LTE Bearer Resource Modification Reject

Message Fact Sheet

Protocol	nas	Network	lte
Spec	3GPP TS 24.301	Spec Section	6.5.4, 8.3.9
Direction	MME to UE	Message Type	ESM signaling

Full message name	LTE Bearer Resource Modification Reject
Protocol	NAS
Technology	LTE
Direction	MME to UE
Interface	N1 over LTE access / S1-MME control path
Signaling bearer / channel	NAS signaling / Sent as the reject branch of a bearer resource modification procedure.
Typical trigger	Triggered when the network does not accept the requested QoS or traffic-flow change on an existing bearer resource.
Main purpose	Returns the ESM cause that explains why the requested bearer-resource change was not accepted.
Main specification	3GPP TS 24.301, 6.5.4, 8.3.9
Release added	Release 8
Procedures where used	Bearer Resource Modification Procedure
Related timers	T3480
Related cause values	ESM cause

What is LTE Bearer Resource Modification Reject in simple terms?

Bearer Resource Modification Reject is the LTE NAS message the network sends when it refuses the UE's request to modify an existing bearer resource.

Returns the ESM cause that explains why the requested bearer-resource change was not accepted.

Why this message matters

Bearer Resource Modification Reject means the network refused the UE's requested change to an active bearer resource.

Where this message appears in the call flow

Requested bearer-resource change rejected

LTE flow showing Bearer Resource Modification Reject after a bearer-resource modification request — If the network does not accept the requested change to an active bearer resource, it returns Bearer Resource Modification Reject.

Call flow position: Network reject message used when the UE-requested change to an active bearer resource is not accepted.

Typical state: The bearer stays active with its older definition.

Preconditions:

The UE sent Bearer Resource Modification Request.

Next likely message: Later retry or continued use of the older bearer definition

QoS or filter update rejected

LTE flow showing Bearer Resource Modification Reject due to QoS or traffic-filter handling — The reject branch explains why the active bearer stayed on its older definition.

Call flow position

Previous message(s): Bearer Resource Modification Request

Next message(s): Later retry or continued use of the older bearer definition

Message direction and transport

Sender and receiver: MME to UE

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

Domain: Core-side EPS session management failure handling for bearer resource modification.

Signaling bearer: NAS signaling

Logical channel: Sent as the reject branch of a bearer resource modification procedure.

Transport / encapsulation: EPS NAS ESM message sent by the MME to reject a UE-requested bearer-resource change.

Security context: Protected by the active NAS security context.

Message Structure Overview

Bearer Resource Modification Reject is the failure branch of UE-requested bearer-resource modification.

ASN.1 Message Syntax for LTE Bearer Resource Modification Reject

Bearer Resource Modification 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 requested bearer-resource change failed.

LTE Bearer Resource Modification Reject - Example Dump

Bearer Resource Modification Reject
  Protocol discriminator: EPS session management
  EPS bearer identity: 0
  Procedure transaction identity: 10
  Message type: Bearer Resource Modification Reject
  ESM cause: EPS QoS not accepted

How to read this dump

The ESM cause is the main field that matters.

Important Information Elements

IE	Required	Description
`ESM cause`	Yes	Explains why the network rejected the requested bearer-resource modification.
`Protocol configuration options`	Optional	May carry additional configuration-side detail related to the reject branch.

Detailed field explanation

`ESM cause`

Explains why the network rejected the requested bearer-resource modification.

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

Check the earlier bearer resource modification request.
Inspect the returned ESM cause first.
Confirm which active bearer behavior remained unchanged.

Common Issues and Troubleshooting

The requested change to an active bearer never takes effect.

Likely cause: The branch may have ended in Bearer Resource Modification Reject.

What to inspect: Check the requested change and the returned ESM cause.

Next step: Treat the problem as a rejected resource-modification branch rather than later bearer misbehavior.

FAQ

What is Bearer Resource Modification Reject in LTE?

It is the network message that rejects a UE-requested change to an existing bearer resource.

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.