- [Instructor] There are many
software defined networking packages,
but I'm only going to mention a few.
First is OpenDaylight.
Of all the controllers that supported the OpenFlow system,
OpenDaylight emerged on top.
OpenFlow is a software protocol
that directly interfaces with the forwarding plane.
OpenDaylight is now officially managed
by the Linux Foundation
and is still actively being developed.
ODL has multiple protocols it can support
on the Southbound interface,
like multiple versions of OpenFlow, BGP-LS, and NETCONF.
At one time Cisco supported a commercial version of ODL
and branded it as Cisco Open SDN Controller.
This has been deprecated
in favor of their intent based networking products.
Cisco really developed three different products,
Software-Defined networking, SD-WAN, for the network edge,
Software-Defined Access, SDA for the LAN,
and Application Centric Infrastructure,
ACI for the data center.
ACI has a specific design aesthetic,
known as Spine-And-Leaf.
There are a few spine switches
that aggregate all of the leaf switches.
The leaf switches then connect to server infrastructure.
Generally any server equipment
like the Cisco Unified Computing System, or UCS,
will connect to multiple leaf switches
for increased redundancy and capacity.
The spine and leaf configuration has a few key points.
Each spine and leaf must connect to each other.
Leaf switches won't connect to each other,
nor will spines directly connect between one another,
and servers should only connect to leaf switches.
In ACI the servers, whether virtual or physical,
are considered endpoints.
ACI will then enact policies for said endpoints.
These policies are enacted
via the Application Policy Infrastructure Controller, APIC,
which is the centralized control software for ACI.
Intent-based networking thinks more about application
and what needs to be done on the network
for them to perform correctly.
A web server is the classic example.
A web server is often broken into several pieces
like a load balance, the web server itself,
and a database server.
As in this diagram, the web server
should be the only thing connected to the database servers.
Also only traffic sourced through the load balancer
should be able to reach the web server.
The Application Policy Infrastructure Controller
will reach out to the networking devices
and put the policies in place
to not only allow the applications
to communicate on the LAN among each other,
but also the WAN policy to allow connections
in to the correct resources.
The beauty part here is that the admin
no longer connects to each individuals piece of equipment.
In fact, configuration is generally done
via the APIC GUI interface.
Now I'll take a look at Enterprise SDN.
Cisco has one of the largest install bases
of any vendor in the enterprise market.
Knowing this they couldn't expect all of these enterprises
to completely replace their equipment
to automate configuration.
Keeping this in mind, Cisco develop APIC-EM
to use the standard southbound interfaces
that admins use to connect to equipment
like SSH, Telnet, and SNMP.
Using this package doesn't change
the control plane to be centralized.
Rather it uses centralized administration.
This also allows for northbound APIs
to do some interesting things for troubleshooting,
configuration, and quality of service.
Having said all of this, APIC-EM is being deprecated,
but it's likely you will still see references to it.
SDN is only going to be more prevalent
as we move toward streamlining network engineering,
which makes these topics so fundamental.