Originating PE Label Reduces ESI Count in All-Active Multi-Homing
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Solution Overview
Problem
Conventional Ethernet VPN (EVPN) systems require a large number of Ethernet Segment MPLS labels for All-Active multi-homing, which exceeds the capabilities of white-box PE devices with low-cost ASICs, leading to inefficiencies in label allocation and distribution.
Innovation Solution
The introduction of an Originating PE (0-PE) label reduces the number of ESI labels required from N per PE device to one, allowing for efficient replication and forwarding of BUM packets by identifying the originating PE device through a single MPLS label, thereby reducing the need for multiple labels across the network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional EVPN systems use N ESI MPLS labels per PE device for All-Active multi-homing, then network redundancy and connectivity are maintained, but the number of labels exceeds the capabilities of white-box PE devices with low-cost ASICs
Solution Approach 1:
The patent merges the functionality of multiple ESI labels into a single Originating PE label. Instead of maintaining separate labels for each Ethernet segment (N labels), the system uses one label that identifies the originating PE device, which then replicates BUM packets to all active PEs. This consolidation reduces label complexity while preserving redundancy functionality.
Solution Approach 2:
The Originating PE label serves multiple functions simultaneously: it identifies the source PE device, enables BUM packet replication, and provides split-horizon filtering information. This multi-functional label replaces what would traditionally require multiple specialized labels, reducing overall label complexity.
2Productivity
If N ESI MPLS labels are allocated per PE device for All-Active multi-homing, then broadcast, unknown unicast, and multicast packets can be properly forwarded, but label allocation and distribution becomes inefficient
Solution Approach 1:
The patent extracts the essential identifying information from multiple ESI labels and concentrates it into a single Originating PE label. By taking out only the necessary identifier (originating PE device) and eliminating redundant label information, the system reduces allocation and distribution complexity while maintaining forwarding efficiency.
3Reliability
If multiple ESI labels are used per PE device, then split-horizon filtering can be implemented for each Ethernet segment, but the number of labels required exceeds ASIC capabilities
Solution Approach 1:
The patent combines the split-horizon filtering functionality across all Ethernet segments into a single filtering decision based on the Originating PE label. Instead of implementing separate filtering mechanisms for each segment (requiring N labels), the system uses one label to trigger unified filtering logic that applies to all segments, reducing label count while preserving filtering capability.
Data Source
AI summary
First, a packet may be received by a first provider edge device from a first customer edge device locally connected to the first provider edge device. Then the first provider edge device may replicate the packet to a second customer edge device locally connected to the first provider edge device and encapsulate the packet with an address of the first provider edge device. Next, the first provider edge device may transmit the encapsulated packet to a second provider edge device. Then, the second provider edge device may determine from the determined address of the first provider edge device, that the first provider edge device is not locally connected to a third customer edge device. The second provider edge device may then replicate the packet to the third customer edge device in response to determining that the first provider edge device is not locally connected to the third customer edge device.