EVPN Multi-homing provides active-active server connectivity to two or more leaf switches (VTEPs) in a VXLAN fabric. The control plane state synchronization between these peer switches occurs via BGP EVPN messages exchanged over the IP underlay network (the fabric). This architecture inherently eliminates the need for a direct, dedicated layer 2 inter-switch link (ISL) between the multi-homing peer switches, as all communication, including failure detection and traffic forwarding, is handled through the IP fabric.

A. MLAG: MLAG (Multi-Chassis Link Aggregation) fundamentally requires a direct, physical "peer link" between the two switches to synchronize the control plane and forward traffic between them.

B. VSS: Virtual Switching System (VSS) is a Cisco-proprietary technology not available in Cumulus Linux. Furthermore, it also requires a dedicated inter-switch link called a Virtual Switch Link (VSL).

1. NVIDIA Cumulus Linux User Guide 5.8, "Ethernet VPN-Virtual Extensible LAN (EVPN-VXLAN)": In the "EVPN Multi-homing" section, the architecture described relies on the BGP EVPN control plane over an IP fabric. The diagrams and configuration examples show multi-homed PEs (leaf switches) connected via a spine layer, not directly to each other. This confirms the absence of a required ISL.

2. NVIDIA Cumulus Linux User Guide 5.8, "Multi-Chassis Link Aggregation - MLAG": The "MLAG Components" section explicitly states, "MLAG requires a peer link between the two switches in the MLAG pair to synchronize information." This directly contradicts the condition in the question.

3. RFC 7432, "BGP MPLS-Based Ethernet VPN," Section 8.5, "Multihoming Functions": This foundational RFC for EVPN describes the multi-homing procedures, which are based on BGP updates for auto-discovery and mass withdrawal to manage redundancy. The mechanism operates over the established BGP sessions through the core network, not a direct link. (DOI: https://doi.org/10.17487/RFC7432)