Unicast MAC Routing for VPNs Over Multicast-Filtered DC Interconnects
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Solution Overview
Problem
In client-based virtual private networks, multicast packets are filtered by access nodes in the data center interconnect network, preventing customer edge nodes from exchanging routing information using routing protocols.
Innovation Solution
A method where a virtual private network server collects and sends MAC address routing information in a unicast manner to customer edge nodes, using a VPN server to manage and distribute MAC address information across sites, ensuring that routing information can be exchanged despite multicast packet filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If multicast packets are used to exchange routing information between customer edge nodes, then routing information can be efficiently distributed across the virtual private network, but the access nodes filter out these multicast packets preventing the exchange
Solution Approach 1:
The patent introduces a unicast communication mechanism as an intermediary between customer edge nodes, where routing information is encapsulated in unicast packets with special protocol identifiers. This intermediary approach bypasses the multicast filtering at access nodes while still achieving the goal of routing information distribution across the virtual private network.
Solution Approach 2:
The patent changes the transmission parameter from multicast to unicast mode. By modifying the packet type from multicast to unicast and adding specific protocol type identifiers, the routing information can traverse the access network infrastructure that filters multicast traffic, thereby resolving the contradiction between information distribution and packet delivery reliability.
2Reliability
If unicast routing information exchange is implemented to overcome multicast filtering, then routing information can be delivered reliably, but the network overhead and complexity increase
Solution Approach 1:
The patent makes the existing unicast communication infrastructure perform the additional function of routing information exchange by using protocol type identification. Instead of creating a separate dedicated routing protocol mechanism, the solution reuses the existing unicast channel with enhanced packet formatting, thereby reducing overall system complexity while maintaining reliable delivery.
Solution Approach 2:
The patent creates a simplified copy of the routing information exchange mechanism that operates over the existing unicast infrastructure. By copying the essential routing advertisement function into the unicast packet format with appropriate protocol identifiers, the system achieves reliable delivery without the full complexity of implementing a completely new routing protocol stack.
Data Source
AI summary
The present invention discloses a method for advertising routing information, and embodiments of the present invention further provide a virtual private network server device, an IP edge node device, and a client-based virtual private network system. In the technical solutions of the present invention, a virtual private network server first collects MAC address routing information of each site on a local virtual private network and then sends MAC address routing information of each site except a destination site in a unicast manner to a customer edge node that corresponds to each site on the virtual private network. This solves the problem that CE nodes in sites on the virtual private network cannot exchange routing information with each other by using a routing protocol because multicast packets are filtered by an access node of the data center network.