Multicast Expansion Table Latency Fairness via Sequence Rotation
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Solution Overview
Problem
Current communication networks face challenges in managing multicast traffic effectively, particularly in latency-sensitive environments like financial trading, where high availability and throughput are required, and existing technologies struggle to provide differentiated services based on throughput and latency.
Innovation Solution
The implementation of a multi-linked Multicast Expansion Table (MET) that serially replicates packets across network destinations using different sequences to ensure delay-fairness or prioritize latency, allowing for real-time updates without disrupting multicasting operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multicast traffic is distributed across multiple network links using ECMP and flowlet hashing, then network utilization is maximized, but latency distribution becomes uneven across destinations
Solution Approach 1:
The patent implements dynamic sequence selection in the Multicast Expansion Table where the traversal sequence changes based on the flowlet identifier. Different flowlets are assigned different sequences that rotate through multiple destinations, making the system adaptive rather than static. This dynamic approach ensures that over time, each destination receives a fair share of traffic while maintaining high network utilization through parallel path usage.
Solution Approach 2:
The patent employs periodic rotation of traversal sequences through the Multicast Expansion Table. The sequence index is incremented periodically for different flowlets, creating a cyclic pattern where each destination gets turns in the replication sequence. This periodic action distributes latency evenly across all destinations while maintaining continuous high-speed forwarding through ECMP paths.
2Loss of time
If packets are serially replicated to multiple destinations, then latency can be controlled and distributed evenly, but network throughput is reduced compared to parallel replication
Solution Approach 1:
The patent segments the multicast traffic into different flowlets, where each flowlet is assigned a specific traversal sequence through the Multicast Expansion Table. This segmentation allows the system to apply serial replication control within each flowlet while maintaining overall high throughput across multiple flowlets. The segmentation breaks down the conflict between latency control and throughput by handling them at different granularities.
Solution Approach 2:
The patent changes the traversal sequence parameter in the Multicast Expansion Table based on the flowlet identifier. By varying the sequence index parameter, the system dynamically adjusts which destination receives the next packet in the serial replication process. This parameter change enables flexible control of latency distribution without requiring fixed serial replication, thereby maintaining higher throughput through parallel flowlet processing.
3Device complexity
If the Multicast Expansion Table uses a fixed traversal sequence, then implementation is simple, but latency distribution is uneven and cannot adapt to changing network conditions
Solution Approach 1:
The Multicast Expansion Table is enhanced with dynamic sequence selection capability where the traversal sequence is determined by the flowlet identifier rather than being fixed. The table maintains multiple destination sequences and selects among them dynamically. This adds moderate complexity to the table structure but provides significant benefits in latency fairness and adaptability to changing network conditions.
Solution Approach 2:
The patent introduces a sequence index parameter in the Multicast Expansion Table that can be changed based on flowlet identification. This parameter change mechanism allows the table to switch between different traversal sequences, enabling adaptive latency distribution. The parameter change approach maintains relatively simple table implementation while achieving dynamic latency fairness through configurable sequence selection.
Data Source
AI summary
Exemplified systems and methods facilitate multicasting latency optimization operations for router, switches, and other network devices, for routed Layer-3 multicast packets to provide even distribution latency and/or selective prioritized distribution of latency among multicast destinations. A list of network destinations for serially-replicated packets is traversed in different sequences from one packet to the next, to provide delay fairness among the listed destinations. The list of network destinations are mapped to physical network ports, virtual ports, or logical ports of the router, switches, or other network devices and, thus, the different sequences are also traversed from these physical network ports, virtual ports, or logical ports. The exemplified systems and methods facilitates the management of traffic that is particularly beneficial in in a data center.