Top CISCO Wireless Interview Questions and Answers

1 .

Cisco wireless networking combines the mobility of wireless with the performance of wired networks, offering a dramatic performance increase compared to legacy 802.11a/g networks. Cisco delivers 802.11n and 802.11ac excellence designed to effectively support a vast range of business-focused wireless networks. from the most basic to today's most demanding high-density environments.

2 .

What Is a WLAN Controller?

A WLAN is a wireless architecture that aims to meet changing network demands. A WLAN controller manages wireless network access points that allow wireless devices to connect to the network.

What a wireless access point does for your network is similar to what an amplifier does for your home stereo. It takes the bandwidth coming from a router and stretches it so that many devices can go on the network from farther distances away.

3 .

Does the size of a controller matter?

Simply put: yes. It's important to choose the right type of deployment and to make sure your controller matches the size of your organization.

Usually your choice of controller will depend on the number of devices that typically attach to a wireless network. A large office building that has hundreds of workers has different needs than a small business.

Some controllers, such as the Catalyst 9800-80 Wireless Controller, are built to handle the traffic of a large organization. That same controller would be overkill for a small business. Similarly, a controller like the Cisco 3504 Wireless Controller is intended for smaller business offices and manages a few access points--it would never be able to handle the day-to-day activity of a large enterprise.

4 .

How do WLAN controllers fit into intent-based network?

Cisco's wireless controllers are a key component of intent-based networking. This means that with an intent-based network from Cisco, your network grows more intuitive every day, because it is informed by context and powered by design.

5 .

Can you list other wireless controller deployment options?

In addition to managing access points, a WLAN controller is integral when it comes to the type of network deployment you choose. There are two deployments that use physical controllers:

* Centralized deployment. The most common type of wireless network system, traditionally deployed in campuses where buildings and networks are in close proximity. This deployment consolidates the wireless network, allowing for easier upgrades and enabling advanced wireless functionality. Controllers are based on-premises and are installed in a centralized location.

* Distributed deployment. This solution is tailored for small campuses or branch offices. It allows customers consistency in their wireless and wired connections. This deployment converges wired and wireless on one network device--an access switch--and performs the dual role of both switch and wireless controller.

6 .

Explain some Benefits of a Cisco WLAN controller.

Cisco WLAN controllers are state-of-the-art. They all adhere to the 802.11ac Wave 2 standard and the Catalyst controllers are ready for the upcoming standard. All controllers have fast, optimized network performance.

Flexible : Flexibility is also paramount. Cisco can help scale a small, medium-sized, or large enterprise network, whether your solution involves a cloud-based controller, or an on-premises controller designed to handle your organization's needs. Catalyst cloud controllers are able to be deployed in either the public or private setting.

Secure : Security is another important consideration for any organization, with hacking and data breaches in the news every day. Cisco WLAN controllers battle all kinds of threats to your business based on user ID and location thanks to built-in security features.

Always on : Cisco Catalyst controllers are always on meaning that they limit your network’s downtime and allow for upgrades and patches to be deployed while the network is still running.

Simple : Finally, Cisco provides simplicity. With a Cisco WLAN controller, your network has a centralized hub where you can manage and control your access points.

7 .

What is Application Visibility and Control (AVC)?

Cisco Application Visibility and Control (AVC) solution for wireless networks identifies more than 1000 business- or consumer-class applications using deep packet inspection (DPI). With this extraordinary visibility into application traffic, administrators can mark applications for further prioritization, or block them for security reasons or to conserve limited network bandwidth. AVC offers these benefits:

Improved Quality of Experience : Proactive monitoring and end-to-end application visibility accelerate troubleshooting and reduce network downtime.

Better Network Management : Network capacity management and planning improve through greater visibility of application usage and performance.

More Intelligent Prioritization : Business-critical applications and sub-flows are prioritized, including unified communications and collaboration applications like Cisco Jabber, Cisco WebEx, Microsoft Lync, Microsoft Skype, Apple FaceTime, and Google Voice.

