EVPN Gateway Route Logic to Prevent DCI Traffic Blackholing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
EVPN DCI networks experience traffic blackholing due to EVPN aliasing, particularly when WAN connections fail or gateways reboot, leading to inadvertent dropping of L2 traffic as network elements incorrectly infer paths through redundant gateways.
Innovation Solution
Modify the AD route advertisement logic in EVPN gateways to only advertise AD per ES routes for I-ESs, disabling EVPN aliasing for these segments to prevent incorrect path inference and traffic blackholing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EVPN aliasing is enabled for I-ESs to provide path redundancy, then network redundancy is improved, but traffic blackholing occurs when WAN connections fail or gateways reboot
Solution Approach 1:
The patent applies local quality by differentiating the treatment of Ethernet segments: EVPN aliasing is enabled for local ESs (where it provides beneficial redundancy) but disabled for I-ESs (where it causes harmful blackholing). This is achieved by modifying the EVPN gateway to identify I-ESs and suppress aliasing route advertisements specifically for these segments, thereby applying different quality characteristics to different parts of the network fabric.
Solution Approach 2:
The patent segments the EVPN route advertisement process into two distinct paths: regular ES routes and I-ES routes. By segmenting the route advertisement logic, the system can apply EVPN aliasing selectively - enabling it for local ESs while disabling it for I-ESs. This segmentation allows the network to maintain redundancy benefits where applicable while avoiding blackholing in I-ES scenarios.
2Productivity
If EVPN aliasing is used to enable load balancing across redundant gateways, then network efficiency is improved, but incorrect path inference causes traffic dropping
Solution Approach 1:
The patent applies local quality by enabling EVPN aliasing for local ESs where load balancing improves network efficiency, while disabling it for I-ESs where it causes incorrect path inference and traffic dropping. The modified EVPN gateway identifies the type of Ethernet segment and applies appropriate aliasing behavior, thereby achieving different quality characteristics in different network contexts.
Solution Approach 2:
The patent introduces an intermediary mechanism in the EVPN gateway that mediates between the desire for load balancing (via EVPN aliasing) and the need for accurate path determination. This intermediary logic examines the Ethernet segment type and conditionally suppresses aliasing route advertisements for I-ESs, acting as a mediator that prevents harmful path inference while preserving beneficial aliasing for local ESs.
3Reliability
If multiple physical links are configured as I-ES for redundancy, then network resilience is improved, but EVPN aliasing causes inadvertent traffic dropping
Solution Approach 1:
The patent applies local quality by differentiating between local ESs and I-ESs in terms of EVPN aliasing behavior. For I-ESs configured with multiple physical links for redundancy, the system disables EVPN aliasing specifically for these segments by suppressing aliasing route advertisements, thereby preventing traffic blackholing while maintaining the underlying link redundancy for failover purposes.
Solution Approach 2:
The patent segments the route advertisement process to handle I-ESs differently from regular ESs. By identifying I-ESs through configuration parameters and segmenting the aliasing route advertisement logic, the system maintains multiple physical links for redundancy while preventing EVPN aliasing from causing harmful traffic dropping scenarios specific to I-ES topologies.
Data Source
AI summary
Techniques for avoiding traffic blackholing problems in an Ethernet Virtual Private Network (EVPN) Data Center Interconnect (DCI) network topology that are caused by EVPN aliasing are provided. In one set of embodiments, a gateway device in the EVPN DCI network topology can determine whether an Ethernet Segment (ES) to which the gateway device is connected is an Interconnect ES (I-ES). If so, the gateway device can advertise an Auto-Discovery (AD) per ES route for the ES to one or more other network elements in the EVPN DCI network topology, without advertising any AD per EVPN Instance (EVI) routes for the ES.