802.1aq EVPN Interworking for Network Stability
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Solution Overview
Problem
Existing EVPN implementations do not consider the implications of a provider backbone bridging network (PBBN) and lack symmetry and congruency across the core network, leading to configuration complexities and potential network failures due to duplicate MAC issues and excessive configuration overhead.
Innovation Solution
The solution involves encoding backbone media access control (B-MAC) addresses and service instance identifiers (I-SID) in network layer reachability information (NLRI) to infer B-VID locally and reconstruct multipath symmetric congruence, allowing decoupling of multipath design between EVPN interconnected SPBM-PBBNs, and electing a designated forwarder (DF) for each B-VID to ensure unique B-MAC presence and minimize configuration overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If EVPN implementations are used without considering PBBN implications, then deployment is simplified, but network stability deteriorates due to duplicate MAC issues and configuration errors
Solution Approach 1:
The patent introduces a control plane interworking function that acts as an intermediary between the IS-IS control plane and BGP control plane. This intermediary translates and coordinates information between the two protocols, ensuring that MAC addresses are properly advertised and tracked, thereby preventing duplicate MAC issues while maintaining deployment simplicity through automated interworking.
2Productivity
If symmetric shortest path routing is implemented in 802.1aq, then bandwidth utilization improves, but device complexity increases due to distributed computations and forwarding table generation
Solution Approach 1:
The patent merges the control plane functionalities by introducing an interworking function that coordinates between IS-IS and BGP. This consolidation allows distributed computations to be managed more efficiently, maintaining high bandwidth utilization through symmetric shortest path routing while reducing the operational complexity through unified control plane management.
3Adaptability or versatility
If multiple PEs advertise the same B-MAC in EVPN, then multicast tree coverage improves, but network reliability deteriorates due to duplicate MAC conflicts
Solution Approach 1:
The patent implements a feedback mechanism through the control plane interworking function that tracks which PE is the designated forwarder for each B-VID. This feedback system ensures that only the designated PE advertises the B-MAC in BGP, while other PEs receive notifications about DF changes, thereby maintaining multicast tree coverage without duplicate MAC conflicts.
4Manufacturing precision
If DF election and NLRI synchronization between IS-IS and BGP are implemented, then configuration overhead increases, but manufacturing precision improves by preventing configuration errors
Solution Approach 1:
The control plane interworking function operates autonomously to perform DF election, track DF status, and synchronize NLRI between IS-IS and BGP without requiring manual configuration. This self-service approach automatically prevents configuration errors by ensuring consistency between the two control planes, thereby improving configuration accuracy while minimizing the need for manual intervention.
Data Source
AI summary
A method is implemented in a provider edge switch (PE) for interworking an 802.1aq control plane with an Ethernet Virtual Private Network (EVPN) Border Gateway Protocol (BGP) control plane. The method includes receiving an Intermediate System-Intermediate System (IS-IS) protocol data unit (PDU) including an IS-IS Type Length Value (TLV) by the PE and determining whether the received IS-IS PDU requires a change in a configuration of designated forwarder (DF). The method further includes determining whether the PE is still the DF for one or more Backbone-Virtual Local Area Network Identifiers (B-VIDs), and removing local DF associated network layer reachability information (NLRI) from a BGP database.