The NSX-T platform consists of several components that are relevant to the network virtualization design.
NSX-T creates a network virtualization layer, which is an abstraction between the physical and virtual networks. You create all virtual networks on top of this layer.
Several components are required to create this network virtualization layer:
NSX-T Edge Nodes
NSX-T Distributed Routers (DR)
NSX-T Service Routers (SR)
NSX-T Logical Switches
These components are distributed in different planes to create communication boundaries and provide isolation of workload data from system control messages.
Performs stateless forwarding or transformation of packets based on tables populated by the control plane, reports topology information to the control plane, and maintains packet level statistics.
The following traffic runs in the data plane:
N-VDS virtual switch, distributed routing, and the distributed firewall in NSX-T
The data is carried over designated transport networks in the physical network.
Contains messages for network virtualization control. You place the control plane communication on secure physical networks (VLANs) that are isolated from the transport networks for the data plane.
The control plane computes the runtime state based on configuration from the management plane. Control plane propagates topology information reported by the data plane elements, and pushes stateless configuration to forwarding engines.
Control plane in NSX-T has two parts:
Central Control Plane (CCP). The CCP is implemented as a cluster of virtual machines called CCP nodes. The cluster form factor provides both redundancy and scalability of resources.
The CCP is logically separated from all data plane traffic, that is, a failure in the control plane does not affect existing data plane operations.
Local Control Plane (LCP). The LCP runs on transport nodes. It is adjacent to the data plane it controls and is connected to the CCP. The LCP is responsible for programming the forwarding entries of the data plane.
Provides a single API entry point to the system, persists user configuration, handles user queries, and performs operational tasks on all management, control, and data plane nodes in the system.
For NSX-T, all querying, modifying, and persisting user configuration is in the management plane. Propagation of that configuration down to the correct subset of data plane elements is in the control plane. As a result, some data belongs to multiple planes. Each plane uses this data according to stage of existence. The management plane also queries recent status and statistics from the control plane, and under certain conditions directly from the data plane.
The management plane is the only source of truth for the logical system because it is the only entry point for user configuration. You make changes using either a RESTful API or the NSX-T user inteface.
For example, responding to a vSphere vMotion operation of a virtual machine is responsibility of the control plane, but connecting the virtual machine to the logical network is responsibility of the management plane.