8 .

What is Cisco High Density Experience?

Cisco High Density Experience (HDX) improves the performance of legacy and cutting edge wireless and mobile devices with advanced technologies. HDX consists of Turbo Performance, CleanAir with 80MHz support, ClientLink 3.0, and Optimized Roaming.

Cisco High Density Experience (HDX) for 802.11ac : HDX helps optimize performance, mitigation, scalability, and roaming for high-density wireless networks.

Turbo Performance : This technology allows the access point to support a large number of clients without performance degradation.

CleanAir : It offers 80 MHz support and uses silicon-level intelligence to create a self-healing, self-optimizing wireless network that mitigates the effects of wireless interference.

ClientLink 3.0 : It helps access points bridge gaps in coverage caused by mixed client devices (802.11a/g/n and ac). It increases access performance and range while providing a better wireless experience.

9 .

What is Connected Mobile Experiences in Cisco Wireless?

Cisco Connected Mobile Experiences (CMX) is enabled by the Mobility Services Engine (MSE), with the CMX license working in coordination with the Cisco Wireless Network. The CMX Wi-Fi location-based services offering helps venue owners and retailers engage and better understand their customers using mobility and location intelligence from the Wi-Fi network. CMX capabilities of Mobility Services Engine offer :

* Location-based Wi-Fi analytics for visibility into the number of visitors, their dwell time, and their movements

* Simple guest access and a customized landing experience

* Online and social analytics to better understand customer demographics and their mobile behavior

* An API and SDK to make it easy to create location-based applications and services

* CMX helps you build a stronger relationship with customers through a more personalized mobile user experience.

10 .

What's the difference between 5G and Wi-Fi 6?

The Difference Between 5G and Wi-Fi 6 : For years, two different types of wireless technology have coexisted. Wi-Fi is a type of local area network (LAN) used primarily indoors—for example, inside a home or workplace. Cellular networks, like the 4G LTE networks used by major operators, are a type of wide area network (WAN) used both indoors and outdoors, generally over long distances.

Both 5G and Wi-Fi 6 are complementary technologies that provide higher speeds, lower latency, and increased capacity over their predecessors. But what is each technology best for?

What Is 5G?

5G networks will provide 50x more speed, 10x less latency, and 1,000x more capacity than 4G/LTE.1 This means 5G will be able to connect more devices and transmit more data than ever before, delivering fast connectivity and significantly enhanced user experiences. As with LTE, mobile carriers will offer subscriptions to their 5G network, which requires 5G-capable devices.

What Is Wi-Fi 6?

Wi-Fi 6, based on the IEEE 802.11ax standard, will deliver 4x higher capacity and 75 percent lower latency, offering nearly triple the speed of its predecessor, Wi-Fi 5.2 Anyone can operate a Wi-Fi network—and most of us have one in our homes and offices, connected to broadband service. Wi-Fi 6 devices require a Wi-Fi 6‒compliant access point to get the full speed, latency, and capacity improvements.

11 .

How Do 5G and Wi-Fi Complement Each Other?

Wi-Fi and 5G offer complementary functionalities. Where the user experience is concerned, 5G and Wi-Fi 6 can both achieve gigabit speeds and low latency.

Because Wi-Fi has a lower cost to deploy, maintain, and scale—especially where access points need to serve more users—it will continue to be the predominant technology for home and business environments. This provides great support for dozens of data-hungry devices, like PCs, tablets, smartphones, streaming devices, TV sets, and printers, which must all connect to the network. Thanks to its longer range, 5G will be used for mobile connections, like smartphones. It will also be used for connected cars, smart city deployments, and even for large manufacturing operations.

12 .

What is Campus LAN and Wireless LAN?

Designing a LAN for the campus use case is not a one-design-fits-all proposition. The scale of campus LAN can be as simple as a single switch and wireless AP at a small remote site or a large, distributed, multi-building complex with high-density wired port and wireless requirements. The deployment may require very high availability for the services offered by the network, with a low tolerance for risk, or there may be tolerance for fix-on-failure approach with extended service outages for a limited number of users considered acceptable. Platform choices for these deployments are often driven by needs for network capacity, the device and network capabilities offered, and the need to meet any compliance requirements that are important to the organization.

