EVPN ESI Status Mechanism for Faster Network Convergence
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Solution Overview
Problem
Current EVPN networks experience prolonged outages and inefficient traffic routing due to the time-consuming process of withdrawing MAC/IP routes after a redundant network device's link is interrupted, which affects Layer 3 route convergence.
Innovation Solution
Implementing an ESI connected status mechanism that allows remote network devices to quickly update Layer 3 routes by associating eligibility with the ESI connected status, enabling simultaneous update of L3 routes upon withdrawal of an AD per ES route, thereby minimizing interruptions and optimizing traffic rerouting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MAC/IP routes are withdrawn one at a time after a link interruption, then each route withdrawal is processed individually, but this results in prolonged outages and inefficient traffic routing
Solution Approach 1:
The patent merges multiple individual MAC/IP route withdrawals into a single consolidated withdrawal operation. When a link interruption is detected, the system withdraws all affected MAC/IP routes associated with that link in one action, rather than processing them sequentially. This combining approach dramatically reduces the time required for network convergence and eliminates the prolonged outages caused by sequential processing.
2Productivity
If multiple MAC/IP routes are withdrawn simultaneously, then convergence speed improves, but the complexity of route management increases
Solution Approach 1:
The patent segments route management into distinct functional components: route advertisement, route withdrawal, and convergence triggering. By organizing routes into groups associated with specific links and implementing structured withdrawal procedures, the system achieves simultaneous route updates without proportionally increasing overall system complexity. The segmentation allows for manageable, modular route control.
3Measurement precision
If L3 routes are updated individually after each MAC/IP route withdrawal, then routing accuracy is maintained, but convergence time increases
Solution Approach 1:
The patent implements preliminary action by establishing link-route association mappings before link failures occur. When a link interruption is detected, the system has pre-configured knowledge of which MAC/IP and L3 routes are affected, allowing for immediate bulk withdrawal and update operations. This preliminary organization enables simultaneous route updates while maintaining routing accuracy, as all affected routes are identified and updated together in a coordinated manner.
Data Source
AI summary
Systems and methods are provided herein for a mechanism for faster convergence of network traffic after a network device's link is interrupted by leveraging the withdrawal of the ethernet virtual private network (EVPN) auto discovery (AD) route. This may be accomplished by a first device checking an ethernet segment identifier (ESI) status flag before generating an entry in the first device's forwarding table, where the entry is based on an IP route for a host received by a second network device. In response to receiving a withdrawal of an EVPN AD route from the second device, the first device may update the ESI status flag to indicate that the host on the ethernet segment (ES) is reachable only via the third device and update the entry that was based on the IP route for the host received by the second network device to prevent sending traffic to the host via the second device.