WiFi and Networking Tutorial

With AV, security, and home automation systems all running over IP networks, professional installers have a tremendous opportunity to grow their businesses by offering wired and wireless networking solutions.  While installing an IP network can be a daunting  task for the uninitiated, by understanding the purpose and function of a few key components—as well as what to look for when selecting those components—a professional installer can easily learn to deliver reliable and powerful IP networking solutions.  With this in mind, as a professional installer, the primary components with which you should become familiar are as follows:

  • Modem:  Converts the incoming signal from an internet service provider (ISP) to IP traffic. Depending on the type of connection, the modem may be for cable, DSL, fiber, or even satellite.
  • Router (or Gateway):  The primary interface between the Internet (via the Modem) and the local area network (LAN), providing IP services such as assigning IP addresses to client devices, network security and controlling access to the network.
  • Ethernet Switch: Connects devices on the local network and is typically attached directly to the Router.
  • Wireless Access Point (AP):  Provides wireless network access to devices on the local network and can be connected as a device on a Switch or directly to the Router.
  • Client Devices:  Any device that connects to the network either via Ethernet cable or wirelessly. Client devices include Tablets, Smart Phones, Laptops, VoIP Phones, Security Systems, Streaming Media and Gaming Solutions, etc.
Typical IP Networking Components and Topology

Once you understand the primary components that go into an IP network, how do you determine which components to choose?  As an installer, the first thing to understand is that all networking gear is not made equal and equipment choice will impact installation complexity, network performance, and the overall customer experience.  Let’s further explore each of these components and discuss the various options and things to look for in selecting the right products for your installation.


Most internet service providers (ISPs) have limited Modem options available and it is important to research those options in order to best meet the customer’s needs. Many ISPs also offer an “all-in-one” option that includes a Modem, Router, and Wireless Access Point in a single device. These devices are good for small networks of perhaps 5 to 10 client devices, but as the number of devices in the network increase, these all-in-one devices are quickly overwhelmed and performance is compromised. Think about the number of IP devices (i.e. smart phones, tablets, computers, gaming systems, media servers, etc.) an average family of 4 might use on the network and that number gets above 10 very quickly.  Because of this, we always recommend stepping up to a standalone Modem either from the ISP or from a 3rd party (check with the ISP to see what standalone Modems are supported). This option does require a separate Router to perform the Local Area Network (LAN) functions, but results in a network that can handle a significantly higher load.  The next step up from the standalone Modem is a multi-connection gateway. However, this is something most custom installers would not need to be familiar with as such systems are typically only viable in large business environments.


When a Modem connects to the Internet it is issued a single publicly routable IP Address.  A Router is then used to allow multiple devices to share that one publicly routable address through a process called Network Address Translation (NAT).  In addition Routers typically provide a number of other network services, including:

  • Domain Name Service (DNS), which allows a website name (rather than the public IP address) to be typed into the Web Browsers address bar.
  • Dynamic Host Configuration Protocol (DHCP), which issues an automated IP Address to client devices that connect to the private network.
  • Firewall services to protect the private network from attacks targeting your public IP Address.
  • VPN for secure remote access into the local network

Because the Router is such a critical component of the network, Router choice can make or break the network.  A device that combines multiple functions (i.e. the 3-in-1 device mentioned above or a wireless Router) can make for a less than stellar user experience due to insufficient memory and/or processing capability. Using separate dedicated devices that handle the processing and memory load for each specific function can significantly increase the number of devices a network can accommodate and improve the user experience.  Additionally, the ideal placement of the Wireless AP may not be the best location for the Modem and/or Router.  Separating these functions allows you to optimize the performance of your AP.  As a general rule:

  • Multi-function devices are good for small networks with 5-10 devices
  • Consumer class standalone Routers typically handle 10-50 devices
  • Business class Routers are more robust, often supporting 250 or more devices

Having a solid understanding of various Router options and capabilities, while being able to select the right Router for your customer’s requirements is essential to the overall network performance and user experience.