* Traditional Access - Dedicated Distribution and Access Layers (L2 or L3). You impose most of the campus wired LAN design complexity when aggregating groups of access switches by interconnecting the access layers to the distribution layers. If devices connecting to the access layer have a requirement to communicate with a Layer 2 logical adjacency and those connections cover multiple physical wiring closets connected to a distribution layer, then it is possible to adapt the traditional multilayer campus design to address the Layer 2 adjacency needs. However, the traditional designs drive more complex configurations with additional protocols that must be kept consistent across multiple devices.

* Simplified Access – Virtualized StackWise Access & StackWise Virtual Distribution. To improve the design, there are preferred alternatives that make the deployment easier to manage and less prone to mistakes, while enhancing overall network performance. Such alternatives include the simplified distribution layer using options such as a switch stack or a StackWise Virtual system, and the simplified access layer using a switch stack with StackWise technology. Both make deployment and troubleshooting much easier for support staff.

* Cisco Software Defined Access – Campus Fabric and Automation of the Distribution & Access Layers. A design alternative is available for organizations that either don't have the need to extend Layer 2 connectivity across an access-to-aggregation boundary or have other means of implementing this functionality, such as when using fabric technology for campus designs—an integral part of Cisco SD-Access. The alternative to the Layer 2 designs is to extend Layer 3 connectivity to the access layer. The implementation of a well-designed Layer 3 access network ensures consistent, configuration, performance, scalability, and high availability of the network versus the traditional multilayer campus design.

13 .

What is Campus Wired LAN?

The LAN is the networking infrastructure that provides access to network communication services and resources for end users and devices spread over a single floor or building. You create a campus network by interconnecting a group of LANs that are spread over a local geographic area. Campus network design concepts include small networks that use a single LAN switch, up to very large networks with thousands of connections.

The campus wired LAN enables communications between devices in a building or group of buildings, as well as interconnection to the WAN and Internet edge at the network core.

Specifically, this design provides a network foundation and services that enable :

* Tiered LAN connectivity.

* Wired network access for employees.

* IP Multicast for efficient data distribution.

* Wired infrastructure ready for multimedia services.

14 .

What is Cisco Embedded Wireless Controller?

The Cisco® Embedded Wireless Controller on Catalyst® Access Points (EWC-AP) is the next-generation Wi-Fi solution, combining the most advanced controller – the Cisco Catalyst 9800 Series Wireless Controllers – with the latest Wi-Fi 6 access points – the Cisco Catalyst 9100 Access Points – creating a best-in-class wireless experience for your evolving and growing organization.

With the 9800 Series wireless controller embedded on the Cisco Catalyst 9100 Access Points, organizations can now benefit from enterprise-class resiliency, security, and IT simplicity for single or multisite enterprise deployments.

Built for intent-based networking and Cisco DNA, the EWC-AP helps you simplify complexity, optimize IT, and reduce operational costs by leveraging intelligence, automation, and human expertise that no other vendor can deliver, regardless of where you are in the intent-based networking journey.

15 .

What is the Difference between Wi-Fi 6 vs Wi-Fi 6E?

Wi-Fi 6 brought with it several new features to increase wireless performance compared with Wi-Fi 5. Those include orthogonal frequency-division multiplexing access, which enables routers and devices to use bandwidth more efficiently; target wait time, which reduces power consumption and saves device battery life; and increased speed and range.

As wireless vendor Netgear notes in a post on its site, Wi-Fi 6E builds on these features and includes support for up to 14 80MHz channels or seven 160 MHz channels. More available channels mean more available spectrum for Wi-Fi service “and less overlap between networks in crowded areas like apartment complexes or offices”.

