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Notes on Interworking with External Networks

This presentation provides an overview of the main features in the current draft D_10.0 of Interworking with External Networks, including network discovery, emergency services, QoS map distribution, and SSPN interface service. Comments and suggestions are requested from other SDOs.

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Notes on Interworking with External Networks

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  1. Date: 2010 08 06 Notes on Interworking with External Networks Authors: George Bumiller, Research In Motion

  2. This presentation provides an overview of the main features included in the current draft D_10.0 of Interworking with External Networks, together with the approved comment resolutions from 11-10/0766r4 Extracts from the draft are provided, to stimulate discussion, comment and suggestions from other SDOs. The draft has been proceeding through Sponsor Ballot status, indicating a reasonable degree of maturity. Note that it is only a draft, not a standard, and may change. Abstract George Bumiller, Research In Motion

  3. IEEE 802.11 IEEE 802.11u IEEE 802.11u Features Network Discovery and Selection Emergency Services QoS Map distribution SSPN Interface service between the AP and the SSPN Comments and Suggestions Requested References Extracts from IEEE 802.11u draft D_10.0 Agenda George Bumiller, Research In Motion

  4. IEEE 802.11-2007 is (together with recently-standardized amendments) the current standard. IEEE 802.11p, Wireless Access in Vehicular Environments is the latest amendment standardized. TGu, Interworking With External Networks is the initiative which supports and extends the current use of WLAN for other Wide Area Networks (WANs). It has progressed through letter ballot, and is now in Sponsor Ballot (the final balloting stage) at draft D_10.0. IEEE 802.11 George Bumiller, Research In Motion

  5. Today’s standard: IEEE 802.11-2007 + 802.11 k, r, y, n, p. Single document in process. • Today’s drafts in Sponsor Ballot: 802.11 u, v, and z. Note that the draft amendments refer to items being added by other draft amendments. These are based on an expected approval sequence, and will be adjusted if approvals are in a different sequence. IEEE 802.11 – Current and Draft Amendments George Bumiller, Research In Motion

  6. There are three draft amendments before this draft, 11u. There are dependencies, with some draft amendments making use of certain functions defined in earlier draft amendments. Therefore, for a better understanding of this (u) draft, one needs to refer to those functions in the draft amendments scheduled for standardization before 11u. The sequence is: z AP-Independent Direct Link Setup v Wireless Network Management u Interworking with External Networks Sequencing of Draft Amendments George Bumiller, Research In Motion

  7. Study Group • Technical Group, TGu • Develop Requirements • Develop Draft Specification, then start balloting • Ballot Draft (until no required technical comments remain) • Sponsor Ballot (IEEE-wide balloting) current status • Adoption as Approved Amendment (& published) • Integration into IEEE 802.11-20xx Steps in IEEE 802.11u George Bumiller, Research In Motion

  8. This adds and enhances four major features: Network Discovery and Selection, Emergency Services , QoS Map distribution, SSPN Interface service between the AP and the SSPN. The discovery of these services is enabled through advertisement services, providing interchange of data between the STA (mobile) and the AP, without need for the STA to be associated. The AP is able to provide generic container data [provided by each of the WAN technologies], to assist the STA in its interworking. Interworking with External Networks,IEEE 802.11u George Bumiller, Research In Motion

  9. ANQP: Access Network Query Protocol Non-AP STA – non-Access Point Station, i.e. a mobile unit GAS: The Access Network Query protocol transported by GAS Public Action frames [does not require association with the AP] HESSID (homogenous ESS Identifier): A collection of BSSs, within the same extended service set (ESS), in which the SSPN or other external network reachable at one BSS, is reachable at all of them. OI: organization identifier [may be used to identify SSPNs, aggregators and other operating organizations.] SSPN: subscription service provider network Abbreviations and Definitions George Bumiller, Research In Motion

  10. Previously • Use SSID, associate. Destination reachable? • Associate with next AP,…(if the first one unusable) • Continue until usable AP reached • With 802.11u • Check APs concurrently without association • Up to three OIs in beacon or probe response • Result • Faster discovery and selection, compared to sequential association with APs Network Discovery and Selection George Bumiller, Research In Motion