Ethernet Switches

An Ethernet Switch is required when the number of Router ports is not sufficient to provide connections to all the devices on a network. Switches are the backbone of the private network, allowing locally connected devices to talk to each other as well as access Router services.  There are two primary types of Switches:

  • Unmanaged (sometimes referred to as dumb) Switches provide simple plug and play connectivity between devices on the network.
  • Managed (smart) Switches allow you to enhance the user experience by optimizing the network for certain applications. Common Managed Switch features include:
  • Quality of Services (QoS) Settings:  Useful for prioritizing certain types of network traffic, such as VoIP phone services, to ensure such traffic gets through first.
  • Virtual Local Area Network (VLAN) Support:  Allows partitioning of ports in a large Switch into multiple logical smaller Switches that cannot speak with each other, but still share a single connection to the internet.  This is useful for setting up dedicated networks with different functions (i.e. guest network).
  • Security Features such as Media Access Control Binding (MAC Binding) and Radius Server authentication.

Another thing to consider is the Switch speed.  Fast Ethernet (10/100 Mbps) Switches are a cost-effective common standard. However, for high data usage (i.e. streaming media servers) Gigabit Ethernet (10/100/1000 Mbps) is typically the best option.  Also, be sure the Switch supports full upstream and downstream bandwidth (sometimes referred to as non-blocking architecture).

Routers, switches, and wireless networking

Wireless Access Points (AP)

Think of a Wireless AP as a switch that does not require network devices to have a physical connection. As there are a number of wireless networking methods and technologies—each with its own advantages and disadvantages—we will cover this topic in greater detail in a future article. For now, we will simply discuss the basic issues to be considered.

With Wireless Networking there is no “one size fits all” solution.  APs come in a wide variety of flavors, form factors, and performance options. Consider the following when selecting an AP:

  • Coverage Area: Output power, type of antennas used and the technology standards implemented all play a role in how much coverage you can expect with a given AP. For example, a standard consumer-grade AP typically has 100mW of output power and will reasonably cover 2000+ square feet.  A high powered AP provides 1000mW of output power and will typically cover 10,000 square feet or more.
  • AP Placement: Depending on where the AP will be placed can determine the type of AP to use. For example, if placed in the center of the desired coverage area, an AP with omnidirectional antennas is optimal; while placement at the edge of desired coverage is better served with the use of a directional antenna.  AP aesthetics may also play a role in the selection process if placement must be on a wall, ceiling or other high traffic area.
  • Environmental Issues: The environment can play a role in determining which AP to use. Outdoor implementations will certainly require an outdoor rated AP. For indoor applications, the type of construction can impact the effectiveness of wireless signals and determine the choice of AP.  There are a number of wireless survey tools that can help identify environmental issues as well as be used to demonstrate network reach and effectiveness to the customer. These tools include Kperf/Iperf, InSSIDer, and Ekahau Heatmapper.

Client Devices

At the end of the day, the only real reason to setup an IP Network is to enable the efficient use of Client Devices.  Whether the application is security, entertainment, VoIP, home control, or just plain internet access, a successful installation is dependent not only on the quality of the network itself, but also on the devices used on the network.  Regardless of how well the network performs, devices selected for use on the network can make or break the customer experience.

While installers don’t always have control over the Client Devices being used on a network, in cases where devices are provided (i.e. security cameras, control panels, AV equipment, etc.), be sure to use products that are proven to function well in IP networking environments. With wireless devices—especially those that are mobile—this becomes even more important. As with all networking equipment, networking devices are not all created equal and some perform much better than others.

Common Client Devices that Run on an IP Network


For professional installers, IP networking is as complex or as simple as you make it. While it takes time and effort to become proficient at network implementation, focusing on and learning the basics goes a long way towards delivering a solution that satisfies the needs of the majority of your customers.

There are 4 key considerations when determining which Router to use:

Typical IP Networking Components and Topology with a Focus on Routers

Processing Power

The amount of processing power available to serve the connection needs of the network is a big part of what differentiates the better Routers from the standard consumer grade fare available at the local big box store.

A good determination of processing power is the number client device connections supported.  This information can usually be found on the box, spec sheet, or user manual.  Most “All-In-One” devices and Wireless Routers are designed for basic consumer use and serve only a minimal number of client device connections (typically 24-32). Contrast this with a commercial grade Router which supports up to 256 client devices.

Another measurement of processing power is the maximum number of simultaneous connections supported (also may be known as “concurrent data streams” or “maximum available sessions”).  When considering this measurement, note that the average client device typically has anywhere from 6-12 active data streams at the same time with a data stream being 6-10 simultaneous connections. So any given device can easily consume 100 or more simultaneous connections.  A standard consumer grade wireless Router will average around 6500-8200 maximum simultaneous connections, while a more robust Router will support significantly more.  The web site www.SmallNetBuilder.com has rankings on some of the more popular Router models and even provides software that can evaluate a Router in real time.

