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Content for  TS 23.402  Word version:  17.0.0

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4.8.2a  UE Procedures |R12|p. 67

4.8.2a.1  Selection of Active ANDSF Rulesp. 67

The UE may be provisioned with multiple valid ISMP, ISRP, IARP and WLANSP rules (by the HPLMN and by the VPLMN when it is roaming). The UE does not apply all these valid rules but selects and applies only the "active" rules. Specifically:
  • A UE that cannot simultaneously route IP traffic over 3GPP access and over WLAN access shall select an active ISMP rule, an active IARP rule and an active WLANSP rule, as specified below.
  • A UE that can simultaneously route IP traffic over 3GPP access and over WLAN access shall select an active ISRP rule, an active IARP rule and an active WLANSP rule, as specified below.
When the UE is not roaming, it shall select the active ISMP/ISRP rule, the active IARP rule and the active WLANSP rule to apply from the valid rules provided by the HPLMN based on the individual priorities of these rules (or based on other criteria specified in TS 24.312). For example, the highest priority valid WLANSP rule is selected as the active WLANSP rule.
When the UE is roaming, it may have valid rules from both HPLMN and VPLMN. In this case, the UE shall select the active rules as follows:
  1. The active IARP rule is selected from the valid IARP rules provided by the HPLMN.
  2. The active ISMP/ISRP rule and the active WLANSP rule are selected based on the UE configuration as follows:
    1. The UE is configured to "prefer WLAN selection rules provided by the HPLMN" or not. This configuration can be done either by the user or by the H-ANDSF via the list of "VPLMNs with preferred WLAN Selection Rules" (see clause 4.8.2.1.7). User configuration takes precedence over the H-ANDSF configuration.
    2. If the UE is configured not to prefer WLAN selection rules provided by the HPLMN (i.e. the VPLMN to which the UE is registered is included in the list of "VPLMNs with preferred WLAN Selection Rules"), then the UE shall check the WLANSP rule of the VPLMN and shall determine if there are available WLAN access networks that match one or more groups of selection criteria in this rule.
      1. If there is at least one WLAN access network that matches one or more groups of selection criteria in the WLANSP rule of the VPLMN, then the UE shall select the active WLANSP rule and the active ISMP/ISRP rule from the valid rules provided by the VPLMN (based on their priority values).
      2. If there is no WLAN access network that matches one or more groups of selection criteria in the WLANSP rule of the VPLMN, then the UE shall select the active WLANSP rule and the active ISMP/ISRP rule from the valid rules provided by the HPLMN. When the UE determines that at least one WLAN access network that matches one or more groups of selection criteria in the WLANSP rule of the VPLMN becomes available, it shall operate as in bullet i) above and may re-select to such WLAN access network.
    3. If the UE is configured to prefer WLAN selection rules provided by the HPLMN (i.e. the VPLMN to which the UE is registered is not included in the list of "VPLMNs with preferred WLAN Selection Rules"), then the UE shall check the WLANSP rule of the HPLMN and shall determine if there are available WLAN access networks that match one or more groups of selection criteria in this rule.
      1. If there is at least one WLAN access network that matches one or more groups of selection criteria in the WLANSP rule of the HPLMN, then the UE shall select the active WLANSP rule and the active ISMP/ISRP rule from the valid rules provided by the HPLMN (based on their priority values).
      2. If there is no WLAN access network that matches one or more groups of selection criteria in the WLANSP rule of the HPLMN, then the UE shall select the active WLANSP rule and the active ISMP/ISRP rule from the valid rules provided by the VPLMN. When the UE determines that at least one WLAN access network that matches one or more groups of selection criteria in the WLANSP rule of the HPLMN becomes available, it shall operate as in bullet i) above and may re-select to such WLAN access network.
During power-up, while the UE has not registered to any PLMN, the UE shall consider the WLANSP rules provided by the HPLMN as valid and shall select an active WLANSP rule as described above (the one with the highest priority). Thus during power-up the UE can select a WLAN network based on the WLANSP rules provided by HPLMN.
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4.8.2a.2  UE Behavior Based on the ANDSF Informationp. 68

