The hierarchical aggregation configuration shown in Hierarchical aggregation Service Assurance configuration uses multiple Global Managers at the aggregation layer to address these configurations:
More than 10 underlying domains: It is recommended that each Global Manager at the aggregation layer supports a maximum of 10 VMware Smart Assurance domains. The example in Hierarchical aggregation Service Assurance configuration, therefore, would support 20 domains.
Geographically separate groups of domains: Using a standard Global Manager configuration would force some domains to connect to a Global Manager over a high-latency link. Additional Global Managers at the aggregation layer would be located in the same geographical area as the domains.
To ensure that acknowledgements and ownership of notifications are properly propagated, Service Assurance clients should connect only to the Global Manager at the presentation layer.