
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The patent implements a dynamic content delivery system that adapts the transmission mode based on content type and client needs. Common content segments are delivered via multicast to multiple clients simultaneously, while client-specific metadata is exchanged via unicast. This dynamic approach optimizes network efficiency without sacrificing information exchange capabilities.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent merges unicast and multicast protocols into a hybrid architecture where both protocols work together complementarily. Unicast handles control plane traffic (requests with client-specific information), while multicast handles data plane traffic (content delivery). This combination leverages the strengths of both protocols to resolve the contradiction.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If hybrid unicast-multicast solutions are used, then network efficiency is improved, but accurate demand monitoring is lost

Engineering Contradiction:
Improvenetwork efficiencyVSAvoiddemand monitoring accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where clients send unicast requests to the hybrid proxy that include information about their content consumption patterns. The proxy aggregates this feedback from multiple clients and uses it to monitor actual demand accurately, enabling the CDN operator to make informed decisions about content caching and delivery strategies.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The hybrid proxy serves as an intermediary that maintains visibility into client requests while enabling efficient multicast delivery. It translates unicast requests into multicast transmissions but retains knowledge of the original client-specific requests, allowing accurate demand monitoring without compromising network efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4201001B1Content delivery
Publication Date: 2024.09.04 BRITISH TELECOM PLC
  • EP4201001B1 patent drawingFigure 1
  • EP4201001B1 patent drawingFigure 2
  • EP4201001B1 patent drawingFigure 3

AI summary

Described is a method of delivery of content to a client device. In particular, the method can be applied to hybrid unicast/multicast delivery networks, where content is provided by a content server to a root proxy, and that root proxy delivers the content to edge proxies over multicast. However, requests for that content in the form of HTTP GET requests from a client device are received by an edge proxy, which subsequently sends an HTTP HEAD request for header information associated with that content directly to the content server. The content server responds over unicast with a suitable response to the HTTP HEAD request, which is received by the edge proxy. The edge proxy takes the response together with the payload from the content segment received over multicast, to generate a client specific content segment for delivery to the client device over unicast.