What guidance does Cisco give us on the data center
architecture that they would recommend?
What exam questions might we expect on this topic?
Let's answer those questions and more in this Nugget.
We really want to focus this Nugget into three
areas, by the way.
We want to talk about why it is that we see Local Area
Networks and Storage Area Networks segregated.
I mean, why wasn't always the desire of organizations to
take this traffic and mesh it together.
We'll see why in this Nugget.
We'll also talk about the three layered architecture
that Cisco likes to recommend for network infrastructures.
And we'll talk about a variation of it called the
collapsed core.
And then finally, we'll wrap up just by giving you some
overview information of the most important categories of
what Cisco calls this new evolution of their data center
networking.
They call it 3.0.
I know I've taught it to you in other courses.
But in this particular course, let's make sure that we
understand the major tenants of Data Center 3.0.
So why is that we so often see the Local Area Network
completely segregated from the Storage Area Network?
There's a real attempt to keep the Local Area Network traffic
and the Storage Area Network traffic separate.
Well one of the important reasons
has always been security.
The idea is that hacking methodologies that would work
in the Local Area Network.
If we segregate the storage stuff off of that LAN, those
same hacking methodologies would not work.
Another real big reason was always bandwidth.
The Local Area Network was perceived to be a much lower
bandwidth infrastructure then the Storage Area Network.
So we'd take our data, put it in the SAN, and give it
really, really high bandwidth amounts.
Now we know today the Local Area Network is certainly
catching up with the bandwidth capabilities of the SAN.
And that's definitely a consideration.
Another major factor for the segregation has always been
flow control.
Let me elaborate on flow control next in this
particular Nugget.
But just suffice it to say that in TCP/IP based LAN
environments, there can be a lot of bottlenecks.
And these bottlenecks can lead to dropped packets.
Dropped packets is something that is not tolerated in the
Storage Area Networking environment.
And finally, overall performance.
It was deemed that the Storage Area Network segregated
information would achieve higher performance levels than
that all of the Local Area network.
Now something else to keep in mind-- as I alluded to-- is
Storage Area Networks just don't really appreciate the
way in which LANs do their flow control.
Remember what happens.
In a LAN environment, a transmitter will be firing
packets off at the receiver.
If the receiver gets congested, it
will drop some packets.
And it will try and signaled to the transmitter that it is
experiencing congestion.
At that point, the transmitter can slow down-- can reduce the
number of packets that it is sending in a
specific time interval.
This lost packets problem with the flow control mechanisms of
ethernet is something that Storage Area Networks just
cannot tolerate.
So what happens in the Storage Area Network environment
that's so different?
Well the protocol over there is called fibre channel.
And what it's going to do is it's going to have the
receiver really control the situation, instead of the
transmitter.
Specifically, it's a credit based system.
So the receiver will say, OK, go for it.
The transmitter will then transmit.
The receiver will say, OK, you can send x amount.
The transmitter will say, OK, there is your x amount.
So the transmitter will not send information unless it has
credits that it receives from that particular receiver.
This results in what appears to be inefficient
communications.
But that is traded off for the fact that we are absolutely
not losing packets of data.
Now as I'll talk about in a moment--
and as we'll elaborate on in future
Nuggets of this course--
one of the cool technologies that we can do is unification
of the LAN and SAN traffic.
And you're probably aware that we're going to use the gigabit
per second Ethernet of the Local Area Network,
specifically the 10 gigabit per second.
And we're going to take the fibre channel of the SAN, and
we are going to be able to transmit them in the same
environment.
How do we do this?
Well of course, it's fibre channel over Ethernet.
We're going to take that fibre channel traffic, and we're
going to insert it inside of a 10 gigabit per
second Ethernet frame.
Once again, this unified traffic--
this fibre channel over Ethernet technology--
is something that we'll elaborate on
later in this course.
Now keep in mind, when Cisco is designing these modern data
center infrastructures, they will still use a layered and
modular approach.
This really helps the scalability of the design.
It is very easy to go ahead and scale it out.
And it's also very resilient, so this is a reliable
resilient type of design.
The layered approach says that we're going to have particular
equipment that we consider the data center access layer.
