With 802.11n, enterprise Wi-Fi networks are shifting from convenient to critical. They’re becoming the preferred and primary network access for users – which means IT groups have to rethink how they deploy, secure, manage and run the wireless LAN.
Evidence from the front lines of IT shows that it’s easy to squander the 3x to 5x improvement in Wi-Fi data rate and throughput that 11n offers, as compared to 802.11abg. If that happens, WLANs that were expected to easily handle the surging number of Wi-Fi clients, absorb the sharp uptake in latency-sensitive multimedia traffic, and deliver consistent, high throughput across the enterprise fail to live up to their potential.
Rapidly evolving characteristics are forcing IT professionals to rethink their approach to WLANs.
Designing a WLAN that can meet specific throughput targets to support those applications; and creating an “infrastructure” that goes beyond just the access points and controllers to include network and user security, end-to-end network management, continual monitoring, and a trained WLAN response team and help desk.
Here’s what you need to be aware of to take your enterprise WLAN to the next level.
* Design for capacity not coverage: With 802.11n, a relatively few access points can create a Wi-Fi blanket wall-to-wall in the enterprise. But with the evolution of traffic types, applications and clients, that’s no longer enough. Designing and building for capacity means taking into account the actual use-case of a given area, and deploying enough APs to meet your performance expectations. A key element in such an approach is an understanding of how access points perform under the expected types and volumes of traffic, number of users, and applications. Thorough testing will clarify client requirements, what the AP can deliver, and how and where to deploy them to meet service level requirements.
One practice has been to deploy Wi-Fi networks that have traffic prioritization combined with bandwidth limitations for applications or users; this is part of an overall focus on constantly optimising wireless performance. However, designing the WLAN from the outset for the emerging multimedia challenge may be a more effective long-term solution.
Tariq Hassan, Regional Sales Manager, Motorola Solutions, says architecture is also important. “It should be scalable. Wireless is a dynamic environment and large networks require continuous tweaking either automatically or manually.”
He adds network planning is important as the initial design will plays an important role in determining how efficient the network is. “It is therefore important for the initial design to be done by a competent design engineer, using the right simulation tools and/or planning/estimation tools such as site survey software.”
Matthew Gast, Director of Product Management, Aerohive Network, says the cardinal rule in building an efficient network is to use the 5 GHz spectrum. “There are many more channels for radio management algorithms to pick from, and most devices support using 5G channels. Every laptop supports them, as does almost every device that’s not a telephone. A dual-radio AP is only a small additional investment above the cost of a single-radio AP, but it can move twice as much traffic. To ensure that your investment is used, look for a wireless system that can determine if client devices that attach to the network are capable of 5G operation and actively steer them towards those channels.”
* Treat 802.11n migration differently : An 11n network is not just “faster Wi-Fi.” It comes with higher speeds, but also higher expectations. To meet those expectations, IT groups may need to formalise new deployment schemes, or update existing ones.
* Don’t forget the back-end: The best designed WLAN can be crippled because back-end services are overlooked. Two examples are RADIUS servers and DHCP servers that for various reasons start fumbling when hit with a flood of Wi-Fi requests.
In addition, DHCP servers often are not aware that a Wi-Fi user has disconnected, or may not release IP addresses in a timely manner. That can lead to the WLAN running out of IP addresses.
* Manage WLAN management: One emerging issue for some enterprise Wi-Fi networks is radio management challenges as the number of access points and wireless clients grow. Wireless LAN vendors have been adding an array of innovative features to address the issues, and to automate the network’s response. But large-scale WLANs continually stretch those innovations.
“Using outdated tools to manage wireless networks leads to frequent escalations of routine issues to increasingly scarce network engineering resources, poor network performance and rapidly increasing support costs. With thousands of new wireless users and whole new categories of wireless devices coming online — VoIP phones, printers, handhelds, asset tags and more — the problem is getting worse every day,” says Ammar Enaya, GM of Aruba Networks Middle East.
Agrees Hasan from Motorola Solutions: “Yes, WLANs are growing bigger by the day. It is not unusual to see a 1000 plus AP network deployed in sites such as university campuses or retail organisations. Management of these networks can be a challenge if adequate attention is not given to arming the administrators with appropriate tools. Today most WLAN vendors have tools that can cater to almost all management requirements, including configuration management, remote troubleshooting, audit reporting and so on. So the key really is for the enterprise to recognise and assemble a good set of tools which can take care of foreseen and unforeseen needs.”
Aruba says its AirWave network management portfolio delivers operational efficiency for teams managing rapidly changing networks and supporting mobile users who connect via the wireless LAN as well as wired Ethernet ports. With its easy-to-use interface and user-centric approach, AirWave lets businesses’ service desk triage connectivity issues while their valuable network engineering staffs focus on more strategic work.
* Expand the repository of Wi-Fi best practices: Research by Aberdeen Group has found that enterprises with the best WLAN performance, reliability, and user satisfaction are those that bring together clusters of best practices, to address different parts of the overall wireless network. These clusters mutually reinforce each other, improving network reliability and performance.
For example, top performing WLANs tend to be those with centralized Wi-Fi management, a wireless intrusion detection/prevention system, bandwidth priorities, and spectrum analysers for continuous troubleshooting and network fine-tuning. Each of these has a group of associated practices: IT policies and schedules ensure the spectrum analyzers will be used regularly, for instance, while site survey applications can use the data to map fluctuations and identify trouble spots. Likewise, intrusion control systems complement regular site-wide assessments of security vulnerabilities, security training and certification for IT staff, and security-awareness education for users.
