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IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-06-0817-01-0000 Title: 802.21 – TGu Joint Discussions Date Submitted: December, 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 1 TGu Inputs • 11-06-1492-00-000u tgu-802-21-joint-session-update-tgunetwork-selection-mih-support • 11-06-1543-00-000u-planning-november-2006-joint-sessionbetween-802-21-and-802-11u 2 Discussion Items 1. Initial Network Selection vs Handovers 2. Information Elements Organization 3. Static vs Dynamic IEs 4. Queries 5. Maximum message length in State 1 Issues 6. MIH Events 7. MLME primitives 8. Security Implications 9. Next Steps 3 1. Initial Network Selection vs Handovers • 802.21 IS Applicable in two cases: When MN is ALREADY connected to some other network and needs to Handover an existing connection to 802.11 o o o The 802.11 radio may be in OFF state in this case 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 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 to o 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 4 1. Initial Network Selection vs Handovers • During the joint session of Sept, 802.21 we discussed the difference between initial network selection and handover. Please provide details on what is different that impacts our interface (802.11 > 802.21) • Does 802.21 expect 802.11u to provide any service beyond network selection which is already defined? • E.g., does 802.21 expect 802.11u to pre-provision QoS? • From 802.21 perspective there is NO difference in the two cases • IS can be used in both state-1 and state-3 5 2.Information Elements Organization • 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. • Feedback from Dallas: Most of PoA information may be common. Provide single instance of this information at Access Network level 6 2.Information Elements Organization List of Access Network Types (802.11, 802.16, Cellular) Access Network Properties 802.11 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 7 Information Elements-1 Information Element Description Comments General Network Information (List of Networks) Network Type Operator Identifier Service Provider List of all Network types that are available in a particular area Core Network Identifier E.g., 802.11, 802.16, CDMA, UMTS Networks (Table-8) Provider of services Service (such as VoIP) Provider name Operator Type + Operator name (May not be applicable in all cases) 8 Information Elements-2 Information Element Description Comments Access Network specific Information Access 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 Access Network specific applicable revisions to base standards Cost of accessing the network SSPN partners for 802.11 Network Standards Cost Security QoS (a/b/e/g/i/k/n/p/r/s/t/u/v/….) Currency+Unit+Value+Service-Info (Table-10) Authentication Methods and Cipher Suites Packet Transfer Delay (Min/Max/Avg) Jitter Packet Loss Rate Packet Error Rate 9 Information Elements-3 Information Element Description Comments Address PoA specific Information MAC Address BSSID Location PoA location Data Rate Min-Max Range Channel Range Subnet Information PoA Capabilities IP Config Methods Spectrum Range See Table 11,12,13 List of subnets to which PoA belongs Services Supported DHCP, etc. 10 2.Information Elements Organization • Changes in Draft: • Change organization of IEs and provide common PoA information as part of Access Network Properties • Location of Network • Data Rate • PoA Capabilities (Services supported by network) • IP Config Methods • Leave following as PoA properties • MAC Address • Channel Range • Location of PoA • Subnet Information 11 3. Static vs Dynamic IEs • What 802.11 IEs should be stored on 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 12 3. Static vs Dynamic IEs • What 802.11 IEs should be stored on Information Server? • 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 (Supported) • 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) 13 3. Static vs Dynamic IEs • QoS Parameters in current 802.21 draft: • • • • • • • • Throughput Link Packet Error Rate Supported number of Classes of Service Min Packet Transfer Delay Avg Packet Transfer Delay Max Packet Transfer Delay Packet Transfer Delay Jitter Packet Loss Rate • Does it make sense to add these? 