RTSP Protocol Extension for Multicast Delivery in Mixed Networks
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Solution Overview
Problem
Current network infrastructure, particularly in cellular networks, faces inefficiencies in delivering multicast data due to nodes that do not support multicast routing, leading to suboptimal use of resources and limitations in providing mobile TV services.
Innovation Solution
The method involves extending the Real-Time Streaming Protocol (RTSP) to enable media servers to send multicast packets within unicast tunnels dynamically, using encapsulation and decapsulation techniques to ensure delivery even in networks where multicast support is lacking, by including multicast destination addresses and unicast gateway addresses in RTSP messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multicast packets are sent directly over the network, then delivery efficiency is improved, but network compatibility deteriorates due to nodes that do not support multicast routing
Solution Approach 1:
The patent encapsulates multicast packets within unicast packets, creating a nested structure where the outer unicast packet provides compatibility with non-multicast nodes while the inner multicast packet preserves efficient multicast delivery. This nesting allows the system to maintain both delivery efficiency and network compatibility simultaneously.
Solution Approach 2:
The patent introduces an intermediary mechanism (encapsulation layer) that translates between multicast and unicast protocols. The outer unicast wrapper acts as a mediator that allows multicast traffic to traverse networks with mixed multicast support, while the inner multicast payload maintains efficient group delivery where supported.
2Adaptability or versatility
If unicast encapsulation is used for multicast packets, then network compatibility is improved, but resource usage deteriorates due to increased packet size and processing overhead
Solution Approach 1:
The patent applies local quality by making the encapsulation adaptive rather than universal. Multicast packets are only encapsulated in unicast wrappers when necessary (when multicast support is detected as absent), while packets traversing multicast-capable networks remain in their efficient native format. This localized application of encapsulation minimizes resource overhead while maintaining compatibility where needed.
Data Source
AI summary
A method and apparatus are provided for delivering multicast media in a network in which at least some nodes do not support delivery of multicast packets. A RTSP SETUP request is sent to a streaming server to send multicast packets, encapsulated within unicast wrappers, to a gateway node in the network. The RTSP SETUP request includes details both of the multicast destination address, and of the unicast destination address of the gateway node, requiring an extension to the RTSP protocol as currently defined and enabling the media server to send multicast packets in a unicast tunnel dynamically.