Business-class Router

Network Reliability

Applications and services are the reason we want and need a highly reliable network. We get excited because we can stream our favorite music anywhere throughout our home or business—not because the Router has been running for 97 days straight. A flaky network means application downtime and, ultimately, unhappy customers.

Commercial grade Routers are designed to be up and running 24/7. This is a function of high quality materials, construction and reliable software.  Better hardware is important but what about the Internet connection itself?  We know that even the best Internet Service Providers (ISPs) have occasional outages.  So even with superior hardware how can you guarantee reliable connectivity?  For this reason, some commercial grade Routers have a multi-WAN capability. This means you can have more than one Internet connection from different service providers—resulting in more bandwidth capacity as well as failover reliability in case one of the providers has a failure.

Secure Remote Access

As technology advances, there are more and more devices and services in our home or business we want to access when we are away. Examples include media servers, security cameras, or even the thermostat. But how to remotely access your network while maintaining good security? The answer is with a Virtual Private Network (VPN). Routers that support VPN services allow you to securely connect to your network from anywhere there is an Internet connection from your computer, tablet, or smart phone device. Routers such as the XBR-2300 that can provide reliable VPN access are in a class all their own—allowing an encrypted connection to the private network that enables access to all files and services as if at home or in the office.  For installers, this feature can also be used for troubleshooting network problems without a truck roll. Also, be sure the Router supports Dynamic Domain Name Services (DDNS) to avoid changes being made to the IP address by the ISP. This will make connecting remotely much simpler and more reliable.

Other Advanced Features

Advanced features like VPN and those discussed below typically use up more processing power.  They also tend to only be found on commercial grade Routers that have the processing power to handle these extra services. Filtering content and managing Internet access is becoming more and more important in our homes as well as our businesses. When selecting a Router, specifically, look for one that has a Configurable Firewall with options for URL Blocking, Client Filtering, and Access Control.

URL Blocking allows for the filtering/blocking of specific URLs via the complete name or keywords, as well as the blocking of specified file extensions (i.e. exe, txt, zip, etc.).  With Client Filtering, ports to services for certain devices can be blocked or filtered, thus controlling content to certain clients as well as eliminating unauthorized downloading. Access Control allows for setting time limits on when certain devices on the network have Internet access. This can be very useful for keeping kids focused on homework instead of playing online games or surfing the internet.

While there are certainly other factors in determining the right Router for any given installation, these tips and suggestions will hopefully give you a good idea of what to look for when making a selection.  In most cases, the better options will cost more in initial investment but will provide additional performance, reliability and feature benefits that will pay off big when it comes to customer satisfaction.

it comes to customer satisfaction.

Switches: Fast Ethernet or Gigabit?

The decision of whether to use Fast Ethernet (10/100Mbps) or Gigabit (1000Mbps) is really a matter of economics, practicality and where the switch resides within the network.  A network is only as good as its weakest link, so it stands to reason that using Gigabit (which delivers 10X the performance of Fast Ethernet) is typically the safe and recommended choice to ensure network performance and longevity.  This is especially true for any core switch within the network.  At the same time, Fast Ethernet is relatively inexpensive and 100Mbps is more than sufficient for many applications. That being the case, Fast Ethernet may be a reliable and cost-effective option for connecting non-critical devices at the edge of the network.

Switch Fabric

The Switch Fabric or Backplane determines how much bandwidth the switch really offers.  All switches are not created equal and it is important to understand the switching capacity before making a buying decision.  For optimal network performance, be sure to choose a switch with a Non-Blocking (Full Duplex) architecture. What this means is that the switch can send and receive data simultaneously at full data rates.  For example, a Gigabit (1000Mbps) connection based on a Full Duplex architecture provides a download rate of 1000Mbps as well as an upload rate of 1000Mbps—essentially making the true throughput of each port 2000Mbps. On the other hand, a Half Duplex switch architecture does not allow for simultaneous data transfers. Rather, it uses one channel for both send and receive data, creating a bottleneck and dramatically reducing network performance.

A Non-Blocking/Full Duplex switch fabric essentially doubles the amount of bandwidth available. So, if buying a 24-port Gigabit switch, look for one that has a 48 Gigabit (48000Mbps) Switch Fabric/Backplane Bandwidth. Making sure your switch choice is capable of non-blocking performance will provide an optimal local network backbone and improve user experience tremendously.