Another technical difference between Wi-Fi 6 and Wi-Fi 6E is that 6E does not require dynamic frequency selection channels. “Unlike 160MHz channels in the 5GHz wireless band, devices operating in 6GHz don’t share the spectrum with radar devices or TV stations,” according to Netgear. “As a result, people who cannot take advantage of 160MHz channels because they live near places like airports or TV stations can benefit from vacant 160MHz channels.”

Wi-Fi 6E also has mandatory Wi-Fi Protected Access 3 security controls, which is the highest Wi-Fi Alliance security certification. “WPA3 provides the latest in security and authentication protocols. As a result, 6GHz Wi-Fi traffic is more secure than ever, and 6GHz networks are more difficult to hack,” Neatgear states.

16 .

What is the Benefits of Wi-Fi 6E?

Wi-Fi has more presence in various devices, including smartphones, and is easier to use, allowing it to become the dominant connectivity technology for homes and businesses. Being established in more ecosystems than 5G provides Wi-Fi 6E with a natural marketplace and the following advantages:

• The cost of Wi-Fi 6E modems is lower than 5G alternatives.

• Installation and deployment of Wi-Fi are typically easy for owners and businesses to accomplish without assistance.

• Some device operating systems establish Wi-Fi connectivity preference ahead of the cellular network, allowing it to select the Wi-Fi 6E network automatically.

• The spectrum used by Wi-Fi 6E is available to all, as Wi-Fi 6E operates in unlicensed spectrum, while 5G being deployed today, called 5G New Radio (5G NR), requires licensed spectrum.

• Usability, simplicity, and flexibility make Wi-Fi easier to deploy and support for system integrators and enterprises.

• Vendors that provide Wi-Fi devices have well-established relationships with integrators and enterprises.

• Users that have data-limited wireless packages are accustomed to offloading to Wi-Fi.

17 .

What is the frequency range of 802.11 standards?

802.11 details a wireless interface between devices to manage packet traffic (to avoid collisions, etc.). Some common specifications and their distinctive attributes are listed below:

802.11a : Operates in the 5 GHz frequency range (5.125 to 5.85 GHz) with a maximum 54 Mbps signaling rate. The 5 GHz frequency band isn’t as crowded as the 2.4 GHz frequency because it offers significantly more radio channels than the 802.11b and is used by fewer applications. It has a shorter range than 802.11g, is actually newer than 802.11b and is not compatible with 802.11b.

802.11b : Operates in the 2.4 GHz Industrial, Scientific and Medical (ISM) band (2.4 to 2.4835 GHz) and provides signaling rates of up to 11 Mbps. This is a commonly used frequency. Microwave ovens, cordless phones, medical and scientific equipment, as well as Bluetooth devices, all work within the 2.4 GHz ISM band.

802.11e : Ratified by the IEEE in late September 2005, the 802.11e quality-of-service specification is designed to guarantee the quality of voice and video traffic. It will be particularly important for companies interested in using Wi-Fi phones.

802.11g : Similar to 802.11b, this standard supports signaling rates of up to 54 Mbps. It also operates in the heavily used 2.4 GHz ISM band but uses a different radio technology to boost overall throughput. Compatible with older 802.11b.

802.11i : Also sometimes called Wi-Fi Protected Access 2 (WPA 2), 802.11i was ratified in June 2004. WPA 2 supports the 128-bit-and-above Advanced Encryption Standard, along with 802.1x authentication and key management features.

802.11k : Passed in June 2008, the 802.11k Radio Resource Management Standard provides measurement information for access points and switches to make wireless LANs run more efficiently. For example, it better distributes traffic loads across access points and allows dynamic adjustments of transmission power to minimize interference.

802.11n : Ratified in September 2009, 802.11n is a set of standards for wireless local area network (WLAN) communications, developed by the IEEE LAN/WAN Standards Committee (IEEE 802) in the 5 GHz and 2.4 GHz public spectrum bands. The proposed amendment improves upon the previous 802.11 standards by adding multiple-input multiple-output (MIMO) and many other newer features.

