Multicast Loop Prevention via PE Node Hint Tagging
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Solution Overview
Problem
In modern communication networks, especially those employing multi-homing techniques, issues such as looping and duplicate frame delivery occur due to the complexity of routing and multicast forwarding, which can lead to network instability and increased operational costs.
Innovation Solution
The implementation of a system where provider edge (PE) nodes tag multicast packets with hint data to identify the original source, and designate a forwarding node within redundancy groups to prevent looping and duplicate delivery, using data structures and control plane messaging to manage forwarding decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-homing techniques are employed to increase connection reliability, then network reliability is improved, but looping and duplicate frame delivery occur causing network instability
Solution Approach 1:
The patent introduces an intermediary mechanism (redundancy group with designated forwarding node) that mediates between multiple multi-homed connections. This intermediary structure prevents direct looping by routing traffic through a designated node, allowing multiple connections to coexist without causing network instability or duplicate frame delivery.
Solution Approach 2:
The patent applies preliminary action by pre-designating a forwarding node within redundancy groups before any looping or duplicate delivery issues occur. This advance configuration establishes clear traffic flow paths, preventing the formation of loops and ensuring stable network operation while maintaining connection reliability.
2Productivity
If multicast packets are flooded to all nodes in the broadcast domain, then delivery coverage is improved, but duplicate frame delivery and network overhead increase
Solution Approach 1:
The patent applies local quality by allowing different forwarding behaviors at different network nodes based on their roles. Designated forwarding nodes within redundancy groups perform selective forwarding, while other nodes refrain from forwarding. This localized differentiation ensures comprehensive delivery coverage without unnecessary duplicate transmissions, reducing network overhead.
3Reliability
If multiple edge nodes are used for multi-homing, then connection redundancy is improved, but device complexity and operational difficulty increase
Solution Approach 1:
The patent merges the forwarding functions of multiple edge nodes into a coordinated redundancy group with a single designated forwarding node. This consolidation maintains connection redundancy through multiple physical paths while simplifying the forwarding decision logic, as only the designated node performs active forwarding, reducing operational complexity.
4Stability of the object's composition
If forwarding nodes are designated within redundancy groups, then looping is prevented, but control plane messaging overhead increases
Solution Approach 1:
The patent uses preliminary action by establishing forwarding node designations through control plane messaging before data plane traffic flows. This one-time or periodic designation process prevents loops while minimizing ongoing control plane overhead, as the designated forwarding nodes maintain stable forwarding states without requiring continuous control plane communication.
Data Source
AI summary
Methods, systems, and apparatus, including computer programs encoded on a storage media, for preventing looping and duplicate frame delivery in a network environment. A first control plane message is received from a first edge node in a plurality of edge nodes in a plurality of network elements of a network, the first control plane message identifying a first hint to be included in first multicast packets that include data originating from a first computing device interfaced with the first edge node and are forwarded to the network through the first edge node. A data record is stored identifying the association between the first hint and the first computing device. The data record is used to determine that multicast packets including the first hint originate from the first computing device and are not to be forwarded to the first computing device by edge nodes interfacing with the first computing device.