SIP 300 Multiple Choices vs 603 Decline
SIP 300 (Multiple Choices) is a 3xx Redirection response, while 603 (Decline) is a 6xx Global Failure response. 300 indicates that the address in the request resolved to several choices, each with its own location. The user or UA can select a preferred communication endpoint. In contrast, 603 means that the callee's machine was contacted successfully but the user explicitly does not wish to or cannot participate. Unlike 600, this may be because the callee doesn't want to communicate, not necessarily
Description
The address in the request resolved to several choices, each with its own location. The user or UA can select a preferred communication endpoint.
When You See It
When a user has multiple registered devices or contact addresses and the server cannot determine which one to use.
How to Fix
Select one of the provided Contact addresses and resend the request to that specific URI.
Description
The callee's machine was contacted successfully but the user explicitly does not wish to or cannot participate. Unlike 600, this may be because the callee doesn't want to communicate, not necessarily because they're busy.
When You See It
When the callee explicitly declines the call. This is an active rejection, not a busy or unavailable state.
How to Fix
The callee has declined. Respect their decision. Consider alternative communication methods (email, messaging).
Key Differences
300 is a 3xx Redirection response, while 603 is a 6xx Global Failure response.
SIP 300: The address in the request resolved to several choices, each with its own location. The user or UA can select a preferred communication endpoint.
SIP 603: The callee's machine was contacted successfully but the user explicitly does not wish to or cannot participate. Unlike 600, this may be because the callee doesn't want to communicate, not necessarily
You encounter 300 when when a user has multiple registered devices or contact addresses and the server cannot determine which one to use.
You encounter 603 when when the callee explicitly declines the call. This is an active rejection, not a busy or unavailable state.
When to Use Which
For 300 (Multiple Choices): Select one of the provided Contact addresses and resend the request to that specific URI. For 603 (Decline): The callee has declined. Respect their decision. Consider alternative communication methods (email, messaging).