Explore VXLAN technology its advantages, operational dynamics, and superiority to VLAN in network virtualization for cloud computing and data centers.
Introduction
As network virtualization becomes increasingly vital in data
centers and cloud computing, VXLAN (Virtual Extensible LAN) emerges as a key
player. It is a network virtualization technology designed to address the
limitations of traditional network methods such as VLAN. This article sheds
light on VXLAN's key advantages, the network challenges it overcomes, its
primary use cases, its operational dynamics, and how it compares with VLAN.
What is VXLAN: A comprehensive overview
VXLAN standing for Virtual extensible LAN. IETF the Internet
Engineering Task Force creates it as network virtualization technology standard,
which allows to share a single physical network with different multiple
organizations in such a way that no one can see the traffic of another one. It
is designed to overcome scalability issues in massive cloud computing
deployments. It facilitates creating logical networks on existing physical
networks, thereby boosting network infrastructure's scalability and flexibility.
In other word’s Virtual extensible LAN is the technology
which can segment the physical network into almost 16 million logical, or you
may call it virtual networks. It encapsulates layer 2 ethernet frame in UDP
packet (layer 4) including VXLAN header. VXLAN extend the layer 2 networks to
across a layer 3 IP or MPLS network when it merges with EVPN (Ethernet virtual
private network), which uses WAN protocols to transmit ethernet traffic in
virtualized networks.
The Significant Benefits of VXLAN
Scalability Beyond Traditional Means:
With support for up to 16 million logical networks, VXLAN
surpasses traditional VLANs in scalability. More over as the VXLAN frames are
encapsulated in a UDP packet, so it can run on all those networks which are
able transmit the UDP packets. It doesn’t matter how the underlying network is
physically laid up or how far a part its nodes are geographically, all that
matter is that the UDP datagrams are routed from the encapsulating VXLAN Tunnel
Endpoint (VTEP) to the decapsulating VTEP.
Enhanced Isolation and Security:
It ensures secure tenant isolation in environments with
multiple tenants, essential for cloud-based services.
Network Topology Flexibility:
VXLAN allows the creation of logical network topologies
independent of physical network configurations.
Addressing Networking challenges with VXLAN
Similar to how the quick uptake of server virtualization has
resulted in significantly more agility and flexibility, operating virtual
networks that are independent of physical infrastructure is simpler, quicker,
and less expensive. For instance, they let several tenants safely share a
single physical network, which enables network operators to scale their
infrastructures more quickly and affordably in response to increasing demand.
Network segmentation is mostly done for security and privacy purposes, mainly
to keep one tenant from viewing or accessing another tenant's traffic.
Similar to how they have long deployed traditional virtual
LANs (VLANs), operators logically partition their networks; however, VXLANs
transcend the scaling limits of VLANs in the following ways:
In contrast to standard VLANs, which have a 4094 limit,
VXLANs enable you to create up to 16 million in one administrative domain. In
order to support a large number of tenants, cloud and service providers require
network segmentation at the scale that VXLANs offer.
You can build network segments that connect different data
centers with VXLANs. Broadcast domains are created via traditional VLAN-based
network segmentation; however, all of the VLAN information is erased as soon as
a packet containing VLAN tags reaches a router. In other words, VLANs can only
go as far as your Layer 2 network can. Certain use cases, such as virtual
machine (VM) migration, which generally prefers not to traverse Layer 3
boundaries, have an issue with this. In contrast, VXLAN network segmentation
encapsulates a UDP packet that contains the original packet. As long as all
switches and routers along the way support VXLAN, this enables a VXLAN network
segment to travel as far as the real Layer 3 routed network can. The
applications operating on the virtual overlay network do not need to traverse
any Layer 3 boundaries. Even though the underlying UDP packets may have passed
via one or more routers, the servers that are connected to the network are all
part of the same Layer 2 network.
The ability to provide Layer 2 segmentation over the top of
an underlying Layer 3 network, combined with the high number of supported
network segments, allows servers to be part of the same VXLAN even if they are
remote from one another while enabling network administrators to keep Layer 2
networks small. Having smaller Layer 2 networks helps avoid MAC table overflow
on switches.
Key Uses of VXLAN in Modern Networking
VXLAN is pivotal in areas such as:
Efficient Data Center Operations: Facilitating vast,
virtualized environments in data centers.
Cloud Service Enablement: Providing secure, isolated
environments for multiple tenants in cloud services.
Overlay Network Implementation: Assisting in the development
of scalable overlay networks over existing network infrastructures.
The Operational Mechanism of VXLAN
You can establish virtualized Layer 2 subnets that span physical Layer 3 networks by using the VXLAN tunneling technology, which encapsulates Layer 2 Ethernet frames in Layer 4 UDP packets. Every segmented subnet is uniquely identified by the VXLAN Network Identifier.
The VXLAN Tunnel Endpoint (VTEP) is the entity responsible
for packet encapsulation and decapsulation. A virtual switch that is installed
on a server or an autonomous network device like a hardware router or switch
can both be VTEPs. Ethernet frames are converted by VTEPs into VXLAN packets,
which are subsequently transmitted via an IP or other Layer 3 network to the
destination VTEP, where they are decapsulated and routed to the intended
server.
Hardware VTEPs, such as certain Juniper switches and
routers, can encapsulate and decapsulate data packets to support devices that
cannot function as VTEPs on their own, such as bare-metal servers. Furthermore,
in order to directly support virtualized workloads, VTEPs can live on
hypervisor hosts, such as kernel-based virtual machines (KVMs). A software VTEP
is the name given to this kind of VTEP.
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| Fig - 1.1 VXLAN |
Conclusion
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