Wi-Fi (Wireless Fidelity) is a trademark of the Wi-Fi Alliance for certified products based on the IEEE 802.11 standards. This certification warrants interoperability between different wireless devices.
WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-multipoint links to portable and fully mobile internet access. The technology provides up to 3 Mbit/s broadband speed without the need for cables. The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access). The name “WiMAX” was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as “a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL”. The so-called “last mile” of broadband is the most expensive and most difficult for broadband providers, and WiMax provides an easy solution. Although it is a wireless technology, unlike some other wireless technologies, it doesn’t require a direct line of sight between the source and endpoint, and it has a service range of 50 kilometers. It provides a shared data rate of up to 70Mbps, which is enough to service up to a thousand homes with high-speed access
Service Set identifier (SSID)
Service set identifier, or SSID, is a friendly name that identifies a particular 802.11 wireless LAN. Unless disabled, a client device receives broadcast messages from all access points within range advertising their SSIDs. The client device can then either manually or automatically—based on configuration—select the network to associate. The SSID can be up to 32 characters long
Basic service set identifier (BSSID)
The basic service set (BSS) is the basic building block of an IEEE 802.11 wireless LAN (according to the IEEE 802.11-1999 standard). In infrastructure mode one access point (AP) together with all associated stations (STAs) is called a BSS. This is not to be confused with the coverage of an AP, which is called Basic Service Area (BSA). An AP acts as a master to control the stations within that BSS. In IBSS mode a set of synchronized STAs, one of which acts as master, forms a BSS. Each BSS is identified by a BSSID. The most basic BSS is two STAs in IBSS mode. In infrastructure mode, a basic BSS consists of at least one AP and one STA…..
IEEE Standard for Wireless
|802.11g||Super g||Turbo g||MIMO|
|Key Using Point||Crowded 2.4ghz area or backhaul||Internet access||Internet access and file sharing||Internet access and file sharing||Internet access and file sharing||Internet access and file sharing||Internet access, File sharing and Media streaming|
Wireless Operating Mode
|AP||Central hub for all wireless device|
|Bridge||Connect 2 LANs together wirelessly|
|Client||Turn into a wireless card to connect with remote AP|
|WDS Repeater||To increase the wireless coverage of a WDS enabled AP/Router|
|Universal Repeater||Universal repeater function let the AP extend the coverage of your AP/Router, even if AP/Router doesn’t have WDS function!|
|WISP Mode||WISP mode is similar to Client Mode. IP sharing function is added so we can share the WISP connection with many PCs|
|WISP + Universal Repeater||The WISP + Universal Repeater mode let you share WISP connection on both wireless and wired side|
|Gateway||Will behave as a Broadband Router and one LAN port will be as a WAN Port.|
Wireless Distribution System (WDS)
Enables the interconnection of access points wirelessly and Expanded using multiple access points without the need for a wired backbone to link them.
Access Point vs Router
|Uses||Allow multiple wireless devices to access resources on a network||Allow multiple computers together to use/Share the internet connection|
|Ports||No WAN Port||WAN Port|
|IP Address||Single Network Address||Two Different Network Address|
Why Controller is important to implement enterprise Wireless Networking?
Application & Advantages in using WLAN Controller in Enterprise Wireless Networking: With today’s centralized Controller based Wireless networks, wireless users can be further segregated in to sub-groups and each group can be given separate network access policies. For example, all the wireless users accessing the network from the finance department can be given SAP/ERP access while the sales department can be denied the same. Internet access for the junior management staff can be blocked and guests can be given temporary internet access without giving access to internal network. IT department and senior management can be given full unrestricted access to the network resources. Certain laptops/ wireless clients can even be blocked network access if they do not have the latest versions of the anti-virus/ OS patch running on their systems. WLAN Controller can be the best choice to implement such solution at the corporate industry.
- Centralized Authentication: Centralized user name and password authentication for all users. In addition centralized MAC Filter tables, Certificate/shared key can also be implemented. Also facilitate Customized captive portals for web-based authentication of visitors or guests
- Role based user policies: supports Bandwidth Control, Traffic Classification & QoS , Firewall , profiles, Routing Policies, Concurrent Sessions Limitation, User Idle Timeout
- Interference Mitigation: Adjacent Access Points are always maintained to operate in different non-overlapping channels by the controller so that there is no loss of packets due to interference in a dense wireless network.
- Load Balancing: The users are automatically shifted to adjacent access points if the load (number of users connecting) on one access point is high and the neighboring access point is lesser.
- Fail Over: Clients are automatically shifted to neighboring access points if any access point suddenly fails, thereby introducing redundancy in the network.
- Monitoring and Troubleshooting: The coverage pattern, signal strength, users associated in each access point and various parameters can be viewed LIVE through web based application) sitting in a central location. You can also locate any active Wireless client in the network map by just typing its MAC ID in the software.
What forms can the WLAN controllers take?
This is the most common solution I hear touted as “controller-less.” As with most cloud computing, the controller is actually hosted in a data center somewhere, and connects via the internet. Meraki is the most common example that people have heard of. You pay for an annual or multi-year subscription that allows to you to connect to a cloud controller, which means you don’t need any form of a controller on-site.
This is a particularly good match for simple wireless networks today due to its ease of deployment and management.
Access Point Based:
This is another solution often marketed as “controller-less.” An access point based controller has hardware in the APs that is capable of serving as a controller for a set number of APs. Once an AP has been chosen as the controller, the APs will report to it, and the network is managed by controller in the AP. The upsides to this approach are that no additional controller hardware is needed. The downside to this is that the controller is nowhere near as robust as a dedicated controller can be. There is usually a fairly low limit to the number of APs a single AP can manage and a limit to how many features can be provided.
That said, this can also be a good match for simple wireless networks today due to its ease of deployment and management.
Virtual Controller Based:
Virtual controllers do exist. Cisco is one example of a wireless manufacturer that offers a Virtual Machine (VM) based wireless controller. This has the advantage of fitting into your existing data center without needing to purchase a physical controller. Virtual controllers can do a good job of managing the control plane data but do not have the dedicated, purposefully-built hardware that allows physical controllers to process all data plane traffic as well.
This choice can be a good match for companies that have a robust VM environment in their data center and want to leverage their existing data center resources to host their WLC.
Physical Controller Based:
Lastly, physical controllers offer the most control over one’s wireless network, and offer the widest range of functionality. Some physical controllers process all control plane data and data plane data, while others can only process control plane data. Those that only process control plane data are sometimes marketed as “private cloud” or “on-premise cloud” solutions as they can provide the same kind of control seen in could based solutions, but APs can send their control plane data across the Internet to a WLC you control instead of in the cloud. Those that process the data plane as well offer the greatest level of control over your network, but also bring down the entire wireless network if there is no available controller.
Many of today’s physical controllers can use a stateful or non-stateful high-availability (HA) controller to prevent wireless network outages. A stateful HA controller is essentially a carbon copy of the primary controller, and when the primary controller goes down, the stateful HA controller takes over the same IP address and the network continues as if nothing has happened. A non-stateful HA controller is a controller that exists specifically for backing up one or more controllers, and allows APs to connect in the event of a primary controller failure.
Physical controllers provide the most control, but often require skilled technicians to manage and may be more expensive than other solutions that lack a dedicated physical controller.