Multicast Relay for mDNS Bandwidth Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In mDNS-based multi-VLAN networks, the Known-Answer mechanism leads to network bandwidth waste due to the need to transmit multiple multicast service query packets, as the gateway cannot distinguish user terminals based on source addresses, resulting in redundant responses.
Innovation Solution
A relay converts multicast Known-Answer service query packets into unicast packets, including terminal identities, which are then processed by the gateway to return unicast service answer packets, allowing the relay to convert these back to multicast packets for the user terminal, thus reducing redundant transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the gateway transmits service information to user terminals in each VLAN, then service discovery functionality is achieved, but network bandwidth is wasted due to redundant transmissions
Solution Approach 1:
The relay performs preliminary action by converting multicast service query packets into unicast packets before they reach the gateway. This pre-processing includes adding terminal identity information to the packets, enabling the gateway to identify and filter redundant queries, thus preventing bandwidth waste from duplicate responses while maintaining service discovery functionality
Solution Approach 2:
The relay acts as an intermediary between user terminals and the gateway. It intercepts multicast service query packets, converts them to unicast packets with terminal identity information, and forwards them to the gateway. This intermediary role enables the gateway to distinguish between different terminal requests and avoid redundant transmissions, resolving the contradiction between service discovery and bandwidth efficiency
2Device complexity
If the gateway cannot distinguish user terminals based on source addresses, then multicast packet processing is simplified, but redundant responses are generated
Solution Approach 1:
The relay extracts the source address information from incoming multicast packets and incorporates it into the unicast packet as terminal identity information. This extraction process enables the gateway to identify individual terminals without complicating the gateway's packet processing logic, as the identity information is already embedded in the unicast packet format
Solution Approach 2:
The relay changes the packet type parameter from multicast to unicast, and adds terminal identity as a new parameter. This parameter transformation allows the gateway to process packets individually based on terminal identity while maintaining simplified processing logic, thereby reducing the quantity of redundant transmissions without increasing device complexity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention discloses a packet transmission method, apparatus, and system in a multicast domain name system mDNS, which are used to resolve a network bandwidth waste problem because generally much service information needs to be transmitted in an mDNS-based network. The method includes: converting, by a relay, a Known-Answer service query packet that is sent by a user terminal and used to query service information in an mDNS, into a unicast Known-Answer service query packet and sending the unicast Known-Answer service query packet to a gateway; receiving, by the relay, a unicast Known-Answer service answer packet that is sent by the gateway and includes service information unknown to the user terminal; and converting, by the relay, the unicast Known-Answer service answer packet into a multicast Known-Answer service answer packet and sending the multicast Known-Answer service answer packet to the user terminal.