Multicast Data Distribution Using Source Address Filtering
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Solution Overview
Problem
Current multicast data distribution systems cannot accurately deliver data to specific terminals based on both destination and source addresses, leading to unnecessary data transmission and security concerns due to the reliance on outdated protocols like IGMPv1 and MLDv1, which only use destination addresses for forwarding decisions.
Innovation Solution
A data distribution method and apparatus that generate a correspondence table associating source and destination addresses with port information, allowing the insertion of forwarding destination information into multicast data packets, enabling the L2 switch to selectively forward data to subscribed terminals using a combination of destination and source addresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the latest IGMPv3 or MLDv2 protocol is used to determine multicast groups based on both destination address and source address, then data delivery accuracy and security are improved, but existing hardware cannot support these protocols
Solution Approach 1:
The patent introduces a correspondence table as an intermediary data structure that maps source addresses and destination addresses to port information. This table acts as a mediator between the latest protocol requirements (which need source address information) and existing hardware capabilities (which only support destination address-based forwarding). The router uses this table to simulate IGMPv3/MLDv2 functionality on legacy hardware by translating combined address matching into port-based forwarding decisions.
2Adaptability or versatility
If multicast data is transmitted to all terminals using outdated protocols, then hardware compatibility is maintained, but network traffic increases and security decreases
Solution Approach 1:
The patent performs preliminary actions by pre-establishing the correspondence table that contains port information for each combination of source address and destination address. This table is built in advance based on subscription information from terminals. When multicast data needs to be forwarded, the router consults this pre-prepared table to determine exactly which ports should receive the data, rather than broadcasting to all terminals. This eliminates unnecessary network traffic while maintaining compatibility with existing hardware that uses destination address-based forwarding.
3Device complexity
If only destination address is used for forwarding decisions, then hardware implementation is simple, but data cannot be delivered to specific terminals and security is compromised
Solution Approach 1:
The patent adds another dimension to the forwarding decision process by introducing source address as an additional matching criterion alongside destination address. Instead of using only destination address (one-dimensional forwarding), the system now uses a combination of source address and destination address (two-dimensional forwarding). The correspondence table stores port information indexed by this combined address pair, enabling precise delivery to specific terminals while maintaining relatively simple hardware implementation through table-based lookup.
Data Source
AI summary
Disclosed is a data distribution apparatus delivering multicast data to a terminal belonging to a multicast group, including: a table generating unit to generate a table including a source address (SA) of the terminal and a destination address (DA) for requesting the multicast data in association with port information of the terminal; an address discrimination unit to discriminate a combination of DA and SA contained in the multicast data; a forwarding destination information generation unit to generate forwarding destination information designating a forwarding destination of the multicast data by obtaining the port information in the table, corresponding to the discriminated combination, and inserts the forwarding destination information in the multicast data for transfer to a L2 switch; and a port selection unit provided in the L2 switch to select port to transfer the multicast data referring to the forwarding destination information and a routing table provided in the L2 switch.