Name

AVP Code

Data Type

Vendor

Access-Network-Info

1526

Grouped

3GPP

Provides details about the wireless access network to which the User Equipment (UE) is connected. Must contain the SSID of the WLAN. Should include at least one of the following: BSSID, Location-Information, Logical-Access-ID.

The AVP structure is defined as follows:

SSID (Optional, UTF8String): The Service Set Identifier (SSID) of the WLAN.

BSSID (Optional, UTF8String): The Basic Service Set Identifier (BSSID) of the WLAN access point.

Location-Information (Optional, OctetString): Encodes civic location profile data (as per RFC 5580).

Location-Data (Optional, OctetString): Additional location data (per RFC 5580).

Operator-Name (Optional, OctetString): Identifies the operator of the Trusted or Untrusted WLAN. Can be: Realm format [RFC 5580] or PLMN-ID (MCC + MNC, per IANA values). First 8 bits represent the Namespace ID:

1: Realm format

2: PLMN-ID (MCC + MNC)

Logical-Access-ID (Optional, OctetString): The Logical Access ID of the access point defined in ETSI [ES 283 034].

ANID (Access Network Identity)

1504

UTF8String

3GPP

Contains the Access Network Identity (ANID). This AVP is used to identify the specific access network the User Equipment (UE) is connected to. The defined values and usage are specified in 3GPP [TS 24.302].

AN-Trusted (Access Network Trusted Status)

1503

Enumerated

3GPP

Used in Diameter-based authentication and policy control. It is sent from the 3GPP AAA Server to a Non-3GPP access network to indicate whether the access network is considered trusted or untrusted by the Home Public Land Mobile Network (HPLMN).

Enumerated Values:

0: (TRUSTED): The Non-3GPP access network is considered trusted by the HPLMN.

1: (UNTRUSTED): The Non-3GPP access network is considered untrusted by the HPLMN.

Connectivity-Flags

1529

Unsigned32 (Bitmask)

3GPP

Provides connectivity status indicators that help distinguish between different types of access procedures. This bit may be set by the 3GPP AAA Server.

Bitmask Definition:

0: Initial-Attach-Indicator: When set, it indicates that the UE is performing an Initial Attach procedure from a Non-3GPP access network.

When cleared, it indicates that the UE is performing a Handover procedure instead.

NOTE: Bits not defined in this table shall be cleared by the sender and discarded by the receiver of the command.

DEA-Flags

1521

Unsigned32 (Bitmask)

3GPP

Used in Trusted WLAN (TWAN) authentication and authorization. It provides network policy control indicators for Non-Seamless WLAN Offload (NSWO), EPC access, and IMEI checks.

Bitmask Definition:

0: NSWO-Authorization: When set, it authorizes Non-Seamless WLAN Offload (NSWO) service, allowing the UE to use WLAN without seamless integration into EPC.

1: TWAN-S2a-Connectivity-Indicator: This bit is only applicable to the TWAN authentication and authorization procedure, when authorizing the SCM for EPC access. When set, it confirms that EAP-AKA' authentication has been successfully performed. This means the 3GPP AAA Server has validated the challenge response, and the TWAN can proceed with network connectivity setup.

2: IMEI-Check-Request-In-VPLMN: This bit is only applicable to the TWAN authentication and authorization procedure, when the UE and the network support Mobile Equipment Identity signalling over trusted WLAN. When set, it instructs the Visited PLMN (VPLMN) to perform an IMEI check for the UE and report the result back to the 3GPP AAA Server.

NOTE: Bits not defined in this table shall be cleared by the sender and discarded by the receiver of the command.

DER-Flags

1520

Unsigned32 (Bitmask)

3GPP

Provides capability and service indications for NSWO, EPC access, IMEI checks, emergency capabilities, and EAP re-authentication.

Bitmask Definition:

0: NSWO-Capability-Indication: When set, it indicates to the 3GPP AAA proxy/server that the TWAN supports Non-Seamless WLAN Offload (NSWO) service.

1: TWAN-S2a-Connectivity-Indicator: This bit is only applicable to the TWAN authentication and authorization procedure, when authorizing the SCM for EPC access. When set, it indicates to the 3GPP AAA Server that the TWAN has completed the S2a network connectivity setup, and the EAP authentication can be finalized.

2: IMEI-Check-Required-In-VPLMN: This bit is only applicable to the TWAN authentication and authorization procedure, when the UE and the network support Mobile Equipment Identity signalling over trusted WLAN. When set, it instructs the 3GPP AAA Server to retrieve the IMEI(SV) from the UE and return it to the Visited PLMN (VPLMN) by setting the IMEI-Check-Request-In-VPLMN bit in the DEA-Flags AVP.

