1. AP Load Balancing Requirements
Month Year
May 2005
May 2005
AP Load Balancing Requirements
Authors:
Date:
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 < ieee802.org/guides/bylaws/sb-bylaws.pdf>, 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
Emily Qi, Intel Corporation
Emily Qi, Intel Corporation

2. Month Year
May 2005
May 2005
Abstract
This document suggests BSS load balancing requirements for Wireless Network Management.
Emily Qi, Intel Corporation
Emily Qi, Intel Corporation

3. Agenda Rationale for BSS Load Balancing
Month Year
May 2005
May 2005
Agenda
Rationale for BSS Load Balancing
AP-STA Cooperative Load Balancing
Suggested Load Balancing Messages
Emily Qi, Intel Corporation
Emily Qi, Intel Corporation

4. Unbalanced Wireless Network
May 2005
Unbalanced Wireless Network
Throughput
No. of users
AP and Clients need to collaborate for optimal network use
Emily Qi, Intel Corporation

5. AP and Clients balance load to optimize network use
May 2005
BSS Load Balancing
Throughput
No. of users
AP and Clients balance load to optimize network use
Emily Qi, Intel Corporation

6. Rationale for BSS Load Balancing
May 2005
Rationale for BSS Load Balancing
Increase WLAN aggregate throughput by increasing individual STA throughput
Improve user experience by more optimally distributing the load over serving APs
Balancing load to improve QoS effectiveness for VoIP and Video stream
Suggested Requirement:
TGv shall support BSS load balancing to improve wireless network throughput and QoS effectiveness.
Emily Qi, Intel Corporation

7. Possible Approaches Network Controlled Load Balancing
May 2005
Possible Approaches
Network Controlled Load Balancing
AP directs STA to a lightly loaded AP and initiates connection
Pros: Network has a broad vision of BSS load and STA can be better redistributed between serving APs
Cons: STA may not be able to achieve optimum throughput because Network may not know STA’s local receiving signal strength and SNIR
STA controlled load Balancing
STA selects the best AP to optimize its own throughput/QoS, based on QBSS load information and local SNIR/RSSI
Pros: STA has the best idea about when to roam and which AP to serve its needs
Cons: May result in a “Gold rush” in a heavily loaded environment
Emily Qi, Intel Corporation

8. AP-STA Cooperative Load Balancing
May 2005
AP-STA Cooperative Load Balancing
AP sends STA Load Balancing management message, which includes:
A list of one or more nearby lightly loaded APs (candidate APs) that it offers, which may include fields from Neighbor Report Element (TGk) and Fast BSS Transition IEs (TGr)
Timeliness indication for expiration time
Strong/Mild indication for gravity (e.g. Strong = STA really should consider this or face potential service degradation or disruption; Mild = service would probably be better if STA moved; etc)
Once STA receives this message, STA can decide which AP to roam to and when to roam
Suggested Requirement:
TGv shall support AP and STA Cooperative Load Balancing
Emily Qi, Intel Corporation

9. Suggested Load Balancing Messages
May 2005
Suggested Load Balancing Messages
Direct Roaming
WNM Management frame
Admission Control Response Message if the status is rejected
802.11e Action Frame
(Re-)association Response Message if the status is rejected
Management Frame
Emily Qi, Intel Corporation

10. May 2005
Feedback?
Emily Qi, Intel Corporation