OISM-based L3 Multicast with Selective PMSI with PEG

In today's complex data center network, various scenarios can arise. For example, there may be receivers within an EVPN Tenant Domain that are interested in multicast flows originating from sources outside the EVPN domain. Conversely, receivers outside the EVPN Tenant Domain may want to access multicast flows from sources within the EVPN domain. The external sources or receivers may connect via IP, with Layer 3 multicast routing managed through PIM (Protocol Independent Multicast). In such cases, the interworking between the PIM domain and the EVPN Tenant Domain is facilitated by Layer 3 Gateways that implement PIM/EVPN Gateway (PEG) functionality. RFC 9625 outlines the working procedures and technical details of the PEG.
In our test, we simulated both external PIM and EVPN domains, with PEGs as the primary DUTs responsible for interworking between these two domains. The external PIM domain was configured with PIM-SM (Sparse Mode), and the IGMP (Internet Group Management Protocol) was version 3 with (S, G) configured. Using the Spirent test center, EANTC generated multicast traffic from the EVPN and PIM domains simultaneously, and we did not observe any duplicates or packet loss.
Following this, we conducted two runs involving a switchover. The first run employed a preference-based DR (Designated Router) election, while the second used a modulo-based election method. We triggered the switchover by changing the preference in the first run and shutting down the interface in the second run. Although some packet loss occurred during the switchover, it recovered within three seconds.