doc.: ieee 802.11-07/2889r0 submission november 2007 vijay patel, andrew corporationslide 1 lis-ale...

November 2007

Vijay Patel, Andrew Corporation

Slide 1

doc.: IEEE 802.11-07/2889r0

Submission

LIS-ALE Architecture, and FLAPDate: 2007-11-12

Name Affiliations Address Phone email Vijay Patel Andrew

Corporation 19700 Janelia Farm Blvd, Ashburn, VA 20147

+1 (703) 726-5693

[email protected]

Authors:

November 2007


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Submission

Abstract

Emergency Services Interconnection Forum (ESIF), a division of ATIS, is working on FLAP. The purpose of FLAP (Flexible LIS-ALE Protocol) is to facilitate transfer of values of location measurement parameters from the network to the LIS (Location Information Server) enabling the latter to compute the location of an IP end-device.

LIS interacts with ALE (Access Location Entity) residing in the access network to retrieve location measurements.

ESIF/NGES plans to send a liaison shortly to many SDOs (including IEEE802, 3GPP, IETF, and ITU-T) to seek input from the industry on this work for developing a standardized location parameter conveyance framework (requirements, architecture, and protocols) following the ANSI guidelines.

November 2007


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Submission

Internet location services model – Location Information Server (LIS)

Internet

Service

AccessDomain

InternetDomain

ServiceDomain

12

Location by value1. Device obtains location from

the location server in the access network

2. Device conveys location* to the service in the applicable application protocol.

Location by reference1. Device obtains reference from

the location server in the access network

2. Device conveys reference to the service in the applicable application protocol.

3. Service queries location server directly for location value one or more times

Internet

Service

AccessDomain

InternetDomain

ServiceDomain

12

3LIS

The protocol used for 1 & 3 is HELD (HTTP Enabled Location Delivery). Step 2, location conveyance, is application protocol dependent (e.g. SIP supports location conveyance)

* Location values are encoded as a PIDF-LO per RFC4119

November 2007


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Submission

Internet location services model – OBO Requests

On-Behalf-Of (OBO)1. Trusted third party application

(service) queries for location of the device. A client identity which is understood by the LIS is used as a query parameter (e.g. IP address)

2. If applicable, third party provides location information to external service entities.

3. If location was requested and provided by-reference, the external entity queries back to the LIS for location value updates.

* OBO requests are typically applicable where the target device and/or application protocol do not have native support for the communication of location information. For example a large enterprise with legacy deployment of standard form factor VoIP phones using H.323 may need to provide location-based routing for emergency and other calls from geographically diverse sites. The IP PABX in this case may perform OBO queries to the LIS using the IP address of the phone(s) as the query parameter. The PABX may use SIP conveyance externally if the location needs to sent to an external service entity. OBO implies two important characteristics of the service making the query. The service needs to be trusted by the LIS such that it is authorized, by whatever mechanism is suitable to the situation, to query for the location of devices in the LIS’ network. Where there are multiple possible LIS that the service could query, it needs to be able to ensure that it is associating the device with the correct LIS to provide the location.

Internet Service

AccessDomain

InternetDomain

ServiceDomain

12

3LIS

Trusted Service

Application*protocol

Target device

HELD

HELD

November 2007


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doc.: IEEE 802.11-07/2889r0

Submission

How does a LIS “know” Location

• The Internet location services model describes how LIS clients request and receive location information from the LIS

• It does not describe how a LIS determines the location associated with the device

• The value of parameters derived from the communication network used by the device can be used by the LIS to determine location

• In order to make use of these parameters, it is necessary for their values to be transferred from the communication network elements to the LIS

• This is the purpose of FLAP.

