What does 200 OK mean in IMS?
It means the SIP request completed successfully and the final accepted result is now visible.
| Protocol | ims | Network | 5G and LTE |
|---|---|---|---|
| Spec | RFC 3261 / 3GPP TS 24.229 | Spec Section | SIP 200 OK success response in IMS procedures |
| Direction | UE <-> IMS network | Message Type | SIP success response |
| Full message name | IMS SIP 200 OK |
|---|---|
| Protocol | IMS |
| Technology | 5G and LTE |
| Common deployment | VoNR and VoLTE |
| Direction | UE <-> IMS network |
| Interface | Gm with onward IMS routing |
| Signaling bearer / channel | IMS SIP signaling / Final SIP success response |
| Typical trigger | The request was accepted and the transaction completed successfully. |
| Main purpose | Carries the final success result for the request and, for INVITE, usually the accepted session description. |
| Main specification | RFC 3261 / 3GPP TS 24.229, SIP 200 OK success response in IMS procedures |
| Release added | See specification history |
| Procedures where used | IMS Registration, IMS Session Setup, IMS Call Release, VoNR, VoLTE |
200 OK confirms that the SIP request completed successfully.
Carries the final success result for the request and, for INVITE, usually the accepted session description.
200 OK means the request was accepted successfully.
Previous message(s): IMS SIP INVITE, IMS SIP REGISTER, IMS SIP BYE
Next message(s): IMS SIP ACK
Security context: Uses the same protected IMS signaling path as the request it answers.
SIP/2.0 200 OK
Via:
From:
To:
Call-ID:
CSeq:
Contact: OPTIONAL
Content-Type: OPTIONAL
Content-Length:
SDP body OPTIONAL
This is SIP response syntax rather than ASN.1.
SIP/2.0 200 OK
Via: SIP/2.0/UDP ue.example.net;branch=z9hG4bK-inv1
From: <sip:alice@example.net>;tag=mo1
To: <sip:bob@example.net>;tag=term1
Call-ID: call-001@example.net
CSeq: 1 INVITE
Contact: <sip:bob@198.51.100.20:5060>
Content-Length: 0
| IE | Required | Description |
|---|---|---|
Status-Line | Yes | Shows the 200 OK success code. |
Contact | Optional | Provides the confirmed contact for the successful branch. |
SDP body | Optional | For INVITE, often carries the accepted session description. |
Status-LineShows the 200 OK success code.
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.
ContactProvides the confirmed contact for the successful 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.
SDP bodyFor INVITE, often carries the accepted session description.
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.
Likely cause: The transaction succeeded, but the accepted branch, contact, or SDP may not match expectations.
What to inspect: Read the full 200 OK body and headers, not just the response code.
Next step: Compare the accepted result with the original request and any follow-up ACK.
It means the SIP request completed successfully and the final accepted result is now visible.
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.