ToR Switch LBT Egress Control for Loop-Free Multi-Fabric Networks
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Solution Overview
Problem
In multi-fabric virtual networks, existing technologies face challenges with network loops and isolation due to dependencies on network topology, leading to congestion and reduced performance, and require costly spine switches for high availability.
Innovation Solution
Implementing Load-Based Teaming (LBT) egress control values in packets to prevent network loops and establishing inter-switch links between Top-of-Rack (ToR) switches without a spine switch, allowing nodes to handle packets effectively and maintain connectivity even when one ToR switch fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional network topology with spine switches is used to ensure high availability, then network reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the spine switch component from the traditional three-tier network architecture, eliminating the need for expensive spine switches while maintaining network functionality through direct ToR switch interconnections and host-based load balancing
Solution Approach 2:
The patent replaces expensive spine switches with more economical ToR switches that can be interconnected directly, using commodity hardware to achieve the same high availability function without requiring specialized expensive equipment
2Productivity
If Load-Based Teaming is implemented without egress control, then load balancing is improved, but network loops and congestion occur
Solution Approach 1:
The patent implements feedback mechanisms where ToR switches monitor packet flow and exchange control information about egress ports, allowing the network to dynamically adjust and prevent loops by informing upstream switches about downstream egress decisions
Solution Approach 2:
The patent applies preliminary action by pre-configuring LBT egress control values in outbound packets before they traverse the network, enabling downstream switches to make informed forwarding decisions that prevent loops before they can form
3Reliability
If inter-switch links are established between ToR switches, then redundancy is improved, but network congestion may increase
Solution Approach 1:
The patent implements dynamic packet routing where ToR switches adaptively select egress ports based on real-time network conditions and packet characteristics, allowing the system to dynamically optimize traffic flow across inter-switch links to prevent congestion while maintaining redundancy
Data Source
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AI summary
A disclosed example of managing a network include receiving a packet at a first top-of-rack (ToR) switch via a first load-based teaming (LBT) port; determining whether a network location of a destination node of the packet is unknown; based on the network location being unknown, setting an LBT egress control value in the packet, the LBT egress control value to indicate that the packet is not to be transmitted via a second LBT port of a second ToR switch; and sending the packet from the first ToR switch to the second ToR switch via an inter-switch link between the first and second ToR switches and from the first ToR switch to at least a first host that is identified in the packet as the destination node.