November 2007


Slide 6

doc.: IEEE 802.11-07/2889r0

Submission

Flexible LIS-ALE Protocol (FLAP) - ScopeExternal applications

Access Network LIS

User Device

FLAP

Location dereference request path

Networkmeasurement

requests

Devicemeasurement

requests

Networkmeasurements

Other measurements

Externalmeasurement sources

(e.g. GPS, RFID beacons)

Other measurements

Internet


(e.g. GPS, LMUs)

ALEALE

ALEALE

Scope of FLAP

November 2007


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doc.: IEEE 802.11-07/2889r0

Submission

Location Measurement• Location measurement involves determining the value of a number of

parameters associated with the network connection in use by the IP device.• Since devices will typically connect to a network using some form of link, the

parameters will often be layer 2 information directly associated with the physical link in use by the device – though not always– e.g. Typical layer 2 pieces of information are the Ethernet switch port the

device is connected to or the identity of a wireless access point the device is using.

– e.g. The permanent virtual circuit (PVC) identifier on the ATM aggregation of a DSL network may be measured even though it is physically separate from the copper pair or DSLAM connections of the physical link.

• Parameters taken from access networks need to be uniquely associated with the IP device in question and this association will often, if not always, be able to be done against the IP address of the device or terminating equipment.

• A common framework for access networks to transfer parameter values from the network equipment to the LIS is desirable.– The XML based flexible LIS-ALE protocol (FLAP) is proposed for this

purpose

November 2007


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Submission

LIS-ALE Architecture

ALEALE ALE

ALE messages

HELD

LIS

HELD HELD

November 2007


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doc.: IEEE 802.11-07/2889r0

Submission

Location Determination: LIS-ALE Ntwk Model

November 2007


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Submission

FLAP - message structure and content

• The LIS is responsible for establishing connections to each of the ALE instances in its service area.

• FLAP messaging is XML based– XML objects are sent as part of a continuous stream on a reliable secure link – recommended to

be TLS.– The XML schema defines the messages supported by the FLAP protocol and includes the meta-

objects of terminal and access.– The base definition of terminal includes the IP address of the terminal. This will generally apply

to IP devices that measurements are being provided for.– FLAP also supports sending measurements for access parameters not immediately associated

with an IP device, particularly where the LIS may subsequently be able to make the association. In this case, the ALE may exclude the IP address.

• The base XML schema supports technology and vendor extensions– Standard technology schema extensions define the detail of what defines a terminal in a given

technology as well as the standard subset of access parameters that apply to that technology• E.g. A layer 2 Ethernet switch extension defines a terminal by MAC address. Access parameters include

switch identity, connected port, and vlan ID.

– Vendor extensions permit new terminal and access parameters to be defined.• This permits a vendor to provide additional measurement information which may contribute to improved

location measurement performance.• A LIS may recognize, and utilize, vendor extensions or it may ignore them.

November 2007


Slide 11

doc.: IEEE 802.11-07/2889r0

Submission

FLAP – Hierarchical definitionsTechnology specific ALE capabilities

FLAPFLAPBase XML SchemaBase XML Schema

Ethernet Ethernet switchswitch

WiFi WiFi AccessPointAccessPoint

WiMAXWiMAXBase StationBase Station

DSL DSL AggregatorAggregator

CableCableHead EndHead End

Vendor Vendor ExtensionsExtensions





Etc.

November 2007


Slide 12

doc.: IEEE 802.11-07/2889r0

Submission

FLAP - XML Structure, Base definitionsType definitions

Header definitionTerminal definition

[vendor]ipaddress

Access definitionTimeExpiryTime

Messaging definitionsMessage component definitions

Transaction IDTechnologyVendor ID

Message definitionsAccessQueryAccessQueryResponseNotifySynchSynchResponse

Parameter definitionsError codesResult codes

Vendor…e.g. Alcatel_LiteSpanDSL_definitions

Extensions#include EthernetSwitchExtension#Include DHCPRelayExtension#Include DSLAggregatorExtension

Base definitions augmented by including vendor and technology specific extensions

Base definitions define semantic objects and messages

November 2007


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doc.: IEEE 802.11-07/2889r0

Submission

FLAP - messagingTo avoid unnecessary polling in the network, FLAP also supports the ability of the ALE to provide asynchronous indications of client location measurement changes. This is done via a “Notification” message from the ALE to the LIS.