As you can see here in my depiction, this might be
C-series rack mounted servers.
These might be those B-series blade
servers in a UCS chassis.
We then have what's called an aggregation layer.
And then finally, there is a high speed core layer.
So if you're familiar with other design classes--
maybe even the CCDA training that we deliver here at CBT
Nuggets, if you're familiar with this three layer concept
of core aggregation and access--
you're going to feel really comfortable with the modular
approach that's used in the data center.
Because these three layers exist here as well.
Now what you can run into in the Storage Area Network a lot
of times is a small number of switches that have just a
single layer.
And these single layer of switches will make redundant
connections to the servers that are actually providing
your storage.
Notice this is a pretty inexpensive and easy way to
manage your environment, because you have a few number
of switches to handle that have redundant connections out
to the storage devices themselves.
But as you might guess, this is not the only particular
your architecture that is utilized.
A lot of organizations will indeed start to scale this out
by adding additional layers of storage switches.
And we'll be talking about these types of designs and
even how they are implemented in the course.
One of the things that we're going to have obviously here
is larger numbers of inter switch links connections in
this particular Storage Area Networking environment.
Now let us talk about these particular modular designs in
more detail.
For example, when we talk about the core layer of, let's
say, a LAN data center infrastructure, what
technologies are we really discussing in that core layer?
The core layer of the layered modular approach in a Cisco
environment make sure that we have
large amounts of bandwidth.
10 gigabit per second is the standard in the core.
And we even see 40 and 100 gigabit per second pipes in
this high-high bandwidth environment.
Administrative domains and policies are sketched out, so
that we couldn't have separate cores in our infrastructure
that help really define the administrative boundaries of
our environment.
And also the core can really help us implement new high
speed data center technologies that may result from future
developments in our organization.
Now while these layers are awesome and each can have
their own particular functions--
as we've sketched out for you--
I need you to be perfectly clear on something.
Many, many organizations today-- both in their LAN and
they're SAN designs--
they are doing what we call a collapsed core.
What does this mean?
It means the aggregation layer is moved up into the core.
So whenever you hear collapsed core, I want you to realize we
were talking about a design that has core layered devices,
and then it has access layered devices.
So we really just define a core and an access.
This can be done with Layer 3 throughout.
This can be done with a mix of Layer 3 and Layer 2.
Layer 3 traditionally being done in the core.
And Layer 2 being done out at the access layer.
So please keep in mind that in both Local Area Network
designs and in Storage Area Network designs, we can go
with a collapsed core approach.
The minute you hear collapsed core, I want you thinking of
just that two layer core and access design.
Now as promised, let's talk about Cisco's Data Center 3.0
initiative a little bit.
This is a nice preview of what we're going to be dealing with
in depth in this course.
When it comes to the 3.0 Data Center, Cisco really
emphasizes virtualization.
When you say virtualization, it means different things to
different people.
For instance, if you have a VMware background, you would
immediately think about virtualization in your server
environment.
You would think about perhaps a C-series rack mounted server
from Cisco that is actually running many different
operating systems thanks to the VMware hypervisor.
While certainly we're going to deal with that concept in this
course, we don't just stop there.
We're talking virtualization in the network environment--
something like the 1,000V from Cisco Systems.
And we talk about things like Cisco's VN-Link technology.
We're going to talk about this a lot in
this particular course.
What this means is when we have one of these-- let's say
it's a C-series rack mounted server and it's got different
VMs was running on top of it.
When each of these VMs is communicating through a single
10 gigabit per second pipe, we want to be able to track the
traffic of that individual VM as it is moving through our
network infrastructure.
This is what VN-link is all about--
to literally be able to tag and distinguish the traffic of
one virtual machine from another virtual machine.
So virtualization.
Yes, it's going to be very much present in our modern
data center.
And we'll be dealing with it throughout
this CBT Nugget course.
As I alluded to in this particular Nugget, the fabric
is unified.
This is thanks to technologies like fibre
channel over Ethernet.
We'll talk about data center bridging in here.
We'll talk about iSCSI technology in here.
So all these technologies are going to be defined and
supported by Cisco in order to marry the traffic of the LAN
and the Storage Area Networking wherever we need to
do in our data center environment.
