5G NAS - Relay Key Accept Explained
Relay Key Accept is the positive network response to Relay Key Request. It means the network accepted the relay-key handling request and is returning the relay-specific response data needed for the next relay-security step.
For beginners, the simple meaning is: the network accepted the relay key request and sent back relay-related key information.
For engineers, the key point is that this is a specialized relay-security success branch, not a mainstream registration or service message.
What is Relay Key Accept in simple terms?
The UE asked for relay-related key handling with Relay Key Request. The network accepted that request and answered with Relay Key Accept.
Why Relay Key Accept matters
This message matters because it proves the relay-key request was accepted and the procedure is moving forward. If the relay procedure fails after this point, engineers should usually investigate the next relay-specific step instead of treating the key request itself as the failure point.
The most useful practical checks are:
- whether the relay transaction identity matches the request
- whether the response parameters look valid for the relay scenario
- what relay-specific step follows next
Where Relay Key Accept appears in the call flow
UE Network
|--- Relay Key Request --------->|
|<-- Relay Key Accept -----------|
|<-- Relay-specific continuation-|It is best interpreted as part of a relay key procedure rather than as part of ordinary registration or service signaling.
Transport characteristics
- Direction: Network to UE
- Interface: N1
- Transport on access side: carried over the existing NAS path
- Security expectation: normally tied to an already established protected relay-capable NAS context
What Relay Key Accept means operationally
Operationally, Relay Key Accept tells engineers that the trace has successfully passed the request phase of a relay-specific security exchange.
That means the first practical questions are:
- which relay transaction this accept belongs to
- what response parameters were returned
- what the next relay-specific action is
Important Information Elements
| IE | Why it matters |
|---|---|
ProSe relay transaction identity | Ties the accept to a specific earlier relay-key request. |
Relay key response parameters | Carries the relay-specific response details that drive the next step. |
Example message dump
Relay Key Accept
Extended Protocol Discriminator: 5G Mobility Management
Security Header Type: Integrity protected and ciphered
Message Type: Relay Key Accept
ProSe Relay Transaction Identity: 7
Relay Key Response Parameters: 0x98ab34cd...How to read this dump
- Start with the relay transaction identity.
- Then inspect the relay key response parameters.
- After that, move directly to the following relay-specific procedure step, because the accept mainly confirms successful request handling.
What to check in logs
- verify that the message follows the expected
Relay Key Request - inspect the relay transaction identity
- check the relay key response parameters carefully
- correlate the accept with the next relay-specific step
Related message pages
FAQ
What does Relay Key Accept do in 5G?
It tells the UE that the relay key request succeeded and carries the relay-related response information needed for the next relay-security step.
Is Relay Key Accept part of ordinary registration?
No. It belongs to a specialized relay security procedure rather than the standard registration path.
What usually comes after Relay Key Accept?
The next step is relay-specific procedure continuation, potentially including later relay authentication handling.
Summary
Relay Key Accept is the NAS message the network sends when the relay key request succeeds and the relay-related key response material can be delivered to the UE.