Supplemental Bridge Domain Forwarding for EVPN Multicast Scale
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Solution Overview
Problem
In Ethernet virtual private network (EVPN) ERB overlay fabrics, maintaining large numbers of leaf devices and VLANs results in substantial computing and resource consumption due to the need for extensive tables of capabilities and associations, impacting traffic forwarding and switching performance.
Innovation Solution
Implementing a supplemental bridge domain (SBD) interface in provider edge (PE) network devices to forward inter-subnet multicast traffic, allowing PE devices to communicate with other PE devices via SBD, reducing the need to maintain detailed tables about other PE devices, and using IRB interfaces for multihomed peers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If extensive tables of capabilities and associations are maintained to support large numbers of leaf devices and VLANs, then device coverage and network scale are improved, but computing and resource consumption increase substantially
Solution Approach 1:
The patent segments the bridge domain functionality by introducing a supplemental bridge domain (SBD) interface that separates multicast traffic forwarding from the main control plane. This segmentation allows PE devices to forward multicast traffic without maintaining extensive capability and association tables for all leaf devices and VLANs, thereby reducing computing resource consumption while preserving network scale capability
Solution Approach 2:
The SBD interface acts as an intermediary mechanism between PE devices for multicast traffic forwarding. Instead of requiring direct knowledge of all leaf devices and VLAN associations, the SBD interface mediates the forwarding process, enabling PE devices to forward inter-subnet multicast traffic efficiently without maintaining detailed capability tables
2Adaptability or versatility
If extensive tables of capabilities and associations are maintained to support large numbers of leaf devices and VLANs, then network scale is improved, but traffic forwarding performance deteriorates
Solution Approach 1:
The patent segments the forwarding function by introducing the SBD interface, which handles multicast traffic forwarding independently from the main control plane operations. This segmentation enables traffic forwarding to proceed without the performance penalty of maintaining extensive capability and association tables, thus preserving network scale while improving forwarding performance
Solution Approach 2:
The patent extracts the multicast forwarding function from the main control plane by implementing it through the SBD interface. This extraction allows the forwarding operation to occur without requiring access to or processing of extensive capability and association tables, thereby improving traffic forwarding performance while maintaining support for large network scales
Data Source
AI summary
In some implementations, a first network device that hosts a bridge domain (BD) may receive inter-subnet multicast traffic associated with the BD. The BD may forward, using a supplemental bridge domain (SBD) interface of the first network device, and via an SBD, a first copy of the inter-subnet multicast traffic to a second network device that hosts the BD. The first network device may forward, using the SBD interface and via the SBD, a second copy of the inter-subnet multicast traffic to a third network device that does not host the BD. The first network device may forward, using an integrated routing and bridging (IRB) interface of the first network device associated with the BD, a third copy of the inter-subnet multicast traffic to a fourth network device that hosts the BD (e.g., when the fourth network device is a multihoming peer of the first network device).