LTE Activate Dedicated EPS Bearer Context Reject

Message Fact Sheet

Protocol	nas	Network	lte
Spec	3GPP TS 24.301	Spec Section	6.4.2.3, 8.3.2
Direction	UE to MME	Message Type	ESM signaling

Full message name	LTE Activate Dedicated EPS Bearer Context Reject
Protocol	NAS
Technology	LTE
Direction	UE to MME
Interface	N1 over LTE access / S1-MME control path
Signaling bearer / channel	NAS signaling / Sent as the failure branch after Activate Dedicated EPS Bearer Context Request.
Typical trigger	Triggered when the UE cannot apply the dedicated bearer parameters returned by the network.
Main purpose	Returns the ESM cause that explains why the UE rejected the proposed dedicated bearer.
Main specification	3GPP TS 24.301, 6.4.2.3, 8.3.2
Release added	Release 8
Procedures where used	Dedicated EPS Bearer Context Activation Procedure
Related timers	T3485
Related cause values	ESM cause

What is LTE Activate Dedicated EPS Bearer Context Reject in simple terms?

Activate Dedicated EPS Bearer Context Reject is the LTE NAS message the UE sends when it cannot accept the dedicated bearer the network tried to activate.

Returns the ESM cause that explains why the UE rejected the proposed dedicated bearer.

Why this message matters

Activate Dedicated EPS Bearer Context Reject means the UE did not accept the dedicated bearer the network proposed.

Where this message appears in the call flow

Service-specific dedicated bearer reject

LTE flow showing Activate Dedicated EPS Bearer Context Reject for a service-specific bearer — If the UE cannot accept the proposed service-specific dedicated bearer, it rejects the activation branch.

Call flow position: UE reject message sent when a dedicated bearer for a service-specific branch cannot be accepted.

Typical state: The default bearer may stay active, but the additional dedicated bearer was not accepted.

Preconditions:

The network sent Activate Dedicated EPS Bearer Context Request.

Next likely message: Service-specific failure handling

IMS or QoS bearer reject

LTE flow showing Activate Dedicated EPS Bearer Context Reject for IMS or QoS-sensitive service — The wider PDN branch can remain active while the dedicated bearer itself is rejected.

Call flow position: UE reject message sent when the dedicated bearer for IMS or another QoS-sensitive service cannot be applied.

Typical state: The wider PDN branch may survive, but the requested dedicated bearer activation failed.

Preconditions:

A dedicated bearer activation branch is active.

Next likely message: Service continuation on default bearer or failure handling

UE requested bearer-resource reject

LTE flow showing Activate Dedicated EPS Bearer Context Reject after a bearer-resource procedure — A bearer-resource procedure can also end in dedicated bearer rejection if the UE cannot apply the proposed dedicated bearer.

Call flow position: UE reject message sent when a dedicated bearer created from an earlier bearer-resource procedure cannot be applied.

Typical state: The resource request reached bearer activation, but the dedicated bearer itself was not accepted.

Preconditions:

An earlier bearer-resource procedure triggered dedicated bearer activation.

Next likely message: Bearer-resource failure handling

Call flow position

Previous message(s): Activate Dedicated EPS Bearer Context Request

Next message(s): Dedicated bearer failure handling

Message direction and transport

Sender and receiver: UE to MME

Interface: N1 over LTE access / S1-MME control path

Domain: Core-side EPS session management error handling for dedicated bearer activation.

Signaling bearer: NAS signaling

Logical channel: Sent as the failure branch after Activate Dedicated EPS Bearer Context Request.

Transport / encapsulation: EPS NAS ESM message sent by the UE to reject dedicated bearer activation.

Security context: Protected by the active NAS security context.

Message Structure Overview

Activate Dedicated EPS Bearer Context Reject is the UE-side failure branch of dedicated bearer activation.

ASN.1 Message Syntax for LTE Activate Dedicated EPS Bearer Context Reject

Activate Dedicated EPS Bearer Context Reject
  ESM cause
  Protocol configuration options       OPTIONAL
  Extended protocol configuration options OPTIONAL

How to read this message syntax

Read the ESM cause first because it explains why the UE rejected the dedicated bearer.

LTE Activate Dedicated EPS Bearer Context Reject - Example Dump

Activate Dedicated EPS Bearer Context Reject
  Protocol discriminator: EPS session management
  EPS bearer identity: 6
  Procedure transaction identity: 9
  Message type: Activate Dedicated EPS Bearer Context Reject
  ESM cause: EPS QoS not accepted

How to read this dump

The ESM cause is the key field.

Important Information Elements

IE	Required	Description
`ESM cause`	Yes	Explains why the UE rejected the dedicated bearer activation.
`Protocol configuration options`	Optional	May carry additional configuration-side detail related to the reject branch.

Detailed field explanation

`ESM cause`

Explains why the UE rejected the dedicated bearer activation.

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.

`Protocol configuration options`

May carry additional configuration-side detail related to the reject branch.

Presence: Optional

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.

What to check in logs and traces

Inspect the earlier dedicated bearer request.
Read the returned ESM cause first.
Check whether the default bearer stayed active while the dedicated bearer failed.

Common Issues and Troubleshooting

The service stayed on the default bearer and the dedicated bearer never became active.

Likely cause: The UE may have rejected the dedicated bearer activation.

What to inspect: Check Activate Dedicated EPS Bearer Context Request and the returned ESM cause.

Next step: Treat the problem as dedicated-bearer activation failure rather than default-bearer loss.

FAQ

What is Activate Dedicated EPS Bearer Context Reject in LTE?

It is the UE message that rejects the dedicated bearer activation proposed by the network.

Related message pages

Related Procedures

Related Tools

Use This Reference in Practice

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.