Fundamentals

 

Basic Wireless Local Network Structure

Most campuses have the same four-tier operating structure:

• Management
• Network Services
• Aggregation
• Network Access

With management at the top of this operating infrastructure, all networks have a centralized location for reporting, configuring, and troubleshooting network matters.

The network services tier consists of wireless LAN (WLAN) controllers that utilize applications that help the network run safely and securely. Typically, these WLAN controllers do not transport end user and access point traffic, but rather are responsible for security, configuration, radio frequency management, and wireless threat management such as rogue AP detection.

The aggregation tier connects all the access points (APs) to the local WLAN controllers which act as the brains behind the entire network. This allows the APs to communicate based on the controllers’ configurations.

Lastly, the bottom tier is network access. The APs and switches fall into this layer since they allow for devices to connect to the network.

 

 

Another option is to have these systems and functions hosted by a third party, typically the manufacturer of the access point hardware. This type of setup is called a cloud managed WiFi solution and is usually subscription based with additional fees for the number of managed access points and enabled features in the system.

The management interface of a cloud WiFi system is access via a browser and typically has fewer configuration options compared to an on-premises controller / management system.

 

 

If you need help or a consultation on your upcoming or renewed WiFi Project, please don't hesitate to reach out.

 

Types

 

Coverage Based Networks vs. Capacity Based Networks

WiFi campuses can be divided into two categories:

• Coverage Based Networks
• Capacity Based Networks

Deploying a wireless network in a large, warehouse-like space falls under the coverage based category. While coverage is the most crucial part of any deployment, in a warehouse or manufacturing facility, it is more important to have full coverage than to be able to support a high density of wireless devices.

Conversely, large spaces that expect a denser wireless presence should focus on capacity based networks. Capacity based networks are found in places that have either a high density (HD) or very high density (VHD) of wireless devices connecting to the network.

High density networks are deployed in places like K-12 schools, corporate office headquarters, hospitals, and universities. Very high density networks are used in large public venues such as indoor and outdoor stadiums.

 

Campus	Campus Description	Access Points
K-12 Schools	19 elementary and middle schools in a Northern California school district.	700 APs for 11,000 students and 1,600 facility / staff members
Universities	Large State University	12,000 existing APs for 75 buildings, 98,783 students
Corporate Headquarters	Microsoft (2008)	11,000 access points for 35,000 employees, 113 sites, 11 million square feet
Hospitals	Medium sized medical center in Texas	6,864 access points, 25,000 current devices
Indoor / Outdoor Stadiums	AT&T Park in San Francisco, California	1,520 APs for 41,915 capacity venue

 

 

Plan and Design

 

WiFi Planning & Design

With the rise of internet enabled devices and accessible WiFi, individuals carry an average of two WiFi capable devices in almost all high density and very high density environments. Therefore, designing networks that can support that kind of traffic require careful planning.

During this initial planning and design phase, it is important to think about and answer the following questions:

1. What types of applications do you expect to run?
2. What type of WiFi device mix do you expect?
3. What type of wired access switches will you need?
4. What is the number of devices you expect your WLAN to support by the end of the service life cycle?
5. Do you need added focus on wireless monitoring?

WiFi Network Design Considerations 

10 Things to Think About Before Meeting with a WiFi Consultant

 

	Applications	Device mix	User and device amount	Wireless monitoring
K-12 Schools	Social media, video, email, data sharing, web browsing	Laptop, mobile devices	50 users per access point	Spectrum
Universities	Social media, video, email, data sharing, web browsing	Laptop, mobile devices	50 users per access point	Spectrum
Corporate Headquarters	Email, data sharing, web browsing, printing	Laptops, mobile devices, Internet of things	50 – 100 users per access point	Security and spectrum
Hospitals / Healthcare	Email, data sharing, voice over WiFi	Medical equipment, laptops, mobile devices	30 – 50 users per access point	Security and spectrum
Indoor / Outdoor Stadium	Generic, social media	Mobile devices, point of sale, ticket scanners	30 users per access point	Spectrum

Applications

 

Network Applications Used

Determining the types of applications that a network will use helps when considering what AP models to install and the placement of the hardware.