This clause specifies the UE behavior when it is provisioned with ANDSF information and has selected the active rules as described in the previous clause.
If the UE has received or has been provisioned with ANDSF information which indicates that there is an access network in its vicinity with higher priority than the currently selected access network(s), the UE should perform procedures for discovering and reselecting the higher priority access network, if this is allowed by user preferences.
(i)
When the UE cannot simultaneously route IP traffic over multiple radio accesses:
  • The UE shall select the most preferable available access network for EPC connectivity and inter-system mobility based on the active ISMP rule, the active WLANSP rule and the user preferences. The user preferences take precedence over the active rules.
  • The UE shall not consider any ISRP rules it may have received from the ANDSF.
  • When automatic access network selection is used, the UE shall not initiate a connection to EPC using an access network indicated as restricted in the active ISMP rule.
  • When the UE selects a non-3GPP radio access based on the active ISMP and the active WLANSP rules, the UE may still use 3GPP access for CS services.
  • When the UE is connected to EPC over 3GPP access, the UE shall use the active IARP rule and the user preferences to determine if an IP flow should be routed inside a specific PDN connection.
  • When the UE is connected to EPC over WLAN access, the UE shall use the active IARP rule and the user preferences to determine if an IP flow should be routed inside a specific PDN connection or if it should be non-seamlessly offloaded to the selected WLAN access network.
  • The UE shall use the active ISMP rule to determine if EPC connectivity is preferred over WLAN access or over 3GPP access. The prioritized list of access networks in the active ISMP rule shall not be used for WLAN selection since WLAN selection is based on the active WLANSP rule and the user preferences.
  • When EPC connectivity is preferred over WLAN access (i.e. the highest priority access in the active ISMP rule corresponds to WLAN access technology / network), the UE shall use the active WLANSP rule to determine the most preferred available WLAN access network (as specified in clause 4.8.2b).
  • When the UE is connected to EPC over WLAN access, the UE should occasionally re-evaluate if the connected WLAN still meets the selection criteria in the active WLANSP rule. The rate of this re-evaluation is defined by the UE implementation. When the UE determines that the currently selected WLAN does not meet the selection criteria in the active WLASP rule for an implementation-specific duration, the UE should attempt to select another WLAN access network as specified in clause 4.8.2b.
  • When the most preferred available WLAN access network has higher priority than 3GPP access (according to the prioritized accesses in the active ISMP rule), then the UE shall connect to EPC over the most preferred available WLAN access network. Otherwise, the UE shall connect to EPC over 3GPP access. For example:
    • If the prioritized access networks in the active ISMP rule are the following: WLAN-A priority 1, 3GPP priority 2, WLAN-B priority 3; then
    • Since the UE determines that one or more WLANs are preferred for EPC connectivity over 3GPP access, the UE uses the groups of selection criteria in the active WLANSP rule to determine the most preferred available WLAN access network (as specified in clause 4.8.2b).
    • If the most preferred available WLAN access network has lower priority than 3GPP access according to the active ISMP rule (e.g. WLAN-B), then the UE shall connect to EPC over 3GPP access.