18 .

When access point starts up, what will be the behavior in regards of LWAPP & CAPWAP?

After 60 seconds of trying to join a controller with CAPWAP, the access point falls back to using LWAPP.

If it cannot find a controller using LWAPP within 60 seconds, it tries again to join a controller using CAPWAP.

The access point repeats this cycle of switching from CAPWAP to LWAPP and back again every 60 seconds until it joins a controller.

Once the access point downloads the CAPWAP image from the controller, it uses only CAPWAP to communicate with the controller.

19 .

What are the basic guidelines for implementing CAPWAP?

If your firewall is currently configured to allow traffic only from access points that use LWAPP, you must change the rules of the firewall to allow traffic from access points that use CAPWAP.

Make sure that the CAPWAP UDP ports 5246 and 5247 (similar to the LWAPP UDP ports 12222 and 12223) are enabled and are not blocked by an intermediate device that could prevent an access point from joining the controller.

If access control lists (ACLs) are in the control path between the controller and its access points, you need to open new protocol ports to prevent access points from being stranded.

20 .

What is the master controller mode on WLC?

When there is a master controller enabled, all newly added access points with no primary, secondary, or tertiary controllers assigned associate with the master controller on the same subnet. This allows the operator to verify the access point configuration and assign primary, secondary, and tertiary controllers to the access point using the All APs > Details page.

The master controller is normally used only when adding new access points to the Cisco Wireless LAN solution. When no more access points are being added to the network, Cisco WLAN solution recommends that you disable the master controller.

21 .

Can a Cisco IOS Software−based access point (AP) that has been converted to lightweight mode register with Cisco 4100 Series WLCs?

No, Cisco IOS Software−based APs that are converted to lightweight mode cannot register with the Cisco 40xx, 41xx, or 3500 WLCs. These lightweight APs (LAPs) can register only with the Cisco 4400 and the 2000 series WLCs.

22 .

Explain Cisco Unified Wireless Network Elements.

The Cisco Unified Wireless Network is composed of five interconnected elements that work together to deliver a unified enterpriseclass wireless solution. The five interconnected elements are client devices, access points, network unification, world-class network management, and mobility services. Beginning with a base of client devices, each element adds capabilities as network needs evolve and grow, interconnecting with the elements above and below it to create a comprehensive, secure WLAN solution (Figure 1). Cisco offers a wide range of WLAN products to support the five interconnecting elements of the Cisco Unified Wireless Network (Figure 2).

Figure 1 :

Figure 2 :
Unified Wireless Network

23 .

If the WLCs in the same mobility group are separated by Network Address Translation (NAT) boundaries, can they communicate mobility messages with each other?

BEFORE VERSION 4.2 : In controller software releases earlier than 4.2, mobility between controllers in the same Mobility Group does not work if one of the controllers is behind a network address translation (NAT) device.

* Reason : Mobility message payloads carry IP address information about the source controller. This IP address is validated with the source IP address of the IP header. This behavior poses a problem when a NAT device is introduced in the network because it changes the source IP address in the IP header.

AFTER VERSION 4.2 : In controller software release 4.2 and later, the Mobility Group lookup is changed to use the MAC address of the source controller. Because the source IP address is changed due to the mapping in the NAT device, the Mobility Group database is searched before a reply is sent to get the IP address of the controller that makes the request. This is done with the MAC address of the controller that makes the request.

24 .

Can we place the lightweight access point (LAP) under Network Address Translation (NAT)? Does LWAPP from access point (AP) to WLC work through NAT boundaries?

Yes, you can place the LAP under NAT. On the AP side, you can have any type of NAT configured, but, on the WLC side, you can have only 1:1 (static NAT) configured. PAT cannot be configured on the WLC side because LAPs cannot respond to WLCs if the ports are translated to ports other than 12222 or 12223, which are meant for data and control messages.

25 .

What is the difference between WLC 5508 and the 3850 WLCs . What is converged access?

