ARP-Based Selective EVPN Route Advertisement for Multicast
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Solution Overview
Problem
In Ethernet virtual private networks (EVPN), the advertising of EVPN routes for multicast groups consumes unnecessary resources, as PEs advertise routes for groups they may not send traffic to, leading to burden on the underlay network and consumption of hardware resources in multicast trees/tunnels that are not used.
Innovation Solution
Implementing selective advertising of EVPN routes by using ARP to determine if a host is behind a PE, thereby only advertising S-PMSI-AD routes when traffic is sent from a source host within the PE, reducing unnecessary resource consumption and advertising only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PEs advertise EVPN routes for every known overlay multicast group, then multicast connectivity is ensured across the EVPN, but unnecessary computing resources, bandwidth, and hardware resources are consumed in the core network and receiving PEs
Solution Approach 1:
The patent applies preliminary action by having PEs perform ARP requests before advertising EVPN routes to determine whether local hosts are actual sources of multicast traffic. This advance verification prevents unnecessary route advertisements, reducing computing resources and bandwidth consumption in the core network while ensuring multicast connectivity is only established when truly needed.
2Adaptability or versatility
If PEs advertise routes for multicast groups without verifying local sources, then multicast groups can be reached across the network, but unnecessary multicast trees/tunnels are created consuming hardware resources
Solution Approach 1:
The patent extracts the verification step of checking whether local hosts are actual multicast sources by performing ARP requests before route advertisement. This removes unnecessary multicast trees and tunnels from the network by ensuring that routes are only advertised when there are actual local sources, thereby reducing hardware resource consumption while maintaining multicast group reachability.
3Speed
If EVPN routes are advertised proactively for all known multicast groups, then multicast traffic can be forwarded efficiently, but the burden of transmitting, updating, and storing routes increases network overhead
Solution Approach 1:
The patent applies preliminary action by verifying local multicast sources through ARP requests before advertising EVPN routes. This reduces the number of routes that need to be transmitted, updated, and stored across the network, thereby reducing network overhead and device complexity while maintaining efficient multicast traffic forwarding capability when actually needed.
Data Source
AI summary
The present disclosure describes using Address Resolution Protocol (ARP) to determine whether a host is behind a PE or not behind a PE. In a use case, for example, advertising a Selective Provider Multicast Service Interface Auto-Discovery (S-PMSI-AD) route to advertise encapsulation of a multicast group is triggered by receiving multicast traffic for that group from a host device behind the provider edge (PE) device. Multicast traffic received from behind remote PEs will not trigger a S-PMSI-AD route.