Cisco ACI introduction Part-1

ACI Design checklist:

Before starting Cisco ACI datacenter implmentation we need to know about below ACI specific terms.

ACI fabric:‐

A Virtual Extensible LAN (VXLAN) overlay configured by APIC on leaf or spine switches to provide end‐to‐end connectivity for clients or servers.

Bridge domains:‐

A bridge domain is a Layer 2 segment equal to VLANs in a traditional network.

Endpoint groups (EPGs)

Endpoint groups are associated with all endpoints in the network. The endpoints are identified by their domain connectivity, It may be virtual, physical, or outside and their connectivity method. For instance, a virtual machine port groups (VLAN, VXLAN), physical interfaces or VLANs including virtual port channels, external VLANs, external

Contracts : ‐

These are directional access lists configured between the provider and the consumer EPGs. They comprise of one or more filters (ACEs) to identify and allow traffic between EPGs. By default, the communication between the EPGs is blocked and it requires a contract to allow the traffic.

Application network profiles:‐

These are containers of that group one or more EPGs together with their associated connectivity policies.

L4‐L7 device:‐

Logical device: It Represents a cluster of two devices that operate in HA mode. This is a logical representation of the physical/virtual device (load balancer) along with logical interfaces that imply the connectivity.

Concrete device:  It Represents a service device, such as a virtual load balancer. In the case of Avi Vantage, these are actual Service Engine VMs.


These are network administrative containers, which are like logical containers for application policies.

ACI Fabric – Provision

APIC provisioning method automatically brings up the ACI fabric with the appropriate connections, APIC start‐up topology auto-discovery, automated configuration, and infrastructure addressing uses these industry‐standard protocols: Intermediate System-to-Intermediate System (IS‐IS), Link Layer Discovery Protocol (LLDP), and Dynamic Host Configuration Protocol (DHCP).

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