For NSX Federation to function correctly, all participating NSX Manager nodes, including the Global Manager (GM) and all Local Managers (LM) at each site, must be running the identical software version and build number. This strict requirement ensures API compatibility, feature parity, and stable synchronization of configuration and policy data across the entire federated environment. Mismatched versions can lead to communication failures, unpredictable behavior, and an unsupported configuration. This is a fundamental prerequisite before a site can be successfully onboarded to the Global Manager.

A. All Sites must use the same VTEP VLAN and IP pools.

VTEP (Virtual Tunnel End Point) configurations are specific to the underlying physical network of each local site. Federation is designed to connect sites with disparate underlay networks.

B. All sites must use identical Tier-0 gateway BGP autonomous system numbers.

BGP AS numbers are part of the site-specific routing design. Tier-0 gateways at different sites can, and often do, use different AS numbers to peer with their local physical routers.

C. All sites must be managed by the same VCF instance.

NSX Federation is explicitly designed to interconnect separate failure domains, which can include different VCF instances or even non-VCF deployments. The question itself refers to separate VCF Fleets.

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1. VMware NSX 4.1 Documentation, NSX Federation Guide, "Install and Configure NSX Federation," Section: "Prerequisites for NSX Federation."

The guide explicitly states: "All NSX Manager nodes in a federation, both Global Managers and Local Managers, must be running the same version of NSX." This confirms that version and build alignment is a mandatory prerequisite.

2. VMware NSX-T Data Center 3.2 Documentation, NSX-T Data Center Installation Guide, "NSX Federation Installation," Section: "Prerequisites for NSX Federation."

This earlier version of the documentation reinforces the same core requirement: "All NSX Manager nodes in a federation, both Global Managers and Local Managers, must be running the same version of NSX-T Data Center."

3. VMware Cloud Foundation 4.5 Design Guide, "NSX-T Data Center Federation with VMware Cloud Foundation," Section: "NSX-T Federation Prerequisites."

This document, in the context of VCF, outlines the prerequisites for federation, which includes the alignment of NSX-T versions across all participating VCF instances. It does not mandate shared VTEP pools or BGP ASNs between the separate instances.