802.11 overview.pdf

Wireless Industry Standards Overview

© 2006, AirWave Wireless, Inc. All rights reserved. Page 1 of 8

Wireless Industry Standards & WLAN Management: What You Need to Know



Standard Summary WLAN Management Implications

802.11a Current Status

Ratified Products now available

Requirements

Requires new AP hardware

Requires new AP firmware

Requires client device update

802.11a uses the less-crowded 5GHz spectrum rather than the 2.4GHz spectrum used by 802.11b and 802.11g. 802.11a delivers faster throughput, with theoretical maximum data rates of 54 Mbit/second and ‘real world’ data rates of 20+ Mbit/second. Because there are more channels available in the 5GHz spectrum, 802.11a wireless LANs typically experience less interference from overlapping channel assignments and other devices. However, signals at 5GHz don’t always travel through some materials as well as 2.4GHz signals, so the overall coverage footprint of an 802.11a radio may be smaller than a comparable 802.11b/g device. Unfortunately, 802.11a is not backward compatible with 802.11b/g – so a user with an 802.11b-enabled laptop cannot connect to an 802.11a wireless access point. Since the majority of Wi-Fi-enabled devices today use 802.11b/g, few organizations have networks that are purely 802.11a. Instead, most organizations using 802.11a today utilize dual radio wireless access points with both an 802.11a radio and an 802.11b/g radio or tri-mode radios (802.11a/b/g) to ensure that all devices can connect to the Wi-Fi network.

WLAN management solutions must support dual radio wireless access points and make it easy for the Help Desk to determine which radio each user is connected to.

Visualization and planning tools must display and monitor information on coverage in both the 2.4GHz and 5 GHz spectrum.

Management tools must understand the 5 GHz frequency restrictions in Europe

Management tools must be able to configure 11a spectrum for specific use – per radio configuration capabilities like voice only.

802.11b Current Status


Requirements




The first shipping update to the protocol for Wi-Fi products, operating in the 2.4 GHz spectrum, 802.11b increased the maximum speed from 2 Mbit/second to 11 Mbit/second. 802.11b radios typically provide an indoor coverage radius of 90-175 feet, depending on the environment. Virtually all wireless devices today support 802.11b. Most organizations use only three of the 14 available channels (channels 1, 6, and 11 in the US regulatory domain), because channels must be spaced at least 5 apart to minimize overlap (to reduce RF interference).. With only three channels available, it is particularly important to optimize channel assignments to avoid interference when multiple access points are installed in close proximity to one another. In addition, many other non-Wi-Fi devices use the 2.4 GHz spectrum, which can create additional interference.

Channel assignments and RF transmission power need to be adjusted to avoid interference as wireless network utilization grows.

Management solutions must provide automated optimization algorithms to control RF settings to eliminate repetitive manual configuration changes.

Where multiple hardware vendors’ products are in use, multi-vendor management is essential to ensure optimization across all platforms sharing the airspace.

Management systems must monitor user signal quality and network performance to help IT diagnose RF interference when it occurs.

Management systems must be able to support 802.11 legacy clients that only support (long preamble).



Standard Summary WLAN Management Implications 802.11g Current Status


Requirements




802.11g was a protocol update using the same 2.4Ghz spectrum as 802.11b adding support for higher speeds (up to a maximum of 54Mbits/second) like 802.11a. Unlike 802.11a, 802.11g is backward-compatible with 802.11b devices. This has made it an extremely popular choice for enterprises, most of which still have a significant number of clients with single-mode 802.11b-enabled client devices. However, the presence of any 802.11b devices (whether they are a part of your network or not) will reduce the throughput of the 802.11g network.

802.11g uses the same spectrum as 802.11b, so it is susceptible to the same issues surrounding RF interference (see discussion above).

802.11e: Quality of Service (WMM) Current Status


Requirements




802.11e is a newly-ratified standard that allows network administrators to differentiate and prioritize classes of traffic. This will allow the Wi-Fi network infrastructure to deliver acceptable performance for a broader range of applications and to support a larger number of simultaneous users. Typically, organizations will use 802.11e to give priority to voice and video traffic, since those applications are highly delay-sensitive and can quickly become unusable if data transmission is interrupted. When voice and data traffic are given priority, ordinary data traffic will typically be given a lower ‘best effort’ priority. 802.11e is thus most immediately important to organizations that will be using wireless Voice Over IP applications. WMM is a subset of 802.11e.

Each of the WMM traffic ‘buckets’ (voice, video, best effort, background) will need to be monitored individually to ensure quality of service – enabling you to see how much traffic is flowing in each category and how much ‘headroom’ you have on your network.

Your management solution will need to display the type of traffic client is generating, along with other appropriate metrics for each class.

