Sign in Subscribe

E-RAB Modify Response

Last updated on 


In Long-Term Evolution (LTE) and 5G mobile networks, an E-RAB (Evolved Radio Access Bearer) Modify Response is a signaling message exchanged between the User Equipment (UE) and the network's core components to confirm the modification of parameters associated with an existing E-RAB. This modification can occur due to various reasons, such as changes in the quality of service (QoS) requirements or network optimization. Here's a detailed technical explanation of the E-RAB Modify Response procedure:

Triggering Event:

  • The E-RAB Modify Response procedure is initiated when the network determines a need to modify the parameters of an existing E-RAB. This need may arise due to changes in network conditions, QoS requirements, or UE mobility.

E-RAB Modify Request:

  • Before the E-RAB Modify Response, there is typically an E-RAB Modify Request. The network generates an E-RAB Modify Request message, which contains information about the changes to be made to the E-RAB. This message is sent to the UE to request the modification.

Contents of E-RAB Modify Request:

  • The E-RAB Modify Request message includes the following information:
  • E-RAB ID: Identifies the E-RAB to be modified.
  • New QoS Parameters: If the modification involves changing QoS parameters (e.g., data rate, latency), the new values are specified.
  • Other Relevant Parameters: Any other parameters to be modified are included in the message.

UE Processing:

  • Upon receiving the E-RAB Modify Request, the UE processes the message and evaluates whether it can comply with the requested modifications.
  • The UE may perform checks to ensure that the requested QoS parameters and other parameters can be supported given the current radio and network conditions.

E-RAB Modify Response Generation:

  • If the UE can accommodate the requested changes, it generates an E-RAB Modify Response message.
  • The E-RAB Modify Response message typically includes:
  • E-RAB ID: The same E-RAB ID as in the request, confirming the specific bearer being modified.
  • Result: Indicates whether the modification was accepted or rejected. If accepted, the result is "successful," and if rejected, it provides the reason for rejection.
  • Updated QoS Parameters: If the requested modification was related to QoS, the UE may include the updated QoS parameters in the response.

Transmission to the Network:

  • The UE sends the E-RAB Modify Response message back to the network, which initiated the modification request.

Network Processing:

  • Upon receiving the E-RAB Modify Response, the network processes the message to confirm the successful modification of the E-RAB.
  • If the response indicates success, the network updates its records and applies the modified parameters to the E-RAB.

Data Transfer with Modified Parameters:

  • After a successful E-RAB Modify Response, data transfer continues with the modified parameters in place.
  • For example, if QoS parameters were modified to increase the data rate, subsequent data traffic on that E-RAB will adhere to the updated QoS.

Procedure Completion:

  • The E-RAB Modify Response procedure is considered complete when both the UE and the network have confirmed the successful modification of the E-RAB, and data transfer is occurring with the updated parameters.

E-RAB Modify Responses are essential for adapting the network's resources and service quality to changing conditions and requirements, ensuring that communication services provided over the mobile network remain efficient and meet the specified QoS criteria.