EVPN Multihoming STP Flapping via Super Root Group
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Solution Overview
Problem
Current methods lack efficient support for Spanning Tree Protocol (STP) in networks using Ethernet Virtual Private Network (EVPN) All-Active (A-A) multihoming, leading to L2 loops and STP flapping due to independent operation of Provider Edge devices with different Bridge Protocol Data Unit (BPDU) messages.
Innovation Solution
Establishing a super root group with a common bridge ID for network devices providing A-A multihoming, allowing them to send BPDU messages with a unified bridge ID, treating them as a single local bridge and enabling STP without flapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Provider Edge devices operate independently with different BPDU messages, then each device can function autonomously, but Layer 2 loops occur and STP flapping ensues
Solution Approach 1:
The patent merges multiple Provider Edge devices into a single logical entity by assigning them a common bridge ID. This allows them to operate autonomously at the physical level while presenting a unified identity to the Spanning Tree Protocol, preventing L2 loops and STP flapping by ensuring all PEs are recognized as part of the same bridge.
2Reliability
If Spanning Tree Protocol is implemented in EVPN A-A multihoming networks, then Layer 2 loops are eliminated, but STP flapping occurs due to different bridge IDs
Solution Approach 1:
The patent applies local quality by maintaining different bridge IDs for individual Provider Edge devices in their respective local contexts (for autonomous operation and routing purposes) while simultaneously using a common bridge ID in the context of Spanning Tree Protocol communication. This allows STP to function稳定ly without preventing the devices from operating independently elsewhere.
3Reliability
If a common bridge ID is used for multiple Provider Edge devices, then STP operation is enabled without flapping, but the devices lose individual identity in BPDU messages
Solution Approach 1:
The patent resolves the identity loss issue by operating in multiple dimensions: at the Spanning Tree Protocol layer, a common bridge ID is used to ensure stable operation and prevent flapping, while at the EVPN and routing layers, individual device identities are preserved through separate MAC addresses and forwarding tables. This multi-dimensional approach allows both unified STP operation and individual device recognition.
Data Source
AI summary
Systems and methods are provided herein for supporting Spanning Tree Protocol (STP) in networks that use Ethernet Virtual Private Network (EVPN) All-Active (A-A) multihoming. This may be accomplished by a network administrator defining a super root group comprising a plurality of network devices, wherein each network device provides A-A multihoming to a multihomed device. All network devices in the super root group use a common bridge ID when generating BPDU messages for STP. All network devices in the super root group will send BPDU messages comprising the common bridge ID to the multihomed device. Because the BPDU messages comprise a common bridge ID, the multihomed device treats the network devices in the super root group as a single local bridge, thus STP is enabled without causing STP flapping.