Which three types of system information are contained in the Cisco Application Policy
Infrastructure Controller? (Choose three.)
A.
API status
B.
Policy configuration
C.
Discovered topology
D.
Operational status
E.
Agent configuration
F.
Policy enforcement
this shold be B, C and D
there is no such thing as policy enforcement and agent configuration in APIC
B,C,D
B,C and D altough A could also be true…
Architecture: Components and Functions of the Cisco APIC
The Cisco APIC consists of a set of basic control functions, including:
● Policy Manager (policy repository)
● Topology Manager
● Observer
● Boot Manager
● Appliance Director (cluster controller)
● VMM Manager
● Event Manager
● Appliance Element
Figure 8 shows the Cisco APIC components.
Figure 8. Cisco APIC Component Architecture
Policy Manager
The Policy Manager is a distributed policy repository responsible for the definition and deployment of the policy-based configuration of the Cisco ACI. This is a collection of policies and rules applied to existing or hypothetical (not yet created) endpoints. The endpoint registry is a subset of the Policy Manager that tracks endpoints connecting to the Cisco ACI and their assignment to endpoint groups as defined by the policy repository.
Topology Manager
The Topology Manager maintains up-to-date Cisco ACI topology and inventory information. Topology information is reported to the Cisco APIC by the leaf and spine switches. The physical topology is based on the information discovered by the Link Layer Discovery Protocol (LLDP) and the routing topology of the fabric as reported by protocols (modified intermediate system to intermediate system [IS-IS]) running within the fabric infrastructure space.
A global view of time-accurate topology information is available in the Topology Manager, including:
● Physical topology (Layer 1; physical links and nodes)
● Logical path topology (reflection of Layer 2 + Layer 3)
Topology information, along with associated aggregated operational state, is asynchronously updated in the Topology Manager upon detection of topology changes, and is available for queries through the Cisco APIC API, CLI, and UI.
A subfunction of Topology Manager performs inventory management for the Cisco APIC and maintains a complete inventory of the entire Cisco ACI. The Cisco APIC inventory management subfunction provides full identification, including model and serial number, as well as user-defined asset tags (for ease of correlation with asset and inventory management systems) for all ports, line cards, switches, chassis, etc.
Inventory is automatically pushed by the DME-based policy element/agent embedded in the switches as soon as new inventory items are discovered or removed or transition in state in the local repository of the Cisco ACI node.
Observer
The Observer is the monitoring subsystem of the Cisco APIC, and it serves as a data repository of the Cisco ACI’s operational state, health, and performance, including:
● Hardware and software state and health of Cisco ACI components
● Operational state of protocols
● Performance data (statistics)
● Outstanding and past fault and alarm data
● Record of events
Monitoring data is available for queries through the Cisco APIC API, CLI, and UI.
Boot Director
The Boot Director controls the booting and firmware updates of the Cisco spine and leaf and the Cisco APIC controller elements. It also functions as the address allocation authority for the infrastructure network, which allows the Cisco APIC and the spine and leaf nodes to communicate. The following process describes bringing up the Cisco APIC and cluster discovery.
● Each Cisco APIC in the Cisco ACI uses an internal private IP address to communicate with the Cisco ACI nodes and other Cisco APICs in the cluster. Cisco APICs discover the IP address of other Cisco APICs in the cluster using an LLDP-based discovery process.
● Cisco APICs maintain an appliance vector (AV), which provides a mapping from an Cisco APIC ID to an Cisco APIC IP address and a universally unique identifier (UUID) of the Cisco APIC. Initially, each Cisco APIC starts with an AV filled with its local IP address, and all other Cisco APIC slots are marked unknown.
● Upon switch reboot, the PE on the leaf gets its AV from the Cisco APIC. The switch then advertises this AV to all of its neighbors and reports any discrepancies between its local AV and neighbors’ AVs to all the Cisco APICs in its local AV.
● Using this process, Cisco APICs learn about the other Cisco APICs in the Cisco ACI through switches. After validating these newly discovered Cisco APICs in the cluster, Cisco APICs update their local AV and program the switches with the new AV. Switches then start advertising this new AV. This process continues until all the switches have the identical AV and all Cisco APICs know the IP address of all the other Cisco APICs.
Appliance Director
The Appliance Director is responsible for formation and control of the Cisco APIC appliance cluster. A minimum of three controllers are initially installed for control of the scale-out Cisco ACI (Figure 9). The ultimate size of the Cisco APIC cluster is directly proportionate to the Cisco ACI size and is driven by the transaction rate requirements. Any controller in the cluster is able to service any user for any operation, and a controller can be seamlessly added to or removed from the Cisco APIC cluster. It is important to understand that unlike an OpenFlow controller, none of the Cisco APIC controllers are ever in the data path.
Figure 9. Appliance Director
VMM Manager
The VMM Manager acts as an agent between the policy repository and a hypervisor and is responsible for interacting with hypervisor management systems such as VMware’s vCenter and cloud software platforms such as OpenStack and CloudStack. VMM Manager inventories all of the hypervisor elements (pNICs, vNICs, VM names, etc.) and pushes policy into the hypervisor, creating port groups, etc. It also listens to hypervisor events such as VM mobility.
Event Manager
The Event Manager is a repository for all the events and faults initiated from the Cisco APIC or the fabric nodes.
Appliance Element
The Appliance Element is a monitor for the local appliance. It manages the inventory and state of the local Cisco APIC appliance.