Service discovery architecture for TGaq April 2013 doc.: IEEE 802.11-13/0796 Nov 2013 Service discovery architecture for TGaq Date: 2013-11-05 Authors: Ping FANG, Huawei Ping FANG, Ping FANG, Huawei

April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Abstract This document presents a service architecture for TGaq. Service indication from AP, network discovery and detailed service information query are described. Possible options and issues are further discussed. Ping FANG, Huawei RYU Cheol. ETRI

April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Background In 13/501r0, a architecture with service registration and service discovery is registered. Per the meeting discussion, the registration can be done in MAC layer or upper layer after association. In 13/796r0, the procedure on how a STA discovers necessary service information before association is described with a high level 2-step service discovery procedure proposed. In 13/796r1, more details on service indication are further discussed. In 13/893r0, different service hash values proposed to be carried in service discovery request and response with public action frame for privacy and security Ping FANG, Huawei RYU Cheol. ETRI

Overall picture of 11aq Nov 2013 April 2013 doc.: IEEE 802.11-13/0426 Ping FANG, Huawei RYU Cheol. ETRI

Service Indication from AP April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Service Indication from AP Option 1 : new Service Indication IE in Beacon/ Probe Response Carried in Beacon or Probe Response, no extra overhead Good for passive scanning to indicate which services are provided or not Option 2: new Public Action frame Extra load for AP to broadcast besides Beacon STA doesn’t know when to receive, broadcast periodically Assumption: Proxy in AP caches general service information Good for scenarios when lots of STA queries Good to indicate what kind of services are provided or not Ping FANG, Huawei RYU Cheol. ETRI

Part 2: Service Information April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Service Indication IE Service Indication IE in Beacon/ Probe Response Service Indication Bitmap Protocol Part: fixed bits to indicate protocols for services Service Information Part: Bits used to indicate available services, each bit corresponds to a service/services with hash value Element ID Length Service indication bitmap 1 octet TBD octet Part 1: Protocol Part 2: Service Information UPnP Bonjour … … 1 1 1 … … Bit 1 Bit 2 Bit 3 Hash(“UPnP:Printer”), then set bit 1 value to be 1. Ping FANG, Huawei RYU Cheol. ETRI

General Service Query General Service Query April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 General Service Query General Service Query To decide whether a service can be provide via AP Query and response can be relatively shorter Option 1 : Combine with AP/Network discovery Carry service hash IE in Probe Request/Response Different Service hash values can be carried in Probe request/response for privacy Option 2: New Public Action frame [4] Carry service hash values in PAM request/response Different Service hash values be in Probe request/response for privacy Option 1 Option 2 Ping FANG, Huawei RYU Cheol. ETRI

Public Action Frame vs. Service IE April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Public Action Frame vs. Service IE Option 1: Service IE in Probe Req/Resp Option 2:New Public Action Frame Option1 vs. option 2 Element ID Length Service Hash Value Service Capability 1 octet 6 octets 0 or variable MAC Header Category(=4) Public Action Length Service Hash Value Service Capability 28 octet 1 octet 1octet 6 octets 0 or variable Features Option 1 Option 2 Help to reduce Probe Response from Legacy APs No Yes Overhead Almost same Ping FANG, Huawei RYU Cheol. ETRI

Detailed Service Query April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Detailed Service Query Detailed Service Query (Different from general query) Can provide detailed service information The query response can be much bigger than that of general query Option 1 : GAS mechanism for further information query Mechanism similar to ANQP as carried in GAS Option 2: new PAM (public action frame)[5] Carry detailed service query information in PAM between STA and AP AP may forward the query to backhaul or associated STAs for further detailed information Option 1 Option 2 Ping FANG, Huawei RYU Cheol. ETRI

New protocol in GAS vs. new Public Action Frame April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 New protocol in GAS vs. new Public Action Frame Option 1: New advertisement protocol ID in GAS Option 2: new Public Action Frame New advertisement protocol vs. new Public Action Frame MAC Header Category(=4) Public Action (=10) Dialog Token Advertisement Protocol element Query Request length Query 28 octet 1 octet 1octet variable 2 MAC Header Category(=4) Public Action Dialog Token Query Request Length Query 28 octet 1 octet 1octet 2 variable Features Option 1 Option 2 Help to reduce queries No (for unicast) Yes (could be multicast) Overhead more less Ping FANG, Huawei RYU Cheol. ETRI