    • If the most preferred available WLAN access network has higher priority than 3GPP access according to the active ISMP rule (e.g. WLAN-A), then the UE shall connect to EPC over the most preferred available WLAN access network.
(ii)
When the UE can simultaneously route IP traffic over multiple radio accesses:
  • The UE shall not consider any ISMP rules it may have received from the ANDSF.
  • The UE shall use the active WLANSP rule and the user preferences to select and connect to the most preferred available WLAN access network, as specified in clause 4.8.2b. User preferences take precedence over the active WLANSP rule. After that, the UE is simultaneously connected to 3GPP access and to the selected (most preferred) WLAN access network.
  • After the UE selects and connects to a WLAN access network based on the active WLANSP rule (as specified in clause 4.8.2b), the UE should occasionally re-evaluate if the connected WLAN still meets the selection criteria in the active WLANSP rule. The rate of this re-evaluation is defined by the UE implementation. When the UE determines that the currently connected WLAN does not meet the selection criteria in the active WLASP rule for an implementation-specific duration, the UE should attempt to select another WLAN access network as specified in clause 4.8.2b.
  • The prioritized lists of access networks in the active ISRP rule shall not be used for WLAN selection since WLAN selection is based on the active WLANSP rule and the user preferences.
  • The UE shall use the active ISRP for MAPCON rules and the user preferences to determine if a PDN connection to a certain APN should be established over 3GPP access or over the selected WLAN access network.
    • When an ISRP for MAPCON rule is used for the PDN connection establishment, the UE shall determine if the selected WLAN access network has higher priority than 3GPP access and establishes the PDN connection accordingly. For example:
      • If the list of prioritized access networks in the ISRP for MAPCON rule are the following: WLAN-A priority 1, 3GPP priority 2, WLAN-B priority 3; then
      • If the UE has selected WLAN-B (or any WLAN network with lower priority than 3GPP access), it shall establish the PDN connection over 3GPP access.
      • If the UE has selected WLAN-A (or any WLAN network with higher priority than 3GPP access), it shall establish the PDN connection over WLAN access.
  • The UE shall use the active ISRP for IFOM rules, the active ISRP for NSWO rules, the active IARP rule and the user preferences to determine how to route outgoing IP flows. Specifically:
  • The UE shall evaluate the above rules in priority order as specified in clause 4.8.2.1.5 (Inter-APN Routing Policy) and shall determine which rule to apply.
  • When the applied rule is an ISRP for IFOM rule, the UE determines that this flow is subject to IP flow mobility and selects an access network to route this flow based on the prioritized list of access networks in the ISRP for IFOM rule. For example:
    • If the prioritized list of access networks in the ISRP for IFOM rule are the following: WLAN-A priority 1, 3GPP priority 2, WLAN-B priority 3; then
    • If the UE has selected WLAN-B (or any WLAN network with lower priority than 3GPP access), it shall route the IP flow over 3GPP access.
    • If the UE has selected WLAN-A (or any WLAN network with higher priority than 3GPP access), it shall route the IP flow over WLAN access.
  • When the applied rule is an ISRP for NSWO or an IARP for NSWO rule, the UE shall route this IP flow to the selected WLAN access network (outside any PDN connection) provided that the rule does not prohibit this IP flow over the selected WLAN access network.
  • When the applied rule is an IARP for APN rule, the UE shall route this IP flow inside the PDN connection specified by this rule.
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4.8.2b  WLAN Selection based on WLANSP |R12|p. 70

