Traffic Redirection in Link Aggregation Groups
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Solution Overview
Problem
Disruptive port configurations in networking topologies with Link Aggregation Groups (LAGs) cause unnecessary traffic loss due to the need to disable traffic on ports during configuration changes, leading to delays and dropped packets.
Innovation Solution
Redirecting egress traffic from the affected port to other LAG members using Link Aggregation Control Protocol (LACP) or Link Layer Discovery Protocol (LLDP messages, allowing configurations to be applied without interrupting traffic flow, and re-enabling the port once configurations are complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If disruptive port configurations are applied to ensure proper configuration settings, then configuration reliability is improved, but traffic loss occurs during the configuration process
Solution Approach 1:
The system performs preliminary actions by detecting when a port is operationally down and proactively redirecting traffic to alternative LAG member ports before the configuration is applied. This prevents traffic loss by ensuring the traffic path is already established before the disruptive configuration occurs.
Solution Approach 2:
The system introduces an intermediary mechanism (traffic redirection logic) that mediates between the disruptive configuration event and the traffic flow. When a port goes down for configuration, the intermediary redirects traffic through other LAG members, preventing direct traffic loss while allowing the configuration to proceed.
2Ease of manufacture
If traffic is disabled on a port during configuration, then configuration can be applied safely, but productivity decreases due to traffic interruption
Solution Approach 1:
The system performs preliminary traffic redirection to alternative paths before the configuration disables traffic on the original port. This ensures that productivity is maintained by pre-establishing alternative traffic flows, so when configuration occurs, no traffic interruption is experienced.
Solution Approach 2:
The system maintains continuity of useful action by keeping traffic flowing through alternative LAG member ports during the configuration process. The traffic flow continues uninterrupted through the alternative path, ensuring productivity is maintained while the configuration is applied on the original port.
3Measurement precision
If LAG table is reprogrammed to remove failed ports, then traffic routing accuracy is improved, but time delay increases during the update process
Solution Approach 1:
The system performs preliminary traffic redirection based on detection of the operationally down state, before the LAG table is reprogrammed. This reduces time delay by initiating traffic redirection immediately upon detection, rather than waiting for the periodic LAG table update cycle.
Solution Approach 2:
The system introduces dynamic traffic redirection that responds in real-time to port state changes, rather than relying on static periodic LAG table updates. This dynamic approach reduces timing delays by adapting traffic paths immediately when ports go down, improving both responsiveness and routing accuracy.
Data Source
AI summary
Various systems and methods take advantage of physical interfaces that are a part of Link Aggregation Group (LAG) to avoid traffic drops when disruptive configurations are applied to a port of a switch or router. In embodiments, in networking topologies using (SAN)-based traffic, where zero losses are expected, lossless deployment may be accomplished by using LACP to proactively intervene and redirect traffic flow in both ingress and egress directions of a to-be-configured port, e.g., to other ports of the LAG.