| Protocol | nas | Network | lte |
|---|---|---|---|
| Spec | 3GPP TS 24.301 | Spec Section | 6.6.1.2, 8.3.14 |
| Direction | UE to MME | Message Type | ESM signaling |
| Full message name | LTE ESM Information Response |
|---|---|
| Protocol | NAS |
| Technology | LTE |
| Direction | UE to MME |
| Interface | N1 over LTE access / S1-MME control path |
| Signaling bearer / channel | NAS signaling / Sent after ESM Information Request in the same protected PDN branch. |
| Typical trigger | Triggered by receipt of ESM Information Request. |
| Main purpose | Returns the protected APN and protocol configuration options the network requested so the PDN-connectivity branch can continue. |
| Main specification | 3GPP TS 24.301, 6.6.1.2, 8.3.14 |
| Release added | Release 8 |
| Procedures where used | ESM Information Request Procedure, UE Requested PDN Connectivity Procedure |
| Related timers | T3489 |
ESM Information Response is the LTE NAS session-management message the UE sends to return APN or protocol configuration detail after ESM Information Request.
Returns the protected APN and protocol configuration options the network requested so the PDN-connectivity branch can continue.
ESM Information Response is the UE returning the missing APN or protocol detail the network asked for.
Call flow position: UE response that returns the detail needed to continue attach-related PDN setup.
Typical state: The PDN branch is still pending and waits for this answer before bearer activation or reject handling.
Preconditions:
Next likely message: Activate Default EPS Bearer Context Request or PDN Connectivity Reject
Call flow position: UE response that returns the detail needed to continue a standalone PDN setup branch.
Typical state: The UE is already registered and only completes the information exchange needed for PDN handling.
Preconditions:
Next likely message: Activate Default EPS Bearer Context Request or PDN Connectivity Reject
Previous message(s): ESM Information Request
Next message(s): Activate Default EPS Bearer Context Request, PDN Connectivity Reject
Security context: Protected by the active NAS security context because the response may contain APN or protocol configuration information.
ESM Information Response
Access point name OPTIONAL
Protocol configuration options OPTIONAL
Extended protocol configuration options OPTIONAL
Read this response together with the earlier request and the later bearer-activation or reject branch.
ESM Information Response
Protocol discriminator: EPS session management
EPS bearer identity: 0
Procedure transaction identity: 3
Message type: ESM Information Response
Access point name: ims
Protocol configuration options: DNS request
| IE | Required | Description |
|---|---|---|
Access point name | Optional | Returns the APN the network asked the UE to provide in protected form. |
Protocol configuration options | Optional | Returns the protocol-configuration detail needed to continue PDN setup. |
Extended protocol configuration options | Optional | Carries protected configuration detail when the extended format is used end to end. |
Access point nameReturns the APN the network asked the UE to provide in protected form.
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.
Protocol configuration optionsReturns the protocol-configuration detail needed to continue PDN setup.
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.
Extended protocol configuration optionsCarries protected configuration detail when the extended format is used end to end.
Presence: Optional
In practice: This is where DNS and other operational configuration can hide. When the session is accepted but applications still fail, EPCO is often one of the first optional fields worth validating.
Likely cause: The network may reject the returned APN or protocol detail, or the branch may fail in later bearer activation.
What to inspect: Read ESM Information Request, ESM Information Response, and the next PDN/bearer message as one chain.
Next step: Treat this response as the turning point between setup detail exchange and final PDN outcome.
The request asks for missing protected detail. The response returns that detail so the PDN branch can continue.
It is the UE message that returns protected APN or protocol configuration detail after ESM Information Request.
Start with the APN and protocol configuration information that the UE returned.
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.