Segment Routing ECMP Scaling via NO-OP Label Operations
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Solution Overview
Problem
Segment Routing in Massively Scalable Data Center networks faces scaling issues due to the depletion of ECMP resources when using unique labels for tunnel end-points, leading to network crippling.
Innovation Solution
Implementing 'NO-OP' and 'NULL' label operations in the control plane of nodes along the segment routing tunnel to preserve the original incoming label stack, allowing sharing of ECMP links and reducing the need for unique ECMP objects, thereby optimizing ECMP resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If unique ECMP objects are allocated for each Segment Routing tunnel end-point, then routing precision and tunnel identification are improved, but ECMP resource depletion occurs and network scalability deteriorates
Solution Approach 1:
The patent merges multiple tunnel end-points that share the same ECMP links into a single shared ECMP object. Instead of allocating separate ECMP objects for each tunnel end-point, the invention groups tunnels by their underlying ECMP link set and assigns a common ECMP object to the group, thereby consolidating resource usage while maintaining tunnel identification through label stacking mechanisms.
Solution Approach 2:
The patent makes ECMP objects universal by enabling a single ECMP object to serve multiple tunnel end-points simultaneously. The ECMP object is designed to be multi-functional, handling forwarding for different tunnels that share the same physical links through label operations (push/pop) that preserve the original incoming label stack, allowing one ECMP object to perform the work of multiple dedicated objects.
2Ease of operation
If ECMP resources are allocated per tunnel end-point, then routing control is improved, but network scalability is reduced due to resource depletion
Solution Approach 1:
The patent combines multiple tunnel end-points into a single ECMP object allocation unit. By merging the resource allocation granularity from per-tunnel-end-point to per-ECMP-link-set, the system maintains routing control through label stack operations while dramatically improving scalability and reducing the total number of ECMP objects required in the network.
Solution Approach 2:
The patent introduces a new dimension to ECMP object usage by implementing label stacking operations (push/pop) that add a logical layer to the forwarding process. This dimensional change allows the same physical ECMP links to be reused across multiple tunnels through label manipulation, transforming the resource allocation model from flat (one object per tunnel) to hierarchical (shared objects with label-based differentiation).
Data Source
AI summary
Disclosed are systems and methods for scaling Massively Scalable Data Center (MSDC) networks with a large number of end-point tunnels utilizing Equal-cost multi-path routing (ECMP). The systems and methods can use the NO-OP label operations to maintain single ECMP objects to switch a set of segment routing tunnels that share the same ECMP links. The forwarding engine can determine the use of the NO-OP label operation and update a received packet to enable the use of the single ECMP objects of the set of segment routing tunnels.