  11. • Discovery of suitable networks through the advertisement of access network type, roaming consortium and venue information, via management frames • Selection of a suitable IEEE 802.11 infrastructure using advertisement services (e.g., ANQP or an IEEE 802.21 Information Server) in the BSS or in an external network reachable via the BSS • Selection of an SSPN or External Network with its corresponding IEEE 802.11 infrastructure Network Discovery and Selection(Extract) George Bumiller, Research In Motion

  12. Name Access Network Query Protocol Emergency Call information Roaming Consortium information Cellular Network information NAI realm information MIH Information Service MIH Command and Event Services Capability Discovery Emergency Alert System (EAS) Location-to-Service Translation Protocol Advertisement Protocol ID definitions George Bumiller, Research In Motion

  13. Provides method for unauthenticated users to access Emergency Services Link level support Requires higher layer application • Emergency Calls Provides the local emergency call numbers • Emergency Alerts Provides emergency alerts, with a unique hash so that STAs (mobiles) know when each alert is new Emergency Services George Bumiller, Research In Motion

  14. For SSPNs and other external networks Re-maps the layer-3 service levels to a common over-the-air service level QoS Mapping George Bumiller, Research In Motion

  15. A service between the AP and the SSPN Supports service provisioning and transfer of user permissions from the SSPN to the AP The IEEE 802.11 network interacts with the SSPN corresponding to the user of the non-AP STA either directly or via a roaming relationship. SSPN Interface service George Bumiller, Research In Motion

  16. “… we recommended the use of the new parameter “HESSID”. We would just like to clarify that this an identifier of the network behind the layer 2 wireless route and that it should be used in conjunction with SSID, which is the existing WLAN radio access identifier. Both HESSID and SSID are therefore used together to discover a specific WLAN and its network attachment. If the HESSID parameter is not available in the WLAN hotspot, then the SSID is used only, as with current implementations.” HESSID (homogenous ESS Identifier) A collection of BSSs, within the same extended service set (ESS), … Use of HESSID George Bumiller, Research In Motion

  17. Interworking With External Networks • Enables faster discovery and selection of WLANs • HESSID assists in the identification of WLANs • Generic Advertisement Service • Locally-stored data is accessible through native query protocol, e.g. provided for each WAN technology • IEEE 802.21 (when available) may be accessed • Support for Emergency Services (calls and alerts) • QoS Map Summary George Bumiller, Research In Motion

  18. Bruce Kraemer IEEE 802.11 Working Group Chair bkraemer@marvell.com +1 321 427 4098 Stephen McCann IEEE 802.11 Secretary & IEEE 802.11 Task Group u Chair smccann@rim.com +44 1753 667099 Your Suggestions, Comments and Questions are requested George Bumiller, Research In Motion

  19. IEEE 802.11u Draft 10.0 (July 2010) Please note that IEEE 802.11u Draft 10.0 (June 2009) is available for purchase at the IEEE shop: https://sbwsweb.ieee.org/ecustomercme_enu/start.swe?SWECmd=GotoView&SWEView=Catalog+View+(eSales)_Standards_IEEE&mem_type=Customer&SWEHo=sbwsweb.ieee.org&SWETS=1192713657 Then go to Individual Standards: Draft Standards (center column) Enter “P802.11u” in the right-hand search box. IEEE 802.11-2007 (the current base standard) Please note that IEEE 802.11 standards are available free six months after publication. http://standards.ieee.org/getieee802/802.11.html Note that amendments k, r, y, n, p are now standards. These amendments are now being integrated into a single document, which will become IEEE 802.11-2010 P802.11u_D10.0 2nd recirc comments spreadsheet These comments have been used to update the extracts in this presentation. 11-10-0766-04-000u-d10-0-2nd-recirc-comments-spreadsheet.xls Freely available at https://mentor.ieee.org/802.11/documents References George Bumiller, Research In Motion

  20. Overview (1 & 2) Generic Advertisement Service Access Network Type Advertisement Protocol ID definitions Access Network Query Protocol information ID definitions Interworking with External Network Procedures (1, 2 & 3) Interactions with SSPN IEEE 802.11u D_10.0 extracts George Bumiller, Research In Motion

