Which wireless networking component is used to connect multiple aps together?

Treat the three types of roles above - Clients, Access Points, and Ad-Hoc nodes - as the building blocks for large networks. Below are several examples that demonstrate how devices configured for different roles can be used.

Access Point - Home or Office network

Wireless networks used in your home or office are generally a combination of a router and a wireless Access Point (AP).

In the diagram above:

• 1 represents the connection to the Internet (Optional - networks can function without the Internet).
• 2 represents the router that assigns IP addresses and provides a firewall between your network and the Internet.
• 3 represents the Access Point, providing a wireless bridge between the router and the users’ devices.
• 4 represent user devices, such as laptops, tablets, and smartphones.

In many home networks, or small office networks, the router and AP may be combined into a single device. This is usually just called a wireless router. It may also have a DSL, Cable, 3G, or 4G port to provide the connection to the Internet. In large office scenarios, there may be several AP devices spread throughout the building to provide more even wireless coverage, connected back to the router through long Ethernet cables.

Point to Point link - Long Distance Connections

Wireless networks can be used to connect distant buildings or areas. It usually requires very focused antennas - such as a dish antenna - that can send a narrow beam in a specific direction. This is discussed in Learn Wireless Basics - so go there for more details on how that works.

A long-distance connection is often called a “point-to-point”, or “PtP” link. The name describes the concept: two points are connected together, and nothing else. This requires two wireless devices: one configured as an Access Point; the other configured as a Client. In the example below, two wireless devices are configured to create a point-to-point link.

Omnidirectional Access Point and Client Link

• 1 represents computers connected with Ethernet cables to the wireless devices. These computers are connected to each other over the Point-to-Point link.
• 2 represents the wireless device setup as an Access Point.
• 3 represents the wireless device setup as a Client, connected to the Access Point.

This could look like the building-to-building connection, as shown below:

Long-distance directional Access Point and Client Link

Here we have another example of a point-to-point link, but where the routers have dish antennas for greater link distance.

In the diagram above:

• 1 represents computers connected with Ethernet cables to the wireless devices. These computers are connected to each other over the Point-to-Point link.
• 2 represents the wireless device setup as an Access Point.
• 3 represents dish antennas that focus the wireless signal, allowing connections over long distances.
• 4 represents the wireless device setup as a Client, connected to the Access Point.

This could look like the network below, where an AP mounted on a tower is able to connect with a Client device in a home very far away, since the dishes are facing one another.

In both of these examples, there are just two wireless devices linked together - and the antennas determine the range at which they can connect. The more focused the signal, the further the point-to-point link can reach. As the distance between the devices grow, it is more an more important to focus the signal with antennas - at both ends of the connection. Otherwise one end may hear the other, but not be loud enough to be heard!

Point to MultiPoint - Wireless Internet Service Provider model

If we combine the two principles used in the networks above - many client devices connecting to an Access Point, and more powerful antennas used for outdoor devices to create longer links - we can create Point to Multipoint networks. These are larger-scale Access Point networks, where there is a single device in the “center”, controlling all of the Clients connected to it and bridging those connections to the Internet.

These types of networks are used by Wireless Internet Service Providers (WISPs) to connect homes and businesses to the Internet. Instead of running cables around a neighborhood or town, they put up one or more powerful Access Points on a tall building or tower. By installing directional wireless devices in a Client role on other rooftops, and pointing them back at the tall building or tower, those buildings can be connected to the WISP’s networks, and thereby the Internet.

The diagram below demonstrates one model for how this works. There is a powerful Access Point mounted on a high building, and several nearby buildings with rooftop wireless Client devices: this forms the Point-to-Multipoint network. Connected to each of the Client devices is an indoor router or Access Point, which allows users to connect their computers, laptops, tablets, or smartphones to the WISP network.

In the diagram above:

• 1 represents the connection to the Internet.
• 2 represents an Access Point providing the signal for Client devices to connect to.
• 3 represents a powerful omnidirectional (all directions) antenna, sending the wireless signal to a large area around the building.
• 4 represent Client wireless devices on the roof of other buildings, linking to the powerful Access Point, and able to connect to the Internet through that AP.
• 5 represents small Access Points distributing wireless service inside the building.

Mesh - Neighbor-to-neighbor Networks

A mesh network takes the principle of Point-to-Multipoint, and extends it to the idea of every node connecting to every other node in range. In effect, this creates a “Multipoint-to-Multipoint” network. This requires that all the devices are in the Ad-Hoc mode - wireless devices all in AP mode or Client mode can’t perform the same function. For more information on how this principle works, see the Introduction to Mesh document.

The diagram below demonstrates one model for how this works. Wireless mesh nodes are installed on the rooftops of various buildings, and those nodes that are in range and don’t have anything blocking the signals will connect. These nodes will share all resources connected to them such as local servers hosting applications and connections to the Internet. They can also be connected to computers, Access Points, or routers inside the buildings so users can access the resources anywhere on the network.

In the diagram above:

• 1 represents the connection to the Internet.
• 2 represents a Mesh Node with a connection to the Internet, with an omnidirectional (all directions) antenna.
• 3 represents Mesh Nodes with omnidirectional (all directions) antennas. These nodes are receiving Internet access from Mesh Node B. They may be connected to different devices inside the building.
• 4 represents small Access Points distributing wireless service inside the building.

Hybrid Networks

When designing and building town or community-sized networks, it may be difficult or impossible to use a single method to connect everyone. For instance, a single Point-to-Multipoint network may not cover an entire community. Mesh nodes can be used to extend client sites to nearby buildings. Point-to-point connections can bridge longer distances and join several disconnected networks together.

In the diagram below, we can see an example of a hybrid network. There is no single example that can cover all of the possible uses for a network! In the activity that follows, you will explore the different ways to build a network by working through scenarios.

One last note before we move on to the activity - in the examples above, and in the activity that follows, the diagrams focus on building networks across rooftops or from building to building. This is generally the best way to build networks that cover neighborhoods, towns, or communities. In the diagrams, the way people connect to this network isn’t always shown.

Keep in mind that these rooftop routers may not provide connections to users on the ground, or in buildings. A good way to provide these connections is by attaching Access Points to an Ethernet port on the rooftop router. This indoor Access Point can be set up to use the rooftop network as the source of connections to the Internet, or to provide access to applications and servers on the network. A detailed look at this is below:

What type of wireless network contains one or more access points that act as a bridge between wired and wireless networks?

In which type of network is data transmitted via wireless access points and radio signals?

Which type of wireless network does not use a wireless access point?

Which network modes can typically be used for both 2.4 GHz and 5 GHz clients?