When the UE has valid 3GPP subscription credentials (i.e. a valid USIM) and WLANSP policies, the UE shall perform WLAN selection based on these policies, the applicable user preferences and the corresponding procedures specified in this document. User preferences take precedence over the WLANSP policies.
The following text specifies how the UE determines the most preferred WLAN access network (and possibly connects to this network, as clarified in clause 4.8.2a.2), when a WLAN access network cannot be selected based on user preferences (e.g. when there are no user preferences or when there is no user-preferred WLAN access network available).
If the UE supports S2a connectivity (see clause 16), then:
  • The UE shall be able to discover WLANs that support S2a connectivity. This discovery shall be performed by using ANQP procedures (as specified in the HS2.0 Rel 2 specification [75]) to retrieve the 3GPP Cellular Network information advertised by WLANs. The 3GPP Cellular Network information (see IEEE 802.11-2012 [64]) advertised by a WLAN indicates the PLMNs that interwork with the WLAN. In addition, the 3GPP Cellular Network information indicates the PLMNs to which the WLAN supports S2a connectivity.
  • The UE shall be able to discover WLANs that support emergency services. This discovery shall be performed by using ANQP procedures (as specified in the HS2.0 Rel 2 specification [75]) to retrieve the 3GPP WLAN Support of Emergency Services information advertised by WLANs.
  • The UE may decide to select a WLAN that supports S2a connectivity to HPLMN, RPLMN or both HPLMN and RPLMN. This decision is based on UE implementation specific mechanisms and the "S2a connectivity preference" provisioned in the UE by the home ANDSF. The "S2a connectivity preference" is either set or not set. The UE performs service provider selection after selecting a WLAN that has S2a connectivity with the UE's HPLMN, RPLMN or both HPLMN and RPLMN.
  • When the "S2a connectivity preference" is set, it indicates that the home operator prefers the UE to establish PDN connections over WLAN by using the applicable S2a procedures specified in clause 16. In this case, when the UE attempts to select a WLAN and determines that a PDN connection will be required over this WLAN, the UE shall attempt to select a WLAN that supports S2a connectivity unless other procedures are applicable for this PDN connection (e.g. S2b or S2c procedures).
The UE shall use the active WLANSP rule, the Home Network Preferences and, if roaming, the Visited Network Preferences to determine the most preferred available WLAN access network. The WLAN selection shall be performed with the following steps.
  1. Step 1: The UE constructs a prioritized list of the available WLANs by discovering the available WLANs and comparing their attributes / capabilities against the groups of selection criteria in the active WLANSP rule. If the UE requests emergency services, the prioritized list shall only contain available WLANs that support emergency services. When a group of selection criteria includes the HomeNetwork attribute and is set, then the UE (a) shall create a list of available WLANs that directly interwork with the home operator (as specified in clause 4.8.2.1.6) and (b) shall apply the group of selection criteria to all the WLANs in this list. Otherwise, when the HomeNetwork attribute is not set or is not present, the UE shall apply the group of selection criteria to all available WLANs. The UE may need to perform ANQP procedures (as specified in the HS2.0 Rel 2 specification [75]) or other procedures in order to discover the attributes / capabilities of the available WLANs. The WLAN(s) that match the group of selection criteria with the highest priority are considered as the most preferred WLANs, the WLAN(s) that match the group of selection criteria with the second highest priority are considered as the second most preferred WLANs, etc. For example, the UE may construct the following prioritized list:
    • WLAN-1 (most preferred)
    • WLAN-4, WLAN-2 (second most preferred)
    • WLAN-3 (third most preferred, supports S2a connectivity to PLMN-a and PLMN-b)
  2. Step 2: If the UE decides to select a WLAN that supports S2a connectivity to one or more PLMNs (as specified above), then from the prioritized list contructed in the previous step the UE shall select the highest priority WLAN that support S2a connectivity to these PLMNs (e.g. WLAN-3 in the example shown above). If the UE does not discover a WLAN that supports S2a connectivity, or the UE does not decide to select a WLAN that supports S2a connectivity, then from the prioritized list contructed in the previous step the UE shall select the most preferred WLAN without considering its capability to support S2a connectivity (e.g. WLAN-1 in the example shown above).
    • If the UE cannot select a single WLAN in this step, i.e. when there are multiple WLANs that could be selected but all have the same priority, then the UE shall select one of these multiple WLANs as follows:
      1. If the UE is not roaming, or if the UE is roaming and the "prefer 3GPP RPLMN" indication is not set, then the UE shall select a WLAN in this order: (a) a WLAN that directly interworks with the HPLMN, (b) a WLAN that directly interworks with a service provider in EHSP, (c) a WLAN that directly interworks with the most preferred service provider in PSPL.
      2. If the UE is roaming and the "prefer 3GPP RPLMN" indication is set, then the UE shall select a WLAN in this order: (a) a WLAN that directly interworks with the RPLMN, (b) a WLAN that directly interworks with a service provider in EVSP. Otherwise the UE shall behave as specified in bullet a) above.
  3. Step 3: After selecting a single WLAN access network (as specified in steps 1 and 2), if the UE needs to perform 3GPP-based access authentication, the UE shall construct the NAI as follows:
    1. If the UE is not roaming, or if the UE is roaming and the "prefer 3GPP RPLMN" indication is not set, then:
      • If the UE has selected a WLAN that directly interworks with the HPLMN, then the UE shall use the root NAI.
      • If the UE has selected a WLAN that directly interworks with a service provider in EHSP list (see clause 4.8.2.1.9), then the UE shall construct a decorated NAI that includes the realm of this service provider.
      • Otherwise, the UE shall determine the most preferred service provider that interworks with the selected WLAN based on PSPL and shall construct a decorated NAI that includes the realm of this service provider.
    2. If the UE is roaming and the "prefer 3GPP RPLMN" indication is set, then:
      • If the UE has selected a WLAN that directly interworks with the RPLMN, then the UE shall construct a decorated NAI that includes the realm of RPLMN.
      • If the UE has selected a WLAN that directly interworks with a service provider in EVSP list provided by the RPLMN (see clause 4.8.2.1.10), then the UE shall construct a decorated NAI that includes the realm of this service provider and the realm of RPLMN.
      • Otherwise, the UE shall behave as specified in bullet a) above.
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4.8.3  Reference Pointsp. 72

