EVPN PE Device Load Sharing via MAC Route Propagation
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Solution Overview
Problem
In Ethernet Virtual Private Networks (EVPN), load sharing between PE devices is inefficient due to the inability of a PE device to directly forward traffic to a CE device that is multihomed, resulting in wasted bandwidth resources and ineffective utilization of system resources.
Innovation Solution
A method where a first PE device notifies a second PE device of the MAC route and VLAN identifier learned from a CE device, allowing the second PE device to generate a MAC forwarding entry and directly forward traffic to the CE device, even if it cannot learn the VLAN information directly from the CE device, thereby enabling effective load sharing between multiple PE devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a PE device uses conventional MAC address learning in the data plane, then MAC address diffusion is reduced, but load sharing between PE devices connected to multihomed CE devices cannot be effectively implemented
Solution Approach 1:
The patent introduces a control plane intermediary (BGP protocol) to enable MAC address learning and publishing between PE devices. Instead of direct data plane learning, the control plane acts as an intermediary that distributes MAC address information to all relevant PE devices, enabling them to make informed forwarding decisions and achieve effective load sharing across multihomed CE device connections.
2Ease of operation
If a PE device does not learn VLAN information directly from the CE device, then device complexity is reduced, but the ability to directly forward traffic to the CE device is lost
Solution Approach 1:
The control plane serves as an intermediary that distributes VLAN information from CE devices to PE devices. Instead of requiring direct VLAN information acquisition from CE devices, the control plane mediates this information exchange, providing PE devices with the necessary VLAN context to perform direct traffic forwarding without increasing device complexity.
Solution Approach 2:
The patent implements preliminary action by having PE devices learn VLAN information through control plane signaling before actual traffic forwarding occurs. This pre-establishment of VLAN information enables PE devices to immediately forward traffic directly to CE devices without requiring real-time VLAN discovery, thus maintaining ease of operation while avoiding the complexity of dynamic VLAN information acquisition.
3Productivity
If MAC address learning is performed only by the PE device directly connected to the CE device, then device complexity is reduced, but bandwidth resources are wasted due to inability to share load
Solution Approach 1:
The control plane provides universal MAC address learning capability to all PE devices in the EVPN. Instead of limiting MAC address learning to only the directly connected PE device, the control plane distributes MAC address information universally to all PE devices that need it, enabling any PE device to forward traffic to any CE device and achieve effective load sharing across the entire EVPN domain.
Data Source
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AI summary
An EVPN packet processing method is provided. A CE device is multihomed to a first PE device and a second PE device. The method includes the following steps: The first PE device sends, to the second PE device, a MAC route learned from the CE device and a VLAN identifier. The second PE device generates a MAC forwarding entry based on the MAC route and the VLAN identifier, where the MAC forwarding entry is used to directly forward, by using the CE device, a packet whose destination MAC address is the CE device or a MAC address of a terminal device accessing the CE device. An outbound interface identifier included in the MAC forwarding entry is an identifier of an interface connected to the CE device. According to the method in this application, load can be effectively shared between the first PE device and the second PE device, and system bandwidth resources can be properly used.