3: IMEI-Check-Request-In-VPLMN: This bit is only applicable to the TWAN authentication and authorization procedure, when the UE and the network support Mobile Equipment Identity signalling over trusted WLAN. When set, it instructs the 3GPP AAA Proxy to perform an IMEI(SV) check in the VPLMN and send the IMEI validation result to the 3GPP AAA Server.

4: Emergency-Capability-Indication: When set, it indicates to the 3GPP AAA Server that the TWAN supports IMS emergency sessions. See clause 4.5.7 of 3GPP [TS 23.402].

5: ERP-Support-Indication: When set, it indicates to the 3GPP AAA proxy/server that the non-3GPP access network supports the EAP Re-authentication Protocol (ERP).

6: ERP-Re-Authentication: When set, it indicates that the authentication request is for EAP re-authentication based on ERP.
NOTE: Bits not defined in this table shall be cleared by the sender and discarded by the receiver of the command.

Full-Network-Name

1516

OctetString

3GPP

Contains the full textual name of the network. It is encoded as the Full name value field of the AT_FULL_NAME_FOR_NETWORK attribute, as specified in 3GPP [TS 24.302], clause 8.2.5.1.

HESSID

1525

UTF8String

3GPP

Contains a 6-octet MAC address that uniquely identifies a Homogeneous Extended Service Set (HESSID) as per IEEE Std 802.11-2012.

The HESSID is encoded as a 17-character uppercase ASCII string.

Each octet is represented in hexadecimal and separated by dashes (-).

Example format: "00-10-A4-23-19-C0".

IMEI-Check-In-VPLMN-Result

1540

Unsigned32

3GPP

Contains a 32-bit cause value field that indicates the result of the IMEI check performed in the Visited Public Land Mobile Network (VPLMN).

Cause Values and Their Meanings:

0: Successful: The IMEI check was successfully performed, and the device is authorized to connect.

1: Illegal_ME: The IMEI check failed due to the device being recognized as illegal (e.g., stolen, blacklisted).

MIP-FA-RK

1506

OctetString

3GPP

Contains the FA-RK (Foreign Agent Root Key), which is essential for calculating security parameters needed in the Mobile Node–Foreign Agent (MN-FA) authentication extension, as defined by 3GPP [TS 33.402].

MIP-FA-RK-SPI

1507

Unsigned32

3GPP

MIP-FA-RK-SPI AVP (Mobile IP Foreign Agent Root Key Security Parameter Index) is used in Mobile IP (MIP) authentication to store the Security Parameter Index (SPI) associated with the Foreign Agent Root Key (FA-RK). This AVP is defined in 3GPP [TS 33.402] and serves as an identifier for the security context related to the FA-RK.

Short-Network-Name

1517

OctetString

3GPP

Contains the shortened version of a network operator's name. It is encoded following the AT_SHORT_NAME_FOR_NETWORK attribute format as specified in 3GPP [TS 24.302], clause 8.2.5.2.

SM-Back-Off-Timer

1534

Unsigned32

3GPP

Specifies the session management (SM) back-off timer value in seconds. This timer indicates the period that a UE (User Equipment) must wait before retrying a failed session management request. The session management back-off timer is provided to the UE as specified in clause 8.1.4.16 of 3GPP [TS 24.302].

SSID

1524

UTF8String

3GPP

Used to identify a specific 802.11 extended service set (ESS) in a Wi-Fi (WLAN) network. IEEE Std 802.11-2012. It carries the SSID value as a UTF8String, with a length between 1 to 32 octets, representing the Wi-Fi network name.

Transport-Access-Type

1519

Enumerated

3GPP

Used to identify the transport access technology that is serving the User Equipment (UE) in a non-3GPP access network. 

Enumerated Values:

0: BBF: Indicates that the transport access network belongs to the Broadband Forum (BBF).

TWAG-CP-Address

1531

Address

3GPP

Used to convey the control-plane (CP) IP address of the Trusted WLAN Access Gateway (TWAG). This AVP specifies the TWAG control-plane (IPv4 or IPv6) address that a User Equipment (UE) should use for WLAN Control Protocol (WLCP) when Multiple Connectivity Mode (MCM) is selected.

TWAG-UP-Address

1532

UTF8String

3GPP

Contains the MAC address of the Trusted WLAN Access Gateway (TWAG) user-plane interface. It is used for encapsulating user-plane packets between the User Equipment (UE) and the Trusted WLAN Access Network (TWAN) when Single Connectivity Mode (SCM) is used.

The MAC address must be formatted as an uppercase ASCII string, where each octet is separated by a dash ('-').

It shall contain a string of 17 octets. Example: "00-10-A4-23-19-C0".

TWAN-Connection-Mode

1527

Unsigned32

3GPP

Used to indicate the connection modes supported by the Trusted WLAN Access Network (TWAN) when included in request messages. It also specifies the authorized connection mode selected by the 3GPP AAA Server when included in response messages.

