In this section we will talk about Cisco software defined access model Cisco software defined access
creates an entirely new way to build campus local area networks as compared with data additional methods
of networking in the middle of 2000 and 10 Cisco set to about to array.
Imagine campus networking with software defined access as the result guys.
Software Defined access uses the software defined architectural module with EQ controller and various
AP eyes.
It still uses a physical network with switches and routers cables and various endpoints also at the
center.
Since the digital network architecture which is DNA Center controller with human users making use of
a graphical user interface and automation using API as in shard DNA center is the controller for software
defined access networks.
Architecturally the southbound side of the controller contains the fabric underlay and the overlay by
design.
SD and implementations most of the interesting new capabilities or care on the northbound side so let's
talk about the fabric underlay and the overlay terms which are the important terms for Cisco's software
defined access.
Let's start with the overlay overlay is the mechanisms to create weeks Len tunnels between software
defined access switches which are then used to transport traffic from one fabric end point to another
over the fabric underlay is the network of devices and connections to provide IP connectivity all nodes
in their fabric with a goal to support the dynamic discovery of all software defined access devices
and end points as a part of the process to create overlay.
We x land tunnels and when it comes to fabric fabric is the combination of the overlay and underlay
which together provide all features to deliver data across the network with the desired features and
attributes in less formal terms guys the underlay exists as a multilayer switches and they are links
with IP connectivity but for a special purpose the underlay supports some new concepts with at tunneling
method called weak land traffic sent by the end point to flows through weeks land tunnels in the overlay
a completely different process than through additional land switching and the IP routing for instance.
Think about the idea of sending packets from hosts on the left of a network over the software defined
access to hosts on the right of the network for instance guys let's imagine a packet enters on the left
side of the physical network and eventually exits the campus out of the switch that you can see in here
from switched to OK.
This underlying network looks like a more traditional network droving with several devices and links
right.
But when you check the figure at the top of the screen which is showing only two switches called Fabric
edge notes because they happen to be at the edges of the software defined access fabric with at tunnel
LaBolt weeks lan connecting the two both concepts.
I mean the underlay and overlaid together create an S the a software defined access fabric.