9.3 Message and Information Element Abstract Syntax (with ASN.1) 61
9.3.1 General 61
9.3.2 Usage of Private Message Mechanism for Non-standard Use 61
9.3.3 Elementary Procedure Definitions 61
9.3.4 PDU Definitions 67
9.3.5 Information Element definitions 90
9.3.6 Common definitions 103
9.3.7 Constant definitions 104
9.3.8 Container definitions 107
9.4 Message transfer syntax 112
10 Handling of unknown, unforeseen and erroneous protocol data 112
Annex A (informative): Change history 112
Foreword
This Technical Specification has been produced by the 3rd Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
1 Scope
The present document specifies the signalling procedures of the control plane between an eNB and WLAN Termination (WT). The Xw Application Protocol (XwAP) supports the functions of Xw interface by signalling procedures defined in this document.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or non‑specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1] 3GPPTR21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 36.300: "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2".
[3] 3GPP TS 29.281: "General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)".
[4] 3GPP TS 36.462: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and Wireless LAN (WLAN); Xw signalling support”
[10] Wi-Fi Alliance® Technical Committee, Hotspot 2.0 Technical Task Group Hotspot 2.0 (Release 2) Technical Specification Version 3.11.
[11] IEEE Std 802.11™-2012, IEEE Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area network.
[12] 3GPP TR 25.921: "Guidelines and principles for protocol description and error handling”
[13] 3GPP TS 23.203: "Numbering, addressing and identification"
[14] 3GPP TS 23.401: "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access"
[15] 3GPP TS 36.464: "Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and Wireless LAN (WLAN); Xw data transport"
[16] 3GPP TS 29.281: "General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U)"
[18] 3GPP TS 36.331: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC) protocol specification".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1].
Elementary Procedure: XwAP protocol consists of Elementary Procedures (EPs). An XwAP Elementary Procedure is a unit of interaction between an eNB and WT. An EP consists of an initiating message and possibly a response message. Two kinds of EPs are used:
- Class 1: Elementary Procedures with response (success or failure),
- Class 2: Elementary Procedures without response.
eNB UE XwAP ID: Defined in TS 36.401 [9].
E-RAB: Defined in TS 36.401 [9].
LWA bearer: Defined in TS 36.300 [2].
LWIP-SeGW: Defined in TS 33.401 [17].
UE-associated signalling: Refers to XwAP messages associated to one UE, and which use the respective UE-associated logical Xw connection.
UE-associated logical Xw connection: The UE-associated logical Xw connection transports UE-associated signalling. The identities WT UE XwAP ID and eNB UE XwAP ID are used to identify the particular UE-associated logical Xw connection that a message relates to.
WLAN Termination: Defined in TS 36.300 [2].
WT UE XwAP ID: Defined in TS 36.401 [9].
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 [1].
AC Access Category
DL Downlink
eNB E-UTRAN NodeB
EP Elementary Procedure
EPC Evolved Packet Core
E-RAB E-UTRAN Radio Access Bearer
E-UTRAN Evolved UTRAN
IE Information Element
IKE Internet Key Exchange
LWA LTE/WLAN Aggregation
LWIP LTE/WLAN Radio Level Integration with IPsec Tunnel
LWIP-SeGW LWIP Security GateWay
PDCP Packet Data Convergence Protocol
RCLWI RAN Controlled LTE-WLAN Interworking
SN Sequence Number
TAC Tracking Area Code
UE User Equipment
UL Uplink
WT WLAN Termination
Xw UP Xw User Plane
4 General
4.1 Procedure specification principles
The principle for specifying the procedure logic is to specify the functional behaviour of the terminating node exactly and completely. Any rule that specifies the behaviour of the originating node shall be possible to be verified with information that is visible within the system.
The following specification principles have been applied for the procedure text in clause 8:
- The procedure text discriminates between:
1) Functionality which "shall" be executed
The procedure text indicates that the receiving node "shall" perform a certain function Y under a certain condition. If the receiving node supports procedure X but cannot perform functionality Y requested in the initiating message of a Class 1 EP, the receiving node shall respond with the message used to report unsuccessful outcome for this procedure, containing an appropriate cause value.
2) Functionality which "shall, if supported" be executed
The procedure text indicates that the receiving node "shall, if supported," perform a certain function Y under a certain condition. If the receiving node supports procedure X, but does not support functionality Y, the receiving node shall proceed with the execution of the EP, possibly informing the requesting node about the not supported functionality.
- Any required inclusion of an optional IE in a response message is explicitly indicated in the procedure text. If the procedure text does not explicitly indicate that an optional IE shall be included in a response message, the optional IE shall not be included. For requirements on including Criticality Diagnostics IE, see section 10.
4.2 Forwards and backwards compatibility
The forwards and backwards compatibility of the protocol is assured by a mechanism where all current and future messages, and IEs or groups of related IEs, include ID and criticality fields that are coded in a standard format that will not be changed in the future. These parts can always be decoded regardless of the standard version.
4.3 Specification notations
For the purposes of the present document, the following notations apply:
Procedure When referring to an elementary procedure in the specification the Procedure Name is written with the first letters in each word in upper case characters followed by the word "procedure", e.g. Handover Preparation procedure.
Message When referring to a message in the specification the MESSAGE NAME is written with all letters in upper case characters followed by the word "message", e.g. HANDOVER REQUEST message.
IE When referring to an information element (IE) in the specification the Information Element Name is written with the first letters in each word in upper case characters and all letters in Italic font followed by the abbreviation "IE", e.g. E-RAB ID IE.
Value of an IE When referring to the value of an information element (IE) in the specification the "Value" is written as it is specified in sub clause 9.2 enclosed by quotation marks, e.g. "Value".
5 XwAP services
5.1 General
The present clause describes the services offered between an eNB and WT.
5.2 XwAP procedures
The Xw interface XwAP procedures may be UE-associated or non UE-associated. UE-associated XwAP procedures are used to handle the configuration and modification to support LWA or LWIP for a specific UE. Non UE-associated procedures support LWA, RCLWI and/or LWIP, and are not related to a specific UE.
5.3 Parallel transactions
Unless explicitly indicated in the procedure specification, at any instance in time one protocol peer shall have a maximum of one ongoing XwAP procedure related to a certain UE.
6 Services expected from signalling transport
The signalling connection shall provide in sequence delivery of XwAP messages. XwAP shall be notified if the signalling connection breaks.
Xw signalling transport is described in TS 36.462 [4].
7 Functions of XwAP
The XwAP protocol provides the following functions:
- Setting up the Xw. This function is used to exchange the necessary data for the eNB and the WT to set up the Xw interface and implicitly perform an Xw Reset.
- WT Configuration Update. This function allows updating of application level data needed for the eNB and the WT to interoperate correctly on the Xw interface.
- WLAN Status Reporting. This function allows the eNB to configure reporting of load-related information from the WT.
- LTE-WLAN Aggregation. This function allows the eNB to request a WT to provide radio resources for LWA operation for a certain UE while keeping responsibility for that UE.
- LTE-WLAN Radio Level Integration with IPsec Tunnel. This function allows the eNB to request a WT to provide tunnel resources for LWIP operation for a certain UE while keeping responsibility for that UE.
- Reporting of General Error Situations. This function allows reporting of general error situations, for which function specific error messages have not been defined.
- Resetting the Xw. This function is used to reset the Xw interface.
The mapping between the above functions and Xw EPs is shown in the table below.
Table 7-1: Mapping between XwAP functions and XwAP EPs
Function
Elementary Procedure(s)
WLAN Status Reporting
a) WT Status Reporting Initiation
b) WT Status Reporting
Setting up the Xw
Xw Setup
WT Configuration Update
WT Configuration Update
LTE-WLAN Aggregation
a) WT Addition Preparation
b) WT Association Confirmation
c) eNB Initiated WT Modification
d) WT Initiated WT Modification
e) eNB Initiated WT Release
f) WT Initiated WT Release
LTE-WLAN Radio Level Integration with IPsec Tunnel
a) LWIP Addition Preparation
b) eNB Initiated LWIP Modification
c) eNB Initiated LWIP Release
d) WT Initiated LWIP Release
Reporting of General Error Situations
Error Indication
Resetting the Xw
Reset
8 XwAP procedures
8.1 Elementary procedures
In the following tables, all EPs are divided into Class 1 and Class 2 EPs.