S14
This reference point is between UE and H ANDSF / V ANDSF for direct queries via pull. It enables dynamic provision of information to the UE for access NW discovery and selection procedures related to non-3GPP and 3GPP accesses. This dynamic provision shall be supported with Pull (UE-initiated session) and with Push (ANDSF-initiated session), if feasible. Communication over S14 is secured as specified in TS 33.402.
Protocol assumption:
  • S14 interface is realized above IP level.

4.8.4  ANDSF Discoveryp. 72

In non-roaming scenario, the H ANDSF is discovered through interaction with the Domain Name Service function or the DHCP Server function. The H ANDSF address may also be provisioned to the UE.
In roaming scenario, the UE shall be possible to retrieve both the H ANDSF and V ANDSF addresses.

4.8.5Void

4.8.6  Support of RAN Assistance Information |R12|p. 72

4.8.6.1  Generalp. 72

As specified in TS 36.331 and TS 25.331, an E-UTRAN or UTRAN (referred to as RAN) may provide RAN Assistance Information to UE. This RAN Assistance Information includes the following thresholds and parameters:
  • 3GPP access thresholds;
  • WLAN access thresholds; and
  • An Offload Preference Indication (OPI) value.
The 3GPP access thresholds define low/high threshold values for some UTRA and/or E-UTRA radio parameters, such as low/high RSRP thresholds for E-UTRA, low/high CPICH Ec/No thresholds for UTRA, etc. The WLAN access thresholds define low/high threshold values for some WLAN access parameters, such as the low/high Beacon RSSI thresholds, the high/low UL/DL backhaul data rate thresholds and the low/high channel utilization thresholds. UL/DL backhaul data rate is defined in Hotspot 2.0 [75]. Channel utilization and Beacon RSSI are defined in IEEE 802.11 2012 [64]. How these thresholds are used in the ANDSF rules is specified in clause 4.8.6.2.
The OPI value provided by RAN is a bitmap (i.e. a one-dimensional bit array) that may be used by UEs in an E-UTRA or UTRA cell to determine when they should move certain traffic (e.g. certain IP flows) to WLAN access or to 3GPP access. The meaning of each bit in this bitmap is operator specific and is not defined in 3GPP specifications. How the OPI value is used in the ANDSF rules is specified in clause 4.8.6.2.
The thresholds and parameters provided to UE in a UTRA or E-UTRA cell may affect the validity of the ANDSF rules (as specified in clause 4.8.6.2) and thus make these rules subject to conditions set by the RAN in a given cell.
The user preferences on WLAN network selection and traffic routing shall take precedence over ANDSF rules and RAN rules.
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4.8.6.2  ANDSF Rules Utilizing RAN Assistance Informationp. 72