And then we have unified computing that is available
from Cisco.
This is going to allow us to do a heavy, heavy intense
amount of virtualization.
But it's also going to enable us to very, very reliably
connect many different servers into the LAN and SAN
infrastructure.
So we're going to bring the intelligence and the
information that's in the LAN and the SAN.
And we're going give it easy access to the server blades
that are wanting to consume this information.
If you have no experience with the Unified Computing System
of Cisco Systems, then don't worry.
You're in the right place.
In this particular course, I'll walk you through this UCS
system, and you can see why it is such an amazing product
line from Cisco Systems.
You're going to be able to deploy servers in your
infrastructure completely ready and raring to go for
particular functions.
Maybe it's e-commerce.
Maybe it's database.
Maybe it's--
I don't know-- some financial analysis.
You'll be able to deploy these servers and have them ready
with just a few clicks of the mouse.
So did we cover information in this particular Nugget that is
certification relevant?
We sure did.
So as such, let's do some sample review questions.
These are the types of multiple choice that you could
certainly see in your exam environment.
Which two are not advantages of a
modular data center design?
We have to choose two here.
Two of these are not necessarily advantages that we
would get when we shoot for modularity in the data center.
Resilience, ease of management, complexity, and
scalability.
Well, we said that when we do a modular data center design,
it adds to the resiliency and scalability.
So the two here that aren't really advantages would be
ease of management and complexity.
Look, we love the ease of management.
But when we do a modular design, it really doesn't lead
itself to ease of management.
In fact, if anything, it makes our lives as managers all the
more complex.
And complexity's another one.
The fact that we do increase the complexity of our design
isn't a good thing, really.
But adding to the complexity of our design helps give us
the resilience and the scalability that
we're looking for.
So think carefully.
Don't answer to quickly when it comes to these questions
about design modularity and the three layered architecture
of core aggregation and access that we'll
run into in the exam.
Let's take a look at another one.
What are two features we might find in the data center
aggregation layer?
Again, our job here is to choose two.
Security, QoS marking, various services,
or high speed switching.
Wow, what a tricky question.
We certainly might find QoS at the
aggregation layer, for sure.
But it really would typically be marking.
This is something we would find at the
access layer instead.
We certainly could have high speed switching, but this is
more likely for a description of what goes on in our core
layer of the infrastructure.
So the best answer, I believe, certainly we can find access
controls and security mechanisms down at the
aggregation layer and a lot of other various services.
One I mentioned was network analysis modules that could be
inserted here for analyzing the traffic that is coursing
through the veins of our modern data center.
Which two layers result in the collapsed core design?
Do you remember this?
When we collapse the core, we end up with the core layer and
the access layer.
Another way to solve this, by the way, is to realize that
distribution and aggregation are a
description of the same layer.
Some people call the aggregation layer actually the
distribution layer.
You'll often see it oftentimes too as the policy-based
control layer.
And all of these are trying to describe
that particular layer.
If you have two of the options that are the same thing, it's
probably not going to be right.
So anyways, this was pretty easy.
We know that when we collapse the core, obviously we get a
core layer.
And the only other layer that exists is that access layer.
So congratulations you just survived your first Nugget of
content in this course.
And we started out mild didn't we?
Sure, we took a look at the segregation of Local Area
Network and Storage Area Network traffic.
And you now really understand why traditionally that
segregation has taken place.
One of the big topics there we saw was flow control.
And Storage Area Networking is really intolerant of the
approach they could lead to drooped packets that we would
find in the traditional Ethernet based LAN.
We talk about that layered architecture--
that core aggregation and access approach--
that's Cisco has always used, and that moves right each of
the data center environment.
And then we wrapped it up with a nice preview of topics that
we'll see in the rest of this course.
We talked about the three pronged approach of Data
Center 3.0.
Do you remember it?
It was a heavy dose of virtualization.
It was our wonderful unified fabric, which is really,
really exemplified by a technology called fibre
channel over Ethernet.
And then finally, it also consists of the Unified
Computing System.
Again, we have Nuggets dedicated to those various
topics coming up in this particular course.
Well I hope this has been informative for you. 363 00:18:20 And I'd like to thank you for viewing.