Table 8.1-1: Class 1 Elementary Procedures
Elementary Procedure
Initiating Message
Successful Outcome
Unsuccessful Outcome
Response message
Response message
Xw Setup
Xw SETUP REQUEST
Xw SETUP RESPONSE
Xw SETUP FAILURE
WT Configuration Update
WT CONFIGURATION UPDATE
WT CONFIGURATION UPDATE ACKNOWLEDGE
WT CONFIGURATION UPDATE FAILURE
WT Status Reporting Initiation
WT STATUS REQUEST
WT STATUS RESPONSE
WT STATUS FAILURE
WT Addition Preparation
WT ADDITION REQUEST
WT ADDITION REQUEST ACKNOWLEDGE
WT ADDITION REQUEST REJECT
eNB Initiated WT Modification
WT MODIFICATION REQUEST
WT MODIFICATION REQUEST ACKNOWLEDGE
WT MODIFICATION REQUEST REJECT
WT Initiated WT Modification
WT MODIFICATION REQUIRED
WT MODIFICATION CONFIRM
WT MODIFICATION REFUSE
WT Initiated WT Release
WT RELEASE REQUIRED
WT RELEASE CONFIRM
Reset
RESET REQUEST
RESET RESPONSE
LWIP Addition Preparation
LWIP ADDITION REQUEST
LWIP ADDITION REQUEST ACKNOWLEDGE
LWIP ADDITION REQUEST REJECT
eNB Initiated LWIP Modification
LWIP MODIFICATION REQUEST
LWIP MODIFICATION REQUEST ACKNOWLEDGE
LWIP MODIFICATION REQUEST REJECT
WT Initiated LWIP Release
LWIP RELEASE REQUIRED
LWIP RELEASE CONFIRM
Table 8.1-2: Class 2 Elementary Procedures
Elementary Procedure
Initiating Message
WT Status Reporting
WT STATUS REPORT
Error Indication
ERROR INDICATION
WT Association Confirmation
WT ASSOCIATION CONFIRMATION
eNB Initiated WT Release
WT RELEASE REQUEST
eNB Initiated LWIP Release
LWIP RELEASE REQUEST
8.2 Xw Setup
8.2.1 General
The purpose of the Xw Setup procedure is to exchange application level configuration data needed for the eNB and the WT to interoperate correctly over the Xw interface. This procedure erases any existing application level configuration data in the two nodes and replaces it by the one received. This procedure also resets the Xw interface.
The procedure uses non-UE-associated signalling.
8.2.2 Successful Operation
Figure 8.2.2-1: Xw Setup, successful operation
An eNB initiates the procedure by sending the Xw SETUP REQUEST message to a candidate WT. The candidate WT replies with the Xw SETUP RESPONSE message. The candidate WT shall reply with a list of relevant WLAN identifiers.
If the WLAN Usage IE is included in the WLAN Information IE, the eNB shall consider that the relevant WLAN identifier(s) may be used for both LWA and LWIP, or for LWIP only; otherwise, the relevant WLAN identifier(s) may be used for LWA only.
If the Neighbour eNB Information IE is included in the Xw SETUP RESPONSE message, the eNB shall consider the included information as the list of eNBs to which the WT is connected.
8.2.3 Unsuccessful Operation
Figure 8.2.3-1: Xw Setup, unsuccessful operation
If the candidate WT cannot accept the setup, it shall respond with an Xw SETUP FAILURE message with an appropriate cause value.
If the Xw SETUP FAILURE message includes the Time To Wait IE the initiating eNB shall wait at least for the indicated time before reinitiating the Xw Setup procedure towards the same WT.
8.2.4 Abnormal Conditions
If the first message received for a specific TNL association is not an Xw SETUP REQUEST, Xw SETUP RESPONSE, or Xw SETUP FAILURE message, then this shall be treated as a logical error.
8.3 WT Configuration Update
8.3.1 General
The purpose of the WT Configuration Update procedure is to update application level configuration data needed for an eNB and a WT to interoperate correctly over the Xw interface.
A WT initiates the procedure by sending a WT CONFIGURATION UPDATE message to an eNB. Such message shall include an appropriate set of up-to-date configuration data, including, but not limited to, relevant lists of added, modified and deleted WLAN identifiers that the WT has just taken into operational use.
If the WLAN Usage IE is included in the WLAN Information IE, the eNB shall consider that the relevant WLAN identifier(s) may be used for both LWA and LWIP, or for LWIP only; otherwise, the relevant WLAN identifier(s) may be used for LWA only.
If the Neighbour eNB Information IE is included in the WT CONFIGURATION UPDATE message, the eNB shall consider the included information as the full updated list of eNBs to which the WT is connected.
If the eNB cannot accept the update, it shall respond with a WT CONFIGURATION UPDATE FAILURE message with an appropriate cause value.
If the WT CONFIGURATION UPDATE FAILURE message includes the Time To Wait IE the WT shall wait at least for the indicated time before reinitiating the WT Configuration Update procedure towards the same eNB. Both nodes shall continue to operate the Xw with their existing configuration data.
8.3.4 Abnormal Conditions
Not applicable.
8.4 WT Status Reporting Initiation
8.4.1 General
This procedure is used by an eNB to request the reporting of load measurements to a WT.
The procedure uses non-UE-associated signalling.
8.4.2 Successful Operation
Figure 8.4.2-1: WT Status Reporting Initiation procedure, successful operation
The procedure is initiated with a WT STATUS REQUEST message sent from the eNB to the WT. Upon receipt, the WT shall initiate the requested measurement according to the parameters given in the request in case the Registration Request IE is set to "start" and shall stop all measurements and terminate the reporting in case the Registration Request IE is set to “stop".
If the Registration Request IE is set to "start" then the Report Characteristics IE shall be included in WT STATUS REQUEST message.
The Report Characteristics IE indicates the type of objects WT shall perform measurements on.
For each BSS, the WT shall include in the WT STATUS REPORT message:
- the BSS Load IE, if the first bit, “BSS Load” of the Report Characteristics IE included in the WT STATUS REQUEST message is set to 1;
- the WAN Metrics IE, if the second bit, “WAN Metrics” of the Report Characteristics IE included in the WT STATUS REQUEST message is set to 1;
- the Available Channel Utilization IE, if the third bit, “Available Channel Utilization” of the Report Characteristics IE included in the WT STATUS REQUEST message is set to 1.
If the Reporting Periodicity IE is included in the WT STATUS REQUEST message, the WT shall use its value as the time interval between two subsequent WT STATUS REPORT messages.
If the WT is capable to provide all requested resource status information, it shall initiate the measurement as requested by the eNB, and respond with the WT STATUS RESPONSE message.
If the WT is capable to provide some but not all of the requested resource status information and the Partial Success Indicator IE is present in the WT STATUS REQUEST, it shall initiate the measurement for the admitted measurement objects and include the Measurement Initiation Result IE in the WT STATUS RESPONSE message.
If the WT received a WT STATUS REQUEST message which includes the Registration Request IE set to "stop", it shall ignore the Report Characteristics, the BSS To Report List, the Reporting Periodicity, and the Partial Success Indicator IEs.
8.4.3 Unsuccessful Operation
Figure 8.4.3-1: WT Status Reporting Initiation procedure, unsuccessful operation
If none of the requested measurements can be initiated, the WT shall send a WT STATUS FAILURE message. The Cause IE shall be set to an appropriate value for each requested measurement object. The eNB may include the Complete Failure Cause Information IE in the WT STATUS FAILURE message.
8.4.4 Abnormal Conditions
If the eNB does not receive either WT STATUS RESPONSE message or WT STATUS FAILURE message, the eNB may reinitiate the WT Status Reporting Initiation procedure towards the WT, provided that the content of the new WT STATUS REQUEST message is identical to the content of the previously unacknowledged WT STATUS REQUEST message.
If the eNB receives the WT STATUS RESPONSE message including the Measurement Initiation Result IE containing no admitted measurements, the eNB shall consider the procedure as failed.
If the Registration Request IE is set to "start" and the Report Characteristics IE bitmap is set to "0" (all bits are set to "0") in the WT STATUS REQUEST message, then the WT shall initiate a WT STATUS FAILURE message, the cause shall be set to appropriate value e.g. "ReportCharacteristicsEmpty".
If the Registration Request IE is set to "start" and the Reporting Periodicity IE value is not specified, then the WT shall initiate a WT STATUS FAILURE message, the cause shall be set to appropriate value e.g. "No Report Periodicity".
If the WT received a WT STATUS REQUEST message which includes the Registration Request IE set to "start" and the eNB Measurement ID IE corresponding to an existing on-going load measurement reporting, then the WT shall initiate a WT STATUS FAILURE message, the cause shall be set to appropriate value e.g. "ExistingMeasurement ID".
If the Registration Request IE is set to "stop" and the WT STATUS REQUEST message does not contain WT Measurement ID IE, the WT shall consider the procedure as failed and respond with the WT STATUS FAILURE message, the cause shall be set to appropriate value e.g. "Unknown Measurement ID".
8.5 WT Status Reporting
8.5.1 General
This procedure is initiated by the WT to report the result of measurements admitted by the WT following a successful WT Status Reporting Initiation procedure.
The procedure uses non-UE-associated signalling.
8.5.2 Successful Operation
Figure 8.5.2-1: WT Status Reporting procedure, successful operation
The WT shall report the results of the admitted measurements in the WT STATUS REPORT message. The admitted measurements are the measurements that were successfully initiated during the preceding WT Status Reporting Initiation procedure.
