| Protocol | nas | Network | 5g |
|---|---|---|---|
| Spec | 3GPP TS 24.501 | Spec Section | 8.2.34 |
| Direction | UE to network | Message Type | 5GMM signaling |
| Full message name | 5G NAS - Relay Key Request |
|---|---|
| Protocol | NAS |
| Technology | 5G |
| Direction | UE to network |
| Interface | N1 |
| Signaling bearer / channel | NAS signaling / Dedicated NAS message, transported over the existing NAS path |
| Typical trigger | Sent when the UE needs relay key material for a relay-related security procedure and the network must provide the corresponding response. |
| Main purpose | Requests the relay key procedure to start by carrying the relay-specific request parameters needed by the network to derive or return the required security information. |
| Main specification | 3GPP TS 24.501, 8.2.34 |
| Release added | Release 17 |
| Procedures where used | Relay key procedure, Relay security handling, ProSe relay context |
Relay Key Request is the NAS message used to request relay-related keying material so the relay security procedure can continue in a 5G relay or ProSe relay context.
Requests the relay key procedure to start by carrying the relay-specific request parameters needed by the network to derive or return the required security information.
Relay Key Request is the UE asking the network for relay-related keying information in a specialized 5G relay security procedure.
Call flow position: Opening request message used to trigger relay key handling.
Typical state: The UE has already reached relay-aware NAS context and now needs the network to provide relay key response material.
Preconditions:
Next likely message: Relay Key Accept or Relay Key Reject
Call flow position: UE-originated request step before relay key response processing.
Typical state: The procedure is focused on relay-specific security rather than generic registration.
Preconditions:
Next likely message: Relay Key Accept
Previous message(s): Relay authentication context establishment, Protected NAS relay-capable context
Next message(s): Relay Key Accept, Relay Key Reject
Security context: This message belongs to the relay-key handling branch, so it should be interpreted together with ProSe relay context, relay transaction identity, and the later Relay Key Accept or Relay Key Reject.
This message is not typically analyzed as ASN.1 on the wire. It is usually read as a NAS or protocol field structure instead.
Relay Key Request follows NAS 24.501 IE structure and is not an ASN.1 message.
Relay Key Request
Extended Protocol Discriminator: 5G Mobility Management
Security Header Type: Integrity protected and ciphered
Message Type: Relay Key Request
ProSe Relay Transaction Identity: 7
Relay Key Request Parameters: 0x01020304...
| IE | Required | Description |
|---|---|---|
ProSe relay transaction identity | Yes | Identifies the relay key transaction so the request and later response can be correlated. |
Relay key request parameters | Yes | Carries the relay-specific request data the network needs to generate the appropriate response. |
ProSe relay transaction identityIdentifies the relay key transaction so the request and later response can be correlated.
Presence: Required
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
Relay key request parametersCarries the relay-specific request data the network needs to generate the appropriate response.
Presence: Required
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
Likely cause: The relay request parameters may be invalid, unsupported, or inconsistent with the relay context.
What to inspect: Check the relay transaction identity, request parameters, and whether the network returns Relay Key Reject.
Next step: Correlate the message with the surrounding relay authentication and relay-session context.
Likely cause: The issue may be specific to the relay security branch rather than the general NAS path.
What to inspect: Focus on relay-specific IEs and the later relay-key response, not on ordinary registration messages.
Next step: Compare with a known-good relay procedure trace and verify relay feature support on both UE and network sides.
It starts the relay key exchange by asking the network to process relay-specific key request parameters and return the corresponding relay key response.
No. It belongs to a specialized relay security procedure rather than the standard registration path.
The usual next branch is Relay Key Accept or Relay Key Reject.
Decode this message with the 3GPP Decoder, inspect the related message database, or open the matching call flow to see where this signaling step fits in the full procedure.