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IEEE 802.21 MEDIA INDEPENDENT HANDOVER

DCN: 21-06-0816-00-0000

Title: 802.21 – TGu Joint Discussions

Date Submitted: November, 2006

Presented at IEEE 802.21 session #17 in Dallas, Texas.

Authors or Source(s):

Vivek Gupta

Abstract: Inputs from 802.21 to questions from TGu

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TGu Inputs

• 11-06-1492-00-000u tgu-802-21-joint-session-update-tgu-network-selection-mih-support

• 11-06-1543-00-000u-planning-november-2006-joint-session-between-802-21-and-802-11u

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Discussion Items

• Information Service• List of IEs• Query Language• Static/Dynamic IEs• State 1 vs State 3 query• Maximum message length in State 1 Issues

• MIH Events• MLME implications

• Security Implications

• Next Steps

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Network Discovery & Selection for 802.11

• Applicable in two cases:

When MN is ALREADY connected to some other network and needs to Handover an existing connection to 802.11o The 802.11 radio may be in OFF state in this caseo When evaluating 802.11 networks the Network Selection entity (in MN or

Network) may need to know more about 802.11 network properties even before deciding to Power On the 802.11 radio

o 802.21 IS can provide these properties

When MN is NOT connected to any network and needs to select an appropriate 802.11 network to connect too 802.11 may be the DEFAULT radio to connect to on Power up or 802.11

may be the only network coverage available in that area

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802.11 based Reference Network

802.21 IS

Hot Spot #1 Hot Spot #N

NAPCore Network

NAP NOC

AAA

SSPN #2Core Network

802.21 IS

SSPN #2 NOC

AAA

SSPN #1Core Network

802.21 IS

SSPN #1 NOC

AAA

InternetTunnel

Tunnel

MIH MIH

Use 802.21 as Protocol for Network Selection

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802.21 Information Service

• Multiple Networks of different Network_Type may be available in a particular geographical area:

• 802.11, 802.16, Cellular

• For each Network_Type (such as 802.11) there may be several operators, providing several instances of a particular Network_Type

• Operator_A, Operator_B, etc. may all have 802.11 network• The properties of these network instances may be different

• 802.11 Network Standards they support (.11a/b/e/g/i/n/p/r/s/u/v…)• Cost, Security, Roaming Agreements etc. for these networks may be different

• For each of the above Network Instance, there are different PoAs (APs for 802.11)

• The properties of these APs may differ• Location, Subnet Information, Capabilities, etc.

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802.21 Information Service

List of Access Network Types

(802.11, 802.16, Cellular)

Access Network Properties802.11 Network from Operator_A 802.11 Network from Operator_B 802.16 Network from Operator_A

802.16 Network from operator_C

PoA Specific Properties

Properties of each AP/BS

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Information Element

Description Comments

General Network Information (List of Networks)

Network Type List of all Network types that are available in a particular area

E.g., 802.11, 802.16, CDMA, UMTS Networks (Table-8)

Operator Identifier

Core Network Identifier Operator Type + Operator name

Service Provider

Provider of services Service (such as VoIP) Provider name

(May not be applicable in all cases)

Information Elements-1

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Information Element

Description Comments

Access Network specific InformationAccess Network Identifier

Used to uniquely identify access network.

For example ESSID in case of 802.11

Roaming Partners Roaming partners that have agreement with Access Network operator

SSPN partners for 802.11

Network Standards

Access Network specific applicable revisions to base standards

(a/b/e/g/i/k/n/p/r/s/t/u/v/….)

Cost Cost of accessing the network Currency+Unit+Value+Service-Info (Table-10)

Security Authentication Methods and Cipher Suites

QoS Packet Transfer Delay (Min/Max/Avg)

Jitter

Packet Loss Rate Packet Error Rate

Information Elements-2

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Information Element

Description Comments

PoA specific Information

Address MAC Address BSSID

Location PoA location See Table 11,12,13

Data Rate Min-Max Range

Channel Range

Spectrum Range

Subnet Information

List of subnets to which PoA belongs

PoA Capabilities

Services Supported

IP Config Methods

DHCP, etc.

Information Elements-3

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What 802.11 Information should be stored in 802.21 Information Server?

• Guiding principles• Put the minimum information needed by STA for network selection

and network identification—minimizes synchronization problems between configuration of 802.11 AN and 802.21-IS database

• Include support for two types of queries:• Remote query (state 3 query): I’m in San Francisco and want to find out what

hotspots are in Melbourne• Local query (state 1 query): I can see 3 hotspots now, which one is the best to

associate with? 802.21 IS does NOT distinguish between Access Network States

• Do not include 802.11 AN dynamic information; examples include:• Channel number, • Transmit power• Traffic Load

None of the above are included in IS

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What 802.11 Information should be stored in 802.21 Information Server (cont.)?

