In this lesson,
we're going to explore the concept
of a virtual extensible local area network.
Now, a virtual extensible local area network,
also known as a VXLAN,
is a network virtualization technology
that addresses the limitations posed
by traditional network infrastructures.
As enterprises and data centers continue to expand,
the need for more scalable, flexible,
and efficient virtual networks has become a critical need.
VXLAN technology plays a pivotal role in catering
to these demands by facilitating the creation of a larger
and more agile network.
VXLAN is a network overlay technology
that's designed to encapsulate ethernet frames
within a UDP packet.
VXLAN extends the Layer 2 network
over a Layer 3 infrastructure
to create a virtualized Layer 2 network
that can span physical Layer 3 networks as well.
This technique enables the deployment of a large number
of virtual networks with isolated address spaces
across a shared physical network infrastructure.
Now, the primary driver
behind VXLAN's inception was the need
to overcome the scalability limitations of traditional VLANs
or virtual local area networks.
VLANs are restricted to a 12 bit VLAN identifier,
so your networks could only have 4,096 unique VLANs,
which may sound like a lot,
but this limitation is really insufficient for our modern,
vast segmented networks
that are used in our large scale
cloud computing environments these days.
So how does a VXLAN work?
Well, VXLANs operate
by encapsulating Layer 2 ethernet frames
within Layer 4 UDP packets.
This encapsulation process allows for the creation
of a tunnel across a Layer 3 network,
which can be a WAN, a LAN, or even the internet.
Each VXLAN packet includes
a 24 bit VXLAN network identifier known as a VNI
and this significantly expands the number
of available identifiers from 4,096
all the way up to over 16 million identifiers
to address the scalability issues
that we have with traditional VLANs.
Now, when using a VXLAN setup,
you're going to find two primary components are going to be used.
These are the VXLAN tunnel endpoints and the VXLAN segments.
First, we have VXLAN tunnel endpoints known as VTEPs.
These VXLAN tunnel endpoints are entities
that perform the encapsulation and de encapsulation
of the ethernet frames into those VXLAN packets.
VTEPs are typically implemented within hypervisors
that host the virtual machines
or within your physical network switches.
Second, we have the VXLAN segment.
The VXLAN segment is a Layer 2 network overlaid
onto a Layer 3 network that is then identified using
that unique 24 bit VXLAN network identifier, or VNI.
Virtual machines within the same VXLAN segment
can communicate with each other
as if they were on the same physical Layer 2 network,
regardless of their actual physical location.
Now, VXLANs offer us
with numerous benefits including scalability, flexibility,
and improved utilization.
First, we have scalability.
Now with a 24 bit VNI, VXLAN can support up
to 16 million virtual networks,
which our organizations to scale their networks
as needed without being constrained
by the previous VLAN ID limits of 4,096.
Second, we have flexibility.
Since VXLANs traverse Layer 3 networks
and they don't require any changes
to the underlying network,
this makes it possible to extend our Layer 2 networks
across different data centers or cloud environments as well.
Third, we have improved utilization.
VXLAN allows for more efficient use of the network paths
and bandwidth by optimizing our traffic flows within
and across our data centers.
So how might VXLANs be used in the real world?
Well, in a typical data center environment,
virtual machines across different servers
need to communicate with each other.
If these servers are spread across multiple locations,
traditional VLANs may not suffice
due to their scalability limitations
and this is where VXLAN steps in
because it can encapsulate
that traffic from these virtual machines
within the UDP packets and allow for the data
to traverse any IP network while maintaining the illusion
of being a single Layer 2 network.
This is especially beneficial for applications
that require a consistent network topology
regardless of the underlying physical network.
Now, even though VXLANs can provide us
with a robust solution for network virtualization,
there are challenges and considerations
that you need to keep in mind when using VXLANs.
VXLANs can be complex to configure.
When you're implementing a VXLAN,
you have to have a good understanding of both Layer 2
and Layer 3 networking, as well as the intricacies
of network overlays.
Also, the encapsulation
and de encapsulation process can introduce latency
and increase the packet size due to the encapsulation
and this can result in higher overhead
inside of your networks.
Finally, VXLANs do require multicast support
within the underlying network,
so you can use that for broadcasting
and unknown unicast traffic
and this can be a challenge in some corporate
or enterprise environments depending on your configuration
and your current security posture.
Now despite these challenges,
the deployment of VXLANs
can be significantly simplified
with the use of management and orchestration tools
that automate the configuration
and management of your VXLAN networks on your behalf,
especially when you're operating in a cloud-based network.
So remember, a VXLAN represents a significant advancement
in network virtualization by providing the means
to create extensible, scalable,
and efficient virtual networks
over existing network architectures.
VXLAN is a network overlay technology
that's designed to encapsulate ethernet frames
within a UDP packet.
VXLAN will extend the Layer 2 network
over a Layer 3 infrastructure
to create a virtualized Layer 2 network
that can span physical Layer 3 networks across the globe.
Understanding VXLAN is going to be an essential thing for you
as a network professional if you aim to design
and manage advanced, scalable,
and flexible network solutions
in our modern distributed networks.