Distributed Link Aggregation Group for Layer 2 Fabric
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Solution Overview
Problem
Current Spanning Tree Protocol (STP) in data networks is inefficient due to limited bandwidth utilization, poor fault tolerance, and inflexibility, particularly in TRILL networks, where only a single active link is supported between nodes, leading to reduced reliability and longer failure recovery times.
Innovation Solution
Implementing TRILL LAG (t-LAG) mechanisms that form a virtual bridge between external network nodes and RBridges, allowing multiple redundant links to be aggregated into a Link Aggregation Group (LAG), enabling efficient bandwidth utilization and fault-tolerant communication by redirecting traffic via an interswitch link in case of link failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If STP is used to ensure loop-free network topology, then network stability is improved, but bandwidth utilization deteriorates due to blocking of alternate paths
Solution Approach 1:
The patent segments the network into multiple active paths instead of blocking alternate paths. TRILL protocols divide the network into RBridge domains with multiple active links, allowing simultaneous use of multiple paths for different traffic flows, thus improving bandwidth utilization while maintaining loop-free topology through distributed routing decisions.
Solution Approach 2:
The patent implements dynamic path selection where traffic can be actively load-balanced across multiple links. The TRILL protocol enables dynamic routing decisions at each RBridge based on current network conditions, allowing the network to adaptively utilize available bandwidth rather than statically blocking paths as in STP.
2Stability of the object's composition
If STP blocks alternate network paths to prevent loops, then network stability is improved, but fault tolerance deteriorates due to single active link between nodes
Solution Approach 1:
The patent segments the network into multiple active paths using TRILL protocols. Each RBridge maintains multiple active links to other RBridges, creating a mesh topology where no single link failure can isolate any node. This segmentation into multiple active paths provides both stability through distributed routing and fault tolerance through redundancy.
Solution Approach 2:
The patent implements prior cushioning by pre-establishing multiple active paths and backup links before failures occur. TRILL networks maintain multiple synchronized forwarding databases and pre-computed alternate paths, so when a link or node fails, traffic can immediately switch to pre-prepared alternate paths without waiting for failure detection and recovery protocols.
3Device complexity
If STP uses a single active link between nodes, then device complexity is reduced, but failure recovery time increases due to lengthy relearning of forwarding paths
Solution Approach 1:
The patent applies preliminary action by pre-establishing multiple active paths and maintaining synchronized forwarding databases across all RBridges before failures occur. TRILL uses distributed link-state routing that continuously updates all nodes about network topology, so when a failure occurs, all RBridges already have the information needed to immediately recalculate and switch to alternate paths without waiting for broadcast-based relearning.
Solution Approach 2:
The patent implements feedback mechanisms where TRILL RBridges continuously exchange link-state information and routing metrics with each other. This real-time feedback allows the network to detect failures immediately and dynamically recalculate optimal paths using distributed algorithms, providing fast failure recovery while maintaining manageable protocol complexity through standardized information exchange.
4Productivity
If TRILL protocols are implemented within the campus network, then multi-pathing is improved for internal traffic, but adaptability deteriorates at the network boundary where external nodes can only use a single active link
Solution Approach 1:
The patent applies universality by making the RBridge itself multi-functional. The RBridge acts as both an internal TRILL router for multi-pathing and as an external Ethernet switch for boundary connectivity. By integrating multiple functions into a single device, the RBridge can present multiple active links to external nodes while maintaining TRILL multi-pathing internally, thus improving both internal productivity and external adaptability.
Solution Approach 2:
The patent uses the RBridge as an intermediary between external Ethernet networks and internal TRILL campuses. The RBridge translates and adapts traffic between external single-link connections and internal multi-path TRILL routing, allowing external nodes to connect via multiple links to different RBridges while the RBridges handle the complexity of internal multi-pathing, thus improving boundary adaptability without compromising internal efficiency.
Data Source
AI summary
Each of first and second bridges of a data network having respective links to an external node implement a network bridge component that forwards traffic inside the data network and a virtual bridge component that forwards traffic outside of the data network. A virtual bridge is formed including the virtual bridge components of the first and second bridges and an interswitch link (ISL) between the virtual bridge components of the first and second bridges. Data frames are communicated with each of multiple external network nodes outside the data network via a respective one of multiple link aggregation groups all commonly supported by the virtual bridge.