Discussion on Practice April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Discussion on Practice Service bitmap For scenario with lots of STAs queries, service bitmap can help to reduce STAs’ queries with passive scanning When the number of services provided by AP is far less than the length of bitmap, the bitmap can provide useful information to indicate which services are not provided General service query vs. detailed service query When there are quite some APs and STAs around, general service query should be used first to reduce channel time For sparse environment, detailed service query can be used directly to query for detailed service information Ping FANG, Huawei RYU Cheol. ETRI

Nov 2013 Summary Overall picture for TGaq is recaptured with service indication from AP, general service query and detailed service query Service bitmap IE in Beacon/Probe Resp for indication from AP New Public Action frame carries different service hash values in general service query/response New Public Action frame carries detailed service query or response of upper layer for detailed service query Ping FANG, Huawei

References IEEE Std 802.11™-2012 11-13-0057-02-00aq-design-options Nov 2013 References IEEE Std 802.11™-2012 11-13-0057-02-00aq-design-options 11-13-0501-00-00aq-service-registration-of-sta-to-an-ap 11-13-0893-00-00aq-service-discovery-proposal 11-13-0788-01-00aq-transaction-protocol Ping FANG, Huawei

Service Indication Performance Analysis April 2013 doc.: IEEE 802.11-13/0426 Nov 2013 Service Indication Performance Analysis Assumption Number of total service number: k = 5000 Length of Service Hash bitmap: m= 128 bit Number of services supported by AP: n = 16, 32, 48, 64, 80 Algorithm Service names are randomly generated with alphabets , digits and phonetic symbols Services supported by AP are randomly chosen from 5000 services Service hash values are calculated with SHA256, and then mod(128) to set a corresponding bit in bitmap Bit value 0 indicate there are no corresponding services The result is to indicate how many percent of services are not supported by the AP, with the 128 bit service indication bitmap and given the n kind of services supported by the AP Percentage of no service n Ping FANG, Huawei RYU Cheol. ETRI

Nov 2013 Straw Polls Ping FANG, Huawei

Straw Polls on Proposed Text to SFD Nov 2013 Straw Polls on Proposed Text to SFD Straw Poll-1: add the following sentence to section 5 Frame Formats of TGaq SFD, 11-13-0300r1 802.11aq shall define a IE with service hash bitmap for service indication. Result Yes No Need more info Ping FANG, Huawei

Straw Polls on Proposed Text to SFD – con’t Nov 2013 Straw Polls on Proposed Text to SFD – con’t Straw Poll-2: add the following sentence to section 5 Frame Formats of TGaq SFD, 11-13-0300r1 802.11aq shall define a new public action frame for service query. Result Yes No Need more info Ping FANG, Huawei

Straw Polls on Proposed Text to SFD – con’t Nov 2013 Straw Polls on Proposed Text to SFD – con’t Straw Poll-3: add the following sentence to section 7 MLME of TGaq SFD, 11-13-0300r1 802.11aq shall define mechanism to provide service indication from AP with service hash bitmap and service protocol bitmap in Beacon and Probe Response Result Yes No Need more info Ping FANG, Huawei

Straw Polls on Proposed Text to SFD – con’t Nov 2013 Straw Polls on Proposed Text to SFD – con’t Straw Poll-4: add the following sentence to section 7 MLME of TGaq SFD, 11-13-0300r1 802.11aq shall define mechanism to provide general service query for a STA to decide the availability of a service from AP before association. Result Yes No Need more info Ping FANG, Huawei

Straw Polls on Proposed Text to SFD – con’t Nov 2013 Straw Polls on Proposed Text to SFD – con’t Straw Poll-5: add the following sentence to section 7 MLME of TGaq SFD, 11-13-0300r1 802.11aq shall define mechanism to provide detailed service query for a STA to get the detailed information of a service from AP before association. Result Yes No Need more info Ping FANG, Huawei

Straw Polls on Proposed Text to SFD – con’t Nov 2013 Straw Polls on Proposed Text to SFD – con’t Straw Poll-6: add the following sentence to section 8 Security of TGaq SFD, 11-13-0300r1 802.11aq shall define mechanism to provide privacy for pre association service queries with different hash values for a service in service query request and response. Result Yes No Need more info Ping FANG, Huawei