• Fundamental binding provided by 802.21-IS• SSPN to WLAN • WLAN identified by {SSID, ESSID} (Supported)

• Recommended information to store in 802.21 database:• SSPN name/realm (Is this same as Operator Identifier?)• SSPN roaming partners (Supported)• Interworking services by SSPN (including emergency services)

(Supported)

• 802.11 AN parameters: Location Country/regulatory domain {SSID, ESSID}• PHY types supported 802.11e QoS support(Supported Phy types can be obtained from Network_Standards)

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(4) (1)VER Ack

(1)Reserved

(10)MIH Message ID

(16)

Transaction ID(16)

Va riable Load Length(16)

SID(4)

Opcode(2)

Action ID(10)

MIHF VaVariable Header(contains Header Identifiers in TLV format)

MIHF Payload(contains other service specific TLV s)

RspAckReq

Octet 1 Octet 2 Octet 3 Octet 4

MIHF

Header

MIHF Variable

Fixed

Load

F

MIHF Fixed Header

MIHF Variable Header

MIHF Payload

MIH Function Frame

MIHF Protocol

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Field Name Size (bits)

Description

Version 4 0: Not used, 1: Current Version, 2-15 Reserved

ACK_Req 1 Request an Acknowledement (N/A for 802.11)

ACK_Rsp 1 Respond to Acknowledgement (N/A for 802.11)

Reserved 10

MIH Message ID

- Service Id (SID)

- Operation Code (Opcode)

- Action Identifier (AID)

16

4

2

10

Combination of following three bit-fields

1: System Mgmt 2: Event Service3: Command Service 4: Information Service

1: Request, 2:Response, 3:Indication

Specific Action to be taken

Transaction ID 16 To match Requests and Response

Variable Load Length 16 Total length of Variable load field

MIHF Protocol – Fixed Header

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• Variable Header fields (Optional)

• Session Identifier• MIHF Identifier

MIHF Protocol – Variable Header

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MIHF IS Query Request

Ver (0) Ack (0) Reserved (0)Rsp (0) SID (4) OpCode (1) AID (21)

Transaction Identifier Payload Length

MIH_Get_Information.Request-- IS Info Query Type-- IS Query Parameters

Type = 4 Length = 1 Value = 1 (TLV)

Fixed Header

Payload

Information Service Request

MIH_Get_Information

IS Info Query Type

Type= 36 Length = ? Value = 1 (TLV Parameters)

IS Query Parameters: Location, Span/Radius, etc.

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MIHF IS Query Response

Ver (0) Ack (0) Reserved (0)Rsp (0) SID (4) OpCode (2) AID (21)

Transaction Identifier Payload Length

MIH_Get_Information.Response-- IS Info Query Type-- IS Response Parameters

Type = 4 Length = 1 Value = 1 (TLV)

Fixed Header

Payload

Information Service Response

MIH_Get_Information

IS Info Query Type

Type= 37 Length = ? Value = 1 (TLV Parameters)

IS Response Parameters…..

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• TLV Containers• List of Access Networks Container

• TYPE_CONTAINER_LIST_OF_NETWORKS

• Access Network Container• TYPE_CONTAINER_NETWORK

• PoA Container• TYPE_CONTAINER_POA

• Other Query parameters• Client Location• Radius of interest for networks

• Queries• Any IE can be queried.• Any number of IEs can be queried in same request

MIHF Supported TLV Query Types

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TGu- Query Examples

• What WLANs support my subscriptions?• STA: provides list of subscriptions• 802.21-IS: provides list of {SSPN, SSID, ESSID} where SSPN’s

includes roaming partners• Need to add

• Is emergency service supported on this WLAN?• STA: provides ESSID(s)• 802.21-IS: provides list of {SSPN, SSID, ESSID} • Need to add

• What interworking services are supported on this WLAN?• STA: provides ESSID(s)• 802.21-IS: provides list of {SSPN, SSID, ESSID, interworking services} • Supported (PoA capabilities IE)

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TGu - Query Examples (cont.)

• Is VoIP services provided on this WLAN?• STA: provides ESSID(s)• 802.21-IS: provides list of {SSPN, SSID, ESSID} which

support VoIP• Note that VoIP is just an example; query could be for any

interworking service• Need to add

• I’m traveling to Melbourne, what hotspots are located there?• STA: provides location (latitude, longitude), search radius• 802.21-IS: provides list of {SSPN, SSID, ESSID} • This could potentially generate a lengthy query response• Supported

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AP to 802.21-IS Protocol Issues

• Mechanism to limit size of Query Response• Important only when client is in state 1• When client is in state 3, any query response length is

acceptable

• Mechanism to identify final fragment of a multi-fragment Query Response

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• Link Layer Events

• MIH Events• Can be local or remote• Remote MIHF entity has to subscribe for events it is interested in• Delivery through MIHF protocol

Event Service

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No Event Name Description New MLME Primitive

1 Link Up L2 Connection established Exists

2 Link Down L2 Connection is broken N/A

3 Link Going Down

L2 connection breakdown imminent May be Needed

4 Link Detected New L2 link has been found N/A

5 Link Parameters Change

Change in specific link parameters has crossed pre-specified thresholds (Link Speed, Quality metrics)

May be Needed

6 Link Event Rollback

Event rollback May be Needed

7 Link SDU Transmit Status

Improve handover performance through local feedback as opposed to waiting for end-to-end notifications

N/A

8 Link Handover Imminent

L2 intra-technology handover imminent (subnet change). Notify Handover information without change in link state.

May be Needed (TGr may be covering this)

9 Link Handover Complete

Notify Handover state May be Needed

Link Layer Events

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Next Steps

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Backup