Managed or Unmanaged?

Ethernet switches can be either Unmanaged plug-and-play devices with no user definable settings; or Managed, allowing for optimization and prioritization of certain ports and applications. When should you use a managed switch? Here are a few cases where a managed switch will help you deliver the best possible solution to your customer:

  • Whenever using VoIP, Streaming Media or other critical applications. Most managed switches support Quality of Service (QoS) functionality, which allows you to set priorities for these applications and ensure optimal performance.
  • If you need to setup a secure guest network or otherwise isolate network traffic of certain applications, a managed switch can be used to configure a Virtual Local Area Network (VLAN).
  • Any applications that call for specific protocol support such as IGMP (Internet Group Management Protocol), or STP-RSTP-MSTP (Spanning Tree Protocols) will require a managed switch.
  • The number of devices on the network may determine whether or not to use a managed switch. With more devices, you have more switches. Anytime you have a network with 3 or more switches, a central managed switch is recommended for optimal control and configuration.
  • Another practical benefit of a managed switch is the ability to gather data. With Port Statistics, SNMP (Simple Network Management Protocol), and Syslog support there are many different ways to see what is going on and even be notified when you are off site (through a supported SNMP Management Suite).

The choice of managed or unmanaged depends on the circumstances and is typically even a mix of both when using multiple switches. The primary consideration really comes down to understanding how many and what types of devices will be on the network as well as any extra support that may be required by the devices or applications.

Managed and Unmanaged Switches

Power over Ethernet (PoE)

Power over Ethernet (PoE) lets you run both data and power to a device using a single Ethernet cable, making device installation very simple and cost-effective. This capability can be especially helpful if the device is in a difficult to reach location or if there is no local power available where the device will be placed. It’s especially useful for IP security camera placement. Another great benefit is that Ethernet cable is relatively inexpensive and pulling it does not require a licensed electrician.

Switches that support PoE are available with the same basic options as non-PoE switches (i.e. Managed, Unmanaged, Gigabit, Fast Ethernet). A Managed PoE Switch will typically provide similar capabilities as a managed non-PoE switch, plus it will give you the capability of remotely managing and power cycling your PoE devices.

Before selecting a PoE switch, be sure to understand the PoE power requirements of the devices that will be connected to the switch. PoE is currently available in three flavors:

  1. 802.3af PoE (Autosensing 48VDC 15.4 Watts)
  2. 802.3at PoE+ (Autosensing 48VDC 30 Watts).
  3. Legacy PoE (48VDC 48 Watts continuous power)

Most modern switches are either 802.3af or 802.3at (backwards compatible with 802.3af). Some switches can support both. Most modern PoE switches are incapable of supporting Legacy PoE.

With so many Ethernet switch choices and options available, the decision of which switch or switches to use is really a function of the specific installation and application requirements. There is no one-size fits all and it is important for an installer to understand the implications of using each of the various options in order to best deliver an efficient and affordable network solution.

802.11 Wireless Standards (a, b, g, n, ac)

  • 802.11a: The first version of wireless networking designed for common use. Because support was limited to 5GHz bands, it was not widely adopted until more recently. 802.11a offers a maximum speed of 54Mbps.
  • 802.11b: Designed for 2.4GHz bands and mass markets, 802.11b quickly became much more popular than its 5GHz predecessor.  802.11b has a maximum speed of 11Mbps.
  • 802.11g: A 2.4GHz upgrade to 802.11b that improves maximum speeds to 54Mbps while also adding better wireless security.
  • 802.11n: The current standard that offers the widest range of support. Although 802.11n is currently most commonly used for 2.4GHz networking, it can also operate in the less crowded 5GHz ranges. This being the case, “Dual-band” wireless devices are becoming more popular.  802.11n supports Multiple Input Multiple Output (MIMO) technology, which essentially means that there are multiple simultaneous data streams in operation, increasing the data throughput rates.  With 802.11n, each data stream offers a maximum of 150Mbps. So, a 3 stream 2.4GHz only AP, has a maximum speed of 450Mbps, while a dual-band AP with 3 streams on each band offers a maximum speed of 900Mbps.
  • 802.11ac: The newest revision to wireless networking is 802.11ac, with the IEEE standard still yet to be ratified.  802.11ac is designed specifically for 5GHz and offers higher maximum speeds that can exceed 1Gbps. A dual-band 802.11ac router can currently reach maximum speeds of 1750Mbps.
While manufactures like to slap on labels stating 1750Mbps or 1Gbps, you would never achieve that in the real world…because science.

