vLAG Switch Multicast Traffic Load Balancing via Hashing
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Solution Overview
Problem
In traditional Virtual Link Aggregation Group (vLAG) Protocol Independent Multicast (PIM) topologies, the primary vLAG switch is overloaded as the dedicated forwarder of data traffic, leading to performance issues and limited data throughput due to the secondary switch dropping packets to avoid duplicates, while the primary switch handles all upstream network sources and downstream receivers.
Innovation Solution
Implementing a load balancing system where both primary and secondary vLAG switches determine the source IP address and multicast group address of incoming data traffic, hash these values, and decide based on the resultant value whether the primary or secondary switch transmits the data to the downstream network device, thereby distributing the traffic load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the primary vLAG switch is designated as the dedicated forwarder of data traffic, then duplicate traffic is avoided, but the primary switch becomes overloaded and data throughput is limited
Solution Approach 1:
The patent segments the traffic forwarding function by dividing the vLAG member switches into different groups (first group and second group). Each group is responsible for forwarding traffic from specific upstream network devices, preventing any single switch from being overloaded while maintaining duplicate traffic prevention through coordinated group behavior.
Solution Approach 2:
The patent implements dynamic load balancing where the control plane device dynamically determines which vLAG member switch forwards traffic based on current network conditions, upstream device identifiers, and hash calculations. This dynamic assignment allows traffic distribution to adapt to changing network states, optimizing throughput while preventing duplicates.
2Reliability
If the secondary vLAG switch drops packets to avoid duplicates, then traffic duplication is prevented, but the secondary switch cannot contribute to data throughput
Solution Approach 1:
The patent segments the traffic forwarding function by dividing the vLAG member switches into different groups (first group and second group). Each group is responsible for forwarding traffic from specific upstream network devices, preventing any single switch from being overloaded while maintaining duplicate traffic prevention through coordinated group behavior.
Solution Approach 2:
The patent enables the secondary vLAG switch to actively participate in traffic forwarding by assigning it responsibility for specific upstream network devices through hash-based determination. The secondary switch no longer passively drops packets but instead autonomously forwards traffic for its assigned upstream devices, contributing to overall throughput while the control plane device ensures no duplicates are sent.
Data Source
AI summary
A PIM vLAG network load balancing system includes a first vLAG switch and a second vLAG switch each connected to, and receive data traffic from, an upstream network device. The first and second vLAG switches balance network data traffic by both determining a source IP address and a multicast group address associated with the received data traffic, hashing the addresses, combining the hashed addresses to determine a resultant value, and either dropping or transmitting the received data traffic to a downstream network device based upon the resultant value. The first vLAG switch may transmit and the second vLAG switch may drop the received data traffic if the resultant value is a first binary value. The second vLAG switch may transmit and the first vLAG switch may drop the received data traffic if the resultant value is a second binary value.