  21. Overview - 1(Extract) • 5.4.8 Interworking with External Networks • The Interworking Service allows non-AP STAs to access services provided by an external network according to the subscription or other characteristics of that external network. An IEEE 802.11 non-AP STA may have a subscription relationship with an external network, e.g., with an SSPN. • An overview of the interworking functions addressed in this standard is provided below: • —Network Discovery and Selection • • Discovery of suitable networks through the advertisement of access network type, roaming consortium and venue information, via management frames • • Selection of a suitable IEEE 802.11 infrastructure using advertisement services (e.g., ANQP or an IEEE 802.21 Information Server) in the BSS or in an external network reachable via the BSS • • Selection of an SSPN or External Network with its corresponding IEEE 802.11 infrastructure • —Emergency Services • • Emergency Call and Network Alert support at the link level • —QoS Map distribution • —SSPN Interface service between the AP and the SSPN George Bumiller, Research In Motion

  22. The Generic Advertisement Service (GAS), described in 5.9, can be used by a STA to provide support for the network selection process and as a conduit for communication by a non-AP STA with other information resources in a network before joining the wireless LAN. The Interworking Service supports Emergency Services (ES) by providing methods for users to access emergency services via the IEEE 802.11 infrastructure, advertising that emergency services are supported (see 11.23.6) and identifying that a traffic stream is used for emergency services. The Interworking Service provides QoS mapping for SSPNs and other external networks. Since each SSPN or other external network may have its own layer-3 end-to-end packet marking practice (e.g., DSCP usage conventions), a means to re-map the layer-3 service levels to a common over-the-air service level is necessary. The QoS Map service provides STAs a mapping of network-layer QoS packet marking to over-the-air QoS frame marking (i.e., user priority). The SSPN Interface service supports service provisioning and transfer of user permissions from the SSPN to the AP. The method and protocol by which these permissions are transferred from the SSPN are out of scope of this standard. Overview – 2(Extract) George Bumiller, Research In Motion

  23. 5.9 Generic Advertisement Service The Generic Advertisement Service (GAS) provides functionality that enables STAs to discover the availability of information related to desired network services, e.g., information about services such as provided in an IBSS, local access services, available Subscription Service Providers (SSP) and/or SSPNs or other external networks. GAS uses a generic container to advertise network services' information over an IEEE 802.11 network. Public Action frames are used to transport this information. While the specification of network services information is out of scope of IEEE 802.11, in an Infrastructure BSS there is a need for STAs to query for information on network services provided by SSPNs or other external networks beyond an AP, before they associate to the wireless LAN. The exchange of information may also be performed after associating to the BSS. In an IBSS, GAS functionality enables a STA to access the availability and information related to desired services provided by other STAs in the IBSS. Exchange of information using GAS may be performed either prior to joining an IBSS or after joining the IBSS. Generic Advertisement Service - 1[Obtaining information from the AP without Association](Extract) George Bumiller, Research In Motion

  24. There are a number of reasons why providing information to a STA in a pre-associated state is beneficial: • It supports more informed decision making about an IEEE 802.11 infrastructure with which to associate. This is generally more efficient than requiring a non-AP STA to associate with an AP before discovering the information and then deciding whether or not to stay associated. • It is possible for the non-AP STA to query multiple networks in parallel. • The non-AP STA can discover information about APs that are not part of the same administrative group as the AP with which it is associated, supporting the selection of an AP belonging to a differ­ent IEEE 802.11 infrastructure that has an appropriate SSP roaming agreement in place. Generic Advertisement Service - 2[Obtaining information from the AP without Association](Extract) George Bumiller, Research In Motion

  25. Table 7-43bk— Access Network Type(Extract) George Bumiller, Research In Motion

  26. Table 7-43bm—Advertisement Protocol ID definitions(Extract) George Bumiller, Research In Motion

  27. Table 7-43bo—Access Network Query Protocol info ID definitions (Extract) George Bumiller, Research In Motion

  28. 11.23 WLAN Interworking with External Networks Procedures 11.23.1 General This subclause describes the actions and the procedures that provide interworking capabilities between 802.11 infrastructure and external networks. 11.23.2 Interworking capabilities and information STAs indicate their support for Interworking Service by setting the dot11InterworkingServiceEnabled MIB variable to true. When dot11InterworkingServiceEnabled is true, APs include the Interworking element in Beacon and Probe Response frames and non-AP STAs include the Interworking element in Probe Request frames. When dot11InterworkingServiceEnabled. and dot11ExtendedChannelSwitchEnabled are both set to TRUE, the AP may provide its operating channel and regulatory class to an Interworked SSPN using the dot11RegulatoryClassesTable MIB entry. The Interworking information element contains signaling for Homogeneous ESSs. The HESSID is a 6 octet MAC address which identifies the homogeneous ESS. The HESSID value shall be identical to one of the BSSIDs in the homogeneous ESS. Thus, it is a globally unique identifier, which in conjunction with the SSID, may be used to provide network identification for an SSPN. NOTE—It is required by this standard that the HESSID field in the Interworking element is administered consistently across all BSSs in a homogeneous ESS. The Interworking information element also provides a Network Type value in Beacon and Probe Response frames to assist the non-AP STA with network discovery and selection. Interworking with External Network Procedures - 1(Extract) George Bumiller, Research In Motion