Today, most customers with wireless voice use multiple VLANs/SSIDs with proprietary voice prioritization schemes. Your management solution will need to allow you to test an 802.11e or WMM scheme on a segment of your network and then migrate efficiently to the rest of the WLAN when successful.

Management systems will need to incorporate network latency metrics along with 802.11e support to provide end-to-end voice quality metrics.

Management systems must provide detailed historical trend reports to enable you to track network usage for capacity planning.

Management systems must provide automated, efficient RF spectrum management to ensure that signal quality is adequate for voice and video applications.



Standard Summary WLAN Management Implications 802.11i: Security Plus: WPA (WiFi Alliance) WPA2 (WiFi Alliance) Current Status


Requirements




There have been several security ‘standards’ and most are still in active use in many enterprises. WEP (Wired Equivalent Privacy) The original Wi-Fi security standard for authenticating and encrypting traffic between client devices and access points. WEP, relies on a single shared key for all users. WEP has been shown to have numerous design and implementation flaws and is not very difficult to crack. However, for some organizations with numerous legacy client devices, WPA and WPA2 may not be supportable and WEP is still used. WPA A Wi-Fi industry standard that ‘repaired’ WEP through improved use of the RC4 cipher (TKIP), message integrity checks, and more effective key management (via RADIUS/802.1x). WPA requires that both client devices and wireless infrastructure be WPA-compliant. The need to ensure client compatibility has slowed WPA roll-outs, and many organizations implement WPA only on certain VLANs that are used by compliant client devices. 802.11i (WPA2) New standard for ‘enhanced security’ that replaces prior encryption algorithms with the stronger AES (Advanced Encryption Standard). WPA2 typically requires updated WLAN hardware and client devices, which has slowed adoption rates. Because of the rapid evolution of technology and the challenges of implementing new standards across all client devices and infrastructure, many large enterprises have multiple security policies in place simultaneously.

Your management solution should support group-based management to allow you to implement new security policies on segments of your network, as appropriate.

Management solutions must support multiple VLANs and SSIDs for organizations that will operate multiple security policies simultaneously.

Management solutions should provide full inventory reports listing all access points and infrastructure devices, indicating which product and firmware versions are in place. With this information, you can verify which devices are capable of supporting the new security schemes.

Migrating to WPA/WPA2 requires massive firmware (or hardware) updates in most organizations. Management solutions must automate firmware management and distribution.

If WEP continues to be used: Your management solution should be able to

rotate keys frequently, across your entire network. Your management solution should be able to

generate random keys for additional security.



Standard Summary WLAN Management Implications 802.11k: Radio Resource Management Current Status

Ratified Products now

available Requirements




802.11k provides a standard statistical measurement framework to properly monitor wireless LANs. This framework provides a mechanism for communication between wireless access points and clients which enables RF and other data to be gathered from client devices to evaluate the quality of their connection and make better roaming and spectrum management decisions. While the 802.11k standard has not yet been fully ratified, some devices currently support a ‘pre-standard’ subset of the features in the proposed standard. NOTE: 802.11k provides a mechanism for monitoring wireless client devices, not for configuration of clients. 802.11v builds on 802.11k to make it possible to configure clients and APs based on this information.

Management solutions need to be designed to request and gather the newly available client information without overloading the network with management traffic.

Management solutions will need to be able to incorporate data from the new “Peer Statistics Table” to gain true insight into the RF environment in which the client is located.

Network management solutions should utilize the new interference measurements in order to dynamically tune the network infrastructure to deliver optimal performance (i.e., detecting new sources of interference and changing RF settings to mitigate their impact). The volume of RF data that will be available dictates that this analysis must be automated.

New location services will enable more accurate client and RFID tracking using RF data from client devices and access points. Management solutions must provide visualization tools that leverage and present this data.

Management solutions should be able to utilize new neighbor reports and channel load reports to assist in load balancing and WLAN optimization.

802.11k will require firmware and/or hardware upgrades. Effective management solutions will provide appropriate inventory reports and will automate the firmware upgrade process.

802.11n Current Status






The 802.11n standard provides enhancements for higher throughput (100-600+ Mbits/second). 802.11n will be based on MIMO/OFDM and will be backwards-compatible to support 802.11a and 802.11g client devices. 802.11n will be particularly useful where bandwidth-intensive services, like video, must be delivered. Caution: The 802.11n standard has not yet been ratified and “pre-n” products may not be upgradeable.

Management solutions must be designed with the flexibility to support 802.11n (when ratified) in addition to previously ratified standards.

With bandwidth-intensive services like video, throughput must be monitored closely to ensure acceptable performance. Management solutions must provide both real-time and historical trending data.

Management solutions must know which devices support the new standard for planning purposes.