8.5.3 Unsuccessful Operation
Not applicable.
8.5.4 Abnormal Conditions
Not applicable.
8.6 Error Indication
8.6.1 General
The Error Indication procedure is initiated by a node to report detected errors in one incoming message, provided they cannot be reported by an appropriate failure message.
If the error situation arises due to reception of a message which used UE-associated signalling, then the Error Indication procedure uses UE-associated signalling. Otherwise the procedure uses non UE-associated signalling.
When the conditions defined in clause 10 are fulfilled, the Error Indication procedure is initiated by an ERROR INDICATION message sent from the receiving node.
The ERROR INDICATION message shall contain at least either the Cause IE or the Criticality Diagnostics IE. In case the Error Indication procedure is triggered by UE associated signalling, the eNB UE XwAP ID IE and the WT UE XwAP ID IE shall be included in the ERROR INDICATION message. If one or both of eNB UE XwAP ID IE and the WT UE XwAP ID IE are not correct, the cause shall be set to an appropriate value, e.g., “Unknown eNB UE XwAP ID”, “Unknown WT UE XwAP ID” or “Unknown pair of UE XwAP ID”.
8.6.3 Unsuccessful Operation
Not applicable.
8.6.4 Abnormal Conditions
Not applicable.
8.7 Reset
8.7.1 General
The purpose of the Reset procedure is to align the resources in the eNB and in the WT in the event of an abnormal failure. The procedure resets the Xw interface. This procedure does not affect the application level configuration data exchanged during, e.g., the Xw Setup procedure.
The procedure is initiated with a RESET message sent from the initiating node. Upon receipt of this message, the receiving node shall abort any other ongoing procedures (except another Reset procedure) over Xw with the initiating node. The receiving node shall delete all the context information related to the initiating node, except the application level configuration data exchanged during Xw Setup or WT Configuration Update procedures, and release the corresponding resources. After completing the release of the resources, the receiving node shall respond with a RESET RESPONSE message.
8.7.3 Unsuccessful Operation
Not applicable.
8.7.4 Abnormal Conditions
If Reset procedure is ongoing and the receiving node receives the RESET message from the peer entity on the same Xw interface, the receiving node shall respond with the RESET RESPONSE message as described in 8.7.2.
8.8 WT Addition Preparation
8.8.1 General
The purpose of the WT Addition Preparation procedure is to request the WT to allocate resources for LWA operation for a specific UE.
The procedure uses UE-associated signalling and, in case of successful operation, establishes a new UE-associated logical Xw-connection.
The eNB initiates the procedures by sending the WT ADDITION REQUEST message to the WT.
The allocation of resources according to the values of the Allocation and Retention Priority IE included in the E-RAB Level QoS Parameters IE shall follow the principles described for the E-RAB Setup Procedure in TS 36.413 [8].
NOTE: Due to inherent features of the WLAN radio interface, it may not always be possible to guarantee a bit rate. If the GBR QoS Information IE is present in the WT ADDITION REQUEST, the WT may accept the request even though it may not be able to guarantee the bit rate signalled in the GBR QoS Information IE. The eNB may therefore need to monitor the bit rate of offloaded GBR bearers.
If the WT ADDITION REQUEST message contains the Serving PLMN IE, the WT may take it into account for the allocation of resources for LWA.
If the WT ADDITION REQUEST message contains the WT UE XwAP ID IE, the WT shall use the included information to identify the UE.
If the DRB-Identity IE is present in an item in the E-RABs To Be Added List IE in the WT ADDITION REQUEST message, the WT shall consider that the respective LWA bearer is configured for uplink.
At reception of the WT ADDITION REQUEST message the WT shall:
- use the information included in the Mobility Set IE as the WLAN Mobility Set configured for LWA, as defined in TS 36.300 [2];
- store the WLAN Security Information IE, if included, and use it to establish the required security relation towards the UE.
The WT shall report to the eNB, in the WT ADDITION REQUEST ACKNOWLEDGE message, the result for all the requested E-RABs in the following way:
- A list of E-RABs which are successfully established shall be included in the E-RABs Admitted To Be Added List IE.
- A list of E-RABs which failed to be established shall be included in the E-RABs Not Admitted List IE.
For each admitted uplink E-RAB to be added, the WT may include the LWA WLAN AC IE in the WT ADDITION REQUEST ACKNOWLEDGE message, and, if included, the eNB shall use the respective information as the LWA WLAN Access Category to be forwarded to the UE, as specified in TS 36.300 [2].
If the WT ADDITION REQUEST ACKNOWLEDGE message contains the WT MAC Address IE, the eNB shall, if supported, communicate this information to the UE.
If the WT is not able to accept at least one of the bearers or a failure occurs during the WT Addition Preparation, the WT sends the WT ADDITION REQUEST REJECT message with an appropriate cause value to the eNB.
8.8.4 Abnormal Conditions
If the WT receives a WT ADDITION REQUEST message containing multiple E-RAB ID IEs (in the E-RABs To Be Added List IE) set to the same value, the WT shall consider the establishment of the corresponding E-RAB as failed.
If the WT receives a WT ADDITION REQUEST message containing an E-RAB Level QoS Parameters IE which contains a QCI IE indicating a GBR bearer (as defined in TS 23.203 [13]), and which does not contain the GBR QoS Information IE, the WT shall consider the establishment of the corresponding E-RAB as failed.
If the WT receives a WT ADDITION REQUEST message containing the WT UE XwAP ID IE but it is not able to identify the UE, it shall reply with the WT ADDITION REQUEST REJECT message with an appropriate cause value.
8.9 eNB Initiated WT Modification
8.9.1 General
This procedure is used to enable an eNB to request a WT to modify the UE context at the WT.
The eNB initiates the procedure by sending the WT MODIFICATION REQUEST message to the WT.
The WT MODIFICATION REQUEST message may contain within the UE Context Information IE:
- E-RABs to be added within the E-RABs To Be Added Item IE;
- E-RABs to be modified within the E-RABs To Be Modified Item IE;
- E-RABs to be released within the E-RABs To Be Released Item IE;
- WLAN security information in the WLAN Security Information IE.
If the WLAN Security Information IE is included in the WT MODIFICATION REQUEST message the WT shall store the information contained in this IE, and use it to establish the required security relation towards the UE.
The allocation of resources according to the values of the Allocation and Retention Priority IE included in the E-RAB Level QoS Parameters IE shall follow the principles described for the E-RAB Setup procedure in TS 36.413 [8].
NOTE: Due to inherent features of the WLAN radio interface, it may not always be possible to guarantee a bit rate. If the GBR QoS Information IE is present in the WT MODIFICATION REQUEST, the WT may accept the request even though it may not be able to guarantee the bit rate signalled in the GBR QoS Information IE. The eNB may therefore need to monitor the bit rate of offloaded GBR bearers.
If the DRB-Identity IE is present in an item in the E-RABs To Be Added List IE in the WT MODIFICATION REQUEST message, the WT shall consider that the respective LWA bearer is configured for uplink.
If the WT MODIFICATION REQUEST message contains the Serving PLMN IE, the WT may take it into account for the allocation of resources for LWA.
If at least one of the requested modifications is admitted by the WT, the WT shall modify the related part of the UE context accordingly and send the WT MODIFICATION REQUEST ACKNOWLEDGE message back to the eNB.
The WT shall include the E-RABs for which resources have been either added or modified or released at the WT either in the E-RABs Admitted To Be Added List IE or the E-RABs Admitted To Be Modified List IE or the E-RABs Admitted To Be Released List IE. The WT shall include the E-RABs that have not been admitted in the E-RABs Not Admitted List IE with an appropriate cause value.
For each admitted uplink E-RAB to be added or modified, the WT may include the LWA WLAN AC IE in the WT MODIFICATION REQUEST ACKNOWLEDGE message, and, if included, the eNB shall use the respective information as the LWA WLAN Access Category to be forwarded to the UE, as specified in TS 36.300 [2].
For each E-RAB to be modified, if the WT MODIFICATION REQUEST message includes the eNB GTP Tunnel Endpoint IE in the E-RABs To Be Modified Item IE, the WT shall act as specified in TS 36.300 [2].
For each E-RAB to be released, if the DL Forwarding GTP Tunnel Endpoint IE is included within the E-RABs To Be Released Item IE in the WT MODIFICATION REQUEST message, the WT may perform data forwarding of downlink packets for that bearer.
If the E-RAB level QoS parameter IE is included in the WT MODIFICATION REQUEST message for an E-RAB to be modified, the WT shall allocate respective resources as described in TS 36.300 [2].
For an E-RAB to be modified, the WT may include in the WT MODIFICATION REQUEST ACKNOWLEDGE message the WT GTP Tunnel Endpoint IE.