14 4. Queries • TLV Containers • List of Access Networks Container • • Access Network Container • • TYPE_CONTAINER_LIST_OF_NETWORKS 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 15 4. Queries • 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) 16 4. Queries • Query Examples • 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 17 5. Maximum Message Length Issues • From TGu: • Proposal to define a maximum message length for state-1 query—merge proposal with 802.11u proposal during meeting • 802.11u should present the requirements we’ve identified for using GAS will be met by 802.21 services • Message lengths • Freshness of information • Synchronization between AP configuration data and 802.21IS database • Contribution IEEE 802.11-06/1784r0 by Dave Stephenson et al 18 6. Event Service • 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 19 6. Event Service/MLME Primitives No Event Name 1 2 3 Link Up Link Down Link Going Down Link Detected Link Parameters Change L2 Connection established L2 Connection is broken L2 connection breakdown imminent Link Event Rollback Link SDU Transmit Status Event rollback 8 Link Handover Imminent L2 intra-technology handover imminent (subnet change). Notify Handover information without change in link state. 9 Link Handover Complete Notify Handover state 4 5 6 7 Description New L2 link has been found Change in specific link parameters has crossed pre-specified thresholds (Link Speed, Quality metrics) Improve handover performance through local feedback as opposed to waiting for end-toend notifications New MLME Primitive Exists N/A May be Needed N/A May be Needed May be Needed N/A May be Needed (TGr may be covering this) May be Needed 20 8.Security Implications • Describe security implications of session hand-off between networks (e.g., Wi-Fi to Cellular) • For example, if Wi-Fi network only has WEP-40 encryption, will cellular network accept the handoff? • The STA needs to know acceptable security levels for different technologies and provide appropriate credentials. 21 Next Steps • Prepare text contribution highlighting these issues • File appropriate comments as part of 802.21 LB #1b 22 Backup 23 802.11 based Reference Network NAP NOC SSPN #1 NOC 802.21 IS AAA 802.21 IS AAA MIH SSPN #1 Core Network MIH NAP Core Network SSPN #2 NOC Internet 802.21 IS AAA SSPN #2 Core Network Hot Spot #1 Hot Spot #N Use 802.21 as Protocol for Network Selection 24 MIHF Protocol MIHF Fixed Header MIHF Variable Header MIHF Payload MIH Function Frame Opcode (2) SID (4) Octet 1 VER Ack MIHF Fixed F Header MIHF Variable Load (4) Octet 2 Ack Req (1) Rsp(1) Reserved (10) Transaction ID (16) Octet 3 Action ID (10) Octet 4 MIH Message ID (16) Va riable Load Length (16) MIHF VaVariable Header (contains Header Identifiers in TLV format) MIHF Payload (contains other service specific TLV s) 25 MIHF Protocol – Fixed Header 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 16 Combination of following three bit-fields - Service Id (SID) 4 1: System Mgmt 2: Event Service 3: Command Service 4: Information Service - Operation Code (Opcode) 2 1: Request, 2:Response, 3:Indication - Action Identifier (AID) 10 Specific Action to be taken Transaction ID 16 To match Requests and Response Variable Load Length 16 Total length of Variable load field 26 MIHF IS Query Request MIH_Get_Information.Request -- IS Info Query Type -- IS Query Parameters Information Service Request MIH_Get_Information Fixed Header Ver (0) Ack (0) Rsp (0) Reserved (0) Transaction Identifier Payload SID (4) OpCode (1) AID (21) Payload Length IS Info Query Type Type = 4 Length = 1 Value = 1 (TLV) Type= 36 Length = ? Value = 1 (TLV Parameters) IS Query Parameters: Location, Span/Radius, etc. 27 MIHF IS Query Response MIH_Get_Information.Response -- IS Info Query Type -- IS Response Parameters Information Service Response MIH_Get_Information Fixed Header Ver (0) Ack (0) Rsp (0) Reserved (0) Transaction Identifier Payload SID (4) OpCode (2) AID (21) Payload Length IS Info Query Type Type = 4 Length = 1 Value = 1 (TLV) Type= 37 Length = ? Value = 1 (TLV Parameters) IS Response Parameters….. 28