Network virtualization {NVF} Vs software-defined networking {SDN} #All you want to know about

Network virtualization may sound a lot like software-defined networking(SDN), but there are actually major differences between these two concepts.

Let’s look at these differences.

Though the term software-defined networking means different

things to different people, this much is clear: SDN allows software

to control the network and its physical devices. SDN is all about

software talking to hardware — you can essentially call it a next generation

network management solution. Though it centralizes

management and allows you to control network switches and

routers through software, SDN doesn’t virtualize all networking

functions and components.

In other words, SDN doesn’t allow you to run the entire network in software. Hardware remains the driving force for the network.

A Software Defined Network (SDN) is an open approach to managing the network.  A centralized controller remotely controls the routers and switches within the network fabric, which are typically located far away at the network’s edge.  SDN uses automation and centralized control to provide speed to network configuration and permit dynamic, on-demand changes to react to fluctuations in the traffic flows.  The SDN solution operates hand-in-hand with server virtualization within data centres.  As servers are brought online or removed from service to react to varying demands for traffic requests, the network can be scaled to map these same traffic flows to the server variations.  The provisioning is automated.  SDN separates the data flow plane from the network control plane to permit this virtualization of the network fabric.

In contrast to SDN, network virtualization completely decouples

network resources from the underlying hardware. All networking

components and functions are faithfully replicated in software.

Virtualization principles are applied to physical network infrastructure

to create a flexible pool of transport capacity that can be

allocated, used, and repurposed on demand.

With your networking resources decoupled from the physical

infrastructure, you basically don’t have to touch the underlying

hardware. Virtual machines can move from one logical domain

to another without anyone having to reconfigure the network or

wire up domain connections. You implement network virtualization

in the hypervisor layer on x86 servers rather than on network

switches. The physical network serves as a packet-forwarding

backplane controlled from a higher level.

Network Function Virtualization (NFV) is similar and interrelated to SDN, but it does not need to be necessarily coupled with SDN.  Although they are often seen together.  NFV is the application of software defined appliances to the network.  These appliances include devices such as edge authentication, firewalls, load balancers, and some routing functions.  Traditionally, these network function appliances were hardware based and now under the NFV approach they are software applications running on network edge servers.  Like SDN, these appliances are centrally controlled and managed, which delivers speedy agility, permitting rapid change to settings and configurations.  Policies and procedural settings can be downloaded and updated dynamically too.  These network appliances are virtualized, exactly like the way the networks are managed with SDN.