| Protocol | ims | Network | 5G and LTE |
|---|---|---|---|
| Spec | RFC 3261 / 3GPP TS 24.229 | Spec Section | SIP 600 Busy Everywhere global failure response |
| Direction | IMS network -> UE | Message Type | SIP global-failure response |
| Full message name | IMS SIP 600 Busy Everywhere |
|---|---|
| Protocol | IMS |
| Technology | 5G and LTE |
| Common deployment | VoNR and VoLTE |
| Direction | IMS network -> UE |
| Interface | Gm with onward IMS routing |
| Signaling bearer / channel | IMS SIP signaling / Global failure response |
| Typical trigger | The service declares a busy result that applies globally, not just to one branch. |
| Main purpose | Stops alternate branch attempts by declaring a global busy outcome. |
| Main specification | RFC 3261 / 3GPP TS 24.229, SIP 600 Busy Everywhere global failure response |
| Release added | See specification history |
| Procedures where used | IMS Global Call Rejection |
600 Busy Everywhere means the request should not be retried elsewhere because the target is considered busy globally.
Stops alternate branch attempts by declaring a global busy outcome.
600 means the target is considered busy everywhere for this request.
Previous message(s): IMS SIP INVITE
Next message(s): Procedure stop
Security context: Uses the same protected IMS signaling path as the original request.
SIP/2.0 600 Busy Everywhere
Via:
From:
To:
Call-ID:
CSeq:
Content-Length: 0
This is SIP response syntax rather than ASN.1.
SIP/2.0 600 Busy Everywhere
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
Content-Length: 0
| IE | Required | Description |
|---|---|---|
Status-Line | Yes | Shows the 600 global busy code. |
Call-ID | Yes | Correlates the global busy result with the request. |
Status-LineShows the 600 global busy 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.
Call-IDCorrelates the global busy result with the request.
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.
Likely cause: The service declared a global busy condition.
What to inspect: Check whether the response was global and whether forked branches were already resolved.
Next step: Do not treat it like a simple branch-level 486 result.
It means the request should not be retried elsewhere because the target is globally busy for that attempt.
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.