If the Mobility Set IE is included in the WT MODIFICATION REQUEST message, the WT shall use the information included in this IE as the WLAN Mobility Set configured for LWA, as defined in TS 36.300 [2].
If the WT does not admit any modification requested by the eNB, or a failure occurs during the eNB initiated WT Modification, the WT shall send the WT MODIFICATION REQUEST REJECT message to the eNB. The message shall contain the Cause IE with an appropriate value.
8.9.4 Abnormal Conditions
If the WT receives a WT MODIFICATION REQUEST message containing multiple E-RAB ID IEs (in the E-RABs To Be Added List IE and/or the E-RABs To Be Modified List IE) set to the same value, the WT shall not admit the action requested for the corresponding E-RABs.
If the WT receives a WT MODIFICATION REQUEST message containing multiple E-RAB ID IEs (in the E-RAB To Be Released List IE) set to the same value, the WT shall initiate the release of one corresponding E-RAB and ignore the duplication of the instances of the selected corresponding E-RABs.
If the WT receives a WT MODIFICATION REQUEST message containing a E-RAB Level QoS Parameters IE which contains a QCI IE indicating a GBR bearer (as defined in TS 23.203 [13]), and which does not contain the GBR QoS Information IE, the WT shall not admit the corresponding E-RAB.
Interaction with the WT initiated WT Modification procedure:
If the eNB, after having initiated the eNB initiated WT Modification procedure, receives the WT MODIFICATION REQUIRED message, the eNB shall refuse the WT initiated WT Modification procedure with an appropriate cause value in the Cause IE.
8.10 WT Initiated WT Modification
8.10.1 General
This procedure is used by the WT to modify the UE context in the WT. In particular, in this Release of the specification, this procedure is used to request to the eNB the release of LWA bearers, or change their WT GTP Tunnel Endpoints.
The WT initiates the procedure by sending the WT MODIFICATION REQUIRED message to the eNB.
The WT MODIFICATION REQUIRED message may contain
- E-RABs to be released within the E-RABs To Be Released Item IE;
- E-RABs to be modified within the E-RABs To Be Modified Item IE.
If the WT GTP Tunnel Endpoint IE is present in the E-RABs To Be Modified Item IE for a particular E-RAB, the eNB shall use this information to change the Xw transport bearer associated to the concerned E-RAB.
For each uplink E-RAB to be modified, the WT may include the LWA WLAN AC IE in the WT MODIFICATION REQUIRED message, and, if included, the eNB shall use the respective information as the LWA WLAN Access Category to be forwarded to the UE, as specified in TS 36.300 [2].
If the eNB is able to perform at least one of the modifications requested by the WT, the eNB shall send the WT MODIFICATION CONFIRM message to the WT with the appropriate information in the E-RABs Confirmed To Be Released List and/or E-RABs Confirmed To Be Modified List IEs. For each E-RAB to be released, if the DL Forwarding GTP Tunnel Endpoint IE is included within the E-RABs Confirmed To Be Released Item IE in the WT MODIFICATION CONFIRM message, the WT may perform data forwarding of downlink packets for that bearer.
In case none of the requested modifications can be performed successfully the eNB shall respond with the WT MODIFICATION REFUSE message to the WT with an appropriate cause value in the Cause IE.
8.10.4 Abnormal Conditions
If the value received in the E-RAB ID IE of any of the E-RABs To Be Released Item IE or of the E-RABs To Be Modified Item IE is not known at the eNB, the eNB shall regard the procedure as failed and may take appropriate actions like triggering the eNB initiated WT Release procedure.
Interaction with the eNB initiated WT Modification Preparation procedure:
If the WT, after having initiated the WT initiated WT Modification procedure, receives the WT MODIFICATION REQUEST message, the WT shall
- regard the WT initiated WT Modification Procedure as failed,
- be prepared to receive the WT MODIFICATION REFUSE message from the eNB, and
- continue with the eNB initiated WT Modification procedure as specified in Section 8.9.
8.11 eNB Initiated WT Release
8.11.1 General
The eNB initiated WT Release procedure is triggered by the eNB to initiate the release of the resources for a specific UE.
The eNB initiates the procedure by sending the WT RELEASE REQUEST message. Upon reception of the WT RELEASE REQUEST message the WT shall stop providing user data to the UE. The eNB may provide appropriate information within the Cause IE.
For each E-RAB, if the DL Forwarding GTP Tunnel Endpoint IE is included within the E-RABs To Be Released Item IE in the WT RELEASE REQUEST message, the WT may perform data forwarding of downlink packets for that bearer.
Upon reception of the WT RELEASE REQUEST message containing the UE Context Kept Indicator IE set to "True", the WT shall, if supported, only initiate the release of the resources related to the UE-associated signaling connection between the eNB and the WT.
8.11.3 Unsuccessful Operation
Not applicable.
8.11.4 Abnormal Conditions
Not applicable.
8.12 WT Initiated WT Release
8.12.1 General
This procedure is triggered by the WT to initiate the release of the resources for a specific UE.
The WT initiates the procedure by sending the WT RELEASE REQUIRED message to the eNB.
Upon reception of the WT RELEASE REQUIRED message, the eNB replies with the WT RELEASE CONFIRM message. For each E-RAB, if the DL Forwarding GTP Tunnel Endpoint IE is included within the E-RABs To Be Released Item IE in the WT RELEASE CONFIRM message, the WT may perform data forwarding of downlink packets for that bearer.
The WT may start data forwarding and stop providing user data to the UE upon reception of the WT RELEASE CONFIRM message.
8.12.3 Unsuccessful Operation
Not applicable.
8.12.4 Abnormal Conditions
Not applicable.
8.13 WT Association Confirmation
8.13.1 General
This procedure is initiated by the WT to give confirmation to the eNB that a certain UE successfully associated with the WLAN following a successful WT Addition Preparation procedure.
The procedure uses UE-associated signalling.
8.13.2 Successful Operation
Figure 8.13.2-1: WT Association Confirm procedure, successful operation
The WT initiates the procedure by sending the WT ASSOCIATION CONFIRMATION message to the eNB.
Upon reception of the WT ASSOCIATION CONFIRMATION message, the eNB shall consider that the UE is associated with the WLAN, and that user plane data for that UE may be sent to the WT.
8.13.3 Unsuccessful Operation
Not applicable.
8.13.4 Abnormal Conditions
Not applicable.
8.14 LWIP Addition Preparation
8.14.1 General
The purpose of the LWIP Addition Preparation procedure is to request the WT to configure tunnel resources for LWIP operation for a specific UE.
The procedure uses UE-associated signalling and, in case of successful operation, establishes a new UE-associated logical Xw-connection.
The eNB initiates the procedures by sending the LWIP ADDITION REQUEST message to the WT.
At reception of the LWIP ADDITION REQUEST message the WT shall use the received information to configure resources for LWIP for the UE, as defined in TS 36.300 [2].
If the LWIP ADDITION REQUEST message contains the Serving PLMN IE, the WT may take it into account for the allocation of resources for LWIP.
If the LWIP ADDITION REQUEST message contains the Mobility Set IE, the WT shall use the included information as described in TS 36.300 [2].
If the LWIP ADDITION REQUEST message contains the eNB GTP Tunnel Endpoint IE, the WT shall use the included information to configure the LWIP user plane for the UE.
The WT shall respond to the eNB with the LWIP ADDITION REQUEST ACKNOWLEDGE message.
If the LWIP-SeGW GTP Tunnel Endpoint IE is included in the LWIP ADDITION REQUEST ACKNOWLEDGE message, the eNB shall use the included information to configure the LWIP user plane for the UE.
If the WT is not able to configure tunnel resources for LWIP operation for the UE or a failure occurs during the LWIP Addition Preparation, the WT sends the LWIP ADDITION REQUEST REJECT message with an appropriate cause value to the eNB.
8.14.4 Abnormal Conditions
Not applicable.
8.15 eNB Initiated LWIP Modification
8.15.1 General
This procedure is used to enable an eNB to request a WT to modify the UE context for LWIP at the WT.
The eNB initiates the procedure by sending the LWIP MODIFICATION REQUEST message to the WT.
If the LWIP MODIFICATION REQUEST message contains the Serving PLMN IE, the WT may take it into account for the allocation of resources for LWIP.
If the Mobility Set IE is included in the LWIP MODIFICATION REQUEST message, the WT shall use the information included in this IE as defined in TS 36.300 [2].
If at least one of the requested modifications is admitted by the WT, the WT shall modify the related part of the UE context accordingly and send the LWIP MODIFICATION REQUEST ACKNOWLEDGE message back to the eNB.
If the WT does not admit any modification requested by the eNB, or a failure occurs during the eNB initiated LWIP Modification, the WT shall send the LWIP MODIFICATION REQUEST REJECT message to the eNB. The message shall contain the Cause IE with an appropriate value.
8.15.4 Abnormal Conditions
Not applicable.
