Split Tiebreakers for 802.1AQ Network Path Selection
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Solution Overview
Problem
In richly connected multipath networks, traditional 802.1aq networks face instability and performance degradation due to the concentration of traffic on a single failover path after a failure, leading to potential cascading network failures and service degradation.
Innovation Solution
The implementation of split tiebreakers in 802.1aq networks, which involves assigning multiple system IDs to nodes and using tiebreaking transforms to distribute traffic across multiple equal cost shortest paths, allowing affected traffic to be diffused across surviving paths without rerouting unaffected paths, and restoring load to original routing upon failure correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional 802.1aq networks use single path selection for equal cost shortest paths, then routing simplicity is maintained, but network stability deteriorates due to traffic concentration on failover paths
Solution Approach 1:
The patent segments the single path selection process into multiple independent path ID computations, each associated with different system IDs. By dividing the traffic distribution mechanism into multiple segments (different path IDs), the system can distribute traffic across multiple paths independently, preventing concentration on a single failover path while maintaining routing simplicity through standardized path selection algorithms.
Solution Approach 2:
The patent applies local quality by assigning different system IDs to different paths, creating path-specific characteristics. Each path gets a unique path ID through local transformation of system IDs, allowing selective traffic distribution to specific paths based on their individual characteristics. This enables fine-grained control over traffic distribution without requiring complex global routing changes.
2Reliability
If traffic is shifted as a block to a single failover path, then failure recovery is achieved, but performance degradation occurs due to overloaded failover path
Solution Approach 1:
The patent segments the failed traffic into multiple smaller streams by associating different traffic flows with different path IDs. Instead of shifting all affected traffic as a single block to one failover path, the system distributes segments of traffic across multiple surviving paths based on their path ID associations. This segmentation prevents any single path from becoming overloaded while maintaining comprehensive failure recovery.
Solution Approach 2:
The patent introduces an additional dimension for traffic distribution by using path IDs as a new classification layer beyond traditional single-path selection. This dimensional expansion allows traffic to be distributed across multiple paths simultaneously based on path ID matching, transforming the single-dimension failover mechanism into a multi-dimensional traffic distribution system that improves both reliability and performance.
3Reliability
If multiple system IDs are assigned to nodes for split tiebreakers, then traffic distribution across multiple paths is achieved, but system complexity increases
Solution Approach 1:
The patent changes the parameter of system ID assignment from single-value to multi-value, allowing nodes to have multiple system IDs associated with different paths. This parameter change enables the tiebreaker mechanism to differentiate between multiple equal-cost paths by transforming system IDs into path-specific path IDs. The complexity increase is managed through systematic parameter transformation rather than fundamental architectural changes.
Solution Approach 2:
The patent applies universality by making the existing tiebreaker mechanism multi-functional. The same tiebreaker algorithm that previously selected among equal-cost paths now also distributes traffic across multiple paths using path ID associations. This multi-functionality allows the system to achieve traffic distribution without requiring entirely new routing protocols, reducing the effective complexity increase despite multiple system IDs.
Data Source
AI summary
A node in a communication network selects between equal cost shortest paths (ECSPs) using split tiebreakers. The node advertises multiple system identifiers (IDs) for that node, and each system ID is associated with a different set of traffic IDs that distinguish different virtual networks in the network. The node receives sets of system IDs for each of the other nodes in the network. After constructing a plurality of different ECSPs between two nodes, the node selects one of the ECSPs for each traffic ID used between the two nodes. For a traffic ID, the node constructs path IDs for each of the ECSPs using one system ID of each node in the path that is associated with that traffic ID. Because of the configuration of the system IDs and the traffic IDs in the network, traffic affected by a failure will be distributed across a plurality of surviving ECSPs.