Overlay Multicast Mapping to Underlay Trees via Rendezvous Points
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Solution Overview
Problem
Existing network devices in overlay networks inefficiently distribute multicast traffic by replicating packets across individual tunnels, leading to bandwidth-intensive and resource-consuming operations.
Innovation Solution
Offload multicast traffic distribution to a root-path multicast tree (RPMT) in the underlay network by mapping overlay multicast groups to underlay multicast groups using a bidirectional multicast protocol, such as PIM-BIDIR, and forwarding packets through RPs instead of replicating them across individual tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If packets are replicated across individual tunnels for multicast distribution in overlay network, then multicast traffic can be delivered to multiple destinations, but bandwidth usage and processing overhead increase significantly
Solution Approach 1:
The patent introduces an intermediary mechanism by mapping overlay multicast groups to underlay multicast groups. Instead of replicating packets across individual tunnels in the overlay network, the system uses the underlay network's multicast infrastructure (Rendezvous Points and root-path multicast trees) as an intermediary to distribute traffic efficiently. This mediator approach allows single-copy packet transmission through the underlay while achieving reliable multicast delivery to multiple overlay destinations.
Solution Approach 2:
The patent transitions from two-dimensional overlay network routing to three-dimensional distribution by leveraging the underlay network's multicast capabilities. The mapping from overlay multicast groups to underlay multicast groups adds a new dimension of distribution, allowing traffic to be forwarded through the underlay's Rendezvous Points and root-path trees rather than through individual overlay tunnels, thereby reducing replication overhead.
2Reliability
If packets are replicated across individual tunnels for multicast distribution, then traffic can reach all destinations, but network device resource consumption increases
Solution Approach 1:
The underlay network's multicast infrastructure acts as an intermediary that handles the complex distribution logic. By mapping overlay multicast groups to underlay multicast groups, the system offloads the replication and distribution tasks from overlay network devices to the underlay's Rendezvous Points and root-path multicast trees, reducing processing overhead at overlay devices while maintaining complete traffic distribution.
Solution Approach 2:
The underlay network's bidirectional PIM protocol provides self-service multicast distribution capabilities. The Rendezvous Points and root-path trees automatically manage packet replication and distribution without requiring explicit control from overlay network devices, allowing the system to serve itself through the underlay's inherent multicast mechanisms.
3Reliability
If source-specific multicast trees are used, then traffic can be distributed to all members, but scalability and efficiency decrease
Solution Approach 1:
The patent applies universality by using a single underlay multicast group mapping that serves multiple overlay multicast groups. The underlay's Rendezvous Points and root-path multicast trees provide universal distribution service that can handle traffic from multiple sources and destinations simultaneously, improving scalability and efficiency compared to source-specific trees that treat each source separately.
Solution Approach 2:
The system changes the parameter of multicast group identification by mapping overlay-specific multicast addresses to underlay multicast addresses. This parameter transformation enables the use of efficient bidirectional PIM protocols in the underlay, allowing shared trees and Rendezvous Points to serve multiple overlay groups with a single configuration, thereby improving distribution efficiency.
Data Source
AI summary
A network device operating as a tunnel endpoint in an overlay network is provided. During operation, the network device can receive a multicast packet destined to a first multicast group via an edge port. The edge port can be coupled to the source of the first multicast group. The network device can then map the first multicast group to a second multicast group configured in an underlying network of the overlay network by applying a mapping rule. Subsequently, the network device can encapsulate the multicast packet with a first encapsulation header with a destination address, which is a multicast address of the second multicast group. The network device can then identify a Rendezvous Point (RP) of the second multicast group and forward the encapsulated multicast packet to the RP based on the multicast address of the second multicast group.