Last Updated on July 9, 2018 by Admin
About The Module
Mobility is the ability of moving readily from place to place. While most current business networks still rely on switch-based LANs for day-to-day operation inside the office, workers have become mobile. People are connected using multiple devices, including computers, laptops, tablets, and smart phones. They want to be able to take their connection to the network with them while on the move.
A wireless LAN (WLAN) is a classification of wireless network and is an extension of the Ethernet LAN. It has become important, popular and commonly used in homes, offices, and campus environments.
This module covers the following topics:
- Essential components in a wireless LAN infrastructure
- Operation of a wireless LAN
- How to plan a wireless LAN
This course contains the following pages:
- Presentations: Nine short recorded video presentations created by various presenters.
- Additional Resources: Links to additional resources are also provided as a convenience to learners. The appearance of external links does not constitute endorsement by Cisco, nor does Cisco exercise any editorial control over the information found at these external sites.
- Quiz: Brief quiz after each module to check your understanding of key concepts presented in each module.
Course Outcome
Upon completion of this module, you will be able to:
- Understand wireless LAN components
- Understand how wireless LAN works
- Understand how to plan a wireless LAN deployment
About Authors and Contributors
The development of this course is a collaborative effort of a Cisco Networking Academy Instructor and a Cisco Technical Field Engagement team member.
Figure 1 : Thanks to Vinh Ho, Instructor Trainer from University of Canberra, Australia.
Figure 2 : Thanks to Eric Kwok, Technical Manager, Cisco, Networking Academy, Greater China and Japan.
Infrastructure Components
Wireless networks include components that make mobile and portable application possible. Users are end points of the wireless network and utilize computer devices running desired applications. Wireless NICs and base stations are key components that communicate over the air medium. To provide roaming throughout a facility or city, a distribution system such as Ethernet interconnects base stations and interfaces users to servers and applications located on the wired network.
Frame Structure
The 802.11 standard defines various frame types that stations (NICs and Access Points) use for communications, as well as managing and controlling the wireless link. The 802.11 frame format is similar to the Ethernet frame format, with the exception that it contains more fields.
Access Point Association
Wireless Access Points (AP) are devices that bridge traffic between wireless devices and other devices on the network. Before a wireless device can send traffic through an AP, it must be in the appropriate connection state.
Channel Management
If the demand for a specific channel is too high, that channel is likely to become over-saturated. This degrades the quality of the communication. Over the years, a number of techniques have been developed to improve wireless communication and alleviate saturation.
Selecting Channel
When designing a wireless LAN, overlapping RF cell coverage is necessary to provide for seamless roaming. However, the overlapping coverage cells should not have overlapping frequency space.
Channel Selection Example
In this example, the author uses Packet Tracer to demonstrate and observe the impacts of channel interference, and shows how this can be mitigated through the careful selection of non-overlapping channels.
Planning a Wireless LAN Deployment
Implementing a WLAN that takes the best advantage of resources and delivers the best service can require careful planning. WLANs can range from relatively simple installations to very complex and intricate designs.
Planning Example
In this example, the author uses Packet Tracer to demonstrate basic planning of RF signal coverage through the placement of Access Points in a wireless LAN design. He shares some best practices through this example.
Activities
Difference between Ethernet Frame and 802.11 Frame
While 802.11 frame is very similar to Ethernet frame, do you know the difference between them? Find out the difference and understand what enhancements are built into 802.11 to support wireless.
Check the answer (Links to an external site.)
Wireless LAN Design Considerations
Check out what are the other design considerations.
1. Is a site survey (Links to an external site.)really necessary when planning a wireless network?
2. What are some of the free site survey tools (Links to an external site.) that provide a simple wireless network survey? Try them out.
Beamforming
What is Beamforming? Why is it important? Beamforming is a method of aiming the wireless signal directly at the mobile device, such as a tablet, rather than somewhat haphazardly broadcasted, as is the case with older Wi-Fi. The device is telling the router where it is so that the router can direct the signal accurately.
Find out how it works (Links to an external site.) and how it optimizes performance. (Links to an external site.)