We will get wire speed when the switch itself takes care of all traffic switching instead of sending to controller. 3850 switch is a controller based switch where access points can terminate its capwap connection and switch traffic at wire speed. WLC 5508 is appliance that can be installed on your network and all traffic just goes to that controller.

26 .

What is the difference between UWB and Wi-Fi?

The main difference between UWB and Wi-Fi lies in the fact that ultra-wideband technology has a higher accuracy, which significantly widens the possibilities of its application for indoor positioning. Ultra-wideband accuracy resulted from the system’s ability to perform updates about 10 times per second and locate objects within 5mm, which is much more than 1m in the case of location-based WiFi.

UWB can track a bigger number of assets at large distances. It can detect with high accuracy where in the room the object is, while Wi-Fi-based RTLS provides information only about the presence or absence of the asset in the required room.

Ultra WideBand RTLS sensor gives less interference. While using Wi-Fi, similar tags make noise and deteriorate the quality of data transmission, which reduces possibilities for localization.

What concerns the cost of technology implementation into the infrastructure, Wi-Fi is cheaper. The tags, which are used for realizing the UWB-based navigation, have a higher cost in comparison with the tags used for Wi-Fi, Bluetooth, or RFID. Because of this, the system is preferred when it’s necessary to track expensive objects whose safety is placed above navigation costs.

Parameters	Technology
Parameters	Wi-Fi	UWB
Object identification accuracy	1–5 m	0.1–0.5 m
Spheres of application	Industry, medical institutions, transport, trading, offices, etc.	Industry
Implementation costs	Medium	High
Energy consumption of the smartphone without recharging	1–2 days	5–6 hours

27 .

What is the difference between Wi-Fi and Bluetooth?

WiFi establishes a wireless network that allows computers and devices with the required wireless capacity to communicate via radio waves. Bluetooth, on the other hand, is a wireless technology that is used to connect devices in short range.

Key	WiFi	Bluetooth
Definition	WiFi stands for Wireless Fidelity. Wi-Fi is a technology that enables devices to connect to the Internet wirelessly.	Bluetooth is a wireless technology that is used to connect devices in short range.
Component	WiFi requires wireless adaptor on all devices and Wireless Router for connectivity.	Bluetooth requires an Bluetooth adaptor on all devices for connectivity.
Power Consumption	WiFi consumes high power.	Bluetooth is easier to use and consumes less power than Wi-Fi because it only requires an adapter on each connecting device.
Security	WiFi is more secure than Bluetooth.	Bluetooth is less secure than other wireless technologies such as WiFi.
Number of Users	Wi-Fi allows more devices and users to communicate at the same time.	Bluetooth restricts the number of devices that can connect at any given moment.
Bandwidth	WiFi needs high bandwidth.	Bluetooth has a low bandwidth.
Coverage	WiFi coverage area is up to 32 meters.	Bluetooth coverage area is about 10 meters.

28 .

What is the difference between Ad-Hoc and Infrastructure topology?

In infrastructure mode, all devices on a wireless network communicate with each other through an access point (wireless router).

In ad hoc mode, a computer with a wireless network adapter communicates directly with a printer equipped with a wireless print server.

	Infrastructure	Ad hoc
*Characteristics*
Communication	Through an access point	Directly between devices
Security	More security options	WEP or no security
Range	Determined by the range and number of access points	Restricted to the range of individual devices on the network
Speed	Usually faster	Usually slower
*Requirements for all devices*
Unique IP address for each device	Yes	Yes
Mode set to	Infrastructure mode	Ad hoc mode
Same SSID	Yes, including the access point	Yes
Same channel	Yes, including the access point	Yes

29 .

What is the difference between CAPWAP and LWAPP?

LWAPP : LWAPP is an abbreviation for Lightweight Access Point Protocol. LWAPP was introduced in RFC5412 and defined the process of authenticating an AP with a controller, distributing firmware and configuration and defining the transport header for LWAPP traffic.

