VPLS to PBB-EVPN Conversion via BGP IMET Routes
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Solution Overview
Problem
Existing packet switching networks face challenges in seamlessly integrating Virtual Private Local Area Network Service (VPLS) with Provider Backbone Bridging Ethernet VPN (PBB-EVPN) due to issues with distinguishing between conversion requests for individual Service Instance VLAN IDs, leading to multicast and looping problems, which require shutting down all pseudowires.
Innovation Solution
The method involves using Border Gateway Protocol (BGP) Network Layer Reachability Information (NLRI) of Route Type 3 Inclusive Multicast Ethernet Tag (IMET) routes to perform per-I-SID based VPN conversions, allowing for seamless integration of VPLS to PBB-EVPN by selectively converting specific bridge domains while maintaining operational connectivity through pseudowires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all pseudowires are shut down to prevent multicast and looping problems during VPLS to PBB-EVPN conversion, then multicast and looping issues are prevented, but network connectivity and service continuity are disrupted
Solution Approach 1:
The patent segments the conversion process by I-SID, allowing individual Service Instance VLAN IDs to be converted independently. This enables selective conversion where only specific bridge domains undergo PBB-EVPN conversion while others remain as VPLS, preventing the need to shut down all pseudowires simultaneously. The segmentation is implemented through per-I-SID conversion declarations that target specific services for conversion while leaving others operational.
Solution Approach 2:
The patent applies local quality by making conversion decisions at the individual I-SID level rather than globally. Each bridge domain can have different conversion states (VPLS or PBB-EVPN) based on local requirements. This allows pseudowires carrying non-converted I-SIDs to remain operational while pseudowires for converted I-SIDs are properly managed, ensuring local optimization without global disruption.
2Adaptability or versatility
If per-I-SID based VPN conversions are implemented using BGP Route Type 3 IMET routes, then seamless integration and service containment are achieved, but system complexity increases
Solution Approach 1:
The patent implements a universal conversion mechanism that works across multiple I-SIDs and bridge domains through a standardized BGP Route Type 3 IMET route structure. The per-I-SID conversion declaration format provides a universal interface for initiating conversions, while the underlying mechanism handles different service types (VPLS, PBB-EVPN) through a common framework. This multi-functionality allows the same conversion infrastructure to serve various conversion scenarios without requiring separate mechanisms for each case.
3Reliability
If traditional VPLS full-mesh pseudowire architecture is used, then layer-2 broadcast domain connectivity is maintained, but scalability and service multiplexing are limited
Solution Approach 1:
The patent implements nesting by embedding PBB-EVPN services within the VPLS framework during conversion. The per-I-SID conversion allows PBB-EVPN bridge domains to be nested within the existing VPLS pseudowire infrastructure. This nested architecture enables service multiplexing where multiple I-SIDs can coexist in the same pseudowire, with some operating as VPLS and others as PBB-EVPN, thereby improving scalability while maintaining layer-2 connectivity.
Data Source
AI summary
In one embodiment, a plurality of virtual private local area network services (VPLSs) are operated among a plurality of packet switching devices, with the plurality of VPLSs including a first VPLS and a different second VPLS. In response to a conversion declaration including a particular Service Instance VLAN ID (I-SID), the first VPLS corresponding to the particular I-SID is converted to a different type of virtual private network (VPN) service, while continuing to operate the different second VPLS which is not related to the particular I-SID. In one embodiment, the different type of VPN service is Provider Backbone Bridging Ethernet VPN (PBB-EVPN). In one embodiment, the conversion declaration is a Border Gateway Protocol (BGP) Network Layer Reachability Information (NLRI) of Route Type 3 Inclusive Multicast Ethernet Tag (IMET) route.