EVPN PE BUM Traffic Packet Loss Reduction
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Solution Overview
Problem
In network infrastructure, when a BGP session is down due to a malfunction, existing technologies face challenges in instantly rerouting Broadcast, Unknown, Unicast, and Multicast (BUM) traffic, leading to increased packet loss as other PEs become non-designated forwarders, unable to forward BUM traffic until new routes are recalculated.
Innovation Solution
A network device and method where PEs in an EVPN multi-home environment detect a ceased BGP session and request reelection of a new designated forwarder from a redundant list, ensuring BUM traffic can be immediately forwarded by another PE, reducing packet loss during route recalculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If route recalculation is performed according to routing protocol when BGP session is down, then routes are eventually switched, but time is taken for recalculation and BUM traffic packet loss increases
Solution Approach 1:
The patent pre-identifies redundant PEs and prepares backup forwarding paths before the BGP session fails. When a BGP session is detected as down, the system can immediately switch to a pre-identified redundant PE without waiting for routing protocol recalculation, thus reducing packet loss and recovery time
Solution Approach 2:
The patent establishes backup designated forwarder candidates in advance through the redundant PE list. When the current designated forwarder fails, these pre-prepared backup candidates can immediately take over, cushioning against the impact of failure and avoiding the need for immediate route recalculation
2Stability of the object's composition
If other PEs become non-designated forwarders when BGP session is down, then routing stability is maintained, but BUM traffic forwarding capability is lost until route recalculation
Solution Approach 1:
The system pre-identifies and stores redundant PEs that can serve as backup designated forwarders. When the current designated forwarder fails, these pre-prepared redundant PEs can immediately assume the forwarding role without requiring route recalculation, thus maintaining both routing stability and forwarding reliability
Solution Approach 2:
The redundant PE list acts as an intermediary mechanism between the failed designated forwarder and the routing protocol recalculation process. It provides a seamless transition path that maintains forwarding capability while preserving routing table stability
Data Source
AI summary
A network device (PE), a network control method and program which can reduce a BUM traffic packet loss even when a time is taken for route recalculation according to a routing protocol due to a malfunction in a network infrastructure are provided. A network device according to the present invention requests each PE connected to the same ES as that of the network device to perform DF reelection on the basis of a redundant PE list from which the network device has been deleted when cease of a BGP session is detected. In addition, the PE requested to perform the DF reelection executes the DF reelection based on the redundant PE list from which the aforementioned PE has been deleted. In the present invention, BUM traffic can be immediately forwarded from a PE that has become a new DF even when a time is taken for route recalculation according to the routing protocol because another PE connected to the same ES is caused to serve as a DF when the BGP session is ceased.