EVPN MAC Route Importing for All-Active E-Tree Leaf Multihoming
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Solution Overview
Problem
In E-Tree scenario 1 of EVPN, PE devices associated with Leaf ACs in an all-active multihoming configuration experience permanent traffic flooding due to the inability to import MAC routes from other Leaf ACs within the same Ethernet Segment, leading to network congestion and bandwidth wastage.
Innovation Solution
Implementing an extended community, such as the ES-Import Route Target, to allow PE devices associated with Leaf ACs to import MAC routes if they are part of the same Ethernet Segment and share the same EVPN service, while preventing importation from different services, thus ensuring service-based separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PE devices associated with Leaf ACs are prevented from importing MAC routes from other Leaf ACs to maintain E-Tree service isolation, then service-based separation is ensured, but traffic flooding occurs and network congestion increases
Solution Approach 1:
The patent applies local quality by differentiating the route import behavior based on the specific Ethernet Segment. Leaf AC-only PE devices are allowed to import MAC routes from other Leaf ACs only when those routes belong to the same Ethernet Segment (identified by matching ES-Import Route Target extended communities), while maintaining the restriction against importing routes from different segments. This localized exception resolves the contradiction by enabling necessary route sharing within segments while preserving service isolation across segments.
2Reliability
If PE devices associated with Leaf ACs cannot import MAC routes from other Leaf ACs, then E-Tree service isolation is maintained, but load balancing capability is lost and bandwidth is wasted
Solution Approach 1:
The patent changes the parameter of route import eligibility by introducing the ES-Import Route Target extended community attribute. This parameter enables PE devices to distinguish between routes from the same Ethernet Segment versus different segments. By changing the import policy from a blanket restriction to a conditional policy based on this parameter, the system achieves both service isolation and efficient bandwidth utilization through proper route sharing within segments.
3Adaptability or versatility
If PE devices associated with Leaf ACs are restricted from importing MAC routes, then policy control per service is maintained, but connectivity issues arise for all-active multihoming configurations
Solution Approach 1:
The patent introduces the ES-Import Route Target extended community as an intermediary mechanism that mediates between the conflicting requirements. This intermediary attribute carries Ethernet Segment identification information in BGP route advertisements, enabling PE devices to automatically determine whether route import should be permitted based on segment membership. This intermediary simplifies the policy implementation by providing clear, automated decision criteria without complex manual configuration.
Data Source
AI summary
Aspects of the subject disclosure may include, for example, identifying, by an apparatus, a media access control (MAC) address of a customer edge (CE) device, and advertising the MAC address in a MAC route based on the identifying, wherein the MAC route is tagged with an extended community that identifies an Ethernet Segment (ES) associated with the apparatus, the extended community enabling another apparatus that is also associated with the ES to import the MAC route. Other embodiments are disclosed.