  29. 11.23.3 Interworking Procedures: Generic Advertisement Services This subclause describes the actions and procedures that are used to invoke Generic Advertisement Services (GAS). GAS may be used to enable network selection for STAs when dot11InterworkingServiceEnabled is true. GAS provides transport mechanisms for advertisement services while STAs are in the un-associated state as well as the associated state. This is accomplished via the use of Public Action management frames which are Class-1 frames. GAS messages shall be transmitted using individually-addressed Public Action frames. When Management Frame Protection is negotiated, stations shall use individually addressed Protect­ed Dual of Public Action frames instead of individually addressed Public Action frames. A GAS message exchange may take place between two STAs; one STA transmits a GAS Query Request and the other STA transmits the GAS Query Response as described in 11.23.3.1. The Advertisement Protocol transported by the GAS is one of the query protocols in Table 7-43bl. GAS shall be supported by a STA when dot11InterworkingServiceEnabled is true. ANQP shall be supported by a STA when dot11InterworkingServiceEnabled is true. Other advertisement protocols shall be supported when the corresponding dot11GASAdvertisementID is present. STAs shall not transmit a GAS Query for any Advertisement Protocol unless that Advertisement Protocol ID is included in the Advertisement Protocol element in a Beacon or Probe response frame. The Advertisement Protocol element specifies the Advertisement Protocols that a STA may use to communicate with Advertise­ment Servers, which may be co-located with a STA or in an external network. The Advertisement Protocol identifies the query language used by the Advertisement Server. The GAS protocol, which is used to transport Queries and Query Responses, is transparent to the Advertisement Protocol. Interworking with External Network Procedures - 2(Extract) George Bumiller, Research In Motion

  30. 11.23.3.1 GAS Protocol Presence of the Interworking element in Beacon or Probe Response frames indicates support for the GAS pro­tocol. Presence of the Advertisement Protocol element in Beacon or Probe Response frames indicates the Ad­vertisement Protocol IDs supported in the BSS or IBSS. A STA transmits a GAS Query using a GAS Initial Request frame and the responding STA provides the query response or information on how to receive the que­ry response in a GAS Initial Response frame. The GAS Query Response shall be delivered in a single GAS Initial Response frame or in one or more GAS Comeback Response frames; the GAS Query Response shall not be split between a GAS Initial Response frame and one or more GAS Comeback Response frames. The GAS message sequence diagrams are shown in Figures 11-17e, 11-17f and 11-17g. Interworking with External Network Procedures - 3(Extract) George Bumiller, Research In Motion

  31. 11.23.4 Interworking Procedures: Interactions with SSPN 11.23.4.1 General Operation To provide SSPN Interface services, the IEEE 802.11 network interacts with the SSPN corresponding to the user of the non-AP STA either directly or via a roaming relationship. As part of setting up the RSN security association, user policies are communicated to the AP. If dot11SSPNInterfaceEnabled is true, these permissions shall be stored in the AP's dot11InterworkingTableEntry for that STA. Thereafter, the AP shall use the dot11InterworkingTableEntry for controlling the service provision to that non-AP STA. User policies from the SSPN affect authentication, authorization, and admission control decisions at the AP. In addition, the AP collects statistics about the non-AP STA and reports the statistics to the SSPN when requested. The SSPN may also send service provision instructions to the AP, e.g., to terminate the connection to a non-AP STA. Non-AP STAs do not support the SSPN Interface. Network deployments typically provide that the AP and the server in the SSPN have a trustworthy channel that can be used to exchange information, without exposure to or influence by any intermediate parties. The establishment of this secure connection between the IEEE 802.11 infrastructure and the SSPN is out of scope of this standard. Interactions with SSPN(Extract) George Bumiller, Research In Motion

  32. Your comments and suggestions are welcome and requested. End George Bumiller, Research In Motion

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