Controller-Driven DF Election for EVPN Load Balancing
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Solution Overview
Problem
Conventional EVPN designated forwarder (DF) election methods are limited in scope, failing to account for multiple Ethernet segments sharing a provider edge, leading to uneven load distribution and inadequate bandwidth management, which results in suboptimal traffic distribution across multi-homed PEs.
Innovation Solution
A network controller collects and analyzes topology information to perform dynamic DF election across multiple Ethernet segments, using a semi-matching algorithm to balance VLAN assignments and consider PE and Ethernet segment weights, ensuring fair load distribution and bandwidth utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional EVPN DF election is performed at the granularity of an individual Ethernet Segment, then the election process is simple and localized, but it results in uneven load distribution and prevents load balancing across PEs that share multiple Ethernet segments
Solution Approach 1:
The patent merges the DF election process across multiple Ethernet segments by introducing a global election mechanism that considers all segments simultaneously. The network controller aggregates topology information from all Ethernet segments and performs a unified DF election, combining localized segment-level decisions into a coordinated network-wide optimization that achieves load balancing while maintaining operational simplicity through automated centralized control
Solution Approach 2:
The network controller acts as an intermediary between Ethernet segments and PEs, collecting topology information, computing optimal DF assignments, and programming results. This intermediary approach enables complex load balancing decisions without requiring complex distributed algorithms at PE level, maintaining ease of operation while achieving high productivity through centralized intelligence
2Reliability
If a PE is elected as DF for all VLANs across all Ethernet segments it shares, then the election outcome is determined by segment-level criteria, but it prevents even load balancing and causes suboptimal traffic distribution
Solution Approach 1:
The patent transitions from segment-level DF election (one dimension) to network-wide DF election across multiple dimensions. By considering all Ethernet segments and their shared PEs simultaneously in a unified election process, the system adds the dimension of cross-segment awareness, enabling optimal load distribution that accounts for both segment reliability requirements and overall traffic distribution efficiency
Solution Approach 2:
The invention changes the parameters used in DF election from segment-local criteria to network-wide criteria. The network controller uses topology information spanning all segments and applies weighting factors that consider both segment-level reliability needs and overall load distribution goals, transforming the election into a multi-parameter optimization that achieves both reliability and productivity objectives
Data Source
AI summary
A method is performed by a network controller. The method includes receiving information that defines a topology of a network having Ethernet Segments configured with virtual local area networks (VLANs) and including provider edges that are multi-homed to customer edges. The method further comprises, based on the topology, determining for the VLANs particular provider edges among the provider edges that are to operate as designated forwarders of traffic for the VLANs, such that the VLANs are load balanced across the particular provider edges. The method also includes programming the particular provider edges as the designated forwarders of traffic for the VLANs.