What is Software-Defined Networking Architecture (SDN)?
Software-Defined Networking Architecture is a networking method. It employs software-based controllers or application programming interfaces (APIs). These APIs communicate with underlying hardware infrastructure and direct network traffic.
This varies from typical networks in that specific hardware devices. These devices can be such as routers and switches. This also helps to regulate network traffic. SDN uses software to establish & control a virtual network and traditional hardware.
Network virtualization enables organizations to segment different virtual networks. It can differentiate the networks within a single physical network. It can also connect devices on different physical networks. This forms a single virtual network. SDN enables a new method of controlling data packet routing through a centralized server.
SDN is significantly more advanced than traditional networking. It also allows for the following:
There is no need to program various vendor-specific hardware devices manually. Instead, developers can design an open standard software-based controller. Moreover, this would govern the flow of traffic over a network. Network managers can also choose more flexible networking equipment. This is because they can use a single protocol to communicate with any number of hardware devices via a central controller.
Administrators using SDN can design network services and distribute virtual resources to update the network infrastructure. All this can take place in real-time from a centralized place. This enables network managers to optimize data flow via the network. It also helps them to focus on applications that demand higher availability.
An SDN provides visibility across the whole network. Thus, allowing for a more comprehensive picture of security concerns. With the rise of smart devices, SDN provides significant advantages over traditional networking. Operators can build discrete zones for devices that need varying levels of protection. Or they can also quarantine compromised devices immediately. This makes sure that they do not contaminate the rest of the network.
This is the simplest SDN architecture in the market. It was mainly promoted by Nicira, a firm bought by VMware in 2012. The main goal of network virtualization is to remove the limits on LAN partitioning. These limits exist in Ethernet Virtual LAN (VLAN). It also aims to address scalability concerns with multicasting in some Ethernet-based virtual network topologies.
OpenFlow switches might become more common over time. Networks could work with open hardware at a much cheaper cost.
To do this, network virtualization technologies augment a software element such as the hypervisor. But, cloud-building software such as OpenStack might also need updating. This update must add an interface that constructs VLANs based on tunnels running on top of standard Ethernet. Network equipment and operations remain unaffected. Many virtual networks can form in this manner.
Network virtualization supports multi-tenant clouds. This does not need any changes to the network itself. This SDN architecture also transfers to popular virtualization interfaces in cloud networking technologies. Moreover, integrating network provisioning with cloud service provisioning becomes simple.
One drawback is that virtual networks above the network layer appear to network devices as traffic. Utilizing deep packet inspection can detect the virtual network header. Without this, those devices cannot focus on or report on individual virtual networks. Also, the virtual networks can only connect virtual machines, not users and devices.
The second SDN model is also called the evolutionary model. This model aims to improve software control of the network and its operations. It does so by remaining within the constraints of present networking technologies. For doing this, networking manufacturers will align with certain standards. These standards are such as VXLAN, GRE, BGP, and MPLS. They use them to partition the network into virtual communities and manage traffic. It also helps them to manage the quality of service.
The manufacturers can also combine their solutions into a set of management interfaces. These interfaces are reusable from the cloud using DevOps tools or a virtual cloud interface. Network devices install this SDN model. Conventional traffic engineering concepts can also apply to this model. Virtual networks can extend from server to the user, given the devices install the relevant standards.
Most SDN suppliers support all the network standards listed above. But, some may not be available on all devices. This is the first of many difficulties with these evolutionary models. Suppliers need to certify the standards that existing equipment supports. Currently, only a few suppliers have offered these evolutionary SDN models. This may not completely interoperate with equipment from other vendors.
This strategy will also need special integration between management systems and cloud virtual networking interfaces. The operator will have to perform if the vendor does not offer.
This is the OpenFlow SDN model, which is what most people think of when they hear the term SDN. OpenFlow substitutes the traditional, discovery-based construction of forwarding tables in switches and routers. It substitutes them with centrally controlled forwarding. This also means that each device's forwarding table needs programming by a central controller.
This allows the central control point complete control over the division of the network. It also gives it control over virtualization, traffic managing, etc.
Any combination of controllers & switches that support compatible versions of OpenFlow are usable. This is the model upon which the concept of SDN was first created. Early testing and deployment show that OpenFlow can also increase network availability and reliability. It can also improve network use. Moreover, this lowers both capital infrastructure costs and operational expenses.
The downside of this model is the existing lack of functional information for all required components. Also, most common switches and routers support OpenFlow. But not usually at the same throughput as previous protocols could achieve. Also, this approach of OpenFlow enablement does little to reduce switching costs.
Because all network administration is centralized and automated, SDN leads to total cost savings. SDN also allows users to reduce costs by improving server usage and virtualization. Aside from these benefits, SDN streamlines network operations by enabling multi-tasking. This also reduces the need for expensive hardware.
SDN includes a controller that secures the entire network. Moreover, this controller guarantees that the network's security regulations and information are followed. SDN also has a centralized management system. The security and features will get managed by a single body.
Because it only uses one central point, this method is very secure. The administrator could also block security risks and prevent them from infecting the system.
SDN enables centralized network management. Also, all networking monitoring and management can take place from a single location. It removes the barrier that traditional methods impose on infrastructure management. SDN also enables system management on an individual basis.
Another advantage of SDN is the level of scalability it provides. The network's infrastructure can also change in an instant. All this without the need to buy or configure resources.
When using SDN, a new method of optimizing hardware devices takes place. With the usage of SDN controllers, it can assign all existing and new hardware a specified role. As a result, it eliminates the limitation of hardware devices committed to a single task.
Every device that connects to a network takes up space on it. The quantity of resources determines the speed of interaction between devices and the network. More virtualized resources can need introduction to increase speed. Now, virtualizing resources may result in a huge lag.
Maintenance is a critical part of networking to carry out its activities. The maintenance aspect of an SDN is lacking. It makes managing the real devices very impossible. Especially when scaling up a network.
There are no defined SDN security mechanisms. Despite the presence of some third-party service providers, there are still security concerns. Only those with competence in handling SDN networks can avert severe attacks.
Reconfiguring an SDN network is a time-consuming and expensive job. To install SDN protocols and controllers, the whole network has to reconfigure.
SDN eliminates the need for traditional routers and switches. As a result, the security that came with them is no longer provided. SDN, for example, lacks the security that comes with a firewall. This makes your network more exposed to outside threats.
Many firms' digital transformation activities have benefited from the updated network infrastructure. SDN gives enterprises more control over the modern infrastructure. It makes it more scalable, flexible, and secure.
The ability for network operators to develop programs that use SDN APIs and provide applications control over network behavior is a fundamental feature of SDN technology. Users can use SDN to create network-aware apps. They also can intelligently track network conditions. Also, SDN allows adjusting network configuration when needed automatically.