The 3GPP access thresholds, the OPI value and some of the WLAN access thresholds included in the RAN Assistance Information may be utilized by the following ANDSF rules:
  • The Inter-System Routing Policy (ISRP) rules specified in clause 4.8.2.1.4, i.e. ISRP rules for IFOM, ISRP rules for MAPCON and ISRP rules for NSWO; and
  • The Inter-APN Routing Policy (IARP) rules specified in clause 4.8.2.1.5, i.e. IARP rules for APN and IARP rules for NSWO.
In this release of the specification the ANDSF rules may use the low/high Beacon RSSI thresholds, the low/high WLAN channel utilization thresholds and the low/high UL/DL WLAN backhaul data rate thresholds included in the RAN Assistance Information. These thresholds subsequently referred to as "RAN provisioned WLAN access thresholds".
The ANDSF rules may also utilize low/high Beacon RSSI thresholds, low/high WLAN channel utilization thresholds and low/high UL/DL WLAN backhaul data rate thresholds provided by the ANDSF. These thresholds are subsequently referred to as "ANDSF provisioned WLAN access thresholds".
An IARP/ISRP rule may utilize the 3GPP access thresholds, the RAN provisioned WLAN access thresholds and the OPI value included in the RAN Assistance Information and ANDSF provisioned WLAN access thresholds. When the rule utilizes any of these access thresholds and/or the OPI value, it shall be constructed as follows:
  1. The IARP/ISRP rule shall contain RAN validity conditions, which indicate when the rule is valid or invalid based on the RAN Assistance Information.
  2. The RAN validity conditions may contain one or more threshold conditions and one OPI condition.
  3. Each threshold condition shall be associated either (i) with a 3GPP access threshold provided by RAN or (ii) with WLAN access threshold(s) provided by ANDSF, RAN, or both. A threshold condition shall be evaluated to true or false as specified in clause 4.8.6.3.
  4. The OPI condition shall contain a provisioned OPI which is a bitmap assigned by ANDSF and is associated with the rule. The meaning of each bit in this bitmap is operator specific and is not defined in 3GPP specifications. The OPI condition shall be evaluated to true or false based on the provisioned OPI and the OPI value provided by RAN, as specified in clause 4.8.6.3.
  5. The RAN validity conditions include an indicator which indicates if the rule may be valid either (a) when all threshold conditions are true or (b) when at least one threshold condition is true.
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4.8.6.3  Evaluation of ANDSF Rules with RAN Validity Conditionsp. 73

When the UE cannot simultaneously route IP traffic to both 3GPP access and WLAN, then
  • When the UE has an IARP rule that contains RAN validity conditions, the UE shall evaluate the rule by ignoring all the RAN validity conditions that may be present, i.e. the UE shall consider these RAN validity conditions as true.
When the UE can simultaneously route IP traffic to both 3GPP access and WLAN access, then:
  • When the UE has an IARP or ISRP rule that contains RAN validity conditions, the UE shall evaluate all included threshold conditions and the OPI condition, as specified below. The UE shall consider the RAN validity conditions as valid when the OPI condition is true and when either (a) all threshold conditions are true or (b) at least one threshold condition is true, according to the indicator described in bullet 5 of clause 4.8.6.2.
  • When a threshold condition is associated with a 3GPP access threshold, the UE shall evaluate the threshold condition by comparing the associated 3GPP access threshold provided by RAN with the corresponding measured value. For example, when a threshold condition is associated with the low RSRP threshold, the UE shall evaluate the condition to true when the measured RSRP value is smaller to the low RSRP threshold. If the associated 3GPP access threshold is not available in the UE (e.g. it is not provided by RAN), then the UE shall consider the threshold condition as false.
  • When a threshold condition is associated with only a RAN provisioned WLAN access threshold, the UE shall evaluate the threshold condition by comparing the associated RAN provisioned WLAN access threshold with the corresponding value received from the selected WLAN. For example, when a threshold condition is associated with the low channel utilization threshold, the UE shall evaluate the condition to true when the channel utilization of the selected WLAN is smaller to the low channel utilization threshold. If the associated RAN provisioned WLAN access threshold is not available in the UE (e.g. it is not provided by RAN), then the UE shall consider the threshold condition as false.
  • When a threshold condition is associated with only an ANDSF provisioned WLAN access threshold, the UE shall evaluate the threshold condition by comparing the ANDSF provisioned WLAN access threshold with the corresponding value received from the selected WLAN. For example, when a threshold condition is associated with a high DL/UL backhaul data rate threshold, the UE shall evaluate the condition to true when DL/UL backhaul data rate of the selected WLAN is higher than the high DL/UL backhaul data rate threshold.
  • When a threshold condition is associated with both a RAN provisioned WLAN access threshold and an ANDSF provisioned WLAN access threshold, then it indicates that the threshold condition shall be evaluated by using only the RAN provisioned WLAN access threshold, if available (i.e. if included in the RAN Assistance Information). If the RAN provisioned WLAN access threshold is not available, the ANDSF provisioned WLAN access threshold shall be used.
  • How often the UE re-evaluates the threshold and the OPI conditions to determine when each condition is true or false depends on the UE implementation.
  • The UE shall evaluate an OPI condition by performing a bitwise 'AND' operation between the OPI value provided by RAN and the provisioned OPI contained in the rule. If the result of this operation in non-zero, the UE shall consider the OPI condition as true. If the OPI value is not available in the UE (e.g. it is not provided by RAN), then the UE shall consider the OPI condition as false.
  • When the UE is roaming and applies IARP rules from HPLMN and/or ISRP rules from HPLMN, the UE shall ignore the RAN validity conditions that may be present in these rules, i.e. the UE shall consider these RAN validity conditions as true.
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4.8.6.4  Co-existence with RAN Rulesp. 74