CAPWAP : CAPWAP is an abbreviation for Control and Provisioning of Wireless Access Points and interoperable protocol that enables a Wireless LAN Controller (WLC) to manage access points (AP) or wireless termination points (WTP). CAPWAP is based on the Lightweight Access Point Protocol (LWAPP).

PARAMETER	CAPWAP	LWAPP
Abbreviation for	Control and Provisioning of Access Points	Lightweight Access Point Protocol
Introduction year	2009	2005 (bought by Cisco)
Controller Software Release	Release 5.2 or later	Releases prior to 5.2
DTLS Security	Yes	No
L2 Mode	Not Supported	Supported
Data plane encryption	5500 WLCs only	No
Fragmentation	CAPWAP fragmentation	IP fragmentation
MTU discovery	Yes	No
Protocol control ports	5246	12222
Protocol data ports	5247	12223
Related RFC	RFC 4564, RFC 5418, RFC 5415 , RFC 4347	RFC5412

30 .

What is FlexConnect in Cisco Wireless?

* Flex Connect is a wireless solution which allows you to configure & control access points in remote/branch offices without configuring controller in each branch office over the wan link.

* FlexConnect is a wireless solution for branch office and remote office deployments.

* Flex Connect previously known as Hybrid Remote Edge Access Point.

* The FlexConnect access points (APs) can send client data traffic locally and perform client authentication locally. When they are connected to the controller, they can also send traffic back to the controller.

Flex Connect capable access point works in two modes,

Local Switched ( Flex Connect Mode) :

* Locally-switched WLAN’s (the SSID you are connected to) will map their wireless user traffic to a VLAN via 802.1Q trunking to a local switch adjacent to the access point.

* Traffic is forwarded using branch router in the network in this mode.

* In this mode, the AP can still function even if it loses connection with the controller.

* AP control/management-related traffic is sent to the centralized Wireless LAN Controller (WLC) separately via Control and Provisioning of Wireless Access Points protocol (CAPWAP).

* In simple terms, the data traffic is forwarded by the Branch Router and Management Traffic is handled by Wireless Controller.

* Minimum Bandwidth between the Acess Point in Branch office and Wireless Controller in Head Quarters need to be 128 Kbps and MTU should be 576 bytes.

* AP will be rebooted if we change the mode of Access Point from Central Switched to Local Switched Prior to 8.0 version of WLC.

* It is recommended that you use a FlexConnect group when deploying FlexConnect AP’s. Some features will not work if FlexConnect AP’s are not in a FlexConnect group, such as CCKM and local authentication.

* FlexConnect AP’s operate in connected mode or standalone mode. If a remote AP is able to reach the controller, it is in connected mode and if it is not able to reach the controller, it is in standalone mode.

Central Switched ( Local ) :

* In Central Switched Mode, an Access Point creates two CAPWAP tunnels to the Wireless Controller.

* One Tunnel is used for forwarding the data traffic and another one is used for forwarding the management traffic.

* If the user wants to access the resources within the branch (where that client is associated) then the data request is forwarded to the wireless controller in Head Quarters and returns back to the branch office.

* This might be the problem if the branch office is having less wan link speed.

* if the user in branch office needs to access services locally and centralized services better to configure local switching ( Flex Connect ) instead of Central Switching ( Local).

31 .

What is Hotspot Terminology?

While some people use the terms “hotspot” and “mobile hotspot” interchangeably, they have distinct meanings.

Hotspot : A hotspot is a physical location where people can access the Internet, typically using Wi-Fi, via a wireless local area network (WLAN) with a router connected to an Internet service provider. Most people refer to these locations as “Wi-Fi hotspots” or “Wi-Fi connections.” Simply put, hotspots are the physical places where users can wirelessly connect their mobile devices, such as smartphones and tablets, to the Internet.

A hotspot can be in a private location or a public one, such as in a coffee shop, a hotel, an airport, or even an airplane. While many public hotspots offer free wireless access on an open network, others require payment. Later in the article you’ll learn how to connect a mobile device to a Wi-Fi hotspot.

