Sub-LAG Segmentation for Switch Interconnect Traffic Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current information handling systems with layer-2 switches experience unnecessary traffic flow over interconnect links, leading to bandwidth consumption and increased network hops due to inefficient packet forwarding between switches in configurations like virtual link trunking (VLT) or virtual switching systems.
Innovation Solution
The implementation of a method involving the formation of link aggregation groups (LAGs), where a first switch maintains associations between destination MAC addresses and ports/LAGs to forward packets efficiently, using LACP data units to determine sub-LAG and main LAG membership, thereby optimizing traffic routing and reducing interconnect link usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If switches use traditional forwarding methods in VLT or stacking configurations, then packet forwarding is simple, but traffic unnecessarily flows over interconnect links consuming bandwidth and increasing hops
Solution Approach 1:
The patent segments the link aggregation group into multiple sub-LAGs, where each sub-LAG is associated with a specific downstream switch. This segmentation enables the upstream switch to selectively forward unicast traffic to the appropriate sub-LAG based on destination MAC address, preventing unnecessary traffic from traversing interconnect links between stacked switches.
Solution Approach 2:
The patent implements local quality by creating sub-LAGs with specific characteristics - each sub-LAG is locally optimized for traffic destined to a particular downstream switch. The upstream switch maintains a mapping between destination MAC addresses and specific sub-LAGs, enabling localized traffic steering that reduces interconnect link utilization while maintaining simple forwarding operations.
2Loss of time
If switches forward packets without sub-LAG segmentation, then forwarding operations are simple, but the number of network hops increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing the mapping between destination MAC addresses and specific sub-LAGs before packet forwarding occurs. The upstream switch learns which downstream switch owns which MAC addresses and configures sub-LAG associations in advance. This preliminary configuration enables direct single-hop forwarding without requiring complex real-time routing decisions or additional hops through intermediate switches.
3Ease of operation
If switches use main LAG for all traffic, then forwarding is straightforward, but interconnect link traffic cannot be reduced
Solution Approach 1:
The patent introduces dynamics by making the forwarding behavior adaptive based on traffic type. For unicast traffic, the system dynamically selects specific sub-LAGs based on destination MAC address lookups, while for broadcast, multicast, or unknown unicast traffic, the system falls back to flooding over the entire main LAG. This dynamic approach maintains ease of operation for common cases while optimizing interconnect link utilization for unicast traffic.
Data Source
AI summary
A first switch forms first and second LAGs and a main LAG comprising the first and second LAGs as sub-LAGs. Forming the first and second LAGs comprises receiving LACP data units which indicate that the first switch is connected to second and third switches through first and second pluralities of ports, and forming the first LAG of the first plurality of ports and the second LAG of the second plurality of ports. The second and third switches share a control plane. In forming the first and second LAGs, LACP data units are received from the second and third switches and include unique identifiers of the second and third switches respectively. Forming the main LAG comprises receiving one or more LACP data units which indicate that the first and second plurality of ports are to be part of the main LAG, and forming the main LAG based on such LACP data units. Other features are also provided.