BFD Synchronization Over VxLAN on vPC Uplinks
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Solution Overview
Problem
In dual-homed vPC configurations, premature failover detection can occur when switching from a primary to a secondary vPC node during BFD sessions over VxLAN tunnels, due to out-of-date synchronization, especially at aggressive intervals or high scales, leading to timing delays and potential misdetected failures.
Innovation Solution
Implementing a method where the primary vPC node generates a copy of received BFD packets and transmits them to the secondary vPC node, ensuring real-time synchronization without relying on out-of-band state synchronization mechanisms, using access control list entries to instruct packet copying based on MAC addresses and inner packet identifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the secondary vPC node relies on out-of-band state synchronization mechanisms to synchronize with the primary vPC node, then synchronization can be maintained, but timing delays occur and premature failover detection may happen due to out-of-date synchronization at aggressive intervals or high scales
Solution Approach 1:
The patent extracts the BFD packet copying function from the out-of-band state synchronization mechanism and integrates it directly into the data plane forwarding path. The primary vPC node copies BFD packets and transmits them to the secondary vPC node through the VxLAN tunnel, eliminating the need for separate synchronization timing mechanisms and their associated delays.
Solution Approach 2:
The primary vPC node performs preliminary copying of BFD packets before they are forwarded to the destination. This preliminary action ensures that the secondary vPC node receives synchronized BFD packets with accurate timing information, preventing premature failover detection without relying on out-of-band synchronization.
2Reliability
If BFD sessions are established over VxLAN tunnels between remote VTEPs and dual-homed VTEP with multiple vPCs configured as redundancies, then failover detection can be provided, but complex issues arise including premature failover detection when switching from primary to secondary vPC
Solution Approach 1:
The patent merges the BFD packet forwarding function with the vPC redundancy mechanism. The primary vPC node combines BFD packet copying and transmission to the secondary vPC node within the same data plane, eliminating the need for separate out-of-band synchronization mechanisms and reducing configuration complexity while maintaining failover detection accuracy.
Solution Approach 2:
The VxLAN tunnel acts as an intermediary carrier for BFD packets between the primary and secondary vPC nodes. The primary vPC node encapsulates BFD packets in VxLAN format and transmits them through the tunnel to the secondary vPC node, providing a unified mechanism that simplifies the overall system architecture.
3Reliability
If the primary vPC node transmits BFD packets to the secondary vPC node through VxLAN tunnels, then real-time synchronization is achieved, but additional packet transmission overhead is introduced
Solution Approach 1:
The primary vPC node creates a copy of each received BFD packet and transmits the copy to the secondary vPC node through the VxLAN tunnel. This copying approach ensures real-time synchronization without requiring additional BFD sessions, as the copied packets carry the same timing and state information as the original packets.
Data Source
AI summary
Disclosed are systems, methods, and computer-readable storage media for synchronizing the secondary vPC node to the primary vPC node in a BFD protocol over a VxLAN channel with a remote node. In some embodiments of the present technology a primary vPC node can receive a packet from the remote node. The primary vPC node can then determine the packet includes either a MAC address corresponding to the primary vPC node or a secondary vPC node, and at least one inner packet identifier. Additionally, the primary networking switch can identify an access control list (ACL) entry from a set of ACL entries based on the at least one inner packet identifier. Subsequently, based on the ACL entry, the primary vPC node can generate a copy of the packet. After which, the primary vPC node can transmit the packet to the secondary vPC node.