TABLE OF CONTENTS

• Ray Access Points Wireless Roaming:
  • DIFFERENCE BETWEEN WIRELESS MESH & WIRELESS ROAMING:
    • A) Wireless Mesh Network (WMN):
    • B) Wireless Network Roaming:

Ray Access Points Wireless Roaming:

DIFFERENCE BETWEEN WIRELESS MESH & WIRELESS ROAMING:

I would like to begin this article by clearing up 2 wireless terms and technologies that most people often mix up or can't differentiate.

These are:

1. Wireless Mesh
2. Wireless Roaming

A) Wireless Mesh Network (WMN):

A Wireless Mesh Network (WMN) is a technology that was introduced to overcome the difficulties and costs that come with the challenges of wiring and dependency of wired infrastructure required when deploying a Wireless Access Point.

Mesh technology enables wireless access points to exchange data among themselves via WiFi so you don't need to connect them all via Ethernet cables.

Mesh is a routing protocol that allows a network of multiple Access Points (Without wired connections)to self organize and automatically route information(Client devices data) through the mesh of Access Points using the most efficient path.

Cons of Mesh:

Each new AP added to the mesh network comes with the cost of using more wireless bandwidth for transferring information between the mesh AP's which would otherwise be available for Wireless client devices to utilize.

Refer to the Ray Mesh Set up Knowledge Base article on Configuration of Mesh: Ray in Mesh Mode (Bridge)

Image below depicts an example of a Mesh Network:

B) Wireless Network Roaming:

In the Last Decade, technology has seen a steep climb in the number of devices that connect to the internet and with this growth in user devices, so as the technology of how these devices connect to the internet. 

With the majority of people around the world now having Wi-Fi capable devices such as smart phones and tablets, A large percentage of enterprise networks are also moving from the typical wired network Environment to BYOD devices to enable mobility. 

The Wireless Network technologies have also had to evolve to adopt to these growth and demands and technologies like wireless roaming are some of these developments that have made it possible for users to be able make VOIP calls and move from one end of an office building to the other end without the VoIP call ever dropping.

Wireless roaming works by having multiple Access Points setup within a building, School or Hospital configured to use the same SSID, belonging to the same LAN Segment and having the same login credentials So that as a mobile client device reaches the outer limits (Coverage) of 1 access point, they are already within the range of another access point enabling  them to transition and make an association and connection to the next access point without losing a connection to the network(internet). 

This process can happen in less than 150 milliseconds (ms).

Note:
The wireless Client is responsible for making the final decision on whether they want to roam, and on to which AP they will roam to.

One thing to note with wireless roaming however, is that the WiFi Standard Organizations ( IEEE 802.11 and WiFi Alliance) do not specify how and when a client should roam from one AP to another AP.

The Wireless Client device is responsible for deciding on when it needs to roam between 2 adjacent AP's.

The Client device makes the decision to roam by scanning, detecting and evaluating which access point is the most suitable to connect to next (Based on factors like AP signal, Load on the AP, Network Metrics etc).

Wireless Roaming Enhancements:

The evolution of wireless roaming wasn't direct. but rather a 2 step journey that started with Wi-Fi repeaters being a first attempt at achieving wireless roaming.

Wi-Fi Repeaters / Boosters / Range Extenders:

With the rapid evolution of Wi-Fi and advantages that came with it such as mobility for the wireless clients, some of these pros had limitations such as the distance/coverage the early Wireless access points could cover. 

(users had now gained mobility and freedom from being bound to their workstations during the wired Ethernet network only days, to being able to work from the break-room or boardroom away from all the office background noise especially during important meetings.)

The advantages that came with wireless networks were great and this inspired the manufacturers and engineers to come up with a way to extend the signal range and strength of Wi-Fi access points by introducing Wi-Fi Boosters /Wi-Fi range  extenders to further increase on Wi-Fi mobility.

Wi-Fi Boosters / Wi-Fi range  extenders were great devices during their inception because they allowed wireless users to enjoy extended range from their Wi-Fi networks without having to buy a whole new Wireless router.

Wi-Fi Boosters work by getting a signal from a wireless router and amplifying and then re-broadcasting it creating a second network from which wireless clients could connect..

Wireless boosters/repeaters served well for sometime and met the low traffic needs of wireless clients during their time.