Within a single PLMN, the WLAN access selection and the traffic routing behaviour of a UE shall be controlled either by the ANDSF rules specified in this specification or by the RAN rules specified in TS 36.304 and TS 25.304, not by any combination of them. The only exception is that when a UE applies the RAN rules, it shall be possible to simultaneously apply the IARP for APN rules provided by HPLMN, as further explained below.
When the UE has both ANDSF rules and RAN rules it shall select which rules to apply according to the following procedures.
When the UE can simultaneously route IP traffic to both 3GPP access and WLAN access:
  • When the UE is not roaming or when the UE is roaming in a VPLMN not contained in the list of "VPLMNs with preferred WLAN Selection Rules" (see clause 4.8.2.1.7), then:
    • If the UE has a valid ISRP rule from HPLMN, the UE shall ignore the RAN rules and shall perform WLAN access selection and traffic routing based on the ANDSF procedures specified in clause 4.8.2a.
    • If the UE has no valid ISRP rule from HPLMN, the UE shall perform WLAN access selection and traffic routing based on the RAN rules. In this case, if the UE has a valid IARP rule from HPLMN, it shall apply the internal IARP for APN rules and shall ignore their RAN validity conditions if present.
  • When the UE is roaming in a VPLMN contained in the list of "VPLMNs with preferred WLAN Selection Rules" (see clause 4.8.2.1.7) then:
    • If the UE has a valid ISRP rule from VPLMN, the UE shall ignore the RAN rules and shall perform WLAN access selection and traffic routing based on the ANDSF procedures specified in clause 4.8.2a.
    • If the UE has no valid ISRP rule from VPLMN, the UE shall perform WLAN access selection and traffic routing based on the RAN rules. In this case, if the UE has a valid IARP rule from HPLMN, it shall apply the internal IARP for APN rules and shall ignore their RAN validity conditions if present.
When the UE cannot simultaneously route IP traffic to both 3GPP access and WLAN access:
  • When the UE is not roaming or when the UE is roaming in a VPLMN not contained in the list of "VPLMNs with preferred WLAN Selection Rules" (see clause 4.8.2.1.7), then:
    • If the UE has at least one ISMP rule from HPLMN, the UE shall ignore the RAN rules and shall perform WLAN access selection and access selection for EPC connectivity based on the ANDSF procedures specified in clause 4.8.2a.
    • If the UE has no ISMP rules from HPLMN, the UE shall apply the RAN rules or RCLWI command to determine when all PDN connections should be handed over to WLAN access or to 3GPP access. When the RAN rules indicate that all PDN connections should be handed over to WLAN access but at least one PDN connection is not allowed to be handed over to WLAN access (as specified in TS 23.401), the UE shall not handover any PDN connection. When all PDN connections are allowed to be handed over to WLAN access, the UE shall perform WLAN access selection based on the RAN rules and shall execute the applicable handover procedures specified in clause 8. In this case, if the UE has a valid IARP rule from HPLMN, it shall apply the internal IARP for APN rules and shall ignore their RAN validity conditions if present.
  • When the UE is roaming in a VPLMN contained in the list of "VPLMNs with preferred WLAN Selection Rules" (see clause 4.8.2.1.7) then:
    • If the UE has at least one ISMP rule from VPLMN, the UE shall ignore the RAN rules and shall perform WLAN access selection and access selection for EPC connectivity based on the ANDSF procedures specified in clause 4.8.2a.
    • If the UE has no ISMP rules from VPLMN, the UE shall apply the RAN rules to determine when all PDN connections should be handed over to WLAN access or to 3GPP access. When the RAN rules indicate that all PDN connections should be handed over to WLAN access but at least one PDN connection is not allowed to be handed over to WLAN access (as specified in TS 23.401), the UE shall not handover any PDN connection. When all PDN connections are allowed to be handed over to WLAN access, the UE shall perform WLAN access selection based on the RAN rules and shall execute the applicable handover procedures specified in clause 8. In this case, if the UE has a valid IARP rule from HPLMN, it shall apply the internal IARP for APN rules and shall ignore their RAN validity conditions if present.
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4.8.7  Support of LWA, LWIP and RCLWI |R13|p. 75