Standard Summary WLAN Management Implications 802.11p: “WAVE” Current Status






802.11p is designed to enable operation of wireless LAN stations in motor vehicles in a highway environment. The communications provided by “Wireless Access in Vehicular Environments” (WAVE) will generally occur over distances up to 1,000 m (between roadside stations or between high-speed vehicles) and at highly variable speeds. Additional performance requirements are needed to address the motion-related effects (see 20.3.10.6).

Management solutions should eventually be able to track and locate clients traveling at a high rate of speed.

Management solutions will need to be able to visualize outdoor RF environments.

802.11r: “Fast Roaming/ Fast Handoff” Current Status






802.11r is defined to minimize the transition time when roaming between wireless access points to maintain seamless connectivity for the user. Client devices are ‘pre-authenticated’ to neighboring access points to which they might roam in order to minimize transition time. ‘Pre-authentication’ may be accomplished over the air or across the wired network via 802.11r’s neighbor report. This is especially important for wireless VOIP and other applications where latency is critical to performance. 802.11r is designed to allow clients to maintain their security and QoS connection status on the new access point. The overall changes to the protocol will not introduce any new security vulnerabilities beyond the current 802.11 standard and its amendments. It preserves the behavior of legacy infrastructure and devices.

Management solution must help IT understand which devices (both client devices and wireless access points) on their networks are capable of supporting this standard.

Management solution will need to configure the wireless access points to support fast roaming, integrating the authentication servers.

Management solutions will need to monitor the entire authentication process to ensure fast roaming, gathering data from APs, clients, and authentication servers. When failures occur, the management system must help the IT staff analyze where the failure occurred.

Wireless management solutions must be able to create a list of ‘neighboring’ access points in order to configure and populate proper roaming targets per cell.



Standard Summary WLAN Management Implications 802.11s: Mesh Networking Current Status






The 802.11s standard is designed to enable self-organizing infrastructure network “meshes”, primarily for outdoor networks. This has the potential to reduce backhaul requirements and installation costs, accelerating the adoption of large municipal networks. The extent to which 802.11s is adopted will depend on the willingness of the hardware vendors to shift from proprietary protocols.

Management solutions will need to monitor the QoS of the network backhaul

Management solutions will need to graphically render large outdoor RF environments and dynamic meshes

Remote provisioning and configuration of outdoor devices will be critical for cost-effective operation of mesh networks.

802.11u: “Wireless Interworking with External Networks” Current Status


available Requirements ?? Requires new AP

hardware Requires new AP firmware

?? Requires client device update

The 802.11u standard is intended to address handoff between 802.11 networks and non-802.11 networks (i.e., cellular). The ratification of this standard is expected to dramatically accelerate the adoption and deployment of wireless voice applications because it will let mobile workers carry a single phone.

Network management systems will need to understand the roaming from network to network as well as from AP to AP.

Management solutions will need to track and display what types of clients are roaming onto the WLAN and what types of services they are consuming (voice, data, and video).

Management solution must be able to dynamically adapt to clients on the network according to what types of services they are demanding.

Management solution should be able to provide QoS reports for the various network operations leveraging the access point.



Standard Summary WLAN Management Implications 802.11v: Current Status


available Requirements ?? Requires new AP

hardware Requires new AP firmware


The 802.11v standard would enable centralized management (monitoring and configuring) of wireless client devices (stations) through a Layer 2 mechanism. While 802.11k is designed to retrieve information from client devices, it does not provide the ability to configure the device itself. 802.11v would create an “Access Point Management Information Base” (AP MIB) to be used for remote configuration of client devices for:

– RF Management

– Dynamic channel selection

– Access Point Coordination

– Spectrum Coexistence

– Load Balancing

– Network Controlled handoffs with client participate

– Location based management

– Updating FW on clients

– Client diagnostics

– MIB Interface to enable centralized control

– Rogue/Fake APs/SSIDs

Wireless management systems would be able to centrally configure client device security settings to comply with policies.

Management solutions would be able to manage firmware distribution to client devices as well as to the Wi-Fi infrastructure.

Management solutions would be able to perform event correlation and diagnostics on client-related issues and automatically implement corrective actions by changing network and/or client settings.

Management solution should be able to configure clients and wireless access points for more effective power-saving to enhance the performance of small form factor 802.11 devices (like phones and palm tops).

With configuration control over client devices, management solutions will be able to prevent clients from associating to unauthorized rogue access points.

802.11w: Protected Management Frames Current Status






802.11w is intended to provide mechanisms to protect 802.11 management frames (including action management frames, deauthentication and disassociation frames). It is needed in order to address security gaps (especially in disassociation and deauthentication) and could help prevent some (but not all) denial of service attacks.

Management solution must help IT understand which devices support this standard (clients and APs) and implement the appropriate settings on those that do.

Documents

802.11 overview.pdf