In this blog post, I will discuss how a cloud-based architecture makes wireless local area network (LAN) easier and more affordable compared with traditional wireless LAN architecture.
For almost a decade, cloud-enabled applications, such as Software as a Service (SaaS) solutions, have seen rapid adoption in various market verticals.
Cloud computing has proven itself easier to setup and maintain, more affordable, and more flexible than traditional client-server solutions. As a result, “The Cloud” has put broad categories of IT within reach to organisations that previously could neither afford to purchase or manage enterprise IT.
The companies delivering cloud-based IT are also benefiting, which is evidenced by their growth. Examples include Google, Amazon.com and WebEx.
Nearly every major IT leader, from HP to IBM to Microsoft, is aggressively developing cloud-based offerings because their customers demand it.
Networking is being revolutionised with cloud-based wireless solutions that enable all the benefits of cloud computing.
To truly understand the benefits of a cloud-based approach, I will first review the evolution of the enterprise wireless LAN.
First Generation: Standalone APs
The first enterprise access points (APs) were standalone APs, also known as autonomous, independent, or fat APs. A stand-alone AP must be configured individually, typically through a serial cable connected to the AP’s console port. To configure the AP, an administrator needs to be familiar with the AP’s command line interface (CLI). Later, vendors added the ability for an AP to run on a web server, which made it possible for an administrator to configure the AP using a GUI. The GUI reduced the level of expertise required to configure an AP. If an administrator needs to deploy multiple standalone APs, he must log into and configure each AP separately; making configuration changes a tedious and error-prone process. In addition, standalone APs make it difficult for an administrator to monitor the wireless network in a centralised manner—obtaining aggregated bandwidth statistics, usage data, or status information across all of the APs in the network must be done manually or not at all.
Second Generation: Controller-Based WLAN with Tethered APs
Recognising the need for centralised monitoring and configuration, vendors introduced a number of controller-based systems with thin APs (also called dependent APs). Unlike standalone APs, most thin APs cannot operate on their own. Rather, they rely on one or more wireless local area network (WLAN) hardware controllers that need to be installed in wiring closets. The hardware controller acts as a centralised management interface for configuration, a router to direct traffic between the wireless and wired networks, and a mobility coordinator to enable clients to roam from one AP to another. Often, the controller supports PoE, so that the Ethernet cable running from the controller to the AP can provide both power and Internet connectivity to the AP. Controller-based deployments with tethered APs have a number of drawbacks. First, WLAN controllers are expensive, and fully-featured controllers can cost more than all of the APs combined. Second, hardware controllers have significant installation costs, since every AP needs to be wired back to them. Third, the WLAN controller is a single point of failure for the wireless network. When a WLAN controller fails, all of the APs connected to that controller fail. Dual-redundant controllers, while technically possible, are often prohibitively expensive.
Third Generation: Controller-Based WLAN with Tunnelled APs
The next generation of WLANs addressed the major problems of the controller-based WLAN with tethered APs. Instead of tethering all APs to the controller, APs simply tunnel back to the controller. In most cases, the controller remains in the data path. Controller-based deployments with tunnelling APs are common today but have a number of drawbacks. First, the need remains for expensive, redundant hardware controllers. Second, the architecture does not scale well to large, multi-site wireless deployments. Additional controllers are required to handle a larger number of APs. In the case of multiple sites (e.g., off-campus sites), a controller at each site may be required. Growth is also an issue, since more switch ports need to be brought than currently required in order to accommodate future growth. Finally, many controller solutions require a separate management server and software license. This additional infrastructure component adds cost and complexity.
The Cloud-Based Approach
Revolutionary cloud-based architecture offers significant advantages over legacy hardware controller-based systems. In the architecture, there is only one hardware component: the access points. All control, configuration, optimisation, and mobility control is centralised and delivered as a service by a cloud controller from hosted data centres. An administrator logs into the cloud controller through a web browser, providing access to all of the wireless networks in its account, regardless of geographical location. An administrator can make configuration changes and obtain reporting information, either on a specific network or in aggregate. The system sends alerts if there is a problem in one of the networks and runs troubleshooting and diagnostics tools to pinpoint the issue. The customer is not required to purchase or install a hardware controller making a wireless LAN much easier to deploy.
