NFV, SDN and VMware NSX


After Compute Virtualization Network Functions Virtualization (NFV) is the next step, moving physical networking devices/equipment and running it in a VM. NFV separates network functions from routers, firewalls, load balances and other dedicated hardware devices and allows network services to be hosted on virtual machines. Virtual machines have a hypervisor, also called a virtual machine manager, which allows multiple operating systems to share a single hardware processor. When the hypervisor controls network functions those services that required dedicated hardware can be performed on standard x86 servers.


SDN makes the network programmable by separating the control plane (telling the network what goes where) from the data plane (sending packets to specific destinations). It relies on switches that can be programmed through an SDN controller using an industry standard control protocol, such as Open Flow.

SDN separates control and data and centralizes control and programmability of the network. NFV transfers network functions from dedicated appliances to generic servers.
Network intelligence is logically centralized in SDN controller software that maintains a global view of the network, which appears to applications and policy engines as a single, logical switch. As virtual device, they require no extra space, power or cooling.
SDN operates in a campus, data center and/or cloud environment Physical devices often rapidly reach EOL or run out of capacity and need to be upgraded to large models
SDN software targets cloud orchestration and networking NFV targets the service provider network
  NFV software targets routers, firewalls, gateways, WAN, CDN, accelerators and SLA assurance

SDN and NFV Are Better Together

 These approaches are mutually beneficial, but are not dependent on one another. You do not need one to have the other. However, the reality is SDN makes NFV and NV more compelling and visa-versa. SDN contributes network automation that enables policy-based decisions to orchestrate which network traffic goes where, while NFV focuses on the services, and NV ensures the network’s capabilities align with the visualized environments they are supporting.

VMware NSX

VMware NSX is a hypervisor networking solution designed to manage, automate, and provide basic Layer 4-7 services to virtual machine traffic. NSX is capable of providing switching, routing, and basic load-balancer and firewall services to data moving between virtual machines from within the hypervisor. For non-virtual machine traffic (handled by more than 70% of data center servers), NSX requires traffic to be sent into the virtual environment. While NSX is often classified as an SDN solution, as per my understanding that is really not the case.

SDN is defined as providing the ability to manage the forwarding of frames/packets and apply policy; to perform this at scale in a dynamic fashion; and to be programmed. This means that an SDN solution must be able to forward frames. Because NSX has no hardware switching components, it is not capable of moving frames or packets between hosts, or between virtual machines and other physical resources. In my view, this places VMware NSX into the Network Functions Virtualization (NFV) category. NSX virtualizes switching and routing functions, with basic load-balancer and firewall functions.



NSX can be used to create a secure infrastructure, which can create a zero-trust security model. Every virtualized workload can be protected with a full stateful firewall engine at a very granular level. Security can be based on constructs such as MAC, IP, ports, vCenter objects and tags, active directory groups, etc. Intelligent dynamic security grouping can drive the security posture within the infrastructure.


VMware NSX provides a full RESTful API to consume networking, security and services, which can be used to drive automation within the infrastructure. IT admins can reduce the tasks and cycles required to provision workloads within the data center using NSX.

NSX is integrated out of the box with automation tools such as vRealize automation, which can provide customers with a one-click deployment option for an entire application, which includes the compute, storage, network, security and L4-L7 services.

Developers can use NSX with the OpenStack platform. NSX provides a neutron plugin that can be used to deploy applications and topologies via OpenStack.

Application Continuity:

NSX provides a way to easily extend networking and security up to eight vCenters either within or across data center in conjunction with vSphere 6.0 customers can easily vMotion a virtual machine across long distances and NSX will ensure that the network is consistent across the sites and ensure that the firewall rules are consistent. This essentially maintains the same view across sites.

NSX Cross vCenter Networking can help build active – active data centers. Customers are using NSX today with VMware Site Recovery Manager to provide disaster recovery solutions. NSX can extend the network across data centers and even to the cloud to enable seamless networking and security.



Logical switching enables extension of a L2 segment / IP subnet anywhere in the fabric independent of the physical network design.


Routing between IP subnets can be done in the logical space without traffic leaving the hypervisor; routing is performed directly in the hypervisor kernel with minimal CPU / memory overhead. This distributed logical routing (DLR) provides an optimal data path for traffic within the virtual infrastructure means east-west communication. Additionally, the NSX Edge provides an ideal centralized point for seamless integration with the physical network infrastructure to handle communication with the external network (i.e., north-south communication) with ECMP-based routing.

Connectivity to physical networks:

L2 and L3 gateway functions are supported within NSX to provide communication between workloads deployed in logical and physical spaces.

Edge Firewall:

Edge firewall services are part of the NSX Edge Services Gateway (ESG). The Edge firewall provides essential perimeter firewall protection which can be used in addition to a physical perimeter firewall. The ESG-based firewall is useful in developing PCI zones, multi-tenant environments, or dev-ops style connectivity without forcing the inter-tenant or inter-zone traffic onto the physical network.


L2 VPN, IPSEC VPN, and SSL VPN services to enable L2 and L3 VPN services. The VPN services provide critical use-case of interconnecting remote datacenters and users access.

Logical Load-balancing:

L4-L7 load balancing with support for SSL termination. The load-balancer comes in two different form factors supporting inline as well as proxy mode configurations. The load-balancer provides critical use case in virtualized environment, which enables devops style functionalities supporting variety of workload in topological independent manner.

DHCP & NAT Services:

Support for DHCP servers and DHCP forwarding mechanisms; NAT services. NSX also provides an extensible platform that can be used for deployment and configuration of 3rd party vendor services. Examples include virtual form factor load balancers (e.g., F5 BIG-IP LTM) and network monitoring appliances (e.g.,Gigamon – GigaVUE-VM).
Integration of these services is simple with existing physical appliances such as physical load balancers and IPAM/DHCP server solutions.

Distributed Firewall:

Security enforcement is done directly at the kernel and vNIC level. This enables highly scalable firewall rule enforcement by avoiding bottlenecks on physical appliances. The firewall is distributed in kernel, minimizing CPU overhead while enabling line-rate performance.

NSX also provides an extensible framework, allowing security vendors to providean umbrella of security services. Popular offerings include anti-virus/antimalware/anti-bot solutions, L7 firewalling, IPS/IDS (host and network based)services, file integrity monitoring, and vulnerability management of guest VMs.

I hope this will help you understanding what NSX does and its use case. Comments are welcome to make this post more accurate and interesting…:)


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