Presentation on theme: "Doc.: IEEE 802.11-05/0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 1 Virtual AP Requirements DATE: July 2005 Author(s) NameCompanyAddressPhoneemail."— Presentation transcript:
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 1 Virtual AP Requirements DATE: July 2005 Author(s) NameCompanyAddressPhone Pat R. CalhounCisco Systems, Inc 170 West Tasman Dr., San Jose, CA Notice: This document has been prepared to assist IEEE It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE Working Group. If you have questions, contact the IEEE Patent Committee Administrator at
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 2 Abstract TGv has identified virtual APs as a possible requirement. This document proposed some requirements that could be adopted by the task group.
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 3 Introduction Most enterprise class WLAN devices on the market today support multiple SSIDs. This allows for segmentation of traffic over the air, extending a “VLAN-like” concept over However, in order to maintain compatibility with stations, these devices have a single BSSID per SSID supported. Consequently, these devices must transmit a beacon for every SSID. This creates two issues: –Utilizes unnecessary air time –Makes it impossible to distinguish a physical device from a logical device
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 4 Terminology Physical AP: An access point advertising a BSSID (base BSSID) Logical AP: Any additional BSSID being advertised by a physical AP –Generally increments off base BSSID, for instance base BSSID is 00:01:02:03:04:00, while first Logical AP is 00:01:02:03:04:01.
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 5 Air Time Imagine a scenario where an AP supports 5 SSIDs, with a beacon period of 100ms (default) In order to advertise its services, the AP must transmit five beacons every beacon period Assuming a basic data rate of 1Mbps, and a beacon size of 90 bytes, the average airtime for each beacon would be 800 usecs. Combining the beacons would eliminate the additional PIFS Currently, optimizations are done by some vendors to only send a portion of beacons every beacon period, and change the list of SSIDs to ensure every SSID is advertised every n period.
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 6 Virtual vs. Physical AP Advertising more than a single SSID (hence BSSID) does not permit a STA (or neighboring AP) to determine whether beacons are generated from a single physical device extensions, such as k, could greatly benefit from knowing whether a BSSID is a physical vs. logical entity.
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 7 Proposed text Add the following text to the requirements document –“TGv will support MAC extensions to allow for proper support of virtual access points, allowing a single AP to advertise multiple BSSIDs through a single beacon, where each SSID may have a separate set of policies”
doc.: IEEE /0xxxr0 Virtual AP Requirements July 2005 Pat R. Calhoun, CiscoSlide 8 Question?