However when the bandwidth requirements of wireless users started to  increase and technology evolved with the rapid expansion of the internet.  It became clear that Wi-Fi Boosters simply couldn't keep up with the ever growing demand of more bandwidth, security and efficiency that was required in wireless  networks and this was because Wi-Fi Boosters had major drawbacks that simply didn't make them suitable as a method of overcoming the range limitation  and offering roaming in the 802.11 protocol.

some of the draw backs of Wi-Fi repeaters/ booster/ extenders include:-

• Wireless throughput was reduced to 50% thanks to (CTS/RTS)
  
• Signal interference was doubled from other networks and the extender and AP before reaching Client devices.
• The potential security risk were high since the host AP could be secure but the booster was some times open.
• Connectivity to the extender was poor than connectivity to the host AP.
• Most of the times wireless clients preferred to remain connected to the host wireless access point than connecting to the Wi-Fi booster despite being closer to the booster.

It was some of the above drawbacks of Wi-Fi range extenders that made the IEEE engineers to go back to the drawing board and come up with the enhancements in wireless roaming that are present today, with technologies like 802.11k, 802.11r and 802.11v which were developed to help improve the speed and efficiency of roaming for wireless clients. 

IEEE 802.11k:

IEEE 802.11k was implemented to specify and control WLAN and radio characteristics and data that impact network performance. Specifications include network data exposure; channel selection and orchestration; signal strength management and optimal access point (AP) selection.

 IEEE 802.11k optimizes network performance by allowing a wireless subscriber to select an AP based on its active subscribers and overall traffic. For example, if there is an AP in close proximity with high traffic, versus an AP with less traffic but not in close proximity, IEEE 802.11k recommends using the latter AP, due to its faster throughput capability. 

With improvements such as those in 802.11k/v/r providing clients with details of the most suitable AP's for a client to roam to by giving details like signal level, traffic load, Fast Authentication and network performance metrics to help the wireless clients quickly and efficiently make roaming decisions.

1. 802.11k - is the wireless roaming improvement standard that provides wireless clients an optimized list of potential access points to roam to. .i.e Neighbor AP reports.
2. 802.11v - Wireless roaming enhancement provides the wireless client devices information about the traffic load of other neighboring access points.
3. 802.11r - is the IEEE enhancement to wireless roaming that is targeted at mitigating the delays that came with wireless client authentication by speeding up the roaming the process through offering Fast Authentication. 

Note* 802.11r (Fast Authentication) support for 802.11r is problematic because some Wireless client devices cannot process 802.11r information from Access Points and will not be able to connect at all to the Access point if 802.11r support is enabled.

The key to note here is that the above 802.11k/r/v must be supported by both the access point and the wireless client for them to be used in the roaming process. If either the AP or Wireless device doesn't support the above standards, then the normal and much slower roaming process will be used.

Below is a small topology of how roaming looks like:

 PREREQUISITES FOR WIFI ROAMING INCLUDE;

• Roaming Can be accomplished when you have 2 or more Access Points Sharing the same configurations i.e SSID, LAN Segment and Password/Login details.
• The Access Points the users will be roaming among should ideally be in the same Operating mode (if in Bridge Mode, all the access points should be in bridge mode and the  same in case of Gateway Mode).
• The Access Points that are going to be set up to support user roaming should belong to the same ray Cluster in the ray cloud controller.
• The signal boundary between access points should be about 67 dBm.         -67dbm is the minimum signal strength necessary for a client device to have a stable and fast access to the internet. thus access points need to placed and overlapped in a way that prevents any device from leaving the 67 dBm range.
  (The closer the dbm measurement  is to 0, the better the signal strength)

The Configuration steps for roaming are as follows:

1. Click on the profiles menu.
2. Select Wlan tab in the profiles sub menu.
3. Under Wlan sub menu window, select the create Wlan tab(Highlighted Step-2).
4. Give the Wlan profile a name and description.
5. Under definitions drop menu chose type of SSID (Captive Portal/Open/Password)
6. On the Name Box, Input the SSID name that you want to Broadcast, then input remaining fields with your details such as Password and radio bands i.e (2.4Ghz,5GHz or Both Dual band 2.4 & 5Ghz Band)                                                                                                                                                                                                                                                                                                                       *Selecting the 2.4GHz & 5GHz dual band radio is recommended for best results in a roaming setup.

Enable wireless roaming by doing the following;

Step 7) Select the Advance Tab and Enable 802.11k ( It’s an IEEE standard for Wireless Fast Roaming FT(Fast Transition).

Step 8) )  In the Advance tab also select and Enable roaming option. (For some of the Ray WiFi 5 models running Firmware versions 17 & 18 although rare you may face some issues with roaming. However all WiFi 6 Access Points fully support wireless roaming.

We hope this article was helpful to you.

Thanks 

Ray Support

Ray Pte Ltd.

www.ray.life