Mobile hotspot : A mobile hotspot (sometimes called a portable hotspot) is a hotspot that’s just that—mobile! While a “regular” Wi-Fi hotspot is tied to a physical location, you can create a mobile hotspot by using your smartphone’s data connection to connect your laptop to the Internet. This process is called “tethering.” More on this process later.

You should also know these terms when you’re talking about Wi-Fi hotspots.

Access point (wireless access point) : A wireless access point (WAP) is a networking device that allows a Wi-Fi compliant device to connect to a wired network. The WAP can either be physically connected to a router or be integrated into the router itself. A WAP is not a hotspot, which is the physical location where Wi-Fi access to a WLAN is available.

Wi-Fi : Wi-Fi is the technology that allows your smartphone or computer to access the Internet through a wireless connection. It uses radio signals to send and receive data between your enabled device and the WAP.

SSID : A service set identifier (more commonly known as an SSID) is the unique name of a wireless network. You’ll need to know the name of the wireless network to connect to it. Your computer or smartphone can search for available wireless networks; often people name their network for easy identification—anything from “Bob’s phone” to “hotel guests” to “Get off my LAN.”

32 .

What are IBSS and BSS?

Independent Basic Service Set (IBSS) allows two or more devices to communicate directly with each other without a need for a central device. This is known as Ad hoc mode where a peer to peer network between stations is formed without the need for an Access Point.

Basic Service Set (BSS) Wireless LAN is established using a central device called an Access Point that centralizes access and control over a group of wireless devices. All wireless devices do not communicate directly with each other but instead they communicate with the AP, and the AP forwards the frames to the destination stations. The Access Point manages the wireless network, advertises its own existence by broadcasting the Service Set Identifier (SSID) and any device that needs to use the wireless network must first send an association request to the Access Point. The Access Point can require any of the following criteria before allowing a client to join.

* A matching Service Set Identifier (SSID)

* A compatible wireless data rate

* Authentication credentials

After a client has associated itself with the Access Point, all communications to and from the client will traverse the AP.

The wireless coverage area of an AP is called the Basic Service Area (BSA), sometimes also referred as Wireless Cell. An AP can also be connected to a wired Ethernet Local Area Network through an uplink port connection unlike the Independent Basic Service Set in which the wireless network cannot be connected to the wired network.

The BSS is uniquely identified by the Basic Service Set Identifier (BSSID) which is the Layer 2 Mac address of the BSS access point. The wireless network although is advertised using an SSID which announces the availability of the wireless network to devices.

33 .

What is Extended Service Set(ESS)?

Extended Service Set (ESS) is created by connecting multiple Basic Service Set (BSS) via a distribution system. Two or more Access Points are connected to the same Local Area Network to provide a larger coverage area which allows the client to move from one AP to another AP and still be the part of the LAN. This process is known as roaming in which a client can physically change locations and still be connected to the LAN. When a client senses that radio signal from the current AP are getting weaker, it finds a new AP with stronger signals starts using that AP. An ESS generally includes a common SSID to allow roaming from access point to access point without requiring client re-conﬁguration.

The wireless coverage area created by joining two or more Access Points via distribution system is called an Extended Service Area (ESA). Stations within the same ESA may communicate with each other, even though these stations may be in different basic service areas and may even be moving between basic service areas, this requires that the wireless medium and the backbone of the ESS must be layer 2 link.

A Distribution System connects multiple Access Points to form an ESS, while doing so it provides the wireless stations with the option of mobility. It is the means by which an access point communicates with another access point to exchange frames for stations in their respective BSSs, forward frames to follow mobile stations as they move from one BSS to another, and exchange frames with a wired network.

34 .

How do I prevent loops on the WLC?

You can enable STP on the WLC to prevent loops. From the WLC GUI click Controller, then navigate to the Advanced submenu located on the left side of the application. Click the Spanning Tree option, and choose Enable for Spanning Tree Algorithm located on the right side of the application.

By default, STP need not be enabled to prevent loops.