When selecting a wireless AP or router, keep in mind that these performance numbers are theoretical and based on best case scenarios in controlled environments. The actual performance depends on a number of things, including the client device, speed of the source network, and interference with other networks.

Now, let’s discuss some issues to consider when selecting wireless equipment:

Wireless Router vs. Access Point

As was mentioned briefly in the first segment of this series, there are two primary options for Wireless networking: 1) An all-in-one device commonly referred to as a Wireless Router; and 2) a Wireless AP, which can take on many forms. Wireless routers offer an excellent amount of coverage and processing power for smaller home networks with 20-30 client devices. For a more robust network in larger homes and commercial environments, using an AP together with a high quality wired router will be much more effective and deliver a better overall experience, especially for data intensive applications.

Wireless routers (desktop-mount)
UniFi AP AC PRO (ceiling-mount)
UniFi AP AC PRO (ceiling-mount)
Speedtest.net results using my UniFi AP-PRO WAP on Asus K501UW stock wifi adapter

2.4 GHz Only or Dual Band?

My opinion…Dual band (both 2.4GHz & 5GHz).

802.11ac White Paper from Aruba Networks (highly technical).

If you want the nitty-gritty: There are a few factors to consider when determining whether to use 2.4GHz only or dual band wireless equipment:

  • Budget:  Dual band equipment will be more expensive
  • Client Device Support: While 2.4GHz is still the de facto standard for most devices, 5GHz is becoming more common.
  • Interference and Signal Coverage:  2.4GHz is superior for propagating signal through dense materials. However, because of its popularity, it is also prone to more interference. 5GHz has less interference and potentially higher data rates (i.e. 802.11ac), but there are some limitations in terms of range.  5GHz can be an especially attractive choice for heavy populated areas, while 2.4GHz is probably sufficient for more rural areas.

When selecting a Dual Band AP, be sure that it supports “simultaneous” or “concurrent” operation.  This means that both 2.4GHz and 5GHz function at the same time, such as the ceiling-mountable UniFi WAP shown above.  Simultaneous dual band equipment is a bit more expensive, but will help ensure better overall wireless performance.

Single Stream vs. Multiple Streams

Whether to choose Single Stream (802.11a, b or g), or Multi-Stream (802.11n, ac) really is a matter of balancing current network performance expectations with long-term relevancy of the network. Keep in mind that for most networks today, the connection from the ISP is the single greatest limiter of network performance. Even 802.11g equipment can still outpace the performance of most cable or DSL connections—although that is starting to change as providers continue to improve their offerings, which is a good reason to consider using later wireless technologies for future-proofing the network.  Also note that for internal Local Area Network (LAN) applications, having higher data rates available through Multi-Stream APs can enhance the network experience for certain demanding LAN-based applications. Finally, for many users there is also a perception that latest and greatest is always the best, yet another reason to consider 802.11n and/or 802.11ac products.

Roaming Issues and Wireless Controllers

No wireless article would be complete without touching on the subject of client roaming and whether or not a wireless controller is necessary.  While controllers are fantastic for ensuring an overall better wireless experience in large installations, they can also increase the network costs significantly.  Also it is important to note that not all “controllers” are created equal and that many of them provide little more than node configuration while doing little to nothing to actually manage the roaming process. To help eliminate and/or minimize roaming issues without breaking the budget, the approach has always been to use high powered APs that deliver broader coverage. Installers have consistently found that this approach can deliver excellent and reliable coverage—essentially doing the work of 3-4 AP’s with only one. That’s not to say there isn’t a place for wireless controllers in larger installations where the budget permits and the right technology is used to actually solve the roaming issue.  We will further discuss controllers and roaming in a future column.

While this is a far from comprehensive list, hopefully it provides a good overview of how to go about selecting which wireless technologies are best for your various client applications. As with all networking gear, there is no one-size fits all and it is important for an installer to understand the implications of using each option in order to best deliver an efficient and affordable wireless network.

Source – www.hometoys.com

Categories: NetworkingVPN
Tags: WiFiWireless
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