8.16 eNB Initiated LWIP Release
8.16.1 General
The eNB initiated LWIP Release procedure is triggered by the eNB to initiate the release of tunnel resources for LWIP operation for a specific UE.
The eNB initiates the procedure by sending the LWIP RELEASE REQUEST message. Upon reception of the LWIP RELEASE REQUEST message the WT shall release LWIP tunnel resources for the UE. The eNB may provide appropriate information within the Cause IE.
8.16.3 Unsuccessful Operation
Not applicable.
8.16.4 Abnormal Conditions
Not applicable.
8.17 WT Initiated LWIP Release
8.17.1 General
This procedure is triggered by the WT to initiate the release of tunnel resources for LWIP operation for a specific UE.
The WT initiates the procedure by sending the LWIP RELEASE REQUIRED message to the eNB.
Upon reception of the LWIP RELEASE REQUIRED message, the eNB replies with the LWIP RELEASE CONFIRM message.
The WT may stop providing user data for LWIP operation to the UE upon reception of the LWIP RELEASE CONFIRM message.
8.17.3 Unsuccessful Operation
Not applicable.
8.17.4 Abnormal Conditions
Not applicable.
9 Elements for XwAP Communication
9.0 General
Sub clauses 9.1 and 9.2 describe the structure of the messages and information elements required for the XwAP protocol in tabular format. Sub clause 9.3 provides the corresponding ASN.1 definition.
The following attributes are used for the tabular description of the messages and information elements: Presence, Range Criticality and Assigned Criticality. Their definition and use can be found in TS 36.413 [8].
NOTE: The messages have been defined in accordance to the guidelines specified in TR 25.921 [12].
9.1 Message Functional Definition and Content
9.1.1 Xw SETUP REQUEST
This message is sent by an eNB to a WT to transfer the initialization information for a TNL association.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
Global eNB ID
M
9.2.2
YES
reject
9.1.2 Xw SETUP RESPONSE
This message is sent by a WT to a requesting eNB to transfer the initialization information for a TNL association.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
WT ID
M
9.2.6
YES
reject
WLAN Identifier List
1
List of identifiers supported by the WT
YES
reject
>WLAN Identifier Item
1..<maxnoofWLANIdentifierItems>
>>WLAN Information
M
9.2.7
Neighbour eNB Information
0..< maxnoofeNBNeighbours >
>Global eNB ID
M
9.2.2
Criticality Diagnostics
O
9.2.5
YES
ignore
Range bound
Explanation
maxnoofWLANIdentifierItems
Maximum number of WLAN Identifier Items. The value is 4096.
maxnoofeNBNeighbours
Maximum number of eNBs a WT can connect to. The value is 256
9.1.3 Xw SETUP FAILURE
This message is sent by the WT to indicate Xw Setup failure.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
Cause
M
9.2.4
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
Time To Wait
O
9.2.29
YES
ignore
9.1.4 WT CONFIGURATION UPDATE
This message is sent by a WT to an eNB to transfer updated information for a TNL association.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
WLAN Identifiers To Add List
0..1
List of identifiers added by the WT
GLOBAL
reject
>WLAN Identifiers To Add Item
1..< maxnoofWLANIdentifierItems>
>>WLAN Information
M
9.2.7
WLAN Identifiers To Modify List
0..1
List of identifiers modified by the WT
GLOBAL
reject
>WLAN Identifiers To Modify Item
1..< maxnoofWLANIdentifierItems>
>>WLAN Information
M
9.2.7
WLAN Identifiers To Delete List
0..1
List of identifiers deleted by the WT
GLOBAL
reject
>WLAN Identifiers To Delete Item
1..< maxnoofWLANIdentifierItems >
>>Old BSSID
M
BSSID
9.2.8
WLAN Identifiers To Delete Extension List
0..1
List of identifiers deleted by the WT
GLOBAL
reject
>WLAN Identifiers To Delete extension Item
1..<maxnoofWLANIdentifierItems >
>>Old SSID
O
SSID
9.2.9
>>Old HESSID
O
HESSID
9.2.10
Neighbour eNB Information
0..< maxnoofeNBNeighbours >
>Global eNB ID
M
9.2.2
Range bound
Explanation
maxnoofWLANIdentifierItems
Maximum number of WLAN Identifier Items. The value is 4096.
maxnoofeNBNeighbours
Maximum number of eNBs a WT can connect to. The value is 256
9.1.5 WT CONFIGURATION UPDATE ACKNOWLEDGE
This message is sent by an eNB to a WT to acknowledge update of information for a TNL association.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
Criticality Diagnostics
O
9.2.5
YES
ignore
9.1.6 WT CONFIGURATION UPDATE FAILURE
This message is sent by an eNB to a WT to indicate WT Configuration Update Failure.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
Cause
M
9.2.4
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
Time To Wait
O
9.2.29
YES
ignore
9.1.7 WT STATUS REQUEST
This message is sent by an eNB to a WT to initiate the requested measurement according to the parameters given in the message.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB Measurement ID
M
INTEGER (1..4095,...)
Allocated by the eNB
YES
reject
WT Measurement ID
C-ifRegistrationRequestStop
INTEGER (1..4095,...)
Allocated by the WT
YES
ignore
Registration Request
M
ENUMERATED(start, stop,
…)
A value set to “stop”, indicates a request to stop all BSS measurements.
YES
reject
Report Characteristics
O
BITSTRING
(SIZE(32))
Each position in the bitmap indicates measurement object the WT is requested to report.
First Bit = BSS Load,
Second Bit = WAN Metrics, Third bit = Available Channel Utilization.
Maximum number of BSS Items in a list. The value is 4096.
Condition
Explanation
ifRegistrationRequestStop
This IE shall be present if the Registration Request IE is set to the value “stop”.
9.1.8 WT STATUS RESPONSE
This message is sent by the WT to indicate that the requested measurement, for all or for a subset of the measurement objects included in the measurement request, is successfully initiated.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB Measurement ID
M
INTEGER (1..4095,...)
Allocated by the eNB
YES
reject
WT Measurement ID
M
INTEGER (1..4095,...)
Allocated by the WT
YES
reject
Measurement Initiation Result List
0..1
List of all BSSs in which measurement objects were requested, included when indicating partial success
YES
ignore
>Measurement Initiation Result Item
1 .. <maxnoofBSSs>
EACH
ignore
>>BSSID
M
9.2.8
–
–
>>Measurement Failure Cause List
0..1
Indicates that WT could not initiate the measurement for at least one of the requested measurement objects in the BSS
–
–
>>>Measurement Failure Cause Item
1 .. <maxnoofFailedMeasObjects>
EACH
ignore
>>>>Measurement Failed Report Characteristics
M
BITSTRING
(SIZE(32))
Each position in the bitmap indicates measurement object that failed to be initiated in the WT.
First Bit = BSS Load,
Second Bit = WAN Metrics, Third Bit = Available Channel Utilization.
Other bits shall be ignored by the eNB.
–
–
>>>>Cause
M
9.2.4
Failure cause for measurement objects for which the measurement cannot be initiated
–
–
Criticality Diagnostics
O
9.2.5
YES
ignore
Range bound
Explanation
maxnoofBSSs
Maximum number of BSSs Items in a list. The value is 4096.
maxnoofFailedMeasObjects
Maximum number of measurement objects that can fail per measurement. Value is 32.
9.1.9 WT STATUS FAILURE
This message is sent by the WT to indicate that none of the requested measurements can be initiated.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB Measurement ID
M
INTEGER (1..4095,...)
Allocated by the eNB
YES
reject
WT Measurement ID
M
INTEGER (1..4095,...)
Allocated by the WT
YES
reject
Complete Failure Cause Information List
0..1
Complete list of failure causes for all requested cells
YES
ignore
>Complete Failure Cause Information Item
1 .. <maxnoofBSSs>
EACH
ignore
>>BSSID
M
9.2.8
–
–
>>Measurement Failure Cause List
1
–
–
>>>Measurement Failure Cause Item
1 .. <maxnoofFailedMeasObjects>
EACH
ignore
>>>>Measurement Failed Report Characteristics
M
BITSTRING
(SIZE(32))
Each position in the bitmap indicates measurement object that failed to be initiated in the WT.
First Bit = BSS Load,
Second Bit = WAN Metrics, Third Bit = Available Channel Utilization.
Other bits shall be ignored by the eNB.
–
–
>>>>Cause
M
9.2.4
Failure cause for measurements that cannot be initiated
–
–
Cause
M
9.2.4
Ignored by the receiver when the Complete Failure Cause Information IE is included
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
Range bound
Explanation
maxnoofBSSs
Maximum number of BSS Items in a list. The value is 4096.
maxnoofFailedMeasObjects
Maximum number of measurement objects that can fail per measurement. Value is 32.
9.1.10 WT STATUS REPORT
This message is sent by the WT to the eNB to report the results of the requested measurements.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
ignore
eNB Measurement ID
M
INTEGER (1..4095,...)