Notification may also occur downstream from the LIS to the ALE, where the LIS has learnt of a change in client connectivity, in order that the ALE may also refresh its state information in a timely manner.

November 2007


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Submission

Example FLAP message

The following message uses the Ethernet extension with additional vendor extension parameters to do a notification message:<ntfy xsi:type=”enet:ntfy” xmlns:vnd1=”http://www.example.com/flap/terminal/hw” xmlns:vnd2=”http://www.example.com/flap/access/skew”> <enet:terminal <ip>192.168.0.1</ip> <enet:hwaddr>12:34:56:78:90:ab</enet:hwaddr> <vnd1:hw revision="1.2"/> </enet:terminal> <enet:access time="2005-04-14T10:51:23.000+10:00"> <enet:switch><ip>192.168.0.1</ip></enet:switch> <enet:port>4</enet:port> <vnd2:skew>0.5127</vnd2:skew> </enet:access></ntfy>

November 2007


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Submission

FLAP - messaging (contd)

A LIS will typically be configured with information about the access networks that it provides location services for. This will include the definitive list of ALE instances that it can obtain location measurements from.The LIS may poll the serving ALE set with a “Query Access” message. Each ALE will provide a response for each connected device and the measurement set applicable to it.The LIS may request a refresh of information from the ALE set using a “Resynchronization” message in the event of, for example, coming back on line after an outage. Each ALE will provide a response covering the state of all currently connected devices or, alternatively, a response covering all changes since a given specific time.

November 2007


Slide 16

doc.: IEEE 802.11-07/2889r0

Submission

Example – WiMax Network Controller ALE

LIS

IP

WiMax extension schemaTerminal definition

MAC addressIP address

Access definition extensionBTS ID

Vendor X extension schemaVendor XProduct WAP-FamilyY-ModelZAccess definition extensions

Channel infoRoundTripTimeRxLevel

WiMax extension schemaTerminal definition

MAC addressIP address

Access definition extensionBTS ID

Vendor X extension schemaVendor XProduct WAP-FamilyY-ModelZAccess definition extensions

Channel infoRoundTripTimeRxLevel

ALE

NetworkController

FLAP

IP@ BTS ID f(Channel, RoundTripTime, RxLevel)Location

IP@ BTS ID Location

Generic LIS record

Vendor X proprietary support LIS recordlocation is determined by an algorithm which is a function of RF signal strength and timing measurements supported by the WiMax manufacturer

WiMax BTS

November 2007


Slide 17

doc.: IEEE 802.11-07/2889r0

Submission

Example – A DSL Aggregator ALE

LIS

ALE

FLAP

Copper PVC IP

Device ATU-R DSLAM

ATM

DSLAggregator

ISP/Enterprise

DSL Aggregator extension schema

Terminal definition

IP address

Access definition extension

Aggregation device ID

ATM port ID

PVC ID

DSL Aggregator extension schema

Terminal definition

IP address


Aggregation device ID

ATM port ID

PVC ID

IP@ Aggregation device ID

ATM Port PVC Location

November 2007


Slide 18

doc.: IEEE 802.11-07/2889r0

Submission

Example – Ethernet Switch ALE

LIS

Ethernet

Switches

IP

Ethernet switch extension schemaTerminal definition

MAC address

IP address


Switch ID

Switch address

Port ID

VLAN ID

Ethernet switch extension schemaTerminal definition

MAC address

IP address


Switch ID

Switch address

Port ID

VLAN ID

ALE

ALE

ALE

Switch

FLAP

IP@ Switch ID Port ID Location

November 2007


Slide 19

doc.: IEEE 802.11-07/2889r0

Submission

Example – 802.11x Access Point ALE

LIS

IP

802.11x AP extension schemaTerminal definition

MAC address

IP address


WAP ID

Channel No

Vendor X extension schemaVendor X

Product WAP-FamilyY-ModelZ

Access definition extensions

RoundTripTime

RxLevel

802.11x AP extension schemaTerminal definition

MAC address

IP address


WAP ID

Channel No

Vendor X extension schemaVendor X

Product WAP-FamilyY-ModelZ

Access definition extensions

RoundTripTime

RxLevel

ALEALE

Switch

FLAP

IP@ WAP ID f(Channel, RoundTripTime, RxLevel)Location

IP@ WAP ID Location

WAP

Generic LIS record

Vendor X proprietary support LIS recordlocation is determined by an algorithm which is a function of RF signal strength and timing measurements supported by the AP manufacturer

