Original subtitles

In our next section we will talk about some network topology architectures the three to architecture

guys consists of three different layers and they are access layer distribution layer and the core layer

the core layer is in charge of first routing simply and it is the layer which is a gateway to Internet

or other sites.

And the core layer also provides scalability and the first three coverage and skies when it comes to

distribution layer in this layer we have multiple multilayer switches capable doing routing also and

they have a high capacity and high port speed and density and this layer aggregates the server access

layer using switches to segment work groups and isolate network problems in a datacenter environment

and the last layer we will talk about is the access layer we can use the layer two switches in this

layer because we are not based on routing but in some mac address forwarding just the access layer is

a layer that is used to guarantee user access to the network to ISIS and mostly on access layers which

we have some end user pieces some printers some IP cameras and et cetera.

All right.

P. cam and that cetera.

OK so let's go ahead with the truth here now the three tier a high risk hierarchical design maximizes

performance network availability and the ability to scale the network design.

Yeah three tier is really great but many small enterprise networks do not grow significantly larger

over time.

Therefore a two tier hierarchical design where the core and the distribution layers are collapsed into

one layer is often more pretty practical a collapsed core is when the distribution layer and the core

layer functions are implemented by a single device.

The primary motivation for the collapse core design is reducing the network cost while maintaining most

of the benefits of the three tier hierarchical model.

Now let's finish this session with the spine Leif for a long long time we have talked about Cisco's

two tier and three tier network design where we just talked about and we had the following players access

this probation and car the access layer connected to our end devices such as clients and servers.

However within two days data centers and new topological design has taken over and it is called spine

and live.

So imagine a cabinet in a data center filled with servers guys for acutely.

There will be a couple of switches at the top of each rack and for redundancy.

Each server in the rack has a connection to both of these devices.

You might have heard the term top of rack used to refer to these kinds of switches because they physically

do side in the top of a rock already.

These tea or are switches acts as as the loose in a leaf and spine topology ports in a live switch.

Have one of responsibilities and one connecting to you.

Note You can see in here.

And second connecting to air space which you will notice in the topology on the screen that each leaf

switch connects to a wrist band switch.

You can see the lift switches in here and here we are connected to this switch here connected to this

storage.

And here we are connected to this spine switch.

So as a result there is no need for interconnections between the spine suites.

Okay you can see there is no interconnection between the spine switch also the lift switch as well it

is also interesting to note that the uplink connections from the left switches to the spine switches

could be either layer two connections or layer three router connections by interconnecting your T or

our data center switches in a leaf and spine topology all of your switches are the same distance away

from one another.