4.8.7.1  Generalp. 75

For WLAN access selection and traffic routing, in addition to the ANDSF procedures, the UE may also support:
  • the LTE-WLAN Aggregation (LWA) procedures specified in TS 36.300 and TS 36.463;
  • the LTE-WLAN Radio Level Integration with IPsec Tunnel (LWIP) procedures specified in TS 36.300; and
  • the RAN controlled LTE-WLAN interworking (RCLWI) procedures specified in TS 36.300.
As defined in TS 36.300, the LWA, the LWIP and the RCLWI procedures are applicable only when the UE operates in ECM-CONNECTED mode (see TS 23.401). When the UE operates in ECM-IDLE mode (see TS 23.401), these procedures are not applied.
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4.8.7.2  Co-existence with LWA and RCLWIp. 75

When the UE supports WLAN access selection and traffic routing based on the ANDSF procedures defined in this specification and based on the LWA/RCLWI procedures specified in TS 36.300 and TS 36.463, then the UE shall support co-existence between these procedures as well as co-existence between these procedures and the user preferences by applying the following behaviour:
  1. When the UE has not selected a WLAN, the UE shall accept the LWA/RCLWI signalling and shall apply WLAN access selection and traffic routing based on the applicable LWA/RCLWI procedures.
  2. When the UE has selected a WLAN based on user preferences, the UE shall ignore the LWA/RCLWI signalling.
  3. When the UE has selected a WLAN based on ANDSF rules, the UE shall accept or shall ignore the LWA/RCLWI signalling based on the UE configuration. Specifically, the UE may be configured via the home ANDSF with an indication that specifies if the UE shall accept or ignore the LWA/RCLWI signalling in a specific PLMN and/or when connected to a specific WLAN access. Examples of such UE configuration include "always accept LWA/RCLWI signalling", "accept LWA/RCLWI signalling expect in PLMN-a", "accept LWA/RCLWI signalling expect when connected to SSID-x" or "ignore LWA/RCLWI signalling expect in HPLMN, EHPLMN-a". If the UE is not configured via the home ANDSF with this indication, then the UE shall always accept the LWA/RCLWI signalling.
  4. Based on implementation specific mechanisms, the UE shall limit the frequency of WLAN re-selection that may occur when the UE has an active ANDSF rule for WLAN selection (WLANSP rule) and it accepts the LWA/RCLWI signalling. For example, the UE may select one WLAN access in ECM-CONNECTED mode (see TS 23.401) based on LWA/RCLWI signalling and another WLAN access based on the active ANDSF rule in ECM-IDLE mode (see TS 23.401). The UE shall not trigger WLAN re-selection every time it transitions between ECM-CONNECTED and ECM-IDLE modes.
  5. When the UE applies WLAN access selection and traffic routing based on the LWA/RCLWI procedures (i.e. in ECM-CONNECTED mode) the UE shall not apply WLANSP, ISRP and IARP for NWSO rules. However, if the UE has a valid IARP rule, it shall apply the internal IARP for APN rules in order to perform traffic routing across the established PDN connections.
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4.8.7.3  Co-existence with LWIPp. 76

All the co-existence procedures between ANDSF and LWA defined in clause 4.8.7.2 are also applied for the co-existence between ANDSF and LWIP. If the UE is configured via the home ANDSF with an indication that specifies if the UE shall accept or ignore the LWA/RCLWI signalling in a specific PLMN and/or when connected to a specific WLAN access, then this configuration shall also be used by the UE to determine when it shall accept or ignore LWIP signalling.
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