Bit Flags and Definitions:

0: TSC-MODE: Indicates that the TWAN supports Trusted Single Connectivity Mode (TSCM).

1: SC-MODE: Indicates that the TWAN supports Single Connectivity Mode (SCM).

- If set by the TWAN, it informs the 3GPP AAA Server about SCM support.

- If set by the 3GPP AAA Server, it instructs the TWAN to use SCM.

2: MC-MODE: Indicates that the TWAN supports Multiple Connectivity Mode (MCM).

- If set by the TWAN, it informs the 3GPP AAA Server about MCM support.

- If set by the 3GPP AAA Server, it instructs the TWAN to use MCM.

NOTE: Bits not defined in this table shall be cleared by the sender and discarded by the receiver of the command.

TWAN-Connectivity-Parameters

1528

Grouped

3GPP

Contains connectivity-related parameters for a Trusted WLAN Access Network (TWAN) session. It conveys both the requested and provided connectivity attributes in authentication and authorization exchanges between the TWAN and the 3GPP AAA Server.

The AVP structure is defined as follows:

Connectivity-Flags (Optional, Bitmask32): Contains bit flags defining connectivity characteristics, such as Initial Attach Indicator.

Service-Selection (Optional, UTF8String): Indicates the Access Point Name (APN) selected by the TWAN or requested by the UE.

PDN-Type (Optional, Enumerated): Specifies the Packet Data Network (PDN) type, which can be IPv4, IPv6, or IPv4v6.

Served-Party-IP-Address (Optional, Address, 0-2 occurrences): Contains UE-assigned IPv4 address and/or IPv6 interface identifier if S2a connection was successfully established.

TWAN-PCO (Optional, OctetString): Contains the Protocol Configuration Options (PCO) exchanged between the UE and the TWAN.

TWAG-UP-Address (Optional, UTF8String): Contains the TWAG User Plane MAC address (used when SCM mode is selected).

TWAN-S2a-Failure-Cause (Optional, Unsigned32): Indicates why the S2a connection failed (if applicable).

SM-Back-Off-Timer (Optional, Unsigned32): Specifies a back-off timer for Session Management (SM), instructing the UE when it may retry connection requests. The exact value of the SM-Back-Off-Timer is operator dependant.

TWAN-PCO

1528

OctetString

3GPP

Contains the Protocol Configuration Options (PCO) exchanged between the UE and the TWAN. PCOs are used to negotiate network-level configurations such as IPv4/IPv6 address allocation, DNS settings, and authentication parameters.

TWAN-S2a-Failure-Cause

1533

Unsigned32

3GPP

Provides a failure reason when S2a connectivity establishment between the Trusted WLAN Access Network (TWAN) and the 3GPP Packet Data Network Gateway (PDN-GW) fails. The TWAN uses this AVP to inform the 3GPP AAA Server about the failure cause.

Failure Cause Values:

26: Insufficient resources: The requested service cannot be provided due to lack of system resources.

27: Unknown APN: The requested APN could not be resolved.

29: User authentication failed: The external PDN rejected the request due to failed user authentication.

30: Request rejected by TWAN or PDN GW: The request was explicitly denied by either TWAN or PDN-GW.

31: Request rejected, unspecified: The request was rejected for unspecified reasons.

32: Service option not supported: The UE requested a service that is not supported by the PLMN.

33: Requested service option not subscribed: The UE requested a service it is not subscribed to.

34: Service option temporarily out of order: Temporary network function outage prevents service.

38: Network failure: An error in the network prevented service execution.

50: PDN type IPv4 only allowed: Only IPv4 PDN connectivity is allowed for this request.

51: PDN type IPv6 only allowed: Only IPv6 PDN connectivity is allowed for this request.

54: PDN connection does not exist: The network lacks information about the requested PDN connection.

113: Multiple accesses to a PDN connection not allowed: The request for additional access to an existing PDN connection was rejected.

WLAN-Identifier

1509

Grouped

3GPP

Contains the IEEE 802.11 identifier information for a Trusted WLAN (TWAN). It includes the SSID (Service Set Identifier) and optionally the HESSID (Homogeneous Extended Service Set Identifier).

The AVP structure is defined as follows:

SSID (UTF8String): Identifies the specific WLAN network (e.g., "MyCompanyWiFi").

HESSID (UTF8String): A 6-octet MAC address that uniquely identifies a Homogeneous Extended Service Set (HESS).

Allows additional optional AVPs to be included.

WLCP-Key

1535

OctetString

3GPP

Contains the Wireless LAN Control Protocol (WLCP) Key. This key is used to protect WLCP signaling between the User Equipment (UE) and the Trusted WLAN Access Network (TWAN) as specified in 3GPP [TS 33.402].