VXLAN Packet Loop Prevention via ESI Label Matching
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Solution Overview
Problem
In VXLAN networks, the use of all-active gateways improves network reliability but introduces a loop problem during packet forwarding, particularly when handling broadcast, unknown unicast, and multicast packets.
Innovation Solution
The solution involves configuring distinct Ethernet Segment Identifiers (ESIs) for interfaces connecting PE devices to CE devices and using designated forwarder selection to ensure that packets are forwarded through primary and secondary interfaces, with the second PE device parsing VXLAN packets to determine if the ESI matches the interface configuration and blocking forwarding to prevent loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all-active gateway networking is used to improve network reliability, then network reliability is improved, but packet loops occur during forwarding
Solution Approach 1:
The patent introduces an ESI label as an intermediary element in VXLAN packet forwarding. This label acts as a mediator that carries identification information about the Ethernet segment, enabling receiving PE devices to determine whether to forward or drop packets based on label matching, thereby preventing loops without compromising the all-active gateway architecture
Solution Approach 2:
The patent implements a feedback mechanism where the receiving PE device checks the ESI label in incoming VXLAN packets against its own interface ESI labels. This feedback loop allows the device to make intelligent forwarding decisions - dropping packets when labels match (preventing loops) and forwarding when they don't match (maintaining connectivity), thus resolving the contradiction between reliability and loop prevention
2Adaptability or versatility
If VXLAN packets are forwarded through multiple PE devices in active-active gateway, then network redundancy is achieved, but loop problems occur
Solution Approach 1:
The ESI label serves as an intermediary that enables PE devices to distinguish between legitimate redundant paths and potential loop-forming paths. By embedding Ethernet segment identification in the VXLAN header, the label allows receiving devices to make informed decisions about packet forwarding, maintaining redundancy while preventing loops
3Object-generated harmful factors
If ESI label is added to VXLAN packet to prevent loops, then loop prevention is achieved, but device complexity increases
Solution Approach 1:
The ESI label in the VXLAN header serves multiple functions simultaneously: it identifies the Ethernet segment, enables loop prevention through label matching, and supports the all-active gateway architecture. This multi-functionality reduces the need for separate mechanisms, thereby limiting the increase in device complexity while achieving loop prevention
Data Source
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AI summary
This application provides a VXLAN packet processing method, a device, and a system. After determining that a data packet sent by a CE device is a BUM packet, a PE device encapsulates the BUM packet to generate a VXLAN packet including an ESI label and a VXLAN packet including a BUM traffic label. The VXLAN packet including the ESI label is sent to an active-active gateway, so that the gateway can block forwarding of traffic to the CE device by using an interface configured with an ESI, to avoid a loop between the PE device and the CE device. The VXLAN packet including the BUM traffic label is sent to a remote PE, to block forwarding of the VXLAN packet to the CE device by using a secondary DF interface, thereby avoiding a multi-packet problem. Reliability of an EVPN VXLAN gateway is improved by using this application.