Bridged Network Traffic Resiliency via Pre-Computed Bypass Routes
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Solution Overview
Problem
The existing bridged network systems, particularly those using the Rapid Spanning Tree Protocol (RSTP), face challenges in quickly recovering from link failures due to the slow re-convergence process and the need for flushing and re-learning MAC addresses, which is not suitable for carrier-grade applications.
Innovation Solution
A bridged network system that includes a route indicator field in packets to quickly switch traffic from a failed link to a pre-identified bypass route, using a bypass table to route packets around the failure without the need for immediate re-convergence, allowing continuous packet transmission during the re-routing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Rapid Spanning Tree Protocol (RSTP) is used to provide loop-free operation and resilience in a bridged network, then reliability is improved, but the re-convergence time following a link failure increases to two to three seconds
Solution Approach 1:
The patent pre-identifies backup routes and pre-configures bypass tables with alternative paths before failures occur. When a link failure is detected, the system immediately switches to pre-computed backup routes using the bypass table, eliminating the need for slow dynamic re-convergence and MAC address re-learning that characterizes traditional RSTP protocols.
2Reliability
If traditional RSTP re-convergence is performed after a link failure, then network resilience is maintained, but MAC addresses must be flushed and re-learned which is an expensive operation causing packet loss
Solution Approach 1:
The bypass table is pre-configured with alternative routing information before failures occur. When a failure is detected, packets are immediately redirected using the pre-stored bypass table entries, eliminating the need to flush and re-learning MAC addresses and preventing packet loss during the transition period.
Solution Approach 2:
The bypass table acts as an intermediary data structure that stores pre-computed alternative routes. This intermediary allows the system to switch paths without triggering the expensive MAC address flush and re-learning process that would otherwise be required when changing routing paths in traditional bridged networks.
3Stability of the object's composition
If the spanning tree protocol is used to prevent loops in broadcast transmissions, then network stability is improved, but the protocol relies on exchange of BPDUs between nodes and the root which slows down failure response
Solution Approach 1:
Alternative routes are pre-identified and stored in the bypass table before failures occur. When a failure is detected, the system immediately uses the pre-computed bypass routes without waiting for BPDU exchange and spanning tree re-convergence, thereby maintaining loop-free operation while dramatically improving failure response speed.
Data Source
AI summary
A bridged network system (10, 10′) is described comprising a plurality of nodes (N1-N7). Each node in the plurality of nodes is coupled to communicate with at least one other node in the plurality of nodes. The plurality of nodes comprise a bridge network between external nodes located externally from the plurality of nodes. Each node of the plurality of nodes is operable to perform the steps of receiving a packet (20, 20′), wherein the packet comprises a route indicator field, and responsive to the packet being received prior to a time of failure along a communication link between two of the plurality of nodes, transmitting the packet along a first route in the system to another node in the plurality of nodes. Conversely, each node of the plurality of nodes is also operable to perform the step of, responsive to the packet being received after a time of failure along a communication link between two of the plurality of nodes and in response to the route indicator field, transmitting the packet along a second route in the system to another node in the plurality of nodes, wherein the second route differs from the first route and is identified prior to the time of failure.