E-Spring Interworking via Link Aggregation Group for Access Protection
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Solution Overview
Problem
Existing techniques for implementing resilient interface connections between edge nodes and G.8032 Ethernet rings face challenges due to single points of failure and complex algorithms required for synchronization, particularly in access and hand-off connections.
Innovation Solution
The implementation of a Link Aggregation Group (LAG) between a first node and at least two ring nodes, with one node designated as Active and the others as Inactive, using extensions of 802.3ad or G.8032 version 2 to provide resilience by routing subscriber traffic only through the Active link, eliminating the need for distributed aggregation functions and reducing control signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a point-to-point Ethernet connection is used between CLE and Access Node, then the implementation is simple, but single points of failure cannot be eliminated
Solution Approach 1:
The access connection is segmented into multiple independent links (first link and second link) connecting the CLE to different ring nodes (first Access Node and second Access Node). This segmentation eliminates single points of failure by providing alternative paths, while each individual link remains simple to implement.
Solution Approach 2:
The solution transitions from a single-dimensional point-to-point connection to a multi-dimensional redundant topology by introducing multiple links and multiple Access Nodes. This dimensional expansion provides resilience while maintaining simplicity at each connection point.
2Reliability
If Split Multi Link Trunking (SMLT) is used to provide dual homed connection, then resilient connectivity is achieved, but complex algorithms and control signaling overhead are required
Solution Approach 1:
The complex distributed aggregation function and synchronization algorithms of SMLT are extracted and replaced with a simpler mechanism. The patent uses a basic active/inactive link selection method where the CLE selectively uses only the active link for traffic, eliminating the need for complex coordination algorithms between multiple Access Nodes.
Solution Approach 2:
The system changes the operational parameter of the links from equal-weighted load balancing (SMLT) to asymmetric active/inactive states. This parameter change simplifies control signaling while maintaining resilience, as the CLE only needs to know which link is active rather than coordinating complex aggregation across multiple links.
3Productivity
If distributed aggregation function is implemented at multiple Access Nodes, then load balancing is achieved, but control signaling overhead increases
Solution Approach 1:
The patent introduces a centralized intermediary mechanism where a single Access Node (the active one) handles all aggregation and control functions. This intermediary approach consolidates control signaling rather than distributing it across multiple nodes, reducing overall signaling overhead while the CLE maintains the ability to utilize multiple links for resilience.
Data Source
AI summary
A method of enabling a resilient interface between a first node and a G.8032 Ethernet ring. A Link Aggregation Group (LAG) comprising respective links is provided between the first node and at least two ring nodes of the Ethernet ring. An aggregation function is instantiated at the first node, for distributing subscriber traffic to the links of the LAG in a conventional manner. A first one of the ring nodes is designated as Active, and each of the other ones of the ring nodes are designated as Inactive. At each Inactive ring node, a logical block is imposed on its respective link of the LAG, such that subscriber traffic between the first node and the Ethernet ring is routed by the aggregation function only through the respective link between the first node and the Active ring node.