As the cloud controller is delivered as a service from hosted data centres, the cost of infrastructure is leveraged across over thousands of network. The customer benefits by purchasing a service that is a fraction of the cost of buying, deploying and managing a traditional hardware controller. An administrator interfaces with a wireless network through any standard web browser and can manage the network with simple web-based tools providing operational ease and takes less time from the IT team.
Benefits of a Cloud-Based Wireless Architecture
The cloud-based approach creates a number of specific benefits for customers. This section will discuss them in detail.
Speed and Ease of Deployment
Controllers and management appliances take time to install, configure, and maintain. Elimination of these components streamlines deployment and drives down the total cost.
The cloud-based approach offers significant cost savings over legacy wireless architectures. The total cost of a wireless network has several components, including the hardware, installation, wiring, training, and maintenance.
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Having a hosted service available makes it easier to create enterprise applications that build on the network. Cloud based solutions can offer a secure, XML-based API that can be used to produce custom monitoring and reporting applications, without installing additional software or hardware on site.
Since data traffic does not flow through the Cloud Controller, a potential performance bottleneck is eliminated. There are two ways that this bottleneck occurs. First, controllers have a finite capacity. If that capacity is exceeded, the controller will begin dropping packets, slowing down the network. Controllers can also introduce unnecessary latency. Imagine that a client is talking to a file server in the same building. In a hardware controller solution, traffic must flow from the AP to the controller, and then back to the file server. The farther away the controller is, the more latency is introduced. In the cloud-based solution, traffic flows directly from the client to the file server.
Figure 2 illustrates how data flows directly from the client to its host.
Scalability on Demand
Cloud based wireless networks can scale up to many hundreds of access points per network, and an unlimited number of networks per cloud controller. In addition, the cloud-based approach eliminates the need to guess the number of sites or access points required, as well as the costs of guessing wrong.
Remote Multi-Site Management
Network administrators can easily monitor multiple sites, including campus housing and labs, from a single remote console. This approach reduces the number of IT staff needed to maintain the wireless networks at multiple locations.
Simplified Remote Site Setup
Typically, a small number of access points can be placed in remote sites without IT administrators on-site to configure and maintain these APs. Cloud based wireless solutions make it easy to support these sites. Installation of the APs requires little skill. Once installed, they can be configured and monitored by the central IT staff.
A centralised service provides round-the-clock optimisation of the network. The channel planning service monitors channel utilisation and interference, ensuring the network is operating at peak performance. Mesh routes are also constantly updated to ensure maximum client throughput.
A hosted system makes upgrades trouble-free. Since the management system is web-based, new features require no client or server-side upgrades. New features are added to the cloud controller several times per year without disruptive downtime. Firmware upgrades can be managed centrally, freeing network administrators from involvement in keeping APs up-to-date. Firmware upgrades take place over the air in a secure, fault-tolerant fashion.
What if there is a WAN Failure?
If your connection to the cloud is interrupted, your wireless network can continue to function and end users won’t even notice a difference. The only thing that will be lost is reporting and the ability to make configuration changes. All of the features that affect data flow continue uninterrupted. For example:
- Users stay authenticated
- New users can authenticate
- Layer 7 traffic shaping rules continue to be enforced
- Wireless mesh routing operates with full functionality
- Users can roam between wireless APs
- RF features like Dynamic Frequency Selection (DFS) continue
- Performance remains at 100%
A cloud-based architecture provides significant advantages over legacy hardware-based solutions. By eliminating separate controllers, and moving intelligence into the cloud, cloud-based wireless LANs reduce deployment time and complexity, while enabling multi-site, scalable wireless networks. In addition, the cloud-based architecture offers significant opportunities for cost reduction through lower deployment, training, and hardware purchase costs. In summary, the cloud-based approach enables a wireless LAN that is significantly easier to deploy and manage, and much more affordable than traditional hardware controller-based solutions.
For confidence in a wireless cloud implementation, the need to have sufficient visibility to see who is doing what and how across the infrastructure is paramount. This means the use of governance, or the ability to monitor, manage, and control all aspects of the architecture, including the ability to trace issues with security to the sources of the problems. Understanding that a wireless cloud architecture creates risks requires a reassessment but not reinvention of security controls and architecture. However, with some forethought and planning, a wireless cloud computing-based system can be just as secure, if not more secure than a traditional wired system.
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