Allocated by the eNB
YES
reject
WT Measurement ID
M
INTEGER (1..4095,...)
Allocated by the WT
YES
reject
BSS Measurement Result List
1
YES
ignore
>BSS Measurement Result Item
1 .. <maxnoofBSSs>
EACH
ignore
>>BSSID
M
9.2.8
>>BSS Load
O
9.2.11
>>WAN Metrics
O
9.2.12
>>Available Channel Utilization
O
9.2.26
Range bound
Explanation
maxnoofBSSs
Maximum number of BSS Items in a list. The value is 4096.
9.1.11 ERROR INDICATION
This message is used to indicate that some error has been detected in the originating node.
Direction: eNB WT and WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
ignore
eNB UE XwAP ID
O
UE XwAP ID 9.2.24
Assigned by the eNB
YES
ignore
WT UE XwAP ID
O
UE XwAP ID 9.2.24
Assigned by the WT
YES
ignore
Cause
O
9.2.4
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
9.1.12 RESET
This message is used to request the Xw interface to be reset.
Direction: eNB WT and WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
Cause
M
9.2.4
YES
ignore
9.1.13 RESET RESPONSE
This message is sent as a response to a RESET message.
Direction: WT eNB and eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
Criticality Diagnostics
O
9.2.5
YES
ignore
9.1.14 WT ADDITION REQUEST
This message is sent by the eNB to the WT to request the preparation of resources for LTE-WLAN aggregation for a specific UE.
This message is sent by the WT to the eNB to confirm that a certain UE successfully associated with the WLAN.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
ignore
eNB UE XwAP ID
M
UE XwAP ID
9.2.24
Assigned by the eNB
YES
ignore
WT UE XwAP ID
M
UE XwAP ID
9.2.24
Assigned by the WT
YES
ignore
9.1.27 LWIP ADDITION REQUEST
This message is sent by the eNB to the WT to request the configuration of tunnel resources for LWIP operation for a specific UE.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
reject
UE Identity
M
9.2.16
YES
reject
LWIP-SeGW Security Information
M
9.2.30
Serving PLMN
O
PLMN Identity
9.2.3
The serving PLMN for the UE.
YES
ignore
eNB GTP Tunnel Endpoint
O
GTP Tunnel Endpoint 9.2.22
Endpoint of the Xw transport bearer at the eNB
YES
reject
Mobility Set
O
9.2.28
YES
reject
9.1.28 LWIP ADDITION REQUEST ACKNOWLEDGE
This message is sent by the WT to confirm to the eNB about the LWIP addition preparation.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
ignore
WT UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the WT
YES
ignore
LWIP-SeGW GTP Tunnel Endpoint
O
GTP Tunnel Endpoint 9.2.22
Endpoint of the Xw transport bearer at the WT
YES
reject
Criticality Diagnostics
O
9.2.5
YES
ignore
9.1.29 LWIP ADDITION REQUEST REJECT
This message is sent by the WT to inform the eNB that the LWIP Addition Preparation procedure has failed.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
ignore
Cause
M
9.2.4
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
9.1.30 LWIP MODIFICATION REQUEST
This message is sent by the eNB to the WT to request the modification of tunnel resources for LWIP operation for a specific UE.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
reject
WT UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the WT
YES
reject
Cause
M
9.2.4
YES
ignore
Serving PLMN
O
PLMN Identity
9.2.3
The serving PLMN for the UE.
YES
ignore
Mobility Set
O
9.2.28
YES
reject
9.1.31 LWIP MODIFICATION REQUEST ACKNOWLEDGE
This message is sent by the WT to the eNB to confirm the modification of tunnel resources for LWIP operation for a specific UE.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
ignore
WT UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the WT
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
9.1.32 LWIP MODIFICATION REQUEST REJECT
This message is sent by the WT to inform the eNB that the eNB initiated LWIP Modification procedure has failed.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
ignore
WT UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the WT
YES
ignore
Cause
M
9.2.4
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
9.1.33 LWIP RELEASE REQUEST
This message is sent by the eNB to the WT to request the release of all tunnel resources for LWIP operation for a specific UE at the WT.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
ignore
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
reject
WT UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the WT
YES
reject
Cause
O
9.2.4
YES
ignore
9.1.34 LWIP RELEASE REQUIRED
This message is sent by the WT to request the release of all tunnel resources for LWIP operation for a specific UE at the WT.
Direction: WT eNB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
reject
WT UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the WT
YES
reject
Cause
M
9.2.4
YES
ignore
9.1.35 LWIP RELEASE CONFIRM
This message is sent by the eNB to confirm the release of all tunnel resources for LWIP operation for a specific UE at the WT.
Direction: eNB WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Message Type
M
9.2.1
YES
reject
eNB UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the eNB
YES
ignore
WT UE XwAP ID
M
UE XwAP ID 9.2.24
Assigned by the WT
YES
ignore
Criticality Diagnostics
O
9.2.5
YES
ignore
9.2 Information Element definitions
9.2.0 General
When specifying information elements which are to be represented by bit strings, if not otherwise specifically stated in the semantics description of the concerned IE or elsewhere, the following principle applies with regards to the ordering of bits:
- The first bit (leftmost bit) contains the most significant bit (MSB);
- The last bit (rightmost bit) contains the least significant bit (LSB);
- When importing bit strings from other specifications, the first bit of the bit string contains the first bit of the concerned information.
9.2.1 Message Type
This IE uniquely identifies the message being sent. It is mandatory for all messages.
Unspecified, Multiple E-RAB ID instances, Switch Off Ongoing, Not supported QCI value, Measurement not supported for the object,
Reduce Load,
Resource Optimisation,
Target not Allowed,
No Radio Resources Available,
Invalid QoS combination, Procedure cancelled, Radio Connection With UE Lost, Failure in the Radio Interface Procedure, ..., No Report Periodicity, Wrong WLAN Interworking Mode)
>Transport Layer
>>Transport Layer Cause
M
ENUMERATED
(Transport Resource Unavailable,
Unspecified, ...)
>Protocol
>>Protocol Cause
M
ENUMERATED
(Transfer Syntax Error,Abstract Syntax Error (Reject),Abstract Syntax Error (Ignore and Notify),Message not Compatible with Receiver State,Semantic Error,Unspecified,Abstract Syntax Error (Falsely Constructed Message), ...)
>Misc
>>Miscellaneous Cause
M
ENUMERATED
(Control Processing Overload,
Hardware Failure,O&M Intervention,Not enough User Plane Processing Resources,Unspecified, ...)
The meaning of the different cause values is described in the following table. In general, "not supported" cause values indicate that the concerned capability is missing. On the other hand, "not available" cause values indicate that the concerned capability is present, but insufficient resources were available to perform the requested action.
Radio Network Layer cause
Meaning
WLAN not Available
The concerned WLAN is not available.
Unknown eNB UE XwAP ID
The action failed because the eNB UE XwAP ID is unknown.
Unknown WT UE XwAP ID
The action failed because the WT UE XwAP ID is unknown.
Unknown Pair of UE XwAP ID
The action failed because the pair of UE XwAP IDs is unknown.
Security Failure
The action is requested (or a previous request by the receiving node failed) due to a failure in security procedures.
ReportCharacteristicsEmpty
The action failed because there is no characteristic reported.
Existing Measurement ID
The action failed because Measurement ID is already used.
Unknown Measurement ID
The action failed because some eNB or WT Measurement ID is unknown.
Measurement Temporarily not Available
The WT can temporarily not provide the requested measurement object.
Multiple E-RAB ID Instances
The action failed because multiple instances of the same E-RAB had been provided to the WT.
Switch Off Ongoing
The reason for the action is an ongoing switch off i.e. either the sending node, or nodes whose actions the sending node triggers or monitors, will be switched off and not be available. It aids the receiving node in taking subsequent actions.
Not supported QCI value
The action failed because the requested QCI is not supported.
Unspecified
Sent when none of the above cause values applies but still the cause is Radio Network Layer related.
Measurement not Supported For The Object
At least one of the concerned BSS(s) does not support the requested measurement.
Reduce Load
The action is requested in order to reduce load in an element controlled by the sending node.
Resource Optimisation
The reason for requesting this action is to improve the load distribution.
Target not Allowed
Requested action towards the indicated target is not allowed for the UE in question.
No Radio Resources Available
The action failed because of insufficient radio resources in the requested node.
Invalid QoS combination
The action was failed because of invalid QoS combination.
Procedure cancelled
The sending node cancelled the procedure due to other urgent actions to be performed.
Radio Connection With UE Lost
The action is requested due to losing the radio connection to the UE.
Failure in the Radio Interface Procedure
Radio interface procedure has failed.
No Report Periodicity
The action failed because the periodicity is not defined.
Wrong WLAN Interworking Mode
The WT cannot support the requested WLAN interworking mode (LWA or LWIP), or it cannot handle a procedure related to one of the modes, or the requested mode is not configured for the UE.
