Proxy Forwarding Same-Site Traffic Edge Devices EVPN
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Solution Overview
Problem
In multi-homed networks, EVPN procedures cause same-site Ethernet Segment traffic to be blindly dropped, leading to traffic loss and connectivity issues when a link fails, as they prevent loops and duplicates by solely relying on local links for forwarding, without enabling proxy forwarding or deterministic handshakes for role transitions.
Innovation Solution
Implementing a Designated Forwarder (DF) edge network device to proxy forward same-site traffic on behalf of a peer edge network device that has lost connectivity, with a deterministic signaling mechanism to transition proxy forwarding roles between peers, ensuring loop-free and duplicate-free traffic handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EVPN procedures drop same-site Ethernet Segment traffic to prevent loops and duplicates, then network stability is improved, but traffic loss occurs when a link fails
Solution Approach 1:
The patent introduces a proxy forwarding mechanism where a peer edge device acts as an intermediary to forward traffic for the failed device. When device A fails, device B can proxy forward traffic that would normally be dropped, maintaining connectivity without creating loops or duplicates through controlled proxy forwarding behavior.
Solution Approach 2:
The patent implements dynamic proxy forwarding roles that can transition between devices based on link status. The system dynamically adjusts which device performs proxy forwarding for each Ethernet Segment, allowing flexible adaptation to failure scenarios while maintaining the loop-prevention benefits of the original EVPN procedure.
2Reliability
If local traffic forwarding relies solely on local links with localbias strategy, then loop prevention is improved, but connectivity is lost when local links fail
Solution Approach 1:
The patent uses peer edge devices as intermediaries to provide alternative forwarding paths when local links fail. The proxy forwarding mechanism allows traffic to be forwarded through peer devices rather than requiring direct local link connectivity, maintaining adaptability while preserving loop prevention through controlled proxy behavior.
3Adaptability or versatility
If proxy forwarding is implemented without deterministic handshakes, then traffic forwarding capability is improved, but loops and duplicates may occur
Solution Approach 1:
The patent implements deterministic handshakes as a feedback mechanism between peer edge devices. Before initiating proxy forwarding, devices exchange signals to coordinate roles and ensure only one device forwards traffic for each failed peer, providing feedback that prevents loops and duplicates while maintaining forwarding capability.
Solution Approach 2:
The patent performs preliminary handshaking actions before proxy forwarding begins. Devices exchange capability advertisements and role assignments in advance, establishing a deterministic framework that prevents loops and duplicates before traffic forwarding starts, rather than reacting to problems after they occur.
Data Source
AI summary
A first provider edge network device that is configured in a multi-homed virtual private network for a data center in which there are one or more peer edge network devices including a second edge network device, receives from the second edge network device a message indicating that a link for a particular Ethernet segment of the second edge network device in the data center is down. Information is stored at the first edge network device indicating state of links for Ethernet segments associated with each of the one or more other edge network devices at the data center. The first edge network device forwards of traffic for the particular Ethernet segment locally on Ethernet segments in the data center on behalf of the second edge network device. The proxy forwarding is performed for traffic for the particular Ethernet segment that originates from the data center, that is, for “same-site” traffic.