Voice and video applications are the most prevalent in campus environments. FaceTime, Skype for Business, and WiFi Calling are often used in university, office, and hospital settings, and the networks must offer seamless roaming so that users are not losing connection.

 

	Low	Mid	High	Highest
Cloud Applications	Up to 750 kbps	1.2 Mbps	2.5 Mbps	>2.5 Mbps
Web Browsing and Streaming	300 kbps	700 kbps	1.2 Mbps	>2.5 Mbps
Collaboration and videoconferencing	640 kbps	1.2 Mbps	2.5 Mbps	>2.5 Mbps

 Source: ACG Research, Cisco Systems

Internet

 

Internet Backhaul

Estimating Internet bandwidth requirements is complex. You should consider the following factors:

• Number of users
• User locations
• Real-time transactions
• Hardware
• Storage technology

It is often best to work directly with your application team / end users to understand the applications being used and WiFi network use cases.

Equipment

 

Networking Equipment Needed

Knowing the kind of device mix on a network will help in choosing the right APs to use. Newer devices will most likely result in the need for newer APs and equipment so that the hardware and devices are compatible. Moreover, when installing new APs, it is vital to determine the amount of power the new hardware will require. While existing switches may have available ports, if the newer APs require more power than before, the switches will need to be upgraded in order to support the new equipment.

Basic Hardware Required For a Wireless Network

 

AP Density

 

Determining the Size & Dimensions for AP Density

The number of required APs will depend on the size of a campus. In a high density campus setting, there should be about 50 users per AP.

Dimensioning is used when trying to determine how many APs are needed for a particular area or section of a campus. By figuring out the expected density of a given area, it is easier to estimate the amount of required APs.

How to Estimate Number of Access Points Needed

Surveys

 

Predictive Surveys and On-Site Surveys

A predictive survey is done off-site and during the design phase to plan and estimate the network’s infrastructure. It takes many different factors into account, such as:

• Building Materials
• Square Footage
• Number of Wireless Users
• Types of Applications
• Many Other Variables

During a predictive survey, a model of the radio frequency (RF) environment is created using simulation tools. Virtual access points are placed on the floor plan to estimate expected coverage and adjust their numbers and locations.

Using the data gathered during the predictive survey, a site survey is conducted to collect additional information about the campus and determine if the design can meet requirements. Additional site surveys are recommended if any part of an existing network has being upgraded, if there have been structural changes to a facility, or if voice and roaming options were not optimized in the previous deployment.

Usually, the site survey also includes a passive survey. The passive survey uses a surveying device to listen to the WiFi environment. Typically, the software used for these surveys is configured to scan specific channels and WiFi networks in order to measure the signal strength and noise levels.

WiFi Surveys: Active vs Passive

AP Placement

 

Strategic AP Placement

Strategic AP placement is key to an optimally functioning network. The ideal placement pattern follows a honeycomb structure. However, depending on the shape of the facility, this design does not always work. There can also be mounting limitations that affect the placement and design of the APs.

Tips for Proper Wireless Accesss Point Placement

AP Mounting

 

Proper AP Mounting

Most indoor APs are mounted on either the ceiling or the wall.

Ceiling mountings are more common and APs are typically installed hanging below the ceiling so that the signal is not obscured by any fixtures, pipes, or ducts that already run above the ceiling.

Wall mountings are more commonly found in hotels and larger spaces since the ceiling is often too high for the AP to be installed.

Determining the right mounting locations will also depend on the cable paths. Cables need to run from the APs to the Telecom closet. If there is not clear access to the closet or the cables cannot run through the ceilings, the placement of the APs will need to be adjusted.

 

Ceiling Mount		Excellent for Office spaces 8-10 foot ceilings space for wiring easily mounted to ceiling tiles
Wall Mount		Excellent for spaces with high ceilings or inaccessable ceilings end of hallways inaccessable ceilings
Floor Mount		Excellent for outdoor venues with no walls or ceilings stadium seating with no other mount available Open areas where wires cannot be run