Transport Network Layer cause
Meaning
Transport resource unavailable
The required transport resources are not available.
Unspecified
Sent when none of the above cause values applies but still the cause is Transport Network Layer related
Protocol cause
Meaning
Abstract Syntax Error (Reject)
The received message included an abstract syntax error and the concerned criticality indicated "reject" (see sub clause 10.3 of TS 36.413 [8]).
Abstract Syntax Error (Ignore and Notify)
The received message included an abstract syntax error and the concerned criticality indicated "ignore and notify" (see sub clause 10.3 of TS 36.413 [8]).
The received message contained IEs or IE groups in wrong order or with too many occurrences (see sub clause 10.3 of TS 36.413 [8]).
Message not Compatible with Receiver State
The received message was not compatible with the receiver state (see sub clause 10.4 of TS 36.413 [8]).
Semantic Error
The received message included a semantic error (see sub clause 10.4 of TS 36.413 [8]).
Transfer Syntax Error
The received message included a transfer syntax error (see sub clause 10.2 of TS 36.413 [8]).
Unspecified
Sent when none of the above cause values applies but still the cause is Protocol related
Miscellaneous cause
Meaning
Control Processing Overload
eNB or WT control processing overload
Hardware Failure
eNB or WT hardware failure
Not enough User Plane Processing Resources
eNB or WT has insufficient user plane processing resources available.
O&M Intervention
Operation and Maintenance intervention
Unspecified
Sent when none of the above cause values applies and the cause is not related to any of the categories Radio Network Layer, Transport Network Layer or Protocol
9.2.5 Criticality Diagnostics
The Criticality Diagnostics IE is sent by the eNB and the WT when parts of a received message have not been comprehended or were missing, or if the message contained logical errors. When applicable, it contains information about which IEs were not comprehended or were missing.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Procedure Code
O
INTEGER (0..255)
Procedure Code is to be used if Criticality Diagnostics is part of Error Indication procedure, and not within the response message of the same procedure that caused the error.
The Triggering Message is used only if the Criticality Diagnostics is part of Error Indication procedure.
Procedure Criticality
O
ENUMERATED(reject, ignore, notify)
This Procedure Criticality is used for reporting the Criticality of the Triggering message (Procedure).
Information Element Criticality Diagnostics
0..<maxnoofErrors>
>IE Criticality
M
ENUMERATED(reject, ignore, notify)
The IE Criticality is used for reporting the criticality of the triggering IE. The value "ignore'" shall not be used.
>IE ID
M
INTEGER (0..65535)
The IE ID of the not understood or missing IE
>Type Of Error
M
ENUMERATED(not understood, missing, …)
Range bound
Explanation
maxnoofErrors
Maximum no. of IE errors allowed to be reported with a single message. The value for maxnoofErrors is 256.
9.2.6 WT ID
This IE is used to identify a WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
CHOICE WT ID Type
M
>WT ID Type 1
>>PLMN ID
M
PLMN Identity
9.2.3
>>Short WT ID
M
BIT STRING (24)
>WT ID Type 2
>>Long WT ID
M
BIT STRING (48)
9.2.7 WLAN Information
This IE contains WLAN configuration information that an eNB may need for the Xw interface. It shall contain at least one of the BSS Item, the SSID, and/or the HESSID IEs.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
BSS Item
O
>BSSID
M
9.2.8
>WLAN Operating Class
O
INTEGER (0..255)
Indicates the Operating Class of WLAN as defined in IEEE 802.11™ [11].
This IE represents the WLAN MAC address of the UE.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
UE Identity
M
OCTET STRING (SIZE(6))
This corresponds to the WLAN MAC address of the UE
9.2.17 Bit Rate
This IE indicates the number of bits delivered within a period of time, divided by the duration of the period. It is used, for example, to indicate the maximum or guaranteed bit rate for a GBR E-RAB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Bit Rate
M
INTEGER (0..10,000,000,000)
The unit is: bit/s
9.2.18 E-RAB ID
This IE uniquely identifies an E-RAB for a UE.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
E-RAB ID
M
INTEGER (0..15, ...)
9.2.19 E-RAB Level QoS Parameters
This IE defines the QoS to be applied to an E-RAB.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
QCI
M
INTEGER (0..255)
QoS Class Identifier defined in TS 23.401 [14].
Logical range and coding specified in TS 23.203 [13].
–
–
Allocation and Retention Priority
M
9.2.20
–
–
GBR QoS Information
O
9.2.21
This IE applies to GBR bearers only and shall be ignored otherwise.
–
–
9.2.20 Allocation and Retention Priority
This IE specifies the relative importance compared to other E-RABs for allocation and retention of the E-UTRAN Radio Access Bearer.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Priority Level
M
INTEGER (0..15)
Desc.: This IE should be understood as “priority of allocation and retention” (see TS 23.401 [14]).
Usage:
Value 15 means “no priority”.
Values between 1 and 14 are ordered in decreasing order of priority, i.e. 1 is the highest and 14 the lowest.
Value 0 shall be treated as a logical error if received.
Pre-emption Capability
M
ENUMERATED(shall not trigger pre-emption, may trigger pre-emption)
Descr.: This IE indicates the pre-emption capability of the request on other E-RABs
Usage:
The E-RAB shall not pre-empt other E-RABs or, the E-RAB may pre-empt other E-RABs
The Pre-emption Capability indicator applies to the allocation of resources for an E-RAB and as such it provides the trigger to the pre-emption procedures/processes of the eNB.
Pre-emption Vulnerability
M
ENUMERATED(not pre-emptable, pre-emptable)
Desc.: This IE indicates the vulnerability of the E-RAB to pre-emption of other E-RABs.
Usage:
The E-RAB shall not be pre-empted by other E-RABs or the E-RAB may be pre-empted by other RABs.
Pre-emption Vulnerability indicator applies for the entire duration of the E-RAB, unless modified, and as such indicates whether the E-RAB is a target of the pre-emption procedures/processes of the eNB.
9.2.21 GBR QoS Information
This IE indicates the maximum and guaranteed bit rates of a GBR E-RAB for downlink.
NOTE: The WT shall regard the GBR QoS Information IE as an E-RAB level parameter for E-RABs configured with the LWA bearer, although the bit rates signalled by the eNB are typically not equal to the bit rates signalled by the MME for that E-RAB (see TS 36.300 [2]).
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
E-RAB Maximum Bit Rate Downlink
M
Bit Rate 9.2.17
Maximum Bit Rate in DL (i.e. from EPC to E-UTRAN) for the bearer.
Details in TS 23.401 [14].
–
–
E-RAB Guaranteed Bit Rate Downlink
M
Bit Rate 9.2.17
Guaranteed Bit Rate (provided that there is data to deliver) in DL (i.e. from EPC to E-UTRAN) for the bearer.
Details in TS 23.401 [14].
–
–
9.2.22 GTP Tunnel Endpoint
The GTP Tunnel Endpoint IE identifies an Xw transport bearer associated to an E-RAB. It contains a Transport Layer Address and a GTP Tunnel Endpoint Identifier. The Transport Layer Address is an IP address to be used for the Xw user plane transport (see TS 36.464 [15]). The GTP Tunnel Endpoint Identifier is to be used for the user plane transport between the eNB and the WT.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Transport Layer Address
M
BIT STRING (1..160, ...)
For details on the Transport Layer Address, see TS 36.464 [15]
–
–
GTP TEID
M
OCTET STRING (4)
For details and range, see TS 29.281 [16]
–
–
9.2.23 E-RAB List
The IE contains a list of E-RAB identities with a cause value. It is used for example to indicate not admitted bearers.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
E-RAB List Item
1..<maxnoofBearers>
EACH
ignore
>E-RAB ID
M
9.2.18
–
–
>Cause
M
9.2.4
–
–
Range bound
Explanation
maxnoofBearers
Maximum no. of E-RABs. Value is 256.
9.2.24 UE XwAP ID
This information element uniquely identifies a UE over the Xw interface within a WT or an eNB.
The eNB UE XwAP ID is allocated by the eNB, and the WT UE XwAP ID is allocated by the WT.
The usage of this IE is defined in TS 36.401 [9].
IE/Group Name
Presence
Range
IE type and reference
Semantics description
UE XwAP ID
M
OCTET STRING (SIZE(3))
9.2.25 Station Count
The Station Count IE indicates the total number of stations associated with the BSS.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Station Count
M
INTEGER (0..65535)
Defined in subclause 8.4.2.30 of IEEE 802.11™ [11]
9.2.26 Available Channel Utilization
The Available Channel Utilization IE indicates the amount of WLAN channel utilization time that is available for LWA services relative to the total channel busy time period, as defined in [11]. The available channel utilization should be measured and reported so that the minimum channel utilization time needed for existing services is reserved according to implementation.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Criticality
Assigned Criticality
Capacity Value
M
INTEGER (0..100)
Value 0 shall indicate no available channel utilization time, and 100 shall indicate that all the channel utilization time is available. Available Channel Utilization should be measured on a linear scale.
