ACI · FABRIC DISCOVERY

ACI-style: discover and register the fabric

An ACI fabric is run from a controller, the APIC, not switch by switch. A new switch announces itself, and stays out of service until you register it with a node ID. The APIC only finds what it can reach through switches already registered, so registration works outward: first the leaf next to the APIC, then the spine, then the other leaves.

Cisco ACI-style track · Cisco ACI-style · 4 objectives

Open in simulator More Cisco ACI-style labs

Objectives

The simulator ticks each one as soon as the network meets it.

show switch on APIC1 lists L101, the leaf cabled to the APIC, with its serial.
Register L101 as node 101, and spine S201 as node 201.
Register L102, L103 and L104 as nodes 102, 103 and 104.
show switch: every switch is active.

Start this lab

Before you start

acidiag fnvread lists what the APIC knows, and show discoveryissues says what stops a switch joining. In this model, node IDs from 201 are spines. Registering builds the underlay for you: each leaf gets a tunnel endpoint, and a routed path to the others. You configure none of that, which is the idea of a controller. The serials here are FDO plus the switch name.

Concept

ACI: a fabric run by policy

An ACI fabric is run from a controller. You describe tenants, bridge domains and groups of hosts, and the controller works out what each switch needs. An endpoint group (EPG) is hosts that share policy, wherever they are. A static path puts a leaf port and VLAN into an EPG, and the access-policy chain limits which VLANs may be used where. Underneath, leaves are VXLAN tunnel endpoints, which you never configure.