Single Active Forwarder Election in Multicast VPNs
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Solution Overview
Problem
In MVPNs, the existing technologies face challenges in efficiently managing multicast traffic, leading to duplicate data packets and inefficient bandwidth utilization due to the lack of a mechanism to selectively choose an active forwarder for forwarding multicast traffic, resulting in suboptimal network performance and resource utilization.
Innovation Solution
The techniques involve using BGP MVPN control plane messages to select a single active forwarder among ingress network devices for forwarding multicast traffic, ensuring that only actively forwarding devices participate in the election process, thereby reducing duplicate traffic and improving scalability by leveraging BGP's capabilities on a per-multicast flow basis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all ingress network devices forward multicast traffic in MVPNs, then multicast traffic delivery is ensured, but duplicate data packets occur and bandwidth utilization deteriorates
Solution Approach 1:
The system uses BGP MVPN control plane messages to enable ingress network devices to autonomously elect a single active forwarder based on locally stored source active route entries, eliminating the need for centralized control while preventing duplicate traffic and optimizing bandwidth utilization
2Reliability
If multiple ingress network devices forward multicast traffic, then traffic redundancy is provided, but network device complexity and state storage requirements increase
Solution Approach 1:
The patent extracts the forwarding decision logic from multiple potential forwarders by using BGP MVPN control plane messages to identify and select a single active forwarder, thereby reducing the state that network devices must store and manage while maintaining traffic redundancy through protocol-level mechanisms
3Ease of operation
If inclusive provider tunnels forward multicast traffic to all PE routers, then multicast distribution is simplified, but computing resources are consumed by devices without interested listeners
Solution Approach 1:
The system performs preliminary action by using BGP MVPN control plane messages to pre-identify and select the active forwarder before multicast traffic is forwarded, allowing network devices to prepare forwarding states in advance and avoid consuming computing resources for devices without interested listeners
Data Source
AI summary
In some examples, a method includes receiving, by a first ingress network device of a network, a source tree join route message from an egress network device of the network, the source tree join route message specifying a multicast source and a multicast group, and in response to receiving, by the first ingress network device, a source active auto-discovery route message from a second ingress network device of the network indicating that the second ingress network device has switched from using a shared multicast tree to using a shortest path tree to deliver multicast traffic from the multicast source, electing one of the first ingress network device or the second ingress network device as a single active forwarder for forwarding the multicast traffic received from the multicast source for the multicast group.