- Cisco ACI provides the capability to automate settings
and networking policies,
and configurations in a very,
very flexible and scalable way.
Now, in this example, I'm actually illustrating
the concept of a centralized policy
and configuration management in the Cisco ACI solution.
For your reference.
Now for you, this exam, you do not need to be an ACI
you know, expert itself, right?
So, there's different CCMP
and CCIE concentrations for data center.
But I strongly suggest to at least become familiar
with the concepts that I'm sharing here with you
and at least, you know, the overall functions,
and the capabilities of the ACI solution.
So, ACI uses a leaf and spine topology.
Each leaf switch is actually connected
to every spine switch in the network
with no interconnection between leaves,
switches, or spine switches.
Now, the leaves have ports that are connected
to traditional ethernet devices, for example,
servers, firewalls, you know, even routers and so on.
And then the leaf switches are actually,
typically deployed at the edge of the fabric.
And these leaf switches provide the virtual extensible LAN
or VXLAN tunnel functionality, right?
And specifically, the VXLAN tunnel endpoint,
or VTEP functionality as well.
And you're gonna learn more
about VXLAN later in this course.
Now, VXLAN, in short,
is a network virtualization technology that leverages
an encapsulation technique very similar to VLANs, right?
To enable and encapsulate layer two ethernet frames
within UDP packets.
And typically, it's actually done
over UDP port 4789 by default.
But it can be actually changed
and configured depending on the implementation.
Now in Cisco ACI, the IP address
that represents the leaf VTEP, right,
or V-T-E-P, is actually called
the physical tunnel endpoint or P-T-E-P.
Now, the leaf switches are responsible for routing
or bridging tenant packets for applying network policies.
Now, the spine nodes interconnected actually leaf devices
or the leaf switches,
and they can also be used to establish connections
from a Cisco ACI's pod.
And that's a concept in ACI pod to an IP network
or to, you know, interconnect multiple ACI pods, right?
And spines or spine switches actually
will store all the endpoint to V-T-E-P
or VTEP mapping entries.
Now, all leaf nodes connect
to all spine nodes within a Cisco ACI pod.
However, there's no direct connectivity allowed
between the spine nodes
or between the lift nodes themselves,
or workloads in ACI connect to leaf switches.
Now, the leaf switches, you know,
used in the ACI fabric are top of rack switches
or ToR switches.
The acronym ToR here here is not the same
as the onion router.
If you're familiar with that, you know
the solution used for anonymity
and to access a deep web.
That's not what I'm talking about here, right?
Now, another thing to highlight is
that the APIC or the controller, right,
can be considered a policy and topology manager, right?
So, basically APIC is the brain of ASIC or ACI rather.
And APIC actually manages
the distributed policy repository responsible
for the definition and deployment
of the policy-based configuration in the ACI infrastructure.
Now, APIC also manages the topology
and the inventory of all the devices within the ACI pod.
Now, APIC also has a few additional functionalities,
you know, different functions
and here are the most common.
First, it actually monitors the subsystem
of, you know, ACI infrastructure.
The API APIC observer is a function
that actually monitors the health, the state
and the performance of the actual ACI pod.
And then, you also have the boot director
which is actually the function in charge
of the booting process
and the firmware updates of the spine switches,
leaf switches and the actual APIC components itself.
Now, the appliance director is an APIC function
that manages the function
and control of the APIC appliance cluster.
And then, you also have the VMM
or the virtual machine manager
that is an agent between the policy repository
and a hypervisor.
For example, something like VMware vCenter and so on.
Now, you also have the event manager
and if the event manager manages
and store all the events, and faults initiated
from the APIC and the a ACI fabric nodes.
Then lastly, you have the appliance element
which maintains the inventory
and the state of the local APIC appliance.
Now, for your reference, I'm actually including a link
to the ACI design guide
which actually provides comprehensive information
about the design, the deployment
and the configuration of the ACI solution.
For this exam, you do not need to know, you know,
very details of a configuration of the ACI solution.
Again, we actually have separate exams
for that and certifications.
But I strongly suggest to at least, you know
read the document and become familiar
with most important components
which actually I already have covered here.
But as a refresher, please use this as your reference.