November 2007


Slide 20

doc.: IEEE 802.11-07/2889r0

Submission

LIS-ALE Procedures

LIS

Device data

Update queries Access device

ALE

Device

Device

Device Device

• FLAP supports the transmission, including periodic updates, of location measurement information to the LIS as it applies to connected devices.

• FLAP messaging is based on streamed XML and a secure and reliable transport is required. * BEEP with TLS is the recommended transport and session protocol.

1. LIS starts up2. LIS establishes FLAP sessions* with ALEs in area of coverage3. LIS optionally requests synchronization information from ALEs4. ALEs report measurements as device-related events occur5. LIS optionally informs ALEs if devices detected elsewhere6. LIS optionally polls ALEs for measurements as HELD requests occur

November 2007


Slide 21

doc.: IEEE 802.11-07/2889r0

Submission

Incorporating device measurementsExternal applications

Access Network LIS

User Device

FLAP

Location dereference request path

Networkmeasurement

requests

Devicemeasurement

requests

Networkmeasurements

Other measurements


(e.g. GPS, RFID beacons)

Other measurements

Internet


(e.g. GPS, LMUs)

Device measured location parameters

As a generic constraint, a LIS cannot assume specific measurement capabilities or protocols supported by visiting devices. However, these capabilities should not be ignored.

As a generic constraint, a LIS cannot assume specific measurement capabilities or protocols supported by visiting devices. However, these capabilities should not be ignored.

November 2007


Slide 22

doc.: IEEE 802.11-07/2889r0

Submission

Device based measurements• In addition to the device being able to make measurements and perform location determination independently, it may be able to: - Provide the raw measurements to the LIS and leave the location determination process up to the LIS - e.g. the device takes wireless RF measurements but the LIS applies these measurements to base station data to calculate location

- Perform the location determination itself but need the assistance of the LIS as part of taking the necessary measurements - e.g. the device can perform GPS but needs GPS assistance data. The LIS calculates approximate location and delivers assistance data.

• The specific protocols used to perform such co-operative location determination can be outside the scope of HELD - E.g. SUPL for AGPS operations or SNMP for LLDP related measurement transfer.• HELD supports the exchange of a “client capability” parameter set between the device and the LIS

- The device volunteers its capabilities and the LIS responds with an indication of which may be supported - Extension types are used in the HELD protocol to identify the specifics of these protocols.

IPdevice

LIS

AccessNetwork

ALE FLAP

LocReqResp(LocCap(SubTechList(…))

GPSsatellites

LocReq( Type(locationURI), LocCap(TechList(…))

AppProtocol(LocationURI)

LocReq(signed)

1

3

4

2

HELD

Protocol specific message exchange Selected Location Technology protocol

5

5

Application

6

LocResp

November 2007


Slide 23

doc.: IEEE 802.11-07/2889r0

Submission

Summary

• FLAP:– Does not convey location– Facilitates location parameter conveyance to LIS, from ALE– Being worked in ESIF (a division of ATIS).

• HELD:– Location dereferencing/conveyance protocol– A standards track specification from IETF/Geopriv

• ESIF/NGES plan to shortly send a liaison to IEEE requesting input on this development effort to create location parameter conveyance framework, in support of next generation emergency services.

November 2007


Slide 24

doc.: IEEE 802.11-07/2889r0

Submission

References

• Technical Report: Location Acquisition and Location Parameter Conveyance for Internet Access Networks in Support of Emergency Services (Draft); Doc#: ATIS-xxxxxx; Source - ESIF

doc.: ieee 802.11-07/2889r0 submission november 2007 vijay patel, andrew corporationslide 1 lis-ale...

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