doc.: IEEE 802.11-11-1250-00-00ai

Submission Paul Lambert, Marvell

TGai Discovery Proposal

Author:

Name Company Address Phone email Paul A. Lambert Marvell 5488 Marvell Lane, Santa

Clara, CA 95054 +1 408 222 8341 paul@marvell.com

Abstract

Short high-level proposal for discovery techniques

September 2011

Slide 1

doc.: IEEE 802.11-11-1250-00-00ai

Submission

Discovery - Background• Current 802.11 Discovery

– Passive scan (listen for beacons)– Active Scan (probe request/response)– 11u action frames

• Issues– Fast scanning with probes can flood network

(Yunoki-san 11-11-1414)

– Broadcast probe has many responses– Passive scan is much slower than active– 802.11 leaves scanning process (active versus

passive) as vendor option. Most clients use active scanning to facilitate faster overall scan.

September 2011

Slide 2 Paull Lambert - Marvell

doc.: IEEE 802.11-11-1250-00-00ai

Submission

Discovery Requirements

• Requirements– Discovery should be focused on what is meaningful

for actual connectivity• Available services• Ability to authenticate successfully• Probes should not be sent immediately without some

determination of the contention environment

– Pre-association discovery should provide clear interoperability requirements• Definition of a service should

– Responses to discovery requests should be fast• ANQP 4 step exchange is not appropriate for basic

discovery

doc.: IEEE 802.11-11-1250-00-00ai

Submission

Service Discovery Requirements• Requirements

– Pre-association messages should provide just enough information to ensure that a particular service/application will work• No need to provide all capabilities or any negotiation

– Detailed negotiation and capability determination can be post association• Existing protocols for L3 service discovery and capabilities

exchanges• More secure to defer capabilities to post-association

– Pre-association discovery should provide clear interoperability requirements

– Extensible• Allow addition of new services, but with guidelines that

encourage interoperability• Some services can map directly to a certification program by

Wi-Fi

doc.: IEEE 802.11-11-1250-00-00ai

Submission

Basic Proposal

• Improve legacy discovery– Modify existing behavior of active scanning

• Require FILS devices to pause before using active probing. Possibly examine environment/contention to determine to use of probe.

– Modify existing passive scanning to use promiscuous information (e.g. use probe responses directed to other MACs)

• Define improved discovery– Use public action frames to differentiate from use of

probes– Provide container for simple service and

authentication capabilities– Action frame based discovery should have clear

back-off rules to prevent flooding

doc.: IEEE 802.11-11-1250-00-00ai

Submission

Extended Proposal

• Discovery of multiple APs– Provide a means for one AP to provide information

about a neighborhood of APs– Define format for a list of APs:

• Identifying information for AP– What should this be?

• Location• Band, etc

– Neighbors may be filtered based on• Ability to authenticate• Availability of services or capabilities

doc.: IEEE 802.11-11-1250-00-00ai

Submission

Identifying Information for Discovery

• For pre-association discovery, the most important information to learn is:– Can a STA be authenticated with the AP– SSID is inadiquate

• 11ai should include a definition of the authentication domain(s) associated with a AP

• Discovery should be focused on:– Authentication domain or similar construct– Required services

doc.: IEEE 802.11-11-1250-00-00ai

Submission

Questions and Comments?