EVPN PE Device ESI-Excluded Label BUM Traffic Handling
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Solution Overview
Problem
Current EVPN solutions face challenges in handling broadcast, unknown unicast, or multicast (BUM) traffic due to limitations in commercial switching chipsets, which do not support combined labels for determining egress broadcast port lists, leading to high costs and increased system complexity when trying to support EVPN.
Innovation Solution
Implementing a method where PE devices share an ESI-excluded label, which replaces the label combination of ESI and VPN labels, allowing for efficient encapsulation and flooding of BUM traffic without requiring hardware replacements, by using existing MPLS forwarding behaviors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If combined labels (ESI label and VPN label) are used to identify egress broadcast port lists in EVPN, then traffic forwarding accuracy is improved, but device complexity and hardware cost increase due to requirements beyond commercial switching chipset capabilities
Solution Approach 1:
The patent merges the ESI label and VPN label into a single combined label structure. The egress PE device receives BUM traffic with this combined label, which simultaneously encodes both the Ethernet segment identifier and the VPN identifier, allowing the device to determine the egress broadcast port list using one label lookup instead of multiple labels, thereby reducing hardware complexity while maintaining forwarding accuracy
Solution Approach 2:
The combined label serves multiple functions: it identifies the Ethernet segment, identifies the VPN, and enables determination of the egress broadcast port list. This multi-functional label reduces the number of separate labeling mechanisms needed, making the system compatible with commercial switching chipsets while achieving EVPN functionality
2Ease of manufacture
If commercial switching chipsets are used without hardware replacements, then cost is reduced, but the ability to handle EVPN BUM traffic efficiently is worsened
Solution Approach 1:
The patent changes the label parameter structure from separate ESI and VPN labels to a combined label format. This parameter change allows commercial switching chipsets to handle EVPN BUM traffic efficiently using their existing single-label lookup capabilities, avoiding the need for expensive hardware replacements while maintaining productivity
3Measurement precision
If multiple labels (ESI and VPN labels) are stacked for BUM traffic forwarding, then traffic routing precision is improved, but MPLS label stack depth is consumed
Solution Approach 1:
The patent combines multiple labels into a single label structure that encapsulates both ESI and VPN identification information. This merging reduces the MPLS label stack depth by eliminating the need for multiple stacked labels, while the combined label maintains the routing precision needed for accurate BUM traffic delivery to the correct egress broadcast port list
Data Source
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AI summary
A provider edge (PE) device and a method implemented thereon are disclosed for Ethernet virtual private network (EVPN). According to an embodiment, a first PE device performs label assignment procedure with a second PE device such that the first and second PE devices share an Ethernet segment identifier (ESI) -excluded label and know a correspondence between the ESI-excluded label and a label combination of an ESI label and a VPN label. The first PE device encapsulates a packet of broadcast, unknown unicast or multicast (BUM) traffic, with the ESI-excluded label instead of the label combination. The first PE device sends the encapsulated packet to the second PE device.