Cisco ACI Multi-Site architecture
The architecture allows you to interconnect separate Cisco ACI APIC cluster domains (fabrics), each representing a different region, all part of the same Cisco ACI Multi-Site Orchestrator domain. Doing so helps ensure multitenant Layer 2 and Layer 3 network connectivity across sites, and it also extends the policy domain end-to-end across the entire system. This design is achieved by using the following functional components:
https://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric- infrastructure/white-paper-c11-739609.html#CiscoACIMultiSiteOrchestrator Hence, Multi-Site Orchestrator cluster nodes can be deployed securely over whatever network infrastructure is available to interconnect them.
The Cisco ACI Multi-Site Orchestrator design is based on a microservices architecture in which three MSO nodes are clustered together in an active/active fashion. The Cisco ACI Multi-Site Orchestrator nodes must communicate with the Out-Of-Band (OOB) interface of the APIC nodes deployed in different sites. MSO also provides northbound access through Representational State Transfer (REST) APIs or the GUI (HTTPS), which allows you to manage the full lifecycle of networking and tenant policies that need to be deployed across sites (Figure 17).
You can choose to deploy the Multi-Site Orchestrator cluster in one of the following two ways:
* Deploy a VM-based MSO cluster directly in VMware ESXi virtual machines (Figure 18): This is the deployment model supported from the very first release of Cisco Multi-Site Orchestrator and still available at the time of writing of this paper.
* Deploy a Cisco Application Services Engine (CASE)-based MSO cluster. This flavor, available from Cisco ACI Multi-Site Orchestrator Release 2.2(3), consists of an application (.aci format) installed on a Cisco Application Services Engine (CASE).