EVPN Multicast State Cleanup for IGMP Host Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Ethernet Virtual Private Networks (EVPNs), host mobility leads to outdated state information at provider edge (PE) routers, causing unnecessary multicast traffic to be forwarded, which wastes bandwidth and resources due to the host device not sending an IGMP leave request when moving to another access network.
Innovation Solution
PE routers detect host movement across access networks and clean up multicast state information by deleting unnecessary multicast group states based on explicit host tracking or IGMP queries, ensuring only interested devices receive traffic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a host device moves from one access network to another in an EVPN, then the host device can maintain connectivity and receive multicast traffic at its new location, but the original PE router retains outdated state information and continues to forward unnecessary multicast traffic
Solution Approach 1:
The patent implements a feedback mechanism where the new PE router (second PE router) detects host movement and sends a notification message back to the original PE router (first PE router). This feedback loop enables the first PE router to understand that the host has moved and to clean up its multicast state information, thereby stopping unnecessary traffic forwarding and eliminating bandwidth waste while maintaining host mobility.
Solution Approach 2:
The patent introduces a messaging mechanism as an intermediary between PE routers. When a host moves from one access network to another, the new PE router acts as an intermediary by sending a notification to the old PE router, enabling coordinated state management across the EVPN without requiring direct host involvement in the state cleanup process.
2Reliability
If the PE router continues to forward multicast traffic after host movement, then the host can receive traffic at its new location through the new PE router, but network resources are wasted on duplicate traffic forwarding
Solution Approach 1:
The notification message sent from the new PE router to the old PE router provides feedback about host movement. This feedback enables the old PE router to terminate its multicast forwarding for the moved host, ensuring that multicast delivery is maintained through the new PE router while eliminating redundant traffic that would waste network resources.
3Ease of operation
If the host device does not send an IGMP leave request when moving, then the host can seamlessly receive multicast traffic at the new location, but the original PE router cannot update its state information
Solution Approach 1:
The new PE router acts as an intermediary that bridges the information gap. Instead of relying on the host to send IGMP leave requests (which may not happen during seamless mobility), the new PE router sends a notification to the old PE router, enabling the old router to update its state information about the host's movement without requiring explicit host action.
Solution Approach 2:
The system performs preliminary action by having the new PE router proactively notify the old PE router about host movement before the old router's state information becomes completely outdated. This preliminary notification allows the old router to clean up its state in a timely manner, preventing prolonged information loss while maintaining host mobility.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An example network device includes memory configured to store packet data and processor circuitry coupled to the memory. The processing circuitry is configured to determine that a first host device has moved from a first access network of an Ethernet virtual private network (EVPN) associated with the first PE router to a second access network of the EVPN, wherein the first host device is interested in receiving traffic of a first multicast group. The processing circuitry is configured to determine whether any other host device on the first access network of the network device is interested in receiving traffic of the first multicast group. Based on no other host device on the first access network of the network device being interested in receiving multicast traffic of the first multicast group, the processing circuitry is configured to delete state associated with the first multicast group.