-
-
9.2.27 WLAN Security Information
The WLAN Security Information IE is used to establish WLAN security as defined in TS 33.401 [17].
IE/Group Name
Presence
Range
IE Type and Reference
Semantics Description
WT Security Key
M
BIT STRING (SIZE(256))
The S-KWT which is provided by the eNB, see TS 33.401 [17].
9.2.28 Mobility Set
The Mobility Set IE contains the mobility set configured for a UE, as defined in TS 36.300 [2]. It shall contain at least one of the BSSID, the SSID, and/or the HESSID IEs.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Mobility Set Item
1..<maxnoofMobilitySetItems>
>BSSID
O
9.2.8
>SSID
O
9.2.9
>HESSID
O
9.2.10
Range bound
Explanation
maxnoofMobilitySetItems
Maximum number of mobility set items in the Mobility Set. The value is 1024.
9.2.29 Time To Wait
This IE defines the minimum allowed waiting times.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
Time To Wait
M
ENUMERATED(1s, 2s, 5s, 10s, 20s, 60s, …)
9.2.30 LWIP-SeGW Security Information
This IE contains security information for the LWIP IPSec tunnel, as defined in TS 33.401 [17].
IE/Group Name
Presence
Range
IE Type and Reference
Semantics Description
LWIP-PSK
M
BIT STRING (SIZE(256))
IKE Initiator Identity
M
OCTET STRING
9.2.31 WLAN Usage
This IE identifies the usage of the given WLAN identifier(s).
IE/Group Name
Presence
Range
IE type and reference
Semantics description
WLAN Usage
M
ENUMERATED (LWA and LWIP, LWIP only, ...)
9.2.32 UE Context Kept Indicator
This IE indicates that the UE Context at the WT is kept in case of inter-eNB handover without WT Change procedure, as specified in TS 36.300 [2].
IE/Group Name
Presence
Range
IE type and reference
Semantics description
UE Context Kept Indicator
M
ENUMERATED (True, …)
9.2.33 DRB-Identity
This IE uniquely identifies the DRB for a UE.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
DRB-Identity
M
INTEGER (1..32,...)
Corresponds to the DRB Identity as defined in TS 36.331 [18]
9.2.34 LWA WLAN AC
This IE identifies the Access Category for uplink LWA.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
LWA WLAN AC
M
ENUMERATED (ac-bk, ac-be, ac-vi, ac-vo)
Corresponds to the Access Categories as defined in TS 36.331 [18]
9.2.35 WT MAC Address
This IE represents the WT MAC address on the network interface towards the WLAN.
IE/Group Name
Presence
Range
IE type and reference
Semantics description
WT MAC Address
M
OCTET STRING (SIZE(6))
This corresponds to the WT MAC Address
9.3 Message and Information Element Abstract Syntax (with ASN.1)
9.3.1 General
XwAP ASN.1 definition conforms to ITU-T Rec. X.680 [6] and ITU-T Rec. X.681 [7].
Sub clause 9.3 presents the Abstract Syntax of the XwAP protocol with ASN.1. In case there is contradiction between the ASN.1 definition in this sub clause and the tabular format in sub clause 9.1 and 9.2, the ASN.1 shall take precedence, except for the definition of conditions for the presence of conditional elements, in which the tabular format shall take precedence.
The ASN.1 definition specifies the structure and content of XwAP messages. XwAP messages can contain any IEs specified in the object set definitions for that message without the order or number of occurrence being restricted by ASN.1. However, for this version of the standard, a sending entity shall construct an XwAP message according to the PDU definitions module and with the following additional rules:
- IEs shall be ordered (in an IE container) in the order they appear in object set definitions.
- Object set definitions specify how many times IEs may appear. An IE shall appear exactly once if the presence field in an object has value "mandatory". An IE may appear at most once if the presence field in an object has value "optional" or "conditional". If in a tabular format there is multiplicity specified for an IE (i.e. an IE list) then in the corresponding ASN.1 definition the list definition is separated into two parts. The first part defines an IE container list in which the list elements reside. The second part defines list elements. The IE container list appears as an IE of its own. For this version of the standard an IE container list may contain only one kind of list elements.
NOTE: In the above, "IE" means an IE in the object set with an explicit ID. If one IE needs to appear more than once in one object set, then the different occurrences have different IE IDs.
If an XwAP message that is not constructed as defined above is received, this shall be considered as Abstract Syntax Error, and the message shall be handled as defined for Abstract Syntax Error in clause 10.
9.3.2 Usage of Private Message Mechanism for Non-standard Use
The private message mechanism for non-standard use may be used:
- for special operator (and/or vendor) specific features considered not to be part of the basic functionality, i.e. the functionality required for a complete and high-quality specification in order to guarantee multivendor inter-operability.
- by vendors for research purposes, e.g. to implement and evaluate new algorithms/features before such features are proposed for standardisation.
The private message mechanism shall not be used for basic functionality. Such functionality shall be standardised.
value XWAP-PRIVATE-IES.&Value ({IEsSetParam}{@id})
}
END
9.4 Message transfer syntax
XwAP shall use the ASN.1 Basic Packed Encoding Rules (BASIC-PER) Aligned Variant as transfer syntax, as specified in ITU-T Rec. X.691 [5].
10 Handling of unknown, unforeseen and erroneous protocol data
Clause 10 of TS 36.413 [8] is applicable for the purposes of the present document, with the following addition to the handling of AP IDs specified in clause 10.6.
If a node receives a message (other than the first or first returned messages) that includes AP ID(s) identifying a logical connection which is known to the node (for the same Xw interface), but was established for the LWIP operation whereas the message relates to LWA operation (or vice-versa), the node shall behave as if the AP ID(s) identify a logical connection which is unknown to the node. If the node subsequently initiates an Error Indication procedure as part of the error handling described in clause 10.6 of TS 36.413 [8], it shall include an appropriate cause value such as "Wrong WLAN Interworking Mode".
Annex A (informative):
Change history
TSG#
TSG Doc.
CR
Rev
Cat
Subject/Comment
New
Initial skeleton
0.0.1
Inclusion of text proposals agreed at RAN WG3#89bis
0.0.2
Editorial revisions and corrections
0.0.3
Inclusion of text proposals agreed at RAN WG3#90
0.0.4
RAN#70
Presentation to RAN#70 for information
1.0.0
Editorial revisions and corrections
1.1.0
Inclusion of text proposals agreed at RAN WG3 Adhoc NBIoT
1.2.0
Editorial revisions and corrections
1.3.0
Inclusion of text proposals agreed at RAN WG3#91
1.4.0
RAN#71
Presentation to RAN#71 for approval
2.0.0
RAN#71
Upgraded to Rel-13 and placed under change control
13.0.0
RAN#72
RP-161046
3
2
F
Addition of measurement configuration
13.1.0
RAN#72
RP-161046
4
1
F
Correction on RESET procedure
13.1.0
RAN#72
RP-161046
5
F
Correction on WT Initiated WT Modification
13.1.0
RAN#72
RP-161046
7
2
F
Correction on WT configuration update
13.1.0
RAN#72
RP-161046
8
2
F
Correction on Global eNB ID
13.1.0
RAN#72
RP-161043
12
F
Correction to WT-Initiated WT Modification
13.1.0
RAN#72
RP-161046
14
3
F
Xw-AP corrections
13.1.0
RAN#72
RP-161046
17
1
F
Rapporteur updates to TS 36.463
13.1.0
RAN#74
RP-162336
0027
2
B
Correction on the reinitiating waiting time in Xw
14.0.0
Change history
Date
Meeting
TDoc
CR
Rev
Cat
Subject/Comment
New version
2017-03
RP-75
RP-170535
0032
B
XwAP Support for Inter-eNB Mobility without WT Change
14.1.0
2017-03
RP-75
RP-170535
0033
B
Introduction of WLAN band indication
14.1.0
2017-03
RP-75
RP-170535
0034
B
Uplink bearer identification
14.1.0
2017-03
RP-75
RP-170535
0035
B
WT Notifying neighbour eNB information on Xw
14.1.0
2017-03
RP-75
RP-170542
0036
B
Introduction of New types of eNB ID
14.1.0
2017-03
RP-75
RP-170543
0031
4
B
LWIP Addition and Modification
14.1.0
2017-03
RP-75
RP-170535
0032
B
XwAP Support for Inter-eNB Mobility without WT Change
14.1.0
2017-03
RP-75
RP-170535
0033
B
Introduction of WLAN band indication
14.1.0
2017-03
RP-75
RP-170331
0037
B
Xw support for WT MAC address signalling
14.1.0
2017-06
RP-76
RP-171326
0038
1
F
Corrections on inter-WLAN interworking mode error handling