Subscription-Based Selective EVPN Route Distribution for Faster Convergence
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Solution Overview
Problem
In Ethernet Virtual Private Networks (EVPNs), traditional route reflectors distribute route updates to all fabric provider edge nodes in random order, leading to unnecessary messaging delays and increased convergence time, as only a handful of nodes need the updated host route for active flows.
Innovation Solution
Implementing a subscription-based selective EVPN route distribution system where a route reflector assigns sequence numbers and communicates EVPN Type 2 Routes only to provider edge nodes with active flows, using a centralized sequence number assignment and optimized BGP messaging to minimize unnecessary updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional route reflector distributes route updates to all fabric provider edge nodes, then all nodes receive route updates, but messaging delays increase and convergence time worsens
Solution Approach 1:
The patent implements preliminary action by having provider edge nodes send subscription requests to the route reflector in advance, indicating their interest in specific EVPN route types. The route reflector maintains a subscription database with this pre-configured information, enabling it to selectively forward route updates only to subscribed nodes without needing to query or wait for responses at update time, thus reducing messaging delays and improving convergence time
Solution Approach 2:
The patent applies segmentation by dividing the broadcast domain into selective subscription groups. Instead of flooding route updates to all provider edge nodes uniformly, the route reflector segments the distribution based on individual node subscriptions to specific EVPN route types (Type 2, Type 5, Type 7), sending updates only to relevant segments (subscribed nodes) rather than the entire network, thereby reducing unnecessary messaging and improving convergence time
2Loss of information
If route reflector sends BGP messages to all remote provider edge nodes, then complete route information is distributed, but messaging overhead and processing load increase
Solution Approach 1:
The patent implements partial action by having the route reflector send only the necessary portion of route information to each provider edge node based on its subscriptions. Instead of sending complete route updates to all nodes (excessive action), the system sends partial updates tailored to each node's subscribed EVPN route types, reducing messaging overhead and processing load while maintaining information completeness for subscribed nodes
Solution Approach 2:
The route reflector performs preliminary action by maintaining a subscription database that pre-stores which nodes are interested in which EVPN route types. When route updates occur, the reflector consults this pre-configured database to determine the minimal necessary set of nodes to contact, avoiding the overhead of querying all nodes or sending updates to non-subscribing nodes, thus reducing messaging overhead while ensuring complete route information reaches all subscribed nodes
Data Source
AI summary
In one embodiment, a method includes receiving, by a route reflector, a subscription request from a first provider edge node in a network and generating a subscription policy for the first provider edge node. The method also includes receiving a first Ethernet Virtual Private Network (EVPN) Type 2 Route from a second provider edge node, assigning a sequence number to the first EVPN Type 2 Route, and communicating the first EVPN Type 2 Route with the sequence number to the first provider edge node. The method further includes receiving a second EVPN Type 2 Route from a third provider edge node, generating an updated sequence number in response to receiving the second EVPN Type 2 Route from the third provider edge node, and communicating the second EVPN Type 